U.S. patent application number 13/585622 was filed with the patent office on 2013-03-21 for image-guided heart valve placement or repair.
This patent application is currently assigned to MEDTRONIC, INC.. The applicant listed for this patent is Carol E. Eberhardt, David E. Francischelli, Alexander J. Hill, James R. Keogh, Timothy G. Laske, Jack D. Lemmon, Timothy R. Ryan, James R. Skarda, Mark T. Stewart. Invention is credited to Carol E. Eberhardt, David E. Francischelli, Alexander J. Hill, James R. Keogh, Timothy G. Laske, Jack D. Lemmon, Timothy R. Ryan, James R. Skarda, Mark T. Stewart.
Application Number | 20130072786 13/585622 |
Document ID | / |
Family ID | 43416321 |
Filed Date | 2013-03-21 |
United States Patent
Application |
20130072786 |
Kind Code |
A1 |
Keogh; James R. ; et
al. |
March 21, 2013 |
IMAGE-GUIDED HEART VALVE PLACEMENT OR REPAIR
Abstract
A device and method for valve replacement or valve repair is
disclosed comprising the steps of acquiring an anatomical image of
a patient, correlating the image to the patient, guiding a valve
replacement delivery member or a valve repair delivery member
within the patient while tracking the position of the delivery
member in the patient, positioning the valve replacement member or
valve repair member in a desired position to replace a valve or
repair valve and removing the delivery member from the patient.
Inventors: |
Keogh; James R.; (Maplewood,
MN) ; Ryan; Timothy R.; (Shorewood, MN) ;
Eberhardt; Carol E.; (Fullerton, CA) ; Stewart; Mark
T.; (Minneapolis, MN) ; Skarda; James R.;
(Lake Elmo, MN) ; Laske; Timothy G.; (Shoreview,
MN) ; Hill; Alexander J.; (Blaine, MN) ;
Lemmon; Jack D.; (St. Paul, MN) ; Francischelli;
David E.; (Anoka, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Keogh; James R.
Ryan; Timothy R.
Eberhardt; Carol E.
Stewart; Mark T.
Skarda; James R.
Laske; Timothy G.
Hill; Alexander J.
Lemmon; Jack D.
Francischelli; David E. |
Maplewood
Shorewood
Fullerton
Minneapolis
Lake Elmo
Shoreview
Blaine
St. Paul
Anoka |
MN
MN
CA
MN
MN
MN
MN
MN
MN |
US
US
US
US
US
US
US
US
US |
|
|
Assignee: |
MEDTRONIC, INC.
Minneapolis
MN
|
Family ID: |
43416321 |
Appl. No.: |
13/585622 |
Filed: |
August 14, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12570888 |
Sep 30, 2009 |
8241274 |
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13585622 |
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|
11298282 |
Dec 9, 2005 |
8221402 |
|
|
12570888 |
|
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|
11128686 |
May 13, 2005 |
7706882 |
|
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11298282 |
|
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|
10464213 |
Jun 18, 2003 |
6936046 |
|
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11128686 |
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09629194 |
Jul 31, 2000 |
6595934 |
|
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10464213 |
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09487705 |
Jan 19, 2000 |
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09629194 |
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10156315 |
May 28, 2002 |
7507235 |
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11128686 |
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09879294 |
Jun 12, 2001 |
6447443 |
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10156315 |
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10643299 |
Aug 19, 2003 |
7338434 |
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11128686 |
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60571182 |
May 14, 2004 |
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60261343 |
Jan 13, 2001 |
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60263739 |
Jan 24, 2001 |
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60282029 |
Apr 6, 2001 |
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60286952 |
Apr 26, 2001 |
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60424243 |
Nov 6, 2002 |
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60404969 |
Aug 21, 2002 |
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61194783 |
Sep 30, 2008 |
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Current U.S.
Class: |
600/424 |
Current CPC
Class: |
A61B 2018/00291
20130101; A61F 2/2433 20130101; A61B 5/0044 20130101; A61B 2090/378
20160201; A61B 2090/397 20160201; A61B 2034/2051 20160201; A61B
34/20 20160201; A61F 2/2496 20130101; A61B 2018/00577 20130101;
A61B 18/1442 20130101; A61B 90/37 20160201; A61B 2017/22098
20130101; A61B 2017/00243 20130101; A61B 2034/2063 20160201; A61F
2250/0096 20130101; A61B 90/39 20160201; A61B 5/6853 20130101; A61B
2018/00351 20130101; A61N 7/02 20130101; A61F 2210/009 20130101;
A61B 8/445 20130101; A61B 5/1076 20130101 |
Class at
Publication: |
600/424 |
International
Class: |
A61B 6/12 20060101
A61B006/12 |
Claims
1. A method of performing a cardiac valve replacement procedure
within a patient, comprising: acquiring an image of the patient;
providing a valve replacement delivery system having one or more
sensors; guiding at least a portion of a valve replacement delivery
system having one or more sensors into a desired position within
the patient while viewing the acquired image; and implanting a
valve within the patient.
2. A method of performing a cardiac valve repair procedure within a
patient, comprising: acquiring an image of the patient; providing a
valve repair delivery system having one or more sensors; guiding at
least a portion of a valve repair delivery system having one or
more sensors into a desired position within the patient while
viewing the acquired image; and repairing a valve within the
patient.
Description
CROSS-REFERENCE TO RELATED SECTION
[0001] This application is a continuation of U.S. Application
Serial No. 12/570,888, filed on Sep. 30, 2009, now U.S. Pat. No.
8,241,274, the contents of which are incorporated herein by
reference.
[0002] U.S patent application Ser. No. 12/570,888 filed Sep. 30,
2009 claims the benefit of U.S. Provisional Patent Application Ser.
No. 61/194,783 filed on Sep. 30, 2008, the disclosure of which is
incorporated herein by reference in its entirety.
[0003] U.S patent application Ser. No. 12/570,888 filed Sep. 30,
2009 is also a continuation-in-part of U.S. patent application Ser.
No. 11/298,282 filed Dec. 9, 2005, which is a continuation-in-part
of U.S. patent application Ser. No. 11/128,686 filed May 13, 2005
now U.S. Pat. No. 7,706,882.
[0004] U.S. patent application Ser. No. 11/128,686 filed May 13,
2005 claims the benefit of U.S. Provisional Patent Application Ser.
No. 60/571,182 filed on May 14, 2004, the disclosure of which is
incorporated herein by reference in its entirety.
[0005] U.S. patent application Ser. No. 11/128,686 filed May 13,
2005 is a continuation-in-part of U.S. patent application Ser. No.
10/464,213 filed Jun. 18, 2003, now U.S. Pat. No. 6,936,046, which
is a continuation of U.S. patent application Ser. No. 09/629,194
filed Jul. 31, 2000, now U.S. Pat. No. 6,595,934, which is a
continuation-in-part of U.S. patent application Ser. No. 09/487,705
filed Jan. 19, 2000, now abandoned, the disclosures of which are
incorporated herein by reference in their entirety.
[0006] U.S. patent application Ser. No. 11/128,686 filed May 13,
2005 is also a continuation-in-part of U.S. patent application Ser.
No. 10/156,315 filed May 28, 2002, now U.S. Pat. No. 7,507,235,
which is a continuation of U.S. patent application Ser. No.
10/156,315 filed Jun. 12, 2001, now U.S. Pat. No. 6,447,443, which
claims the benefit of the filing dates of U.S. Provisional Patent
Application Ser. No. 60/261,343 filed Jan. 13, 2001, Ser. No.
60/263,739 filed Jan. 24, 2001, Ser. No. 60/282,029 filed Apr. 6,
2001 and Ser. No. 60/286,952 filed Apr. 26, 2001, the disclosures
of which are incorporated herein by reference in their
entirety.
[0007] U.S. patent application Ser. No. 11/128,686 filed May 13,
2005 is also a continuation-in-part of U.S. patent application Ser.
No. 10/643,299 filed Aug. 19, 2003, now U.S. Pat. No. 7,338,434,
which claims the benefit of the filing dates of U.S. Provisional
Patent Application Ser. No. 60/424,243 filed Nov. 6, 2002 and Ser.
No. 60/404,969 filed Aug. 21, 2002, the disclosures of which are
incorporated herein by reference in their entirety.
TECHNICAL FIELD
[0008] The present invention relates generally to treatment of
cardiac heart disease. More particularly, the present invention
relates to implantable valve prostheses for implantation into the
cardiac system.
BACKGROUND
[0009] Recently, there has been increasing interest in minimally
invasive and percutaneous replacement of cardiac valves.
Percutaneous replacement of a heart valve does not involve actual
physical removal of the diseased or injured heart valve. Rather,
the defective or injured heart valve typically remains in position
while the replacement valve is inserted into a balloon catheter and
delivered percutaneously via the vascular system to the location of
the failed pulmonary valve. Such surgical techniques involve making
a very small opening in the skin of the patient into which a valve
assembly is inserted via a delivery device similar to a catheter.
There, the replacement valve is expanded by the balloon to compress
the native valve leaflets against the body opening in which it is
inserted, anchoring and sealing the replacement valve. This
technique is often preferable to more invasive forms of surgery,
such as opening a large portion of the chest for cardiopulmonary
bypass, for example.
[0010] In the context of percutaneous, pulmonary valve replacement,
U.S. Patent Application Publication Nos. 2003/0199971 A1 and
2003/0199963 A1, both filed by Tower, et al., describe a valved
segment of bovine jugular vein, mounted within an expandable stent,
for use as a replacement pulmonary valve. The replacement valve is
crimped or compressed around the balloon portion of a catheter
until it is as close to the diameter of the catheter as possible.
The valve is then delivered percutaneously via the vascular system
to the location of the failed pulmonary valve and expanded by the
balloon to compress the valve leaflets against the right
ventricular outflow tract, anchoring and sealing the replacement
valve. As described in the articles: "Percutaneous Insertion of the
Pulmonary Valve", Bonhoeffer, et al., Journal of the American
College of Cardiology 2002; 39: 1664-1669 and "Transcatheter
Replacement of a Bovine Valve in Pulmonary Position", Bonhoeffer,
et al., Circulation 2000; 102: 813-816, the replacement pulmonary
valve may be implanted to replace native pulmonary valves or
prosthetic pulmonary valves located in valved conduits. Other
implantables and implant delivery devices also are disclosed in
published U.S. Pat. Application No. 2003/0036791 A1 and European
Patent Application No. 1 057 460-A1.
[0011] Assignee's co-pending U.S. patent application titled
"Apparatus for Treatment of Cardiac Valves and Method of Its
Manufacture", filed Nov. 18, 2005 and assigned U.S. Ser. No.
11/282,275, describes percutaneous heart valves for use as a
replacement pulmonary valve. Like the valves described by Tower et
al., the heart valves of this co-pending application incorporate a
valved segment of bovine jugular vein, mounted within an expandable
stent.
[0012] In addition to percutaneous valve implantation, heart valve
repair can also be accomplished using catheter-based valve repair
procedures. In the context of annuloplasty ring implantation on a
valve annulus, for example, a variety of repair procedures can be
used, such as procedures that require indirect visualization
techniques to determine the exact location of the heart valve and
annuloplasty ring during placement of the ring at the valve
annulus. Indirect visualization techniques, as described herein,
are techniques that can be used for viewing an indirect image of
body tissues and/or devices within a patient. One example of such a
technique is referred to as endoscopic visualization, which
involves displaying images from endoscopic light guides and cameras
within the thoracic cavity on a video monitor that is viewed by a
surgeon. Effective use of this method depends on having sufficient
open space within the working area of the patient's body to allow
the surgeon to recognize the anatomical location and identity of
the structures viewed on the video display, which can be difficult
to accomplish in certain areas of the heart.
[0013] Another indirect visualization technique involves the use of
fluoroscopy, which is an imaging technique commonly used by
physicians to obtain real-time images of the internal structures of
a patient through the use of a fluoroscope. Fluoroscopy can be
effective in many situations, but does have some drawbacks. For one
example, some tissues, such as the cardiac tissues, do not readily
appear under fluoroscopy, making it very difficult to accurately
align an annuloplasty ring prior to its implantation. To improve
the visualization of the area of interest, radiopaque contrast dye
can be used with x-ray imaging equipment. However, when treating
the mitral valve, for example, repeated injections of contrast dye
are not practical because of rapid wash-out of the dye in this area
of high fluid flow. For another example, to make high-volume
contrast injections of this kind, an annuloplasty catheter system
would require multiple lumens, undesirably large lumens, and/or an
additional catheter, none of which is desirable during
catheterization procedures. Further, multiple high-volume contrast
injections are somewhat undesirable for the patient due to
potential complications in the renal system, where the radiopaque
contrast medium is filtered from the blood.
[0014] A wide variety of other techniques are available for viewing
images of cardiac structures, including ultrasonography such as
trans-thoracic echocardiography (TTE), trans-esophageal
echocardiography (TEE), cardiac magnetic resonance (CMR) including
magnetic resonance imaging (MRI) or magnetic resonance angiography
(MRA), and computed tomography (CT) including computer tomography
angiography (CTA). These techniques, used alone or in combination
with other available techniques, all typically have certain
drawbacks relative to visualization and guidance during
catheter-based valve repair procedures.
[0015] Yet another visualization technique that can be used for
catheter-based valve repair involves mapping a valve annulus, such
as a mitral valve annulus, and obtaining real time imaging during
heating heart surgery through the use of electromagnetic (EM)
imaging and navigation. This type of technique can be effective for
viewing the significant movement of the annulus during both systole
and diastole that occurs during procedures performed on a beating
heart. With EM navigation, a patient is generally placed on a table
having a plurality of sensors either on the surface of the table or
at positions around the table. The sensors are connected to a
processor and the processor knows the positions of the sensors
relative to the table. A patient is then placed on the table and
immobilized, and then an elongated flexible device having at least
three EM coils spaced along its distal portion can then be inserted
into the patient's body (into the vascular system for example). The
coils are typically made from extremely small diameter material
that can be wound around the outside of the device or wound around
an interior layer of the device and then covered with an additional
layer of material. A very thin wire or some other electrically
conductive material can be used to communicate from an external AC
power source to each of these coils. Alternatively, wireless
sensors can be used to eliminate the need to provide a wire to
communicate with the EM coils.
[0016] As the elongated device is moved through the body, the
sensors can detect the EM signal that is created by the moving
coil. The processor then calculates the position of the coils
relative to each sensor. The location of the sensors can be viewed
on a display device, and the EM navigation can be combined with
other navigation/visualization technologies so that the location of
the EM coils in a patient's body can be viewed in real time.
Additional sensors may also be incorporated into a system using EM
navigation to improve the accuracy of the system, such as
temporarily attaching sensors to a patient's body and/or covering
at least a portion of a patient with a blanket that contains
additional sensors. The relationship between all of the sensors can
be used to produce the image of the patient's body on the table.
Examples of methods and systems for performing medical procedures
using EM navigation and visualization systems for at least part of
an overall navigation and visualization system can be found, for
example, in U.S. Pat. No. 5,782,765 (Jonkman); U.S. Pat. No.
6,235,038 (Hunter et al.); U.S. Pat. No. 6,546,271 (Resifeld); U.S.
Patent Application No. 2001/0011175 (Hunter et al.); U.S. Patent
Application No. 2004/0097805, (Verard et al.), and U.S. Patent
Application No. 2004/0097806 (Hunter et al.), the entire contents
of which are incorporated herein by reference.
