U.S. patent application number 12/767816 was filed with the patent office on 2010-11-04 for atherectomy system with imaging guidewire.
This patent application is currently assigned to ArioMedica Ltd.. Invention is credited to Arieh SHER.
Application Number | 20100280534 12/767816 |
Document ID | / |
Family ID | 32108025 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100280534 |
Kind Code |
A1 |
SHER; Arieh |
November 4, 2010 |
ATHERECTOMY SYSTEM WITH IMAGING GUIDEWIRE
Abstract
Systems and methods of increasing blood flow in a blood vessel
with intraluminal plaque. One disclosed method includes inserting
an imaging guidewire into the blood vessel to the intraluminal
plaque, propelling a catheter with a working head over the
guidewire towards the distal end of the guidewire, scanning with
the imaging guidewire to generate a cross-section image, radially
positioning the catheter using a positioning element, monitoring
the image to ascertain that the working head is properly positioned
and operating the working head to remove the plaque. A computerized
system designed, constructed and configured to perform the methods
is further disclosed
Inventors: |
SHER; Arieh; (Petach Tikva,
IL) |
Correspondence
Address: |
DR. MARK M. FRIEDMAN;C/O BILL POLKINGHORN - DISCOVERY DISPATCH
9003 FLORIN WAY
UPPER MARLBORO
MD
20772
US
|
Assignee: |
ArioMedica Ltd.
Tel Aviv
IL
|
Family ID: |
32108025 |
Appl. No.: |
12/767816 |
Filed: |
April 27, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10531184 |
Apr 11, 2005 |
7734332 |
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PCT/IL03/00807 |
Oct 8, 2003 |
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12767816 |
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60419087 |
Oct 18, 2002 |
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Current U.S.
Class: |
606/159 |
Current CPC
Class: |
A61B 2017/00685
20130101; A61B 2090/3614 20160201; A61B 5/0084 20130101; A61B
2017/22068 20130101; A61B 5/0066 20130101; A61B 2090/3784 20160201;
A61B 2017/003 20130101; A61B 17/320758 20130101; A61B 2017/22071
20130101; A61B 2017/22042 20130101; A61B 2017/00017 20130101; A61B
2034/107 20160201; A61B 2090/373 20160201; A61B 2090/3618
20160201 |
Class at
Publication: |
606/159 |
International
Class: |
A61B 17/22 20060101
A61B017/22 |
Claims
1. A method for reducing restriction of blood flow in a lumen of a
blood vessel caused by an intraluminal plaque therein, the method
comprising: (a) inserting an imaging guidewire into the lumen, said
imaging guidewire also being insertable in a plenum of a catheter
such that said catheter is slidable over said imaging guidewire,
said imaging guidewire having a distal tip that includes at least
an imaging sensor; (b) propelling said catheter over said imaging
guidewire towards said intraluminal plaque until said catheter
reaches said distal end of said guidewire, said catheter having a
working head located at a distal tip of said catheter, said working
head configured for removal of at least a portion of the
intraluminal plaque, said catheter and said working head deployed
on said imaging guidewire so as to accept passage of at least a
portion of said imaging guidewire axially through a central region
of said working head and said catheter as said catheter is
propelled towards said intraluminal plaque until said catheter
reaches said distal tip of said imaging guidewire, at least a
portion of said distal tip having a diameter that is larger than
said central region of said catheter; (c) scanning the lumen with
said imaging guidewire to generate said cross-sectional image of
the lumen; (d) positioning said catheter in the lumen by actuating
at least one positioning element; (e) monitoring said cross
sectional image to ascertain that said working head is positioned
at a desired location with respect to said proximal end of the
intraluminal plaque; and (f) operating said working head to remove
at least a portion of the intraluminal plaque.
2. The method of claim 1, further comprising repetition of (c)
through
3. The method of claim 2, iteratively repeated until the
restriction in the lumen has been reduced to a desired degree.
4. The method of claim 3, further comprising advancing the catheter
together with said distal tip of said guidewire in the lumen.
5. The method of claim 4, iteratively repeated until said working
head traverses said intraluminal plaque.
6. The method of claim 1, wherein said intraluminal plaque is of a
type selected from the group consisting of a primary
atherosclerotic lesion, a lesion caused by restenosis, a lesion
residing at least partially within a previously implanted stent, a
lesion situated in close proximity to a bifurcation of the lumen of
the blood vessel, a vulnerable plaque and a lesion which totally
occludes the lumen of the blood vessel.
7. The method of claim 1, wherein said working head includes at
least one cutting edge which is operative only when said working
head moves rotationally.