[0017] Another method for mapping the mitral valve annulus and
obtaining real time imaging during beating heart surgery is through
the use of electro-potential navigation. Electro-potential (EP)
navigation involves the use of external sensors that are placed on
the patient. When using EP navigation, a low frequency electrical
field is created around the patient, and the coils on the
instrument are connected to a DC energy source such that there is a
constant energy signal emitting from the coils. The coils create a
disturbance in the electrical field as they move through the field,
and location of the instrument in the 3D coordinate space is
calculated by determining the location of the disturbance in the
energy field relative to the sensors.
[0018] As described above, delivery of a valve percutaneously to a
remote access site in the body via the vascular system and delivery
of devices for treating cardiac valve disease can be challenging
because precise manipulation of the surgical tools is more
difficult when the surgeon cannot see the area that is being
accessed and when the heart is moving. Thus, there is a need for
heart valve placement or repair systems having visualization
capabilities that permit the surgeon to quickly, easily and
securely implant a heart valve or repair a heart valve in a patient
with minimal resulting trauma to the patient. In certain cases,
there is a further need for heart valve placement systems that can
implant such valves into a failed bioprosthesis, which also
requires precise manipulation by a surgeon. In addition, there is a
need for heart valve repair systems that can repair a failed or
failing heart valve or a failed or failing bioprothesis. Such
systems should further provide the surgeon with a high degree of
confidence that a valve has been properly positioned within the
patient's heart during surgery.
SUMMARY
[0019] While a variety of systems and devices have been developed
to provide tracking and visualization in certain areas of the body
for a number of different applications, these systems are not being
used and are not generally adaptable to be used for placement or
repair of heart valves in certain locations in the heart. That is,
the types of navigation systems used for other areas of the body
have different operating parameters and requirements that are
different from those needed for percutaneous implantation of a
valve or percutaneous repair of a valve within a patient's heart.
The present invention advantageously addresses these operating
parameters and requirements while minimizing the use of fluoroscopy
and providing a 3-dimensional view of the heart structure.
[0020] In one aspect of the invention, a delivery system is
provided for percutaneous delivery of a heart valve to a
predetermined position in the heart of a patient, where the
delivery system itself includes features that allow it to be
accurately positioned in the heart. In another aspect of the
invention, a delivery system is provided for percutaneous repair of
a heart valve in the heart of a patient, where the repair system
itself includes features that allow it to be accurately positioned
in the heart. For example, a delivery or repair system can include
multiple ferromagnetic elements spaced from each other along the
length of an elongated body. Preoperative and intraoperative
imaging can help guide the device or delivery system to the desired
position in the heart using an external magnetic field, which
drives the ferromagnetic objects on the device or delivery system
into position. The imaging, navigation, and movement are all
merged.
[0021] In another aspect of the invention, a method and device are
provided that involve imaging the native root using an
interoperative technique, then introducing a device that is easily
visualized in a chosen imaging modality. The type of balloon used
(e.g., flow-through or non-flow-through) will determine whether the
cardiac motion will then need to be reduced. The balloon is then
inflated and the aortic root is imaged so that the best size can be
chosen that does not allow migration or force the leaflets to block
the coronaries.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The present invention will be further explained with
reference to the appended Figures, wherein like structure is
referred to by like numerals throughout the several views, and
wherein:
[0023] FIG. 1 is a schematic front view of one embodiment of a
heart valve delivery system of the invention, including at least
one ferromagnetic element used for valve placement;
[0024] FIG. 2 is a schematic front view of a portion of a delivery
system for an annuloplasty device, which is positioned adjacent to
a valve annulus;
[0025] FIG. 3 is a schematic front view of another embodiment of a
heart valve delivery system of the invention;
[0026] FIG. 4 is a schematic front view of a portion of another
embodiment of a heart valve delivery system of the invention;
[0027] FIGS. 5 and 6 are schematic front views of an aortic root of
a heart, with FIG. 6 illustrating a delivery system positioned
relative to the aortic root;
[0028] FIG. 7 is a schematic front view of another embodiment of a
heart valve delivery system of the invention;
[0029] FIG. 8 is a schematic front view of another embodiment of a
delivery system of the invention; and
[0030] FIG. 9 is a schematic front view of a guide wire of a heart
valve delivery system of the invention.
[0031] FIG. 10 is an illustration of a tissue-engaging device of
the invention.
[0032] FIG. 11 is an illustration of an imaging device of the
invention.
[0033] FIG. 12 is a flow diagram of one embodiment of the
invention.
[0034] FIG. 13 is a flow diagram of one embodiment of the
invention.
[0035] FIG. 14 is a schematic view of one embodiment of a system in
accordance with the invention.
DETAILED DESCRIPTION
[0036] As set out above, the navigation systems of the present
invention are particularly directed to percutaneous replacement and
repair of cardiac valves, which can be performed using a number of
different delivery systems. One exemplary delivery system and its
use may correspond to that described in the above-cited Tower, et
al. applications, where the stented valve can be expanded against a
failed native or prosthetic valve. The delivery system can be
advanced to the desired valve implant site using a guidewire, after
which the sheath is moved proximally, exposing the balloon mounted
on an inner catheter. The balloon is expanded, which thereby
expands the stented valve until it reaches a desired outer diameter
where it contacts the wall of a heart vessel. The balloon is then
deflated and the delivery system is withdrawn proximally. In order
to locate the valve and delivery systems during the surgical
procedure, one or a combination of the methods, devices, and
systems of the invention described herein may be used.
[0037] Notably, although the term "replacement" normally signifies
removal of a diseased valve and implantation of a new valve, in
accordance with the invention, a new valve may also be implanted
directly over top of or adjacent to a diseased native valve, which
may also generically be referred to as "replacement" or may instead
be referred to as "implantation". Both types of procedures are
contemplated for use with the present invention. In many cases, an
implantation procedure can be the same as a replacement procedure
without the removal of the diseased valve.
[0038] Certain embodiments of the invention described herein may
only be used for placement of particular valves (e.g., aortic
valves); however, some embodiments of the invention may be useful
for valve placements in more than one area of the heart (e.g.,
mitral valves, pulmonic valves), with the methods requiring
different navigation of the device to these areas of the heart. In
any of the methods of the invention, it is desirable to avoid
placing the valve prosthesis in a position that blocks the
coronaries during the surgical process.
[0039] The location for valve implantation or repair can be
determined by various imaging modalities such as ultrasound
imaging, CT, MRI, PET, fluoroscopy, etc. The coordinates for the
desired location for valve implantation or repair from any of these
imaging modalities can be determined. Two or three-dimensional
imaging may be performed as well as phased or annular array imaging
may be performed. For example, two or three-dimensional
echocardiography, such as transesophageal echocardiography, or
ultrasound imaging, such as transthoracic ultrasound imaging may be
employed as described in U.S. Patent Application Publication No.
2005/0080469, the disclosure of which is incorporated by reference
in its entirety. In one embodiment of the invention, an imaging
device may be used to illuminate a valve implantation site, a valve
repair site and/or surgical site.
[0040] In one embodiment of the invention, an ultrasound imaging
transducer assembly may be used to provide a real-time or
multiplexed echo feedback on the progress of the valve implantation
or repair. In one embodiment of the invention, the changes in
mechanical properties of tissue may be observed in eco imaging. In
addition, an ultrasound transducer may sense reflections from the
targeted tissue such as backscatter echo and spatial compound
imaging, etc. to provide one or more properties of the tissue
imaged.
[0041] In addition, with the methods of the invention, it is often
desirable to use a sizing balloon prior to valve placement to
determine the proper size of the valve that will be implanted. One
example of a sizing technique is to use an expandable and
retractable sizing device made out of a material such as Nitinol.
Such a sizing device can be navigated to the implantation site,
such as by using an MRI compatible device, and then an image can be
taken of the sizing device in its compressed or retracted
condition. The device can then be expanded until it is in contact
with the vessel at the implantation site and another image can be
taken of the device in its expanded condition. These images of the
sizing device in its compressed condition and expanded condition
are then compared with each other and with the sizes of the
available valves to determine the optimum valve for implantation.
Additionally or alternatively, the pressure increase of a sizing
device (e.g., an expandable balloon-type device) can be monitored
and recorded during its expansion, and the data obtained can be
compared to a pre-measured pressure increase of a similar
device.
[0042] That is, the information obtained from the pressure increase
in the sizing device will correspond with a certain external size
of the device, which in turn will correspond to a valve of a
certain size. It is further contemplated that the implantation
device can release dye into the implantation area while checking
the pressures to determine if the device is blocking any of the
coronaries.
[0043] In some embodiments of the invention, electromagnetic
navigation can be performed with 4D ultrasound, as opposed to using
fluoroscopy, CT, or MRI, for example. For one particular example,
the 4D ultrasound can be used for intraoperative navigation instead
of using fluoroscopy in order to obtain better resolution of the
heart.
[0044] Referring now to the Figures, wherein the components are
labeled with like numerals throughout the several Figures, and
initially to FIG. 1, a delivery system 10 is illustrated, with a
prosthetic valve 14 mounted thereon and being inserted into an
aorta 12 of a patient. Delivery system 10 includes a guide wire 16
and at least one sensor 18, e.g., a ferromagnetic element, that
establishes an electric field for the system 10 and can be used to
give rotation to the valve. Although it is possible that only one
ferromagnetic element 18 is provided, multiple ferromagnetic
elements may be provided at spaced-apart locations along a portion
of the length of the delivery device to provide additional data
regarding navigation of the system 10. In any case, intraoperative
imaging or preoperative images can be used to define alignment of
annuloplasty devices, for example. The use of these ferromagnetic
elements can precisely locate points within the heart using an
external, 3-dimensional frame of reference.
[0045] Each element 18 of a particular delivery system 10 may be
the same or different from other ferromagnetic elements 18 in that
same system. When the elements are different from each other, the
ferromagnetic elements may be distinguishable to provide the
navigation process with an additional assurance of accuracy. In
particular, each sensor 18 may have a variety of different shapes
and forms, such as a coil that is wound around the delivery system
with a predetermined number of wrappings, a clamp or collar that
extends completely or partially around the delivery system at
certain locations, or any other configuration that can be securely
attached to the delivery system. Further, the sensor elements 18,
e.g., ferromagnetic elements, should be sufficiently large that
they are visible using the imaging devices of the system, but
should not be so large that they interfere with the valve
replacement process.
[0046] FIG. 2 is a schematic view of a delivery system 30
positioned relative to an annulus 32 of a patient's heart. Delivery
system 30 includes multiple sensors 34, e.g., ferromagnetic
elements, spaced from each other along the length of an elongated
body 36. The number, size, spacing, and type of sensor elements 34
may be selected to determine certain characteristics of the annulus
of the patient. In any case, interoperative imaging or preoperative
images can be used to define the alignment of a valve repair
device, e.g., an annuloplasty device, that is to be implanted.
[0047] The delivery systems of FIGS. 1 and 2 can be used with a
system that moves the sensor objects, e.g., ferromagnetic objects,
on the devices via an externally generated magnetic field. In one
specific example, preoperative and intraoperative imaging can help
guide the device or delivery system to an annulus (e.g., a mitral
annulus) using a system that involves the use of an external
magnetic field which drives ferromagnetic objects placed on a
catheter into their desired position. The information provided by
the imaging, navigation, and movement are advantageously merged
together for use by the physician or surgeon.
[0048] FIG. 3 illustrates a delivery system 40, which includes a
catheter 42, a guide wire 44, a sheath 46, and one or more sensor
markers 48 on the sheath 46. The sensor marker or markers 48 on the
sheath 46 allow for precise exposure of the stent or an associated
balloon during a stent delivery process. That is, the location of
each sensor marker 48 can be detected and therefore can allow for
precise movement of the sheath 46. The delivery system 40 further
includes a prosthetic valve 50 that has at least one sensor marker
52, e.g., a radiopaque marker, to allow for rotational orientation
of the valve 50. This delivery system 40 is used for pre-screening
or pre-imaging of the anatomy of a patient to thereby provide a
roadmap of the native anatomy. The delivery system 40 can further
be used to image with a balloon or sizer that is deployed into the
root at various pressures, which will allow for a measurement of
compliance. The system also includes a first sensor navigation coil
54 positioned adjacent to one end of the valve 50, and a second
sensor navigation coil 56 positioned adjacent to the opposite end
of the valve 50.
[0049] FIG. 4 further illustrates a portion of a delivery system
that includes a sensor marker 70 that may be a radiopaque material,
gadolinium, dysprosium oxide, or another material that makes it
visible in certain imaging modalities. For example, gadolinium (Gd)
markers can be used for MRI procedures. The system further includes
at least one sensor electromagnetic receiver coil or electrode 72.
Sensor marker 70 is positioned on a portion of the system that may
be referred to as the passive portion or segment of the system, and
the sensor electromagnetic coil or electrode 72 is positioned on a
portion of the system that may be referred to as the active portion
or segment of the system. This system can be used to capture
preoperative images, register the images to the intraoperative
patient anatomy, and navigate within the anatomy using
electromagnetic or electropotential methods or passively using
intraoperative MRI. Each sensor electromagnetic coil or electrode
72 may be placed at a predetermined location on the catheter
delivery system and on its associated implantable valve. The
predetermined location or locations can be chosen for functional
components to ensure proper positioning. For example, a sensor
element, e.g., an electromagnetic coil, can be placed at the tip of
a catheter so that it is possible to continuously track and
visualize the catheter tip in real time without the continuous use
of fluoroscopy.
[0050] In another alternative, one or more electromagnetic coils
can be placed at the end and/or the middle and/or other
intermediate location(s) of an inflatable balloon to track the
location of the balloon relative to the annulus of the target
valve. In this way, the location of the balloon can be determined
so that the catheter can be maneuvered to accurately position the
balloon at a predetermined location for its inflation and for valve
deployment. In a similar manner, one or more sensor electromagnetic
coils can additionally or alternatively be placed on a valve in
order to enable an operator to track and visualize the valve on the
delivery device and to accurately position the valve in a
predetermined location. One advantage that is provided by the use
of these sensor electromagnetic coils is that the coils provide an
operator with the ability to track the devices (e.g., valves) in a
different visualization modality into which relatively detailed
anatomical information can be incorporated. For example, the
tracking or positioning of the sensor electromagnetic coils can be
superimposed over a 3-dimensional preoperative image of the
patient's anatomy, which provides more detailed information of the
cardiac tissue without contrast use and without repeated exposure
to x-rays or other radiation.
[0051] FIGS. 5 and 6 illustrate a method and device for delivering
a heart valve in accordance with the invention. In general, the
native root 80 is initially imaged using an intraoperative
technique, such as fluoroscopy, 4D echo, interventional MRI, and
the like. This image becomes the baseline or "roadmap" that is used
for the remainder of the processes. A balloon 82 or stent may then
be deployed or a stent can be used to size the aortic valve at
various pressures or stages. The chosen balloon or stent should be
easily visualized in the chosen imaging modality (e.g., if
interventional MRI is used, iron or gadolinium can be used). That
is, the materials chosen for the balloon or stent should make the
device conspicuous with the imaging technique that is used.
[0052] The blood flow may then optionally be reduced by controlled
intermittent asystole, high rate pacing, or other technique(s) used
for slowing cardiac motion or stopping the heart for extended
periods of time. The balloon 82 or stent may alternatively be
designed to allow blood to flow or pass through it, in which case
the blood flow would not necessarily need to be reduced. A
non-compliant balloon can be inflated to various pressures and/or
sizes and the aortic root can be imaged while looking at the
leaflet anatomy. The balloon can then be chosen to be the best size
that will not migrate but that also does not force the leaflets to
block the coronaries. Alternatively or additionally, a compliant
balloon, can be used to determine the compliance of the aortic
root. If stents are used, they are preferably recapturable and the
leaflets preferably function when the device is deployed but not
released. In any case, the deployment diameter or force chosen must
prevent the valve leaflets from covering the coronary ostia.
[0053] In accordance with the invention, additional aspects of
methods and devices for balloon sizing and valvuloplasty using a
valvuloplasty/sizer balloon include a number of steps, some of
which are optional. In one embodiment, a valvuloplasty/sizer
balloon is selected, where multiple balloons can be provided in a
number of different sizes and/or where each balloon can be provided
as a single balloon (compliant or non-compliant), or may comprise
multiple balloons that are coaxial or placed serially in a linear
arrangement on the same catheter. The balloon can include features
that allow for at least some blood flow, such as a certain level of
porosity and/or at least one central hole, for example. The chosen
balloon or balloons can then be inflated to a first pressure that
correlates with a known radial force that will typically be
required by a certain transcatheter valve stent that will
subsequently be implanted.
[0054] Once the balloon or balloons are inflated to this first
pressure, a number of measurements can be performed, which can be
selected for a particular application from a number of measurement
options. One such measurement is to measure the diameter or other
dimensions of the balloon at various anatomical locations (e.g.,
annulus, sinotubular junction, ascending aorta, sinus region, and
the like) using a balloon silhouette or radiopaque fluid within the
balloon. The circularity of diameters at one or more anatomical
locations can then be measured. The orifice area can then be
calculated. The clearance between the native leaflets and the
coronary arteries can then be measured with the balloon or balloons
inflated to simulate the dimensions of the transcatheter valve
stent when it is deployed. The balloon can optionally include
integral markings to facilitate making this measurement. The
balloon could also have indicia or other detectable features that
indicate particular structural features that allow a clinician to
determine a desirable stent height to avoid the coronary ostia, to
provide stable seating of the valve in its space, and the like. The
balloon catheter can incorporate means (e.g., transducer or
calibrated joint or feature) to assess the dislodgement or
migration force of the transcatheter valve stent that will be
deployed.
[0055] Next, the parameters of the system can be evaluated. First,
the calcific locations of the native valve can be identified, and a
determination can be performed of the mobility of the calcium under
balloon inflation. A verification can be made of the coronary
clearance and patency with native leaflets pushed out by the
balloon, which thereby simulates the transcatheter valve stent. The
resulting effect on the adjacent anatomy (e.g., the mitral valve
orifice) can also be evaluated, along with the effect on the heart
rhythm (e.g., heart block, fibrillation, and the like).
[0056] After the chosen measurement and evaluation steps have been
completed, these results can be compared against target values or
guidelines to determine whether an acceptable result has been
achieved. If acceptable results have not been achieved, some or all
of the previous steps can be performed at one or more additional
pressures that are different than the first pressure, where each
new pressure that is used corresponds to a different radial force,
until an acceptable result is achieved. When an acceptable result
is achieved, then a balloon valvuloplasty can be performed, where
the optimum stent radial force, stent height, and stent profile can
be selected based on the measurements and evaluation parameters
discussed above. However, if an acceptable result cannot be
achieved even after using different pressures, it is contemplated
that the procedure be abandoned in that the valve is not suitable
for implant at this location for at least one reason (e.g., that
the coronaries are occluded at all pressures, that the valve will
migrate at all pressures, that arrhythmia or heart block will occur
at all pressures, that the diameter and/or circularity are outside
the feasibility range for the device, and/or the like). It is noted
that the measurements may optionally be repeated after the balloon
valvuloplasty is performed.
[0057] In the methods of imaging of the invention, a number of
materials can be used as contrast medium for the components of the
systems. These materials can provide contrasting markers that are
combined for improved imaging results. For one example, when
magnetic resonance imaging (MRI) techniques are used, iron can be
used for imaging. Alternatively, dysprosium oxide can be
characterized as the negative material and be illustrated as a
black area on a display screen, and gadolinium can be characterized
as the positive material and be illustrated as a white area. For
another example, when echocardiographic techniques are used, gas
can be shown as a black area on a display screen, and microspheres
or nonocoatings may be shown as a white area. For yet another
example, when computed tomography (CT) techniques are used, markers
can be provided with different materials that are illustrated as
either black or white areas, such as can be provided by platinum,
tantalum, BaSO.sub.4, and the like.
[0058] FIG. 7 illustrates a system that provides the dual function
of deploying a stent 71 with an inflatable and expandable balloon
72, while also providing a dilation balloon or leaflet resection
tool 73. The dilation balloon can be used for dilation,
measurement, and/or excising of the native valve.
[0059] FIG. 8 shows a stent 81 positioned relative to an aortic
valve, where the stent includes multiple sensor markers 82 spaced
from each other. These sensor markers provide visualization so that
post-operative follow-up can be accomplished more easily. In
particular, having specific, easily identifiable markers
facilitates being able to repeatably follow the stent over time and
to measure deformation of the stent, as well as to track any
fractures that may occur relative to the identifiable markers. The
markers can also provide guidance for additional valves or stents
that may need to be positioned relative to the stent. For one
example, a second stent or valve can have the same or similar
markers as the original stent or valve so that a physician can
align the markers of both valves or stents in order to deploy the
new valve in the desired position relative to the old stent or
valve. In another example, the second stent or valve can have
different markers than the original stent or valve, such that a
particular relationship or positioning of the new and old stents or
valves can be achieved by positioning the markers in a certain
arrangement relative to each other.
[0060] [59] FIG. 9 is an illustration of an embodiment of an
imaging technique in which a guide wire 91 includes one or more
sensors 92, for example, an echogenic coating, a RF receiver coil,
a gadolinium marker, an electrode, or the like. This element or
portion of the guide wire allows precise passage of the wire
through a stenotic aortic valve using an intraoperative imaging
mode. Using the techniques described herein to visualize or guide a
component or device with these markers, the guidewire can be guided
across the stenotic orifice, which can be challenging if it is
heavily calcified. This can be accomplished more easily if the
guidewire is steerable.
[0061] FIG. 10 is an illustration of a tissue-engaging device 200
being used in a closed chest, non-sternotomy procedure to position
the heart 205 into a non-physiological orientation. Positioning the
heart in a non-physiological orientation can provide access to
areas of the heart that normally would not be available to one or
more devices, for example, through a thoracotomy or port, through
the patient's esophagus or trachea, or positioned outside the
chest.
[0062] In one embodiment of the invention, an imaging device 800
may be used to image tissue such as heart tissue as shown in FIG.
11. The imaging device may be appropriately sized to allow its
placement within the esophagus of the patient. Alternatively, the
imaging device may be appropriately sized to allow its placement
within the trachea and/or bronchi of the lungs of the patient.
Alternatively, one or more imaging devices may be positioned
through one or more other body cavity openings of the patient
and/or positioned on the skin of the patient. For example, one or
more imaging devices may be positioned through the mouth, the nose,
the anus, the urethra and/or the vagina. In one embodiment of the
invention, one or more imaging devises may be placed through a
port, a stab wound, or an incision. In one embodiment of the
invention, a valve replacement device or a valve repair device may
include one or more imaging capabilities. For example, ultrasound
imaging capabilities may be incorporated into a valve replacement
device or valve repair device so that a single device could be used
to both image and repair valve tissue or image and implant a valve
bioprosthesis.
[0063] In one embodiment of the invention, once one or more imaging
devices are placed in the desired position, cardiac tissue is then
imaged and the location of valve tissue to be treated is
determined. To image cardiac tissue not positioned within the
focusing range of an imaging device, a tissue-engaging device 200
may be used to move and position the tissue of interest within the
focusing range of the imaging device. The tissue-engaging device
200 may be used to position tissue prior to an imaging procedure,
during an imaging procedure and/or following an imaging procedure.
In addition to cardiac tissue, other tissue types and/or organs may
be positioned and imaged by one or more positioning and imaging
devices. In one embodiment of the present invention, the
positioning or tissue-engaging device may comprise one or more
imaging capabilities, e.g., ultrasound imaging.
[0064] In one embodiment of the invention, a tissue-engaging device
may include one or more ultrasound imaging elements. The
tissue-engaging device comprising one or more ultrasound imaging
elements may be used to move and position tissue. A tissue-engaging
device may be used to position tissue prior to a valve procedure,
during a valve procedure and/or following a valve procedure, for
example, a valve implantation or repair procedure. In addition to
cardiac tissue, other tissue types and/or organs may be imaged by
one or more ultrasound imaging elements of the device. The distal
end of the tissue-engaging device may be positioned within a
patient through an incision, a stab wound, a port, a sternotomy
and/or a thoracotomy. An endoscope may be used to help position the
tissue-engaging device.
[0065] In one embodiment of the invention, an imaging device or
system may comprise one or more switches to facilitate its
regulation by a physician or surgeon. One example of such a switch
is a foot pedal. The switch may also be, for example, a hand
switch, or a voice-activated switch comprising voice-recognition
technologies. The switch may be incorporated in or on one of the
surgeon's instruments or any other location easily and quickly
accessed by the surgeon or medical practitioner. In one embodiment,
a switch may be physically wired to the imaging device or it may be
a remote control switch.
[0066] In one embodiment of the invention, an imaging device may be
based on one or more imaging modalities such as ultrasound imaging,
CT, MRI, PET, fluoroscopy, echocardiography, etc. An imaging device
may have two and/or three-dimensional imaging capabilities as well
as phased and/or annular array imaging capabilities. For example,
two or three-dimensional echocardiography, such as transesophageal
echocardiography (TEE), or ultrasound imaging, such as
transthoracic ultrasound imaging may be possible with use of an
imaging device.
[0067] The imaging device may comprise one or more light sources
and/or illuminating materials, e.g., glow-in-the-dark materials.
For example, one or more portions of a tissue-engaging device
and/or one or more portions of a valve replacement or repair
delivery system may comprise one or more glow-in-the-dark
materials. The imaging device may be based on fluorescence
technologies. The imaging device may comprise fiber optic
technologies; for example a fiber optic conduit may deliver light
from a remote light source to an area adjacent a treatment
site.
[0068] An imaging device may comprise a light pipe, for example, to
illuminate the tissue-engaging device and/or a valve replacement or
repair delivery device and/or the surgical field adjacent. A
transparent, semi-transparent or translucent tissue-engaging head
may be illuminated merely by placement of the end of a light pipe
or other light source adjacent a portion of the tissue-engaging
device. A transparent, semi-transparent or translucent portion of a
valve replacement or repair device may be illuminated merely by
placement of the end of a light pipe or other light source adjacent
a transparent, semi-transparent or translucent portion of a valve
replacement or repair delivery device or system.
[0069] An imaging device may include a visual display or monitor,
such as, for example, a LCD or CRT monitor, to display various
amounts and types of information. By software control, the user may
choose to display the information in a number of ways. The imaging
device may be powered by AC current, DC current, or it may be
battery powered either by a disposable or re-chargeable battery.
The imaging device may provide UV, IR and/or visible light. The
imaging device may include a laser. The imaging device may be
incorporated into tissue-engaging device and/or a valve replacement
or repair device or system or it may be incorporated into a
separate device. A separate imaging device may be positioned and
used, for example, through a thoracotomy, through a sternotomy,
percutaneously, transvenously, arthroscopically, endoscopically,
for example, through a percutaneous port, through a stab wound or
puncture, through a small incision, for example, in the chest, in
the groin, in the abdomen, in the neck or in the knee, or in
combinations thereof. A separate imaging device may be positioned
through one or more body cavity openings of the patient and/or
positioned outside the patient, e.g., near the patient or on the
skin of the patient. One or more imaging devices may be positioned
in the esophagus, the trachea and/or the bronchi of the lungs.
[0070] In one embodiment of the invention, the beating of a
patient's heart may be controlled before a cardiac valve procedure,
during a cardiac valve procedure, or following a cardiac valve
procedure, e.g., a valve replacement procedure or a valve repair
procedure. In one embodiment of the invention, a nerve stimulator
device comprising one or more nerve stimulation electrodes may be
used to stimulate the patient's vagal nerve to slow or stop the
patient's heart during a valve replacement or valve repair
procedure. The patient may be given one or more drugs to help stop
the beating of the heart and/or to prevent "escape" beats.
Following vagal stimulation, the heart may be allowed to return to
its usual cardiac rhythm. Alternatively, the heart may be paced,
thereby maintaining a normal cardiac output or to increase cardiac
output. Vagal stimulation, alone or in combination with electrical
pacing and/or drugs, may be used selectively and intermittently to
allow a surgeon to perform a valve replacement or valve repair
procedure on a temporarily stopped heart. For example, stimulation
of the vagus nerve in order to temporarily and intermittently slow
or stop the heart is described in U.S. Pat. Nos. 6,006,134,
6,449,507, 6,532,388, 6,735,471, 6,718,208, 6,228,987, 6,266,564,
6,487,446 and U.S. patent application Ser. No. 09/670,370 filed
Sep. 26, 2000, Ser. No. 09/669,961 filed Sep. 26, 2000, Ser. No.
09/670,440 filed Sep. 26, 2000. These patents and patent
applications are incorporated herein by reference in their
entireties.
[0071] Electrodes used to stimulate a nerve such as the vagal nerve
may be, for example, non-invasive, e.g., clips, or invasive, e.g.,
needles or probes. The application of an electrical stimulus to the
right or left vagal nerve may include, but is not limited to
bipolar and/or monopolar techniques. Different electrode positions
are accessible through various access openings, for example, in the
cervical or thorax regions. Nerve stimulation electrodes may be
positioned through a thoracotomy, sternotomy, endoscopically
through a percutaneous port, through a stab wound or puncture,
through a small incision in the neck or chest, through the internal
jugular vein, the esophagus, the trachea, placed on the skin or in
combinations thereof. Electrical stimulation may be carried out on
the right vagal nerve, the left vagal nerve or to both nerves
simultaneously or sequentially. The present invention may include
various electrodes, catheters and electrode catheters suitable for
vagal nerve stimulation to temporarily stop or slow the beating
heart alone or in combination with other heart rate inhibiting
agents.
[0072] Nerve stimulation electrodes may be endotracheal,
endoesophageal, intravascular, transcutaneous, intracutaneous,
patch-type, balloon-type, cuff-type, basket-type, umbrella-type,
tape-type, screw-type, barb-type, metal, wire or suction-type
electrodes. Guided or steerable catheter devices comprising
electrodes may be used alone or in combination with the nerve
stimulation electrodes. For example, a catheter comprising one or
more wire, metal strips or metal foil electrodes or electrode
arrays may be inserted into the internal jugular vein to make
electrical contact with the wall of the internal jugular vein, and
thus stimulate the vagal nerve adjacent to the internal jugular
vein. Access to the internal jugular vein may be via, for example,
the right atrium, the right atrial appendage, the inferior vena
cava or the superior vena cava. The catheter may comprise, for
example, a balloon, which may be inflated with air or liquid to
press the electrodes firmly against the vessel wall. Similar
techniques may be performed by insertion of a catheter-type device
into the trachea or esophagus. Additionally, tracheal devices,
e.g., tracheal tubes, tracheal imaging devices, and/or esophageal
devices, e.g., esophageal tubes, esophageal imaging devices,
comprising electrodes may be used.
[0073] Nerve stimulation electrodes may be oriented in any fashion
along a catheter device, including longitudinally or transversely.