8. The method of claim 1, wherein said positioning of said catheter
in the lumen is implemented such that said at least one positioning
element includes at least one balloon which circumferentially
surrounds at least a portion of said catheter.
9. The method of claim 1, wherein said positioning of said catheter
in the lumen is implemented such that said at least one positioning
element includes at least one set of at least three balloons in a
single cross sectional plane of said catheter.
10. The method of claim 9, wherein said positioning of said
catheter in the lumen is implemented so as to further include at
least one additional set of at least three balloons in a single
cross sectional plane of said catheter.
11. The method of claim 1, wherein said inserting, propelling,
scanning, positioning, monitoring, operating are subject to control
by a single central processing unit (CPU).
12. The method of claim 11, wherein said single CPU is further
subject to input by a physician operator thereof.
13. The method of claim 1, wherein said operating said working head
begins prior to a traverse of the plaque by said working head.
14. The method of claim 1, wherein said operating of said working
head includes rotating said working head at a speed of 1 to 100
RPM.
15. The method of claim 1, wherein said operating of said working
head includes rotating said working head at a speed of 5 to 50
RPM.
16. A system for reducing restriction of flow in a lumen of a blood
vessel caused by an intraluminal plaque therein, the system
comprising: (a) an imaging guidewire insertable in the lumen, said
imaging guidewire also being insertable in a plenum of a catheter
such that said catheter is slidable over said imaging guidewire,
said imaging guidewire having a distal tip that includes at least
an imaging sensor; (b) said catheter including a working head
located at a distal tip, said working head designed and constructed
to remove at least a portion of the intraluminal plaque, said
working head deployed on said imaging guidewire so as to accept
passage of at least a portion of said imaging guidewire axially
through a central region of said working head and said catheter as
said catheter is propelled towards said intraluminal plaque until
said catheter reaches said distal tip of said imaging guidewire, at
least a portion of said distal tip having a diameter that is larger
than said central region of said catheter; (e) at least one
positioning element integrally formed with, or attached to, said
catheter, said at least one positioning element designed and
constructed to position said working head within the lumen of the
blood vessel; (d) a CPU designed and configured to: (i) accept
input from a physician; (ii) to receive said digital data which
describe said cross-sectional image of the lumen and transform said
digital data into said cross-sectional image displayable upon a
display device; (iii) operate actuators which control components of
the system; and (iv) control operation of said positioning element
by means of at least one of said actuators; and (e) one or more
actuators, subject to control by said CPU and including: (i) at
least one positioning element actuator responsible for the control
of said at least one positioning device.
17. The system of claim 16, wherein said CPU is further designed
and configured to perform at least one action selected from the
group consisting of: (i) to rotate said guidewire within said
catheter by means of said actuators; and (ii) control operation of
said working head.
18. The system of claim 16, wherein said CPU further includes at
least one item selected from the group consisting of a display
device and a data input device.
19. The system of claim 16, wherein said actuators further includes
at least one additional actuator designed and constructed to
perform at least one action selected from the group consisting of:
(i) longitudinally reciprocate and rotate said working head; (ii)
advance said catheter within the lumen; (iii) rotate said guidewire
within said catheter; wherein said actuators are subject to control
of said CPU.
20. The system of claim 16, wherein said working head is configured
to operate intermittently as said catheter traverses said
intraluminal plaque.
21. The system of claim 16, wherein said working head includes at
least one cutting edge which is operative only when said working
head moves rotationally.
22. The system of claim 16, wherein said at least one positioning
element includes at least one balloon which circumferentially
surrounds at least a portion of said catheter.
23. The system of claim 16, wherein said at least one positioning
element includes at least one set of at least three balloons in a
single cross sectional plane of said catheter.
24. The system of claim 23, further including at least one
additional set of at least three balloons in a single cross
sectional plane of said catheter.
25. The system of claim 16, wherein said working head is configured
such that operation of said working head begins prior to a traverse
of the plaque by said working head.
26. The system of claim 16, wherein operation of said working head
includes rotating said working head at a speed of 1 to 100 RPM.
27. The system of claim 16, wherein operation of said working head
includes rotating said working head at a speed of 5 to 50 RPM.
28. The system of claim 16, wherein said imaging guidewire further
includes a imaging sensor and wherein said catheter is positionable
upon said guidewire so that only said imaging sensor protrudes from
said working head in a direction facing the plaque.
29. The system of claim 16, wherein an Archimedes screw is further
incorporated into the design of said imaging guidewire in order to
facilitate removal of at least a portion of the plaque.
30. The system of claim 16, wherein said catheter includes at least
one therapeutic lumen.
31. The system of claim 16, wherein said catheter includes a
central vacuum lumen.