Various imaging techniques or modalities, as discussed earlier,
such as ultrasound, fluoroscopy and echocardiography may be used to
facilitate positioning of the electrodes. If desired or necessary,
avoidance of obstruction of air flow or blood flow may be achieved
with notched catheter designs or with catheters, which incorporate
one or more tunnels or passageways.
[0074] In one embodiment of the invention, the location of the
electrodes is chosen to elicit maximum bradycardia effectiveness
while minimizing current spread to adjacent tissues and vessels and
to prevent the induction of post stimulation tachycardia.
Furthermore, a non-conductive material such as plastic may be
employed to sufficiently enclose the electrodes of all the
configurations to shield them from the surrounding tissues and
vessels, while exposing their confronting edges and surfaces for
positive contact with the vagal nerve or selected tissues.
[0075] FIG. 12 shows a flow diagram of one embodiment of the
present invention. The patient is prepared for a medical procedure
at 700. Once the patient is prepared, the heart is engaged and
positioned using tissue-engaging device 200 (Block 705). Once the
heart is positioned in a desired orientation, e.g., a
non-physiological orientation, a nerve that controls the beating of
the heart is stimulated to slow down or stop the contractions of
the heart (Block 708). Such a nerve may be for example a vagal
nerve. During this time, one or more of a variety of
pharmacological agents or drugs may be delivered to the patient.
Drugs may be administered without nerve stimulation. The types of
drugs administered may produce reversible asystole of a heart while
maintaining the ability of the heart to be electrically paced.
Other drugs may be administered for a variety of functions and
purposes. Drugs may be administered at the beginning of the
procedure, intermittently during the procedure, continuously during
the procedure or following the procedure. Examples of one or more
drugs that may be administered include a beta-blocker, a
cholinergic agent, a cholinesterase inhibitor, a calcium channel
blocker, a sodium channel blocker, a potassium channel agent,
adenosine, an adenosine receptor agonist, an adenosine deaminase
inhibitor, dipyridamole, a monoamine oxidase inhibitor, digoxin,
digitalis, lignocaine, a bradykinin agent, a serotoninergic
agonist, an antiarrythmic agent, a cardiac glycoside, a local
anesthetic, atropine, a calcium solution, an agent that promotes
heart rate, an agent that promotes heart contractions, dopamine, a
catecholamine, an inotrope glucagon, a hormone, forskolin,
epinephrine, norepinephrine, thyroid hormone, a phosphodiesterase
inhibitor, prostacyclin, prostaglandin and a methylxanthine.
[0076] Typically, vagal-nerve stimulation prevents the heart from
contracting. This non-contraction must then be followed by periods
without vagal nerve stimulation during which the heart is allowed
to contract, and blood flow is restored throughout the body.
Following initial slowing or stopping of the heart, a medical
procedure, such as imaging and/or valve replacement or valve
repair, is begun (Block 710). In one embodiment of the invention,
one or more imaging devices may be positioned, e.g., outside a
patient or within a patient, for example, within the trachea,
bronchi of the lungs and/or esophagus of the patient, and an
imaging modality is emitted, for example, ultrasound energy is
emitted, from the one or more imaging devices and imaging energy is
focused within tissue, e.g., cardiac tissue such as cardiac valve
tissue. Following a brief interval of nerve stimulation while the
valve replacement or valve repair procedure is performed, nerve
stimulation is ceased (Block 713) and the heart is allowed to
contract.
[0077] In one embodiment of the invention, the heart may be free to
beat on its own or a cardiac stimulator device or pacemaker
comprising one or more cardiac stimulation electrodes may be used
to cause the heart to contract (Blocks 722 and 724). Cardiac
stimulation electrodes used to stimulate the heart may be, for
example, non-invasive, e.g., clips, or invasive, e.g., needles or
probes. Cardiac electrodes may be positioned through a thoracotomy,
sternotomy, endoscopically through a percutaneous port, through a
stab wound or puncture, through a small incision in the chest,
placed on the chest or in combinations thereof. The present
invention may also use various electrodes, catheters and electrode
catheters suitable for pacing the heart, e.g., epicardial,
patch-type, intravascular, balloon-type, basket-type,
umbrella-type, tape-type electrodes, suction-type, pacing
electrodes, endotracheal electrodes, endoesophageal electrodes,
transcutaneous electrodes, intracutaneous electrodes, screw-type
electrodes, barb-type electrodes, bipolar electrodes, monopolar
electrodes, metal electrodes, wire electrodes and cuff electrodes.
Guided or steerable catheter devices comprising electrodes may be
used alone or in combination with the electrodes. In one embodiment
of the invention, one or more cardiac electrodes, e.g., stimulation
and/or monitoring electrodes, may be positioned on a
tissue-engaging device. In one embodiment of the invention, a
cardiac stimulator device may be used to stimulate the heart to
beat rapidly to the point cardiac output is minimized or
significantly decreased from a normal cardiac output. A valve
replacement procedure or valve repair procedure may be performed
during rapid pacing of the heart. In one embodiment of the
invention, the heart may be stimulated to beat so fast it quivers
and cardiac output essentially falls to zero during which a valve
replacement procedure or valve repair procedure may be
performed.
[0078] If the valve replacement or valve repair procedure needs to
continue or a new valve replacement or repair procedure is to be
performed, the heart again may be slowed or stopped via vagal nerve
stimulation. In addition, the heart may be repositioned if
necessary or desired at Block 748.
[0079] In one embodiment of the present invention, a probe device
sized and shaped to fit within the trachea, bronchi and/or
esophagus of the patient may comprise one or more nerve stimulation
electrodes, members or elements and one or more ultrasound members
or elements. The probe device may be positioned within the trachea,
bronchi and/or esophagus of the patient. The nerve stimulation
electrodes may be used to stimulate one or more nerves of the
patient, e.g., a vagal nerve, as disclosed earlier, while the probe
device is positioned within the trachea, bronchi and/or esophagus
of the patient. A valve replacement or valve repair delivery system
may be used, as disclosed earlier, while the probe device is
positioned within the trachea, bronchi and/or esophagus of the
patient. The nerve stimulation electrodes may be coupled to a nerve
stimulator, e.g., used to stimulate the patient's vagal nerve to
slow or stop the patient's heart during a valve replacement or
valve repair procedure.
[0080] In one embodiment of the invention, a valve replacement or
valve repair device or system may include a display and/or other
means of indicating the status of various components of the device
to the surgeon such as a numerical display, gauges, a monitor
display or audio feedback. The valve replacement or valve repair
device or system may also include one or more visual and/or audible
signals used to prepare a surgeon for the start or stop of the
valve replacement or valve repair procedure. A controller may
synchronize deliver of a bioprosthetic valve between heart beats to
reduce inadvertent tissue damage. A controller may be slaved to a
nerve stimulator and/or a cardiac stimulator. Alternatively, a
nerve stimulator and/or cardiac stimulator may be slaved to a
controller. Alternatively, a controller may be capable of nerve
stimulation and/or cardiac stimulation.
[0081] In one embodiment of the invention, electrodes may be used
for cardiac pacing, defibrillation, cardioversion, sensing,
stimulation, and/or mapping prior to, during, or following a valve
replacement and/or valve repair procedure or procedures.
[0082] In one embodiment of the invention, a tissue-engaging device
and/or a valve replacement or valve repair system or device may be
attached to a flexible or rigid hose or tubing for supplying
suction and/or fluids from a suitable suction source and/or fluid
source to the target tissue surface through one or more suction
and/or fluid elements, openings, orifices, and/or ports of the
devices and/or systems. The hose or tubing may comprise one or more
stopcocks and/or connectors such as luer connectors. Suction may be
provided by the standard suction available in the operating room.
Suction source may be coupled with a buffer flask and/or filter.
Suction may be provided at a negative pressure of between 200-600
mm Hg with 400 mm Hg preferred. As used herein, the terms "vacuum"
or "suction" refer to negative pressure relative to atmospheric or
environmental air pressure.
[0083] Suction may be provided via one or more manual or electric
pumps, syringes, suction or squeeze bulbs or other suction or
vacuum producing means, devices or systems. Suction source may
comprise one or more vacuum regulators, resistors, stopcocks,
connectors, valves, e.g., vacuum releasing valves, filters,
conduits, lines, tubes and/or hoses. The conduits, lines, tubes, or
hoses may be flexible or rigid. For example, a flexible suction
line may be used to communicate suction to a tissue-engaging device
and/or a valve replacement or valve repair system or device,
thereby allowing the systems or devices to be easily manipulated by
a physician or surgeon. Another method that would allow the
physician or surgeon to easily manipulate the system or device
includes incorporation of suction source into tissue-engaging
device and/or a valve replacement or valve repair system. For
example, a small battery operated vacuum pump or squeeze bulb may
be incorporated.
[0084] In one embodiment of the invention, a suction source may be
slaved to a tissue-engaging device, a fluid source, one or more
sensors, an imaging device, a drug delivery device, a guidance
device and/or a stimulation device. For example, a suction source
may be designed to automatically stop suction when a controller
sends a signal to stop suction. In one embodiment of the invention,
a suction source may include a visual and/or audible signal used to
alert a surgeon to any change in suction. For example, a beeping
tone or flashing light may be used to alert the surgeon when
suction is present. A suction source may be slaved to a robotic
system or a robotic system may be slaved to a suction source.
Suction may be used to secure, anchor or fix a tissue-engaging
device and/or a valve replacement or valve repair system or device
to an area of tissue. The area of tissue may comprise a beating
heart or a stopped heart. Suction may be used to remove or aspirate
fluids from the target tissue site. Fluids removed may include, for
example, blood, saline, Ringer's solution, ionic fluids, contrast
fluids, irrigating fluids and energy-conducting fluids. Steam,
vapor, smoke, gases and chemicals may also be removed via
suction.
[0085] In one embodiment of the invention, one or more fluid
sources is provided for providing one or more fluids, for example,
to a tissue-engaging device, a valve replacement delivery system or
device, a valve repair delivery system or device, and/or the
patient. A tissue-engaging device may be attached to a flexible or
rigid hose or tubing for supplying fluids from fluid source to the
target tissue through fluid elements, openings, orifices, or ports
of device. A valve replacement or valve repair delivery system or
device may be attached to a flexible or rigid hose or tubing for
receiving fluids from fluid source and for supplying fluids, if
desired, to the target tissue through fluid elements, openings,
orifices, or ports of the system or device.
[0086] A fluid source of the present invention may be any suitable
source of fluid.
[0087] The fluid source may include a manual or electric pump, an
infusion pump, a peristaltic pump, a roller pump, a centrifugal
pump, a syringe pump, a syringe, or squeeze bulb or other fluid
moving means, device or system. For example, a pump may be
connected to a shared power source or it may have its own source of
power. A fluid source may be powered by AC current, DC current, or
it may be battery powered either by a disposable or re-chargeable
battery. A fluid source may comprise one or more fluid regulators,
e.g., to control flow rate, valves, fluid reservoirs, resistors,
filters, conduits, lines, tubes and/or hoses. The conduits, lines,
tubes, or hoses may be flexible or rigid. For example, a flexible
line may be connected to one or more devices, for example, a
tissue-engaging device, an imaging device, a valve replacement
device, or a valve repair device to deliver fluid and/or remove
fluid, thereby allowing the device or system comprising a fluid
source to be easily manipulated by a surgeon. Fluid reservoirs may
include an IV bag or bottle, for example.
[0088] In one embodiment of the invention, one or more fluid
sources may be incorporated into a tissue-engaging device and/or a
valve replacement device and/or a valve repair device, thereby
delivering fluid or removing fluid at the target tissue site. The
fluid source may be slaved to a tissue-engaging device and/or a
valve replacement device and/or a valve repair device, and/or a
suction source, and/or a sensor and/or an imaging device. For
example, the fluid source may be designed to automatically stop or
start the delivery of fluid while a tissue-engaging device is
engaged with tissue or while a valve replacement delivery device is
delivering and positioning a valve or while a valve repair device
is repairing a valve.
[0089] In one embodiment of the invention, one or more valve
replacement delivery systems, valve repair systems, tissue-engaging
devices, suction sources, fluid sources, sensors and/or imaging
devices may be slaved to a robotic system or a robotic system may
be slaved to one or more valve replacement delivery systems, valve
repair systems, tissue-engaging devices, suction sources, fluid
sources, sensors and/or imaging devices.
[0090] In one embodiment of the invention, the fluid source may
comprise one or more switches, e.g., a surgeon-controlled switch.
One or more switches may be incorporated in or on a fluid source or
any other location easily and quickly accessed by the surgeon for
regulation of fluid delivery by the surgeon. A switch may comprise,
for example, a hand switch, a foot switch, or a voice-activated
switch comprising voice-recognition technologies. A switch may be
physically wired to a fluid source or it may be a remote control
switch. The fluid source and/or system may include a visual and/or
audible signal used to alert a surgeon to any change in the
delivery of fluid. For example, a beeping tone or flashing light
may be used to alert the surgeon that a change has occurred in the
delivery of fluid.
[0091] In one embodiment of the invention, fluids delivered to a
tissue-engaging device and/or a valve replacement device and/or a
valve repair device and/or an imaging device and/or a sensor may
include saline, e.g., normal, hypotonic or hypertonic saline,
Ringer's solution, ionic, contrast, blood, and/or energy-conducting
liquids. An ionic fluid may electrically couple an electrode to
tissue thereby lowering the impedance at the target tissue site. An
ionic irrigating fluid may create a larger effective electrode
surface. An irrigating fluid may cool the surface of tissue. A
hypotonic irrigating fluid may be used to electrically insulate a
region of tissue. Fluids delivered according to one embodiment of
the invention may include gases, adhesive agents and/or release
agents.
[0092] Diagnostic or therapeutic agents, such as one or more
radioactive materials and/or biological agents such as, for
example, an anticoagulant agent, an antithrombotic agent, a
clotting agent, a platelet agent, an anti-inflammatory agent, an
antibody, an antigen, an immunoglobulin, a defense agent, an
enzyme, a hormone, a growth factor, a neurotransmitter, a cytokine,
a blood agent, a regulatory agent, a transport agent, a fibrous
agent, a protein, a peptide, a proteoglycan, a toxin, an antibiotic
agent, an antibacterial agent, an antimicrobial agent, a bacterial
agent or component, hyaluronic acid, a polysaccharide, a
carbohydrate, a fatty acid, a catalyst, a drug, a vitamin, a DNA
segment, a RNA segment, a nucleic acid, a lectin, an antiviral
agent, a viral agent or component, a genetic agent, a ligand and a
dye (which acts as a biological ligand) may be delivered with or
without a fluid to the patient. Biological agents may be found in
nature (naturally occurring) or may be chemically synthesized.
Cells and cell components, e.g., mammalian and/or bacterial cells,
may be delivered to the patient. A platelet gel or tissue adhesive
may be delivered to the patient.
[0093] One or more of a variety of pharmacological agents,
biological agents and/or drugs may be delivered or administered to
a patient, for a variety of functions and purposes as described
below, prior to a medical procedure, intermittently during a
medical procedure, continuously during a medical procedure and/or
following a medical procedure. For example, one or more of a
variety of pharmacological agents, biological agents and/or drugs,
as discussed above and below, may be delivered before, with or
after the delivery of a fluid.
[0094] Drugs, drug formulations or compositions suitable for
administration to a patient may include a pharmaceutically
acceptable carrier or solution in an appropriate dosage. There are
a number of pharmaceutically acceptable carriers that may be used
for delivery of various drugs, for example, via direct injection,
oral delivery, suppository delivery, transdermal delivery,
epicardial delivery and/or inhalation delivery. Pharmaceutically
acceptable carriers include a number of solutions, preferably
sterile, for example, water, saline, Ringer's solution and/or sugar
solutions such as dextrose in water or saline. Other possible
carriers that may be used include sodium citrate, citric acid,
amino acids, lactate, mannitol, maltose, glycerol, sucrose,
ammonium chloride, sodium chloride, potassium chloride, calcium
chloride, sodium lactate, and/or sodium bicarbonate. Carrier
solutions may or may not be buffered.
[0095] Drug formulations or compositions may include antioxidants
or preservatives such as ascorbic acid. They may also be in a
pharmaceutically acceptable form for parenteral administration, for
example to the cardiovascular system, or directly to the heart,
such as intracoronary infusion or injection. Drug formulations or
compositions may comprise agents that provide a synergistic effect
when administered together. A synergistic effect between two or
more drugs or agents may reduce the amount that normally is
required for therapeutic delivery of an individual drug or agent.
Two or more drugs may be administered, for example, sequentially or
simultaneously. Drugs may be administered via one or more bolus
injections and/or infusions or combinations thereof. The injections
and/or infusions may be continuous or intermittent. Drugs may be
administered, for example, systemically or locally, for example, to
the heart, to a coronary artery and/or vein, to a pulmonary artery
and/or vein, to the right atrium and/or ventricle, to the left
atrium and/or ventricle, to the aorta, to the AV node, to the SA
node, to a nerve and/or to the coronary sinus. Drugs may be
administered or delivered via intravenous, intracoronary and/or
intraventricular administration in a suitable carrier. Examples of
arteries that may be used to deliver drugs to the AV node include
the AV node artery, the right coronary artery, the right descending
coronary artery, the left coronary artery, the left anterior
descending coronary artery and Kugel's artery. Drugs may be
delivered systemically, for example, via oral, transdermal,
intranasal, suppository or inhalation methods. Drugs also may be
delivered via a pill, a spray, a cream, an ointment or a medicament
formulation.
[0096] In one embodiment of the present invention, a drug delivery
device may be used or incorporated into another device of the
present invention. The drug delivery device may comprise a
catheter, such as a drug delivery catheter or a guide catheter, a
patch, such as a transepicardial patch that slowly releases drugs
directly into the myocardium, a cannula, a pump and/or a hypodermic
needle and syringe assembly. A drug delivery catheter may include
an expandable member, e.g., a low-pressure balloon, and a shaft
having a distal portion, wherein the expandable member is disposed
along the distal portion. A catheter for drug delivery may comprise
one or more lumens and may be delivered endovascularly via
insertion into a blood vessel, e.g., an artery such as a femoral,
radial, subclavian or coronary artery. The catheter can be guided
into a desired position using various guidance techniques, e.g.,
flouroscopic guidance and/or a guiding catheter or guide wire
techniques. Drugs may be delivered via an iontophoretic drug
delivery device placed on the heart. In general, the delivery of
ionized drugs may be enhanced via a small current applied across
two electrodes. Positive ions may be introduced into the tissues
from the positive pole, or negative ions from the negative pole.
The use of iontophoresis may markedly facilitate the transport of
certain ionized drug molecules. For example, lidocaine
hydrochloride may be applied to the heart via a drug patch
comprising the drug. A positive electrode could be placed over the
patch and current passed. The negative electrode would contact the
heart or other body part at some desired distance point to complete
the circuit. One or more of the iontophoresis electrodes may also
be used as, nerve stimulation electrodes or as cardiac stimulation
electrodes.
[0097] A drug delivery device may be incorporated into a
tissue-engaging device and/or a valve replacement device and/or a
valve repair device and/or an imaging device, thereby delivering
drugs at or adjacent the target tissue site or the drug delivery
device may be placed or used at a location differing from the
location of the target tissue site such as a cardiac valve site. In
one embodiment of the invention, a drug delivery device may be
placed in contact with the inside surface or the outside surface of
a patient's heart.
[0098] In one embodiment of the invention, a drug delivery device
may be slaved to a tissue-engaging device, a suction source, a
fluid source, a sensor, an imaging device, a valve replacement
device and/or a valve repair device. For example, a drug delivery
device may be designed to automatically stop or start the delivery
of drugs during tissue engagement of a tissue-engaging device,
during valve replacement via a valve replacement device and/or a
valve repair device. The drug delivery device may be slaved to a
robotic system or a robotic system may be slaved to the drug
delivery device.
[0099] The drug delivery device may comprise one or more switches,
e.g., a surgeon-controlled switch. One or more switches may be
incorporated in or on the drug delivery device or any other
location easily and quickly accessed by the surgeon for regulation
of drug delivery by the surgeon. A switch may be, for example, a
hand switch, a foot switch, or a voice-activated switch comprising
voice-recognition technologies. A switch may be physically wired to
the drug delivery device or it may be a remote control switch. The
drug delivery device may include a visual and/or audible signal
used to alert a surgeon to any change in the medical procedure,
e.g., in the delivery of drugs. For example, a beeping tone or
flashing light that increases in frequency as the rate of drug
delivery increases may be used to alert the surgeon.
[0100] The two divisions of the autonomic nervous system that
regulate the heart have opposite functions. First, the adrenergic
or sympathetic nervous system increases heart rate by releasing
epinephrine and norepinephrine. Second, the parasympathetic system
also known as the cholinergic nervous system or the vagal nervous
system decreases heart rate by releasing acetylcholine.
Catecholamines such as norepinephrine (also called noradrenaline)
and epinephrine (also called adrenaline) are agonists for
beta-adrenergic receptors. An agonist is a stimulant biomolecule or
agent that binds to a receptor.
[0101] Beta-adrenergic receptor blocking agents compete with
beta-adrenergic receptor stimulating agents for available
beta-receptor sites. When access to beta-receptor sites are blocked
by receptor blocking agents, also known as beta-adrenergic
blockade, the chronotropic or heart rate, inotropic or
contractility, and vasodilator responses to receptor stimulating
agents are decreased proportionately. Therefore, beta-adrenergic
receptor blocking agents are agents that are capable of blocking
beta-adrenergic receptor sites.
[0102] Since beta-adrenergic receptors are concerned with
contractility and heart rate, stimulation of beta-adrenergic
receptors, in general, increases heart rate, the contractility of
the heart and the rate of conduction of electrical impulses through
the AV node and the conduction system.
[0103] Drugs, drug formulations and/or drug compositions that may
be used according to one embodiment of this invention may include
any naturally occurring or chemically synthesized (synthetic
analogues) beta-adrenergic receptor blocking agents.
Beta-adrenergic receptor blocking agents or .beta.-adrenergic
blocking agents are also known as beta-blockers or .beta.-blockers
and as class II antiarrhythmics.
[0104] The term "beta-blocker" appearing herein may refer to one or
more agents that antagonize the effects of beta-stimulating
catecholamines by blocking the catecholamines from binding to the
beta-receptors. Examples of beta-blockers include, but are not
limited to, acebutolol, alprenolol, atenolol, betantolol,
betaxolol, bevantolol, bisoprolol, carterolol, celiprolol,
chlorthalidone, esmolol, labetalol, metoprolol, nadolol,
penbutolol, pindolol, propranolol, oxprenolol, sotalol, teratolo,
timolol and combinations, mixtures and/or salts thereof
[0105] The effects of administered beta-blockers may be reversed by
administration of beta-receptor agonists, e.g., dobutamine or
isoproterenol.
[0106] The parasympathetic or cholinergic system participates in
control of heart rate via the sinoatrial (SA) node, where it
reduces heart rate. Other cholinergic effects include inhibition of
the AV node and an inhibitory effect on contractile force. The
cholinergic system acts through the vagal nerve to release
acetylcholine, which, in turn, stimulates cholinergic receptors.
Cholinergic receptors are also known as muscarinic receptors.
Stimulation of the cholinergic receptors decreases the formation of
cAMP. Stimulation of cholinergic receptors generally has an
opposite effect on heart rate compared to stimulation of
beta-adrenergic receptors. For example, beta-adrenergic stimulation
increases heart rate, whereas cholinergic stimulation decreases it.
When vagal tone is high and adrenergic tone is low, there is a
marked slowing of the heart (sinus bradycardia). Acetylcholine
effectively reduces the amplitude, rate of increase and duration of
the SA node action potential. During vagal nerve stimulation, the
SA node does not arrest. Rather, pacemaker function may shift to
cells that fire at a slower rate. In addition, acetylcholine may
help open certain potassium channels thereby creating an outward
flow of potassium ions and hyperpolarization. Acetylcholine also
slows conduction through the AV node.
[0107] Drugs, drug formulations and/or drug compositions that may
be used according to this invention may include any naturally
occurring or chemically synthesized (synthetic analogues)
cholinergic agent. The term "cholinergic agent" appearing herein
may refer to one or more cholinergic receptor modulators or
agonists. Examples of cholinergic agents include, but are not
limited to, acetylcholine, carbachol (carbamyl choline chloride),
bethanechol, methacholine, arecoline, norarecoline and
combinations, mixtures and/or salts thereof.
[0108] Drugs, drug formulations and/or drug compositions that may
be used according to one embodiment of this invention may include
any naturally occurring or chemically synthesized cholinesterase
inhibitor. The term "cholinesterase inhibitor" appearing herein may
refer to one or more agents that prolong the action of
acetylcholine by inhibiting its destruction or hydrolysis by
cholinesterase. Cholinesterase inhibitors are also known as
acetylcholinesterase inhibitors. Examples of cholinesterase
inhibitors include, but are not limited to, edrophonium,
neostigmine, neostigmine methylsulfate, pyridostigmine, tacrine and
combinations, mixtures and/or salts thereof.
[0109] There are ion-selective channels within certain cell
membranes. These ion selective channels include calcium channels,
sodium channels and/or potassium channels. Therefore, other drugs,
drug formulations and/or drug compositions that may be used
according to this invention may include any naturally occurring or
chemically synthesized calcium channel blocker. Calcium channel
blockers inhibit the inward flux of calcium ions across cell
membranes of arterial smooth muscle cells and myocardial cells.
Therefore, the term "calcium channel blocker" appearing herein may
refer to one or more agents that inhibit or block the flow of
calcium ions across a cell membrane. The calcium channel is
generally concerned with the triggering of the contractile cycle.
Calcium channel blockers are also known as calcium ion influx
inhibitors, slow channel blockers, calcium ion antagonists, calcium
channel antagonist drugs and as class IV antiarrhythmics. A
commonly used calcium channel blocker is verapamil.
[0110] Administration of a calcium channel blocker, e.g.,
verapamil, generally prolongs the effective refractory period
within the AV node and slows AV conduction in a rate-related
manner, since the electrical activity through the AV node depends
significantly upon the influx of calcium ions through the slow
channel. A calcium channel blocker has the ability to slow a
patient's heart rate, as well as produce AV block. Examples of
calcium channel blockers include, but are not limited to,
amiloride, amlodipine, bepridil, diltiazem, felodipine, isradipine,
mibefradil, nicardipine, nifedipine (dihydropyridines), nickel,
nimodinpine, nisoldipine, nitric oxide (NO), norverapamil and
verapamil and combinations, mixtures and/or salts thereof.
Verapamil and diltiazem are very effective at inhibiting the AV
node, whereas drugs of the nifedipine family have a lesser
inhibitory effect on the AV node. Nitric oxide (NO) indirectly
promotes calcium channel closure. NO may be used to inhibit
contraction. NO may also be used to inhibit sympathetic outflow,
lessen the release of norepinephrine, cause vasodilation, decrease
heart rate and decrease contractility. In the SA node, cholinergic
stimulation leads to formation of NO.
[0111] Other drugs, drug formulations and/or drug compositions that
may be used according to one embodiment of this invention may
include any naturally occurring or chemically synthesized sodium
channel blocker. Sodium channel blockers are also known as sodium
channel inhibitors, sodium channel blocking agents, rapid channel
blockers or rapid channel inhibitors. Antiarrhythmic agents that
inhibit or block the sodium channel are known as class I
antiarrhythmics, examples include, but are not limited to,
quinidine and quinidine-like agents, lidocaine and lidocaine-like
agents, tetrodotoxin, encainide, flecainide and combinations,
mixtures and/or salts thereof. Therefore, the term "sodium channel
blocker" appearing herein may refer to one or more agents that
inhibit or block the flow of sodium ions across a cell membrane or
remove the potential difference across a cell membrane. For
example, the sodium channel may also be totally inhibited by
increasing the extracellular potassium levels to depolarizing
hyperkalemic values, which remove the potential difference across
the cell membrane. The result is inhibition of cardiac contraction
with cardiac arrest (cardioplegia). The opening of the sodium
channel (influx of sodium) is for swift conduction of the
electrical impulse throughout the heart.
[0112] Other drugs, drug formulations and/or drug compositions that
may be used according to one embodiment of this invention may
include any naturally occurring or chemically synthesized potassium
channel agent. The term "potassium channel agent" appearing herein
may refer to one or more agents that impact the flow of potassium
ions across the cell membrane. There are two major types of
potassium channels. The first type of channel is voltage-gated and
the second type is ligand-gated. Acetylcholine-activated potassium
channels, which are ligand-gated channels, open in response to
vagal stimulation and the release of acetylcholine. Opening of the
potassium channel causes hyperpolarization, which decreases the
rate at which the activation threshold is reached. Adenosine is one
example of a potassium channel opener. Adenosine slows conduction
through the AV node. Adenosine, a breakdown product of adenosine
triphosphate, inhibits the AV node and atria. In atrial tissue,
adenosine causes the shortening of the action potential duration
and causes hyperpolarization. In the AV node, adenosine has similar
effects and also decreases the action potential amplitude and the
rate of increase of the action potential. Adenosine is also a
direct vasodilator by its actions on the adenosine receptor on
vascular smooth muscle cells. In addition, adenosine acts as a
negative neuromodulator, thereby inhibiting release of
norepinephrine. Class III antiarrhythmic agents also known as
potassium channel inhibitors lengthen the action potential duration
and refractoriness by blocking the outward potassium channel to
prolong the action potential. Amiodarone and d-sotalol are both
examples of class III antiarrhythmic agents.
[0113] Potassium is the most common component in cardioplegic
solutions. High extracellular potassium levels reduce the membrane
resting potential. Opening of the sodium channel, which normally
allows rapid sodium influx during the upstroke of the action
potential, is therefore inactivated because of a reduction in the
membrane resting potential.
[0114] Drugs, drug formulations and/or drug compositions that may
be used according to this invention may comprise one or more of any
naturally occurring or chemically synthesized beta-blocker,
cholinergic agent, cholinesterase inhibitor, calcium channel
blocker, sodium channel blocker, potassium channel agent,
adenosine, adenosine receptor agonist, adenosine deaminase
inhibitor, dipyridamole, monoamine oxidase inhibitor, digoxin,
digitalis, lignocaine, bradykinin agents, serotoninergic agonist,
antiarrythmic agents, cardiac glycosides, local anesthetics and
combinations or mixtures thereof. Digitalis and digoxin both
inhibit the sodium pump. Digitalis is a natural inotrope derived
from plant material, while digoxin is a synthesized inotrope.
Dipyridamole inhibits adenosine deaminase, which breaks down
adenosine. Drugs, drug formulations and/or drug compositions
capable of reversibly suppressing autonomous electrical conduction
at the SA and/or AV node, while still allowing the heart to be
electrically paced to maintain cardiac output may be used according
to this invention.