32. The system of claim 16, wherein said catheter and said
guidewire are configured to cross the lesion together by advancing
said catheter together with said distal tip of said guidewire in
the lumen.
33. A system for reducing restriction of flow in a lumen of a blood
vessel caused by an intraluminal plaque therein, the system
comprising: (a) an imaging guidewire insertable in the lumen, said
imaging guidewire also being insertable in a plenum of a catheter
such that said catheter is slidable over said imaging guidewire,
said imaging guidewire having a distal tip that includes at least
an imaging sensor, said imaging guidewire capable of generating
digital data which describe a cross-sectional image of the lumen
and communicating said digital data to a central processing unit
(CPU) and further capable of guiding a catheter to the intraluminal
plaque without traversing the plaque; (b) said catheter includes a
working head, said working head deployed on said imaging guidewire
so as to accept passage of at least a portion of said imaging
guidewire axially through a central region of said working head and
said catheter as said catheter is propelled over said imaging
guidewire until said working head reaches said distal tip of said
imaging guide wire; at least a portion of said distal tip having a
diameter that is larger than said central region of said catheter,
said working head designed and constructed to remove at least a
portion of the intraluminal plaque; and (c) at least one
positioning element integrally formed with, or attached to, said
catheter, said at least one positioning element designed and
constructed to radially position said working head within the lumen
of the blood vessel.
34. An imaging guidewire insertable in the lumen of a blood vessel,
the imaging guidewire also being insertable in a plenum of a
catheter such that the catheter is slidable over the imaging
guidewire, said imaging guidewire comprising: a distal tip that
includes at least an imaging sensor, at least a portion of said
distal tip having a diameter that is larger than the plenum of the
catheter.
35. The system of claim 34, wherein said at least a portion of said
distal tip having a diameter that is larger than the plenum of the
catheter is a preformed curved tip.
36. The system of claim 34, wherein said at least a portion of said
distal tip having a diameter that is larger than the plenum of the
catheter is a ring that is fixed to distal end of imaging
guidewire.
37. The system of claim 34, wherein said at least a portion of said
distal tip has a diameter of up to 800 microns, while the rest of
the guidewire has a diameter of up to 350 microns.
Description
[0001] This application is a continuation of, and claims priority
from, U.S. patent application Ser. No. 10/531,184 filed 11 Apr.
2005, which is National Phase of PCT/IL2003/00807 filed 8 Oct.
2003, which in turn claims priority from U.S. Provisional Patent
Application No. 60/419,087 filed 18 Oct. 2002.
FIELD AND BACKGROUND OF THE INVENTION
[0002] The present invention is directed to minimally invasive
surgical systems and methods of use thereof. More specifically, the
present invention is directed to computerized systems for operation
of atherectomy instruments and methods for intravascular surgery to
increase blood flow in a lumen of a blood vessel. The disclosures
of U.S. Pat. Nos. 5,350,390, 5,806,404 and 5,697,459, issued to
Sher, are incorporated herein by reference in their entirety.
[0003] Atherosclerosis is the principal cause of heart attacks,
stroke, gangrene and loss of function of extremities. It accounts
for approximately 50% of all mortalities in the USA, Europe and
Japan. Atherosclerosis is characterized by a build-up of fatty
deposits in the intimal layer of a patient's blood vessels. Very
often over time, what is initially deposited as relatively soft
cholesterol-rich atheromatous material hardens into a calcified
atherosclerotic plaque. Such atheromas restrict the flow of blood,
which results in chest pain or even in cases severe restriction, to
heart attack. Restriction of blood flow, which leads to heart
attack, is also explained by another mechanism known as vulnerable
plaque. It happens to people that do not have severely narrowed
arteries. In fact the vulnerable plaque may be buried inside the
artery wall and may not always bulge out and block the blood flow
through the artery. Inflammation combined with other stress e.g.,
high blood pressure can cause the covering over the plaque to crack
and bleed, spilling the contents of the vulnerable plaque into the
blood stream. Blood cells that recruit to the site of injury can
form a clot large enough to block the artery. It is of enormous
importance that the physician will have the capability of imaging
the lesion morphologically as well as the plaque composition. There
are imaging techniques that perform these tasks. The modalities of
imaging techniques will be detailed later.
[0004] The present therapeutic strategies for severe
atherosclerosis in coronary arteries rely on angioplasty procedures
(e.g., percutaneous trans-luminal coronary angioplasty (PTCA),
atherectomy devices, stent implantation, excimer laser angioplasty,
etc.), and coronary artery bypass surgery (CABG). Transluminal
angioplasty refers to a technique of dilating significantly blocked
arteries from inside, thus avoiding the need for much more
extensive surgical intervention (CABG).