[0115] Beta-adrenergic stimulation or administration of calcium
solutions may be used to reverse the effects of a calcium channel
blocker such as verapamil. Agents that promote heart rate and/or
contraction may be used in the present invention. For example,
dopamine, a natural catecholamine, is known to increase
contractility. Positive inotropes are agents that specifically
increase the force of contraction of the heart. Glucagon, a
naturally occurring hormone, is known to increase heart rate and
contractility. Glucagon may be used to reverse the effects of a
beta-blocker since its effects bypass the beta receptor. Forskolin
is known to increase heart rate and contractility. As mentioned
earlier, epinephrine and norepinephrine naturally increase heart
rate and contractility. Thyroid hormone, phosphodiesterase
inhibitors and prostacyclin, a prostaglandin, are also known to
increase heart rate and contractility. In addition, methylxanthines
are known to prevent adenosine from interacting with its cell
receptors.
[0116] The drug delivery device may include a vasodilative delivery
component and/or a vasoconstrictive delivery component. Both
delivery components may be any suitable means for delivering
vasodilative and/or vasoconstrictive drugs to a site of a medical
procedure. For example, the drug delivery device may be a system
for delivering a vasodilative spray and/or a vasoconstrictive
spray. The drug delivery device may be a system for delivering a
vasodilative cream and/or a vasoconstrictive cream. The drug
delivery device may be a system for delivering any vasodilative
formulation such as an ointment or medicament etc. and/or any
vasoconstrictive formulation such as an ointment or medicament etc.
or any combination thereof.
[0117] The drug delivery device may comprise a catheter, such as a
drug delivery catheter or a guide catheter, for delivering a
vasodilative substance followed by a vasoconstrictive substance. A
drug delivery catheter may include an expandable member, e.g., a
low-pressure balloon, and a shaft having a distal portion, wherein
the expandable member is disposed along the distal portion. A
catheter for drug delivery may comprise one or more lumens and may
be delivered endovascularly via insertion into a blood vessel,
e.g., an artery such as a femoral, radial, subclavian or coronary
artery. The catheter can be guided into a desired position using
various guidance techniques, e.g., flouroscopic guidance and/or a
guiding catheter or guide wire techniques. In one embodiment, one
catheter may be used to deliver both a vasodilative component and a
vasoconstrictive component. The drug delivery device may be a
patch, such as a transepicardial patch that slowly releases drugs
directly into the myocardium, a cannula, a pump and/or a hypodermic
needle and syringe assembly. The drug delivery device may be an
iontophoretic drug delivery device placed on the heart.
[0118] A vasodilative component may comprise one or more
vasodilative drugs in any suitable formulation or combination.
Examples of vasodilative drugs include, but are not limited to, a
vasodilator, an organic nitrate, isosorbide mononitrate, a
mononitrate, isosorbide dinitrate, a dinitrate, nitroglycerin, a
trinitrate, minoxidil, sodium nitroprusside, hydralazine
hydrochloride, nitric oxide, nicardipine hydrochloride, fenoldopam
mesylate, diazoxide, enalaprilat, epoprostenol sodium, a
prostaglandin, milrinone lactate, a bipyridine and a dopamine
D1-like receptor agonist, stimulant or activator. The vasodilative
component may include a pharmaceutically acceptable carrier or
solution in an appropriate dosage.
[0119] A vasoconstrictive component may comprise one or more
suitable vasoconstrictive drugs in any suitable formulation or
combination. Examples of vasoconstrictive drugs include, but are
not limited to, a vasoconstrictor, a sympathomimetic, methoxamine
hydrochloride, epinephrine, midodrine hydrochloride,
desglymidodrine, and an alpha-receptor agonist, stimulant or
activator. The vasoconstrictive component may include a
pharmaceutically acceptable carrier or solution in an appropriate
dosage
[0120] In one embodiment of the invention one or more sensors may
be used to sense information regarding the patient or the
procedure. A controller may store and/or process such information
before, during and/or after a medical procedure, e.g., a valve
replacement procedure and/or a valve repair procedure.
[0121] A controller may be used according to one embodiment of the
present invention to control, for example, the energy supplied to
one or more energy transfer elements, e.g., electrodes or
transducers, of a tissue-engaging device, an imaging device, a
valve replacement device and/or a valve repair device. The
controller may also gather and process information from one or more
sensors. The gathered information may be used to adjust energy
levels and times. The controller may incorporate one or more
switches to facilitate regulation of the various system components
by the surgeon. One example of such a switch is a foot pedal. A
switch may also be, for example, a hand switch, or a
voice-activated switch comprising voice-recognition technologies. A
switch may be physically wired to the controller or it may be a
remote control switch. A switch may be incorporated in or on one of
the surgeon's instruments, such as surgical site retractor, e.g., a
sternal or rib retractor, a tissue-engaging device, a valve
replacement device and/or valve repair device, or any other
location easily and quickly accessed by the surgeon. The controller
may include a display. The controller may also include other means
of indicating the status of various components to the surgeon such
as a numerical display, gauges, a monitor display or audio
feedback.
[0122] The controller may incorporate a cardiac stimulator and/or
cardiac monitor. For example, electrodes used to stimulate or
monitor the heart may be incorporated into a tissue-engaging
device, a valve replacement device, a valve repair device and/or an
imaging device. The controller may incorporate a nerve stimulator
and/or nerve monitor. For example, electrodes used to stimulate or
monitor one or more nerves, e.g., a vagal nerve, may be
incorporated into a tissue-engaging device, a valve replacement
device, a valve repair device and/or an imaging device. The
controller may comprise a surgeon-controlled switch for cardiac
stimulation and/or monitoring, as discussed earlier. The controller
may comprise a surgeon-controlled switch for nerve stimulation
and/or monitoring, as discussed earlier. Cardiac stimulation may
comprise cardiac pacing and/or cardiac defibrillation. The
Controller, tissue-engaging device, a valve replacement device, a
valve repair device and/or an imaging device may incorporate a
cardiac mapping device for mapping the electrical signals of the
heart.
[0123] A visual and/or audible signal used to alert a surgeon to
the completion or resumption of energy delivery, suction, sensing,
monitoring, stimulation and/or delivery of fluids, drugs and/or
cells may be incorporated into a controller of the present
invention. For example, a beeping tone or flashing light that
increases in frequency as the energy delivered increases.
[0124] In one embodiment of the invention, a tissue-engaging
device, a valve replacement device, a valve repair device and/or an
imaging device may include one or more sensors. Sensor may be
incorporated into a tissue-engaging device, a valve replacement
device, a valve repair device and/or an imaging device or it may be
incorporated into another separate device. A separate sensor device
may be positioned and used, for example, through a thoracotomy,
through a sternotomy, percutaneously, transvenously,
arthroscopically, endoscopically, for example, through a
percutaneous port, through a stab wound or puncture, through a
small incision, for example, in the chest, in the groin, in the
abdomen, in the neck or in the knee, or in combinations thereof
[0125] In one embodiment of the invention, a sensor may comprise
one or more switches, e.g., a surgeon-controlled switch. One or
more switches may be incorporated in or on a sensor device or any
other location easily and quickly accessed by the surgeon for
regulation of a sensor by a physician or a surgeon. A switch may
be, for example, a hand switch, a foot switch, or a voice-activated
switch comprising voice-recognition technologies. A switch may be
physically wired to the sensor or it may be a remote control
switch.
[0126] In one embodiment of the invention, a sensor may include a
visual and/or audible signal used to alert a surgeon to any change
in the measured parameter, for example, tissue temperature, cardiac
hemodynamics or ischemia. A beeping tone or flashing light may be
used to alert the surgeon that a change has occurred in the
parameter sensed.
[0127] In one embodiment of the invention, a sensor may comprise
one or more temperature-sensitive elements, such as a thermocouple,
to allow a surgeon to monitor temperature changes of a patient's
tissue. Alternatively, the sensor may sense and/or monitor voltage,
amperage, wattage and/or impedance. For example, an ECG sensor may
allow a surgeon to monitor the hemodynamics of a patient during a
valve replacement or valve repair procedure. The heart may become
hemodynamically compromised during positioning and while in a
non-physiological position. Alternatively, the sensor may be any
suitable blood gas sensor for measuring the concentration or
saturation of a gas in the blood or tissues. For example, the
sensor may be a sensor for measuring the concentration or
saturation of oxygen or carbon dioxide in the blood or tissues.
Alternatively, the sensor may be any suitable sensor for measuring
blood pressure or flow, for example a Doppler ultrasound sensor
system, or a sensor for measuring hematocrit (HCT) levels.
[0128] Alternatively, the sensor may be a biosensor, for example,
comprising an immobilized biocatalyst, enzyme, immunoglobulin,
bacterial, mammalian or plant tissue, cell and/or subcellular
fraction of a cell. For example, the tip of a biosensor may
comprise a mitochondrial fraction of a cell, thereby providing the
sensor with a specific biocatalytic activity.
[0129] In one embodiment of the invention, the sensor may be based
on potentiometric technology or fiber optic technology. For
example, the sensor may comprise a potentiometric or fiber optic
transducer. An optical sensor may be based on either an absorbance
or fluorescence measurement and may include an UV, a visible or an
IR light source.
[0130] A sensor may be used to detect naturally detectable
properties representative of one or more characteristics, e.g.,
chemical, physical, mechanical, thermal, electrical or
physiological, of a valve replacement system, a valve repair
system, and/or a patient's bodily tissues or fluids. For example,
naturally detectable properties of patient's bodily tissues or
fluids may include pH, fluid flow, electrical current, impedance,
temperature, pressure, tension, components of metabolic processes,
chemical concentrations, for example, the absence or presence of
specific peptides, proteins, enzymes, gases, ions, etc. Naturally
detectable properties may include, for example, pressure, tension,
stretch, fluid flow, electrical, mechanical, chemical and/or
thermal. For example, a sensor may be used to sense, monitor and/or
control suction or vacuum delivered from a suction source. A sensor
may be used to measure suction between a device and tissue. A
sensor may be used to sense, monitor and/or control fluid delivered
from a fluid source. A sensor may be used to sense, monitor and/or
control energy delivered from a power supply via a controller.
[0131] In one embodiment of the invention, a sensor may include one
or more imaging systems, camera systems operating in UV, visible,
or IR range; electrical sensors; voltage sensors; current sensors;
piezoelectric sensors; electromagnetic interference (EMI) sensors;
photographic plates, polymer-metal sensors; charge-coupled devices
(CCDs); photo diode arrays; chemical sensors, electrochemical
sensors; pressure sensors, vibration sensors, sound wave sensors;
magnetic sensors; UV light sensors; visible light sensors; IR light
sensors; radiation sensors; flow sensors; temperature sensors; or
any other appropriate or suitable sensor.
[0132] In one embodiment of the invention, one or more sensors may
be incorporated into a tissue-engaging device, a valve replacement
device, a valve repair device and/or an imaging device or one or
more sensors may be placed or used at a location differing from the
location of a tissue-engaging device, a valve replacement device, a
valve repair device and/or an imaging device. For example, a sensor
may be placed in contact with the inside surface or outside surface
of a patient's heart during a valve replacement procedure or valve
repair procedure.
[0133] In one embodiment of the invention, a tissue-engaging
device, a valve replacement device, a valve repair device, an
imaging device, a suction source, a fluid source, a drug delivery
device and/or a controller or processor may be slaved to one or
more sensors. For example, a tissue-engaging device may be designed
to automatically adjust suction if a sensor measures a
predetermined sensor value, e.g., a particular suction value.
[0134] In one embodiment of the invention, the sensor may include a
visual and/or audible signal used to alert a surgeon to any change
in the one or more characteristics the sensor is sensing and/or
monitoring. For example, a beeping tone or flashing light that
increases in frequency as tissue temperature rises may be used to
alert the surgeon.
[0135] In one embodiment of the invention, one or more devices may
be coupled to a controller, which may include one or more
processors. For example, a processor may receive and preferably
interpret a signal from one or more sensors. A processor may
comprise software and/or hardware. A processor may comprise fuzzy
logic. A suitable amplifier may amplify signals from one or more
sensors before reaching a processor. The amplifier may be
incorporated into a processor. Alternatively the amplifier may be
incorporated into a sensor, a tissue-engaging device, a valve
replacement device, a valve repair device, a suction source, a
fluid source, a drug delivery device, and/or an imaging device.
Alternatively, the amplifier may be a separate device. A processor
may be a device separate from a sensor, a tissue-engaging device, a
valve replacement device, a valve repair device, a suction source,
a fluid source, a drug delivery device, and/or an imaging device. A
processor may be incorporated into a sensor, a tissue-engaging
device, a valve replacement device, a valve repair device, a
suction source, a fluid source, a drug delivery device, and/or an
imaging device. A processor may control the energy delivered from a
power supply. For example, a signal of a first intensity from a
sensor may indicate that the energy level from a power supply
should be lowered; a signal of a different intensity may indicate
that the power supply should be turned off. For example, a
processor may be configured so that it may automatically raise or
lower the suction delivered to a device comprising suction, the
fluids delivered to a device comprising fluid delivery, the drugs
delivered to a device comprising drug delivery, energy delivered to
a device comprising energy delivery, e.g., from a power supply.
Alternatively, for example, the control of the suction source, the
fluid source, drug delivery source, the power supply based on
output from a processor may be manual.
[0136] In one embodiment of the invention, a controller may include
a visual display or monitor, such as, for example, a LCD or CRT
monitor, to display various amounts and types of information. By
software control, the user may choose to display the information in
a number of ways. The monitor may show, for example, a currently
sensed parameter, e.g., blood flow or blood-pressure or cardiac
contractions. The monitor may also lock and display the maximum
sensed value achieved. Sensed information may be displayed to the
user in any suitable manner, such as for example, displaying a
virtual representation of valve replacement device, a valve repair
device, an imaging device and/or tissue-engaging device on the
monitor. Alternatively, a monitor may display the voltage
corresponding to the signal emitted from a sensor. This signal may
correspond in turn to the intensity of a sensed parameter at the
target tissue site. Therefore a voltage level of 2 would indicate
that the tissue was, for example, hotter than when the voltage
level was 1. In this example, a user would monitor the voltage
level and, if it exceeded a certain value, would, for example, turn
off or adjust the power supply.
[0137] The display of a controller according to one embodiment of
the invention may be located on a valve replacement device, a valve
repair device, a power supply, a tissue-engaging device, a suction
source, a fluid source, a sensor and/or an imaging device. An
indicator, such as an LED light, may be permanently or removeably
incorporated into a valve replacement device, a valve repair
device, a power supply, a tissue-engaging device, a suction source,
a fluid source, a sensor and/or an imaging device. The indicator
may receive a signal from a sensor indicating that a measured
parameter has reached an appropriate value. In response, the
indicator may turn on, change color, grow brighter or change in any
suitable manner to indicate that the particular procedure should be
modified or halted. The indicator may also be located on a valve
replacement device, a valve repair device, a power supply, a
tissue-engaging device, a suction source, a fluid source, a sensor
and/or an imaging device and/or may be located on another location
visible to the user.
[0138] In one embodiment of the invention, the controller may
include an audio device that indicates to the user that the
delivery of suction, fluids and/or energy should be halted or
adjusted, for example. Such an audio device may be, for example, a
speaker that broadcasts a sound (for example, a beep) that
increases in intensity, frequency or tone as a parameter sensed by
a sensor increases. The user may adjust, for example, turn down or
turn off power supply when the sound emitted reaches a given volume
or level. In another embodiment, the audio device may also give an
audible signal (such as the message "turn off energy source"), for
example, when a parameter sensed by a sensor reaches a certain
level. Such an audio device may be located on a valve replacement
device, a valve repair device, a power supply, a tissue-engaging
device, a suction source, a fluid source, a sensor and/or an
imaging device, for example. In one embodiment of the invention,
the audio device may be a separate device.
[0139] In one embodiment of the invention, a valve replacement
device, a valve repair device, an imaging device, tissue-engaging
device, a nerve stimulation device, a cardiac stimulation device, a
suction, source, a fluid source, one or more sensors, a drug
delivery device, a guidance device and/or a controller may be
slaved to a robotic system or a robotic system may be slaved to a
valve replacement device, a valve repair device, an imaging device,
tissue-engaging device, a nerve stimulation device, a cardiac
stimulation device, a suction, source, a fluid source, one or more
sensors, a drug delivery device, a guidance device and/or a
controller. Computer- and voice-controlled robotic systems that
position and maneuver endoscopes and/or other surgical instruments
for performing microsurgical procedures through small incisions may
be used by the physician or surgeon to perform precise and delicate
maneuvers. These robotic systems may allow the surgeon to perform a
variety of microsurgical procedures. In general, robotic systems
may include head-mounted displays which integrate 3-D visualization
of surgical anatomy and related diagnostic and monitoring data,
miniature high resolution 2-D and 3-D digital cameras, a computer,
a high power light source and a standard video monitor.
[0140] A medical procedure, e.g., a valve repair procedure, a valve
replacement procedure, or a valve imaging procedure, of the present
invention may be non-invasive, minimally invasive and/or invasive.
The medical procedure may entail a port-access approach, a
partially or totally endoscopic approach, a sternotomy approach or
a thoracotomy approach. The medical procedure may include the use
of various robotic or imaging systems. The medical procedure may be
surgery on the heart. The medical procedure may be a valve
procedure. Alternatively, the medical procedure may be surgery
performed on another organ of the body.
[0141] In one embodiment of the present invention, a positioning or
tissue-engaging device may comprise one or more sensors and/or
electrodes, e.g., sensing electrodes and/or stimulation electrodes.
In another embodiment of the present invention, an imaging device
may comprise one or more sensors and/or electrodes, e.g., sensing
electrodes and/or stimulation electrodes. In another embodiment of
the present invention, a positioning or tissue-engaging device may
comprise imaging capabilities, e.g., ultrasound imaging, and one or
more sensors and/or electrodes, e.g., sensing electrodes and/or
stimulation electrodes.
[0142] In one embodiment of the present invention, a valve
replacement device or system or a valve repair device or system may
comprise one or more sensors and/or electrodes, e.g., sensing
electrodes and/or stimulation electrodes. In another embodiment of
the present invention, a valve replacement device or system or a
valve repair device or system may comprise imaging capabilities,
e.g., ultrasound imaging, and/or one or more electrodes, e.g.,
stimulation electrodes. In another embodiment of the present
invention, a valve replacement device or system or a valve repair
device or system may comprise tissue-positioning capabilities,
e.g., suction engagement of tissue. In one embodiment of the
invention, a valve replacement device or system or a valve repair
device or system may be guided or steerable.
[0143] In one embodiment of the present invention, devices,
systems, and methods that may be used for guidance of a medical
device, e.g., a valve replacement device or a valve repair device,
in a minimally invasive medical procedure, include electromagnetic
devices, systems and methods, electric field devices, systems and
methods, and ultrasound devices, systems and methods. Examples of
various tracking, monitoring, positioning, guiding and/or
navigating technologies are disclosed in U.S. Pat. Nos. 5,782,765;
6,190,395; 6,235,038; 6,379,302; 6,381,485; 6,402,762; 6,434,507;
6,474,341; 6,493,573; 6,636,757; 6,669,635; 6,701,179; 6,725,080,
the entire disclosures of which are incorporated herein by
reference.
[0144] A guidance device, system, and/or method that may be used
according to one embodiment of the invention include the use of
electrical fields, for example, electric fields passing in three
axes through a patient's body. In one embodiment, three pairs of
sensors, e.g., electrode patches, are positioned in electrical
contact with the patient's body. In one embodiment, one set of the
electrode patch sensors are oriented in each of the three axes,
side-to-side, front-to-back, and head-to-toe, e.g., electrode patch
sensors located on neck and thigh. A 40.1 KHz, 40.2 KHz, and 40.3
KHz signal is transmitted, for example, between each of the three
sets of electrode patch sensors, respectively. The three signals
transmitted between the electrode patch sensors, may be picked up
by sensors, e.g., electrodes, positioned on medical devices placed
within the patient's body, e.g., within the patient's
cardiovascular system or thoracic cavity. Sensor electrodes that
are in contact with electrically conductive tissue and/or fluids,
e.g., blood, may be monitored from outside of the body via the
three signals transmitted between the three pairs of electrode
patch sensors, since there will be a voltage drop across each of
the three inter-patch spaces within the body associated with
electrodes of the medical devices. The voltage drop may be used to
calculate the location of the monitored sensor electrode(s) in 3-D
space within the patient's body. One embodiment of an electric
field guidance device may track the position of up to 10 sensor
electrodes simultaneously. An electric field guidance device or
system may include a visual monitor or display to display electrode
locations or positions. For example, the monitored sensor
electrodes may be shown on a three axis coordinate grid on a
monitor or display. In one embodiment, the electric field guidance
device achieves the best accuracy when the electric field gradients
are uniform. Distortions to the electric fields may cause
inaccuracies in the rendered position of the electrodes. Electric
field distortions may be caused by air voids, for example, within
the thoracic cavity. Therefore, sensor electrodes that are being
tracked should maintain contact with conductive tissue and/or
fluids to have their positions monitored continuously, for example,
on the coordinate system.
[0145] A guidance device, system, and/or method may use one or more
imaging devices to acquire images, for example, previously acquired
ultrasound, CT, MRI, PET, fluoroscopy and/or echocardiography
images, to provide real-time medical device monitoring,
positioning, tracking and/or guidance. Previously acquired images
may be registered to the patient. For example, acquired images of
anatomical structures of the patient may be accurately registered
to the patient's anatomy in real-time. The guidance device or
system may then show, for example, on a visual monitor or display,
the locations or positions of the medical device sensors relative
to a previously acquired image or images, thereby providing
real-time monitoring, positioning, tracking and/or guidance of the
medical device or devices relative to an image or images of the
patient's anatomy.
[0146] A guidance device, system, and method that may be used
according to one embodiment of the invention include the use of a
magnetic field. In one embodiment, sensors comprising three small
coils are positioned and oriented in three different axes of a
medical device, e.g., a valve replacement device or system or a
valve repair device or system, and a sensor, e.g., an antenna pad,
is placed in contact with the patient's body, for example, the
antenna sensor pad is placed under the patient. The magnetic field
guidance device and method senses the 3-D location of the three
sensor coils of the medical device. The 3-D location of the sensor
coils may then be displayed or represented on a visual monitor or
display, for example, as shown on a three axis coordinate grid.
Again, the guidance device, system, and/or method may use one or
more imaging devices to acquire images to provide real-time medical
device monitoring, positioning, tracking and/or guidance. For
example, a device comprising sensor coils may be monitored as the
portion of the device comprising the sensor coils is moved around a
space, cavity or chamber, e.g., a cardiac chamber, within the
patient. The geometry of the space, cavity or chamber may then be
mapped and displayed, for example, on a visual monitor or display.
The accuracy of the geometric mapping of a space, cavity or chamber
is generally related to the number of data points collected or
monitored. A magnetic field guidance device or system is generally
not sensitive to air voids within the patient's body.
[0147] A guidance device and method that may be used according to
one embodiment of the invention includes the use of ultrasound. In
one embodiment, sensors comprising ultrasound transducers are
incorporated into a medical device, e.g., a valve replacement
device or system or a valve repair device or system. The ultrasound
transducer sensors of the medical device to be tracked emit
ultrasonic energy. The ultrasonic energy is then received by
ultrasonic transducer sensors on other devices within the patient's
body or in contact with the patient's body. The ultrasound guidance
device may then display the relative positions of one or more of
the ultrasound transducer sensors and renders images of the devices
incorporating the ultrasound transducer sensors. Again, the
guidance device, system, and/or method may use one or more imaging
devices to acquire images to provide real-time medical device
monitoring, positioning, tracking and/or guidance. The 3-D location
of the ultrasound transducer sensors may be displayed or
represented on a visual monitor or display, for example, as shown
on a three axis coordinate, grid layered onto a previously acquired
image. The ultrasound guidance device or system can be very
sensitive to air voids or differences in the speed of sound within
various types of tissues and/or fluids.
[0148] A guidance device, system, and method that may be used
according to one embodiment of the invention include the use of an
electromagnetic field transmitter that may be coupled to an image
intensifier of a fluoroscopic imaging device, e.g., a fluoroscope.
In one embodiment, the guidance device or system may transmit three
alternating magnetic fields that may be received by coils within
the field of interest. The electromagnetic field transmitter may
contain a matrix of small metal spheres that may be used to
normalize a fluoroscopic image. In one embodiment, fluoroscopic
images are acquired in one or more directional orientations using a
fluoroscopic imaging device or system. The acquired images are then
viewed by a physician who is then able to track and guide a medical
device within the field of interest. In one embodiment, each
medical device tracked and/or guided comprises at least one
receiving sensor coil that allows the medical device to which it is
attached to be tracked in 3D space with respect to the previously
acquired fluoroscopic image or images.
[0149] In embodiment of the present invention, previously acquired
images, e.g., images of a patient's thoracic cavity, acquired by
one or more imaging devices may be displayed while displaying
images and precise locations of one or more medical devices
inserted into the patient, e.g., the patient's thoracic cavity. The
medical devices may be hand held, manually controlled, remotely
controlled, e.g., by magnetic fields, and/or robotically
controlled. Each medical device that is to be tracked in real-time
comprises at least one sensor coil. In one embodiment,
electromagnetic navigation or guidance technology utilizes a system
that transmits three separate electromagnetic fields that are
sensed by a single sensor coil or multiple sensor coils mounted on
the medical device to be tracked. In one embodiment, each medical
device to be monitored and/or tracked in 3-D space requires at
least one sensor coil. Additional medical device sensor coils may
provide details regarding the shape and/or path of the medical
device, for example. The shape of a flexible and/or articulating
portion of a medical device may be provided via sensor coils
positioned on or within the flexible and/or articulating portion.
For example, an elongated flexible member of a medical device may
have multiple sensor coils positioned along its length. In one
embodiment, accurate registration of a previously acquired
anatomical image may be performed using surface fiducial
registration points as well as internal, implanted and/or
indwelling reference devices. The form of reference points required
to register the image to the true anatomy may depend on the
accuracy needed for the particular procedure and anatomy of
interest. In terms of information management to the physician or
surgeon, one embodiment of this invention couples visual imaging,
e.g., endoscopic imaging, with navigation or guidance through the
virtual anatomy.
[0150] One embodiment of the present invention involves first
imaging of the patient's area of interest, e.g., the patient's
thoracic cavity anatomy, using, for example, one or more plane
fluoroscopy, computed tomography (CT), magnetic resonance (MR)
imaging, and/or one or more plane 2-D or 3-D ultrasound imaging
prior to the procedure. The initial imaging may be carried out by
first placing fiduciary markers on specific points on or in the
patient's body. The fiduciary markers may be easily identified on
the images via use of one or more contrast agents or materials
identifiable to the particular imaging technique used. The
fiduciary markers may be attached to the skin, positioned
subcutaneously, implanted, positioned in the trachea, bronchi,
and/or esophagus, or may be inserted into the cardiovascular
system, for example. In one embodiment, a medical device, e.g., a
catheter or catheter-like device, having multiple sensor coils may
be placed through the venous system through the inferior vena cava
and/or superior vena cava and extended into various additional
portions of the right side of the heart, e.g., the right atrial
appendage, the coronary sinus, the right ventricle, the
inter-ventricular septum, the right ventricular apex, the right
ventricular outflow tract, and/or the pulmonary arteries. In one
embodiment, delivery to sites such as the pulmonary arteries may be
aided by the addition of a balloon positioned at or near the distal
end of the fiduciary marking device to make use of blood flow to
force the device downstream into the distal end of the right side
of the cardiovascular system and into one or more of the pulmonary
arteries. Additionally, such a fiduciary marking device may be
placed in the arterial side of the cardiovascular system, whereby
it may be introduced via an artery into the ascending aorta and
extended through the descending aorta (or into superior arterial
vessels) and into the aortic valve, the left ventricle, the
inter-ventricular septum, the left ventricular apex, the mitral
valve annulus, the left atrium, the left atrial appendage, and/or
the pulmonary veins. In one embodiment, on or more fiduciary
devices inserted into the esophagus and/or trachea may be used to
track in-real time respiration effects on the posterior aspects of
the heart. One or more reference sensor coils or marking points may
be incorporated into a tracheal tube used for a patient on a
respirator. One or more reference sensor coils or marking points
may be incorporated into an esophageal tube. An esophageal
reference may provide information of the location or position of
the esophagus during procedures.
[0151] In one embodiment, the guidance device or system may include
one or more fiducial marking and/or reference devices. The fiducial
marking and reference devices may be placed, for example, in and
around the heart, e.g., endocardially, epicardially and/or in the
pericardial space, to define the real-time precise location of the
heart's surfaces and structures. An imaging device may be used to
perform an imaging technique while one or more fiduciary marking
and reference devices are positioned at one or more locations.
Imaging may be performed with regard to respiration and/or cardiac
cycle of the patient, such that the motions associated with
respiration and/or the beating of the heart may be accounted for
during the timing of the acquisition of the images. Placement of
fiduciary marking and reference devices may be determined by the
physician according to the anatomy of interest where the highest
accuracy of the medical devices with respect to the anatomical
structures is required. Placements of fiduciary marking and
reference devices may be performed using fluoroscopy.
[0152] In one embodiment, the guidance device or system may be used
during a heart valve replacement or repair procedure. For example,
a pulmonic valve replacement procedure using a transvascular
approach may involve preliminary imaging with an imaging device,
wherein imaging is performed with skin surface fiduciary markers
and a fiduciary marking catheter device placed through the venous
system into the right ventricular outflow tract and to the site of
the pulmonic valve annulus. After the preliminary imaging is
complete and the patient is in the operating room, the pre-acquired
image is then registered to the patient using the surface fiduciary
markers as well as the internal catheter to provide high accuracy
in the region of critical interest at the pulmonic valve annulus.
The fiduciary catheter device may then be removed and a valve
delivery and deployment device may be advanced into the site of the
pulmonic valve for delivery and deployment of a replacement valve.
During valve delivery and deployment, a physician may use the image
guidance navigation device or system to view the real-time location
and advancement of the valve delivery and deployment device and to
view its motion through the cardiovascular system all the way to
the site of deployment at the pulmonic valve annulus, for
example.
[0153] In one embodiment, the guidance device or system may be used
during a minimally invasive procedure or a transcatheter procedure.
In one embodiment of the present invention, the procedure may be
performed from the right side of the patient or the left side of
the patient. One or more structures that may be of interest to a
physician or surgeon upon entry into a patient's thoracic cavity,
e.g., entry through a small incision or port access, may be the
location of the pericardial sac and associated structures such as
the phrenic nerve. Also of interest may be the location and courses
of the caval veins, i.e., the inferior and superior vena cava, the
pulmonary arteries, and/or the pulmonary veins. In one embodiment,
the caval veins and other structures may be registered to one or
more pre-acquired images using fiducial marking devices placed in
the venous cardiovascular system. In one embodiment, the
pericardial reflections that are located between the superior
pulmonary veins are separated. In this region, a surgeon must be
careful to avoid damage to the atrial walls, pulmonary veins, and
in particular, the pulmonary arteries. Therefore, it may be
advantageous to place a fiduciary marking device into one or more
of the pulmonary arteries to ensure precise registration of these
structures upon start of the procedure in the operating room. Such
precise location registration may greatly aid the surgeon in
performance of the dissections of these pericardial reflections. In
one embodiment, the location of the lung surface may be of
interest. In one embodiment, the tracking of the lung surface may
be performed via placement of one or more devices comprising one or
more tracking sensor coils on the surface of the lung. In one
embodiment, an imaging device, e.g., an endoscopic camera and/or
light guide, may be used to allow visual imaging of the surgical
site or sites. The imaging device may be used to produce one or
more images that may be displayed on a monitor. The one or more
images may be coupled with the visual display produced from a
guidance or navigation device or system. The imaging device may
comprise one or more sensor coils, thereby allowing at least a
portion of the imaging device to be tracked and/or guided in 3-D
space by the guidance or navigation device or system. The visual
display produced by the guidance device may be coupled in an
appropriate manner to the visual display produced by the imaging
device, thereby providing a physician with real-time monitoring of
the imaging device and, thereby providing additional information to
allow the physician to easily identify anatomical structures
located in the viewing area of the imaging device. In one
embodiment, imaging devices may be equipped with one or more sensor
coils of a guidance system, thereby allowing distal and proximal
portions to be identified easily. For example, flexible and/or
deflectable medical devices may require multiple sensors, e.g.,
sensor coils, to define the location and path of multiple portions
of the medical device, e.g., the proximal and distal portions of a
flexible and/or deflectable distal medical device.
[0154] In one embodiment, sensors may be incorporated in one or
more medical devices. A sensor may be attached or coupled directly
to the surface of a medical device. A sensor may be incorporated
into a medical device. A sensor may be incorporated into a
removable sheath, cover or insert that may be placed over or
inserted into at least a portion of a medical device. A removable
sensor sheath, cover or insert may be disposable or re-useable. A
sheath or cover may serve to protect one or more portions of a
medical device from one or more body fluids and/or tissues. A
sheath or cover may comprise one or more lumens that allow suction,
irrigation, and/or passage of guide-wires, catheters or similar
flexible, and/or polymeric devices through the sheath and into the
working region at the distal end of the medical device.
[0155] In one embodiment, the guidance device or system may be used
during a procedure of guiding, delivery and placement of a valve
bioprosthesis or guiding, delivery and repair of a valve. In one
embodiment, an imaging device or system may be used to acquire a
detailed CT or MRI scan of one or more cardiac structures, for
example, one or more valves. In one embodiment, an imaging device
or system may be used to acquire a detailed CT or MRI scan of one
or more arteries, for example, the carotid, brachiocephalic trunk,
subclavian, bronchial, phrenic, hepatic, cephalic trunk, splenic,
mesenteric, renal, lumbar, and iliac arteries. It can be important
to identify these branch arteries and their locations prior to a
particular medical procedure so as to not to occlude any of them
during the medical procedure. In one embodiment, the valve
replacement delivery device or valve repair delivery device may be
equipped with one or more sensor coils to allow precise tracking
and guidance of the delivery system through the aortic anatomy. A
previously acquired image may be critical in determining the
optimal valve placement or repair site.
[0156] In one embodiment of the invention, one or more images of a
patient's anatomy may be produced using one or more imaging device,
e.g., an x-ray device, a fluoroscopy device, a CT device, a MRI
device, a PET device and/or an ultrasound imaging device. These
images may be used in combination with tracked positions of one or
more medical devices placed in a patient. These medical devices,
e.g., a valve replacement device or a valve repair device, may be
tracked using one or more guidance devices comprising, for example,
one or more sensors. The medical devices may also comprise one or
more sensors. In one embodiment of the invention, a computer
generated display showing a medical device's position created by a
guidance device or system may be superimposed on a previously
acquired image or images produced by one or more imaging devices.
In one embodiment of the invention, a guidance device or system may
include one or more imaging devices. In one embodiment of the
invention, a guidance device or system may include a controller,
e.g., a controller as discussed above. In one embodiment of the
invention, a guidance device or system may include one or more
sensors, e.g., wherein the sensors are coupled to a controller. In
one embodiment of the invention, a guidance device or system may be
slaved to a robotic system or a robotic system may be slaved to a
guidance device or system.
[0157] In one embodiment of the invention, a method of real-time
image registration includes monitoring in real-time fixed surface
and indwelling fiduciary marking devices so as to update and
correct the registration of previously acquired images, e.g., x-ray
images, fluoroscopy images, CT images, MRI images, PET images
and/or ultrasound images, thereby providing real-time changes in
position of the anatomical structures of interest, e.g.,
respiration, cardiac motion, and intestinal peristalsis.
[0158] In one embodiment of the invention, a guidance device or
system may comprise an electrical sensor, a magnetic field sensor,
an optical sensor, an acoustic sensor and/or an inertial sensor. In
one embodiment of the invention, a guidance device or system may
comprise a magnetic field generator. In one embodiment of the
invention, a sensor coil may comprise an electrically conductive,
magnetically sensitive element that may be responsive to
time-varying magnetic fields for generating induced voltage signals
as a function of, and representative of, the applied time-varying
magnetic field.
[0159] One embodiment of the invention comprises a valve
replacement device or valve repair device and one or more sensors,
e.g., receiving sensor coils that allow electromagnetic tracking
and navigation in 3-D space of the location of one or more portions
of the devices. In one embodiment of the invention, the valve
replacement device is a valve replacement delivery device or
system. In one embodiment of the invention, the valve replacement
device is a replacement valve. In one embodiment of the invention,
the valve repair device is a valve repair delivery device or
system. In one embodiment of the invention, the valve repair device
is an implantable valve repair device. In one embodiment of the
invention, the valve replacement device or valve repair device is a
surgical device. In one embodiment of the invention, the valve
replacement device or valve repair device is a minimally invasive
device and/or an endoscopic device. In one embodiment of the
invention, the valve replacement device or valve repair device is a
transcatheter device. In one embodiment of the invention, the valve
replacement device or valve repair device comprises one or more
portions that are flexible, articulating, malleable and/or
rigid.
[0160] One embodiment of the invention includes one or more
fiduciary marking or reference devices that may be used to update
and correct the registration of previously acquired images, e.g.,
x-ray images, fluoroscopy images, CT images, MRI images, PET images
and/or ultrasound images, thereby providing real-time changes in
position of the anatomical structures of interest, e.g.,
respiration, cardiac motion, and intestinal peristalsis. In one
embodiment, a fiduciary marking or reference device is visualizable
and/or detectable by one or more means of non-invasive imaging such
as x-ray, fluoroscopy, computed tomography, magnetic resonance, PET
and/or ultrasound imaging. In one embodiment, the fiduciary marking
or reference device may include one or more sensors, e.g., sensor
coils, thereby allowing the device's location in 3-D space to be
easily determined and used as a reference and/or real-time
registration point or points for tracking, navigation and/or
guidance, e.g., electromagnetic tracking, navigation and/or
guidance, in 3-D space.
[0161] One embodiment of the invention includes a fiduciary
reference or marking device which may be fixed in location on or
within a patient's body via an adhesive, a tissue fixation screw,
helix, barb and/or hook, a suction source, an inflatable balloon,
an expandable structure, and/or via physical pressure.
[0162] One embodiment of the invention includes an esophageal
device that comprises one or more sensors, e.g., receiving sensor
coils, which allow determination of the location of the esophageal
device in 3-D space. One embodiment of the invention includes a
trans-esophageal device, e.g., a trans-esophageal imaging device
and/or a trans-esophageal stimulation device, which comprises one
or more sensors, e.g., receiving sensor coils, which allow
determination of the location of the trans-esophageal device in 3-D
space.
[0163] One embodiment of the invention includes a tracheal device
that comprises one or more sensors, e.g., receiving sensor coils,
which allow determination of the location of the tracheal device in
3-D space. One embodiment of the invention includes a
trans-tracheal device, e.g., a trans-tracheal imaging device and/or
a trans-tracheal stimulation device, which comprises one or more
sensors, e.g., receiving sensor coils, which allow determination of
the location of the trans-tracheal device in 3-D space.
[0164] One embodiment of the invention includes a vascular device
that comprises one or more sensors, e.g., receiving sensor coils,
which allow determination of the location of the vascular device in
3-D space. One embodiment of the invention includes a
trans-vascular device, e.g., a trans-vascular imaging device, a
trans-vascular stimulation device, a trans-vascular valve
replacement device and/or a trans-vascular valve repair device,
which comprises one or more sensors, e.g., receiving sensor coils,
which allow determination of the location of the trans-vascular
device in 3-D space.
[0165] One embodiment of the invention includes a guiding device,
e.g., a guiding catheter device, which comprises one or more
sensors, e.g., receiving sensor coils, which allow determination of
the location of the guiding device in 3-D space. One embodiment of
the invention includes a catheter-like insert device, which may be
inserted through the lumen of a larger catheter device, the
catheter-like insert device comprising one or more sensors, e.g.,
receiving sensor coils, which allow determination of the location
of the catheter-like insert device in 3-D space.
[0166] One embodiment of the invention includes a stimulation
device that comprises one or more sensors, e.g., receiving sensor
coils, which allow determination of the location of the stimulation
device in 3-D space. One embodiment of the invention includes a
nerve stimulation device, e.g., a vagal nerve stimulation device,
which comprises one or more sensors, e.g., receiving sensor coils,
which allow determination of the location of the nerve stimulation
device in 3-D space.
[0167] One embodiment of the present invention includes a
tissue-engaging device that comprises one or more sensors, e.g.,
receiving sensor coils, which allow determination of the location
of the tissue-engaging device in 3-D space. One embodiment of the
present invention includes a tissue dissection device, which
comprises one or more sensors, e.g., receiving sensor coils, which
allow determination of the location of the tissue dissection device
in 3-D space. One embodiment of the invention includes a tissue
retraction device, which comprises one or more sensors, e.g.,
receiving sensor coils, which allow determination of the location
of the tissue retraction device in 3-D space.
[0168] One embodiment of the invention includes a valve replacement
device or system that comprises one or more sensors, e.g.,
receiving sensor coils, which allow determination of the location
of the valve replacement device or system in 3-D space. One
embodiment of the invention includes a valve replacement delivery
device or system that comprises one or more sensors, e.g.,
receiving sensor coils, which allow determination of the location
of the valve replacement delivery device or system in 3-D
space.
[0169] One embodiment of the invention includes a valve repair
device or system that comprises one or more sensors, e.g.,
receiving sensor coils, which allow determination of the location
of the valve repair device or system in 3-D space. One embodiment
of the invention includes a valve repair delivery device or system
that comprises one or more sensors, e.g., receiving sensor coils,
which allow determination of the location of the valve repair
delivery device or system in 3-D space.
[0170] A medical procedure according to one embodiment of the
present invention may be a non-invasive, minimally invasive and/or
invasive procedure. In one embodiment, the medical procedure may
entail a port-access approach, a partially or totally endoscopic
approach, a sub-xyphoid approach, a sternotomy approach and/or a
thoracotomy approach. In one embodiment, the medical procedure may
entail a trans-vascular procedure, a percutaneous procedure and/or
a transcatheter procedure. The medical procedure may include the
use of various robotic, imaging systems, and/or guidance systems.
The medical procedure may be a procedure comprising the heart,
e.g., valve replacement and/or valve repair. Alternatively, the
medical procedure may be a procedure comprising another organ of
the body. The medical procedure may be a procedure comprising more
than one organ of the body. In one embodiment, on or more medical
devices of the present invention may be positioned and used, for
example, through a sternotomy, through a thoracotomy that avoids
the sternal splitting incision of conventional cardiac surgery,
through a mini-thoracotomy, through a sub-xyphoid incision,
percutaneously, transvenously, arthroscopically, endoscopically,
for example, through a percutaneous port, through a stab wound or
puncture, through a small or large incision, for example, in the
chest, in the groin, in the abdomen, in the neck or in the knee, or
in combinations thereof. In one embodiment, on or more medical
devices of the present invention may be guided into a desired
position using various imaging and/or guidance techniques as
described herein.
[0171] One embodiment of a method according to the present
invention is outlined in FIG. 13. An imaging device acquires one or
more images, as described herein, of a patient's anatomy of
interest at 610. Next an image guidance system comprising reference
markers, as described herein, is used to correlate the acquired
image(s) with the patient's anatomy at 620. A medical device, e.g.,
a valve replacement device or system and/or a valve repair device
or system, comprising one or more image guidance sensors is then
inserted into the patient at 630. The medical device is then guided
into a desired position, e.g., adjacent cardiac tissue, using the
image guidance system at 640. A medical procedure, e.g., a valve
replacement procedure or a valve repair procedure comprising the
replacement of a cardiac valve or repair of a cardiac, is performed
at 650. The medical device, or a portion thereof, is removed from
the patient at 660.
[0172] FIG. 14 shows a schematic view of one embodiment of a system
900 for replacing or repair one or more cardiac valves. In this
embodiment, system 900 is shown to comprise a valve replacement or
repair system 100, a tissue-engaging device 200, a suction source
300, a fluid source 400, a sensor 600 and an imaging device 800.
The valve replacement or repair system 100 may include a valve
replacement delivery device or system or a valve repair delivery
device or system. In one embodiment of the invention, the valve
replacement or repair delivery systems may comprise a power supply
and/or a controller. System 900 may also include a drug delivery
device, a guidance device, a nerve stimulation device and/or
cardiac stimulation device (all not shown in FIG. 14). The
tissue-engaging device may comprise one or more suction or vacuum
ports, openings, orifices, channels or elements positioned on,
along, within or adjacent a tissue contact surface. The suction
ports, openings, orifices, channels or elements may communicate
suction through the tissue contact surface to the atmosphere to
engage or grasp tissue via suction. In one embodiment of the
invention, the tissue-engaging device may be used to position,
manipulate, hold, grasp, immobilize and/or stabilize tissue in
accordance with the present invention. The drug delivery device may
be used to deliver drugs and/or biological agents to a patient. The
imaging device may be used to image or illuminate a tissue site.
The imaging and guidance devices may be used to help control and
guide one or more components of system 900 during a medical
procedure. In one embodiment of the invention, a valve replacement
device or system or a valve repair device or system may comprise a
tissue-engaging device.
[0173] The present invention has now been described with reference
to several embodiments thereof. The foregoing detailed description
and examples have been given for clarity of understanding only. No
unnecessary limitations are to be understood therefrom. It will be
apparent to those skilled in the art that many changes can be made
in the embodiments described without departing from the scope of
the invention. Thus, the scope of the present invention should not
be limited to the structures described herein. Further, it will be
appreciated by those skilled in the art that while the invention
has been described above in connection with particular embodiments
and examples, the invention is not necessarily so limited, and that
numerous other embodiments, examples, uses, modifications and
departures from the embodiments, examples and uses are intended to
be encompassed by the claims attached hereto. The entire disclosure
of each patent and publication cited herein is incorporated by
reference in its entirety, as if each such patent or publication
were individually incorporated by reference herein.
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