[0005] Conceptually, atherectomy devices have the advantage of
positively removing the plaque. In the balloon (PTCA) and the stent
procedures the plaque is not removed but rather pushed towards the
blood vessel wall. Several kinds of atherectomy devices are
currently available but their performances have not stood up to the
expectations and will be discussed later. A major disadvantage of
the stent is that it causes in-stent restenosis, a phenomenon that
will be explained later. Stent implantation involves deployment of
a foreign body that evokes a reaction of the immune system. The
stent and the balloon have the advantage that the procedure is
relatively simple and easy to use.
[0006] Today the stent is the common procedure for clearing blocked
arteries (97% of more than 2 million procedures world wide).
Atherectomy devices are used only for specific procedures such as
debulking of calcified lesions where it is difficult to open the
lesion with the balloon.
[0007] To date none of the available techniques provides a total
safe and effective solution to blocked arteries. The problems that
still exist in clearing blocked arteries are described below:
[0008] Restenosis
[0009] Restenosis is re-occlusion of a peripheral or coronary
artery following trauma to the artery caused by efforts to clear an
occluded portion of the artery by angioplasty, such as, balloon
dilation, stent implantation, atherectomy or laser ablation
treatment. The rate of restenosis following treatment with these
angioplasty procedures is about 30-50% depending upon the vessel
location, lesion length and a number of other variables. Restenosis
occurs also in grafts that are used to bypass blocked arteries.
Restenosis results in significant morbidity and mortality and
frequently necessitates further interventions, such as repeat
angioplasty or coronary bypass surgery. Thus, there is a need for
methods and devices for preventing and/or treating restenosis.
Preferably, these methods and devices should be specific in their
effect, easy to administer, and effective in the long run with
minimal adverse side effects. The processes responsible for
restenosis are not completely understood.
[0010] One aspect of restenosis may be simply mechanical, caused by
the elastic rebound of the arterial wall. Another aspect of
restenosis is believed to be a natural healing reaction to the
injured arterial walls that were damaged by angioplasty procedures.
The final result of the complex steps of the healing process which
involve local inflammation is intimal hyperplasia, and migration
and proliferation of medial smooth muscle cells, until the artery
is again occluded.
[0011] The existing, FDA approved, atherectomy devices have shown a
high rate of restenosis (30-50%). Atherectomy devices have also
additional technical problems. The AtheroCath (Guidant) is complex
to use, is pushed across the lesion and offers inconsistent
results. It has a high rate of blood vessel perforation. The
Rotablator (Boston Scientific) is applicable only to moderate to
heavily calcified atherosclerotic plaque lesions. It does not cut
the plaque but rather pulverizes it while rotating at a very high
speed. This causes problem of heating the blood vessel and also to
the phenomenon known as No Reflow in which blood does not flow in
the vessel even though the lesion was opened.
[0012] In another type of atherectomy device, the cutting head does
not rotate. An example of this type of device is U.S. Pat. No.
5,409,454 to Fischell. In this type of device, the cutting head is
first pushed across the lesion and then pulled back. While pulled
back the cutting head shaves the atheroma. Pushing the catheter
across the lesion causes trauma to the blood vessel.
[0013] My U.S. Pat. No. 5,350,390 describes an atherectomy device
that addresses the trauma problem. However, my own earlier
teachings do not include the idea that removal of a lesion may
begin prior to transversal of the lesion by a guidewire. This
serious inherent disadvantage is addressed by the teachings of the
present invention, as will be detailed hereinbelow. In order to
differentiate the claimed invention from those earlier teachings,
the invention will be referred to hereinbelow as Apparatus for
Removal of Intraluminal Occlusions (ARIO)
[0014] In-Stent Restenosis
[0015] The mechanical aspects of restenosis have been successfully
addressed by the use of stents to prevent elastic rebound of the
vessel, thereby reducing the level of restenosis for many patients.
The stent, though, has created a new problem called in-stent
restenosis, namely the occurrence of excessive late intimal
hyperplasia due to excessive cell proliferation that can restrict
blood flow within the stent itself. In-stent restenosis occurs in
20-30% of stent procedures and in many cases CABG is required to
solve the problem.
[0016] Brachytherapy and drug coated stents are approaches aimed to
reduce in-stent restenosis. Brachytherapy provides only partial
solution to in-stent restenosis. The drug coated stents succeeded
in reducing in-stent restenosis from 20-30% to 5-9% but failed to
eliminate it. The drug-coated stent is a new procedure. In
follow-up tests, problems such as late incomplete apposition
emerged, however no long-term results are currently available.
[0017] Existing atherectomy devices such as the Rotablator and
AtheroCath were tested for clearing in-stent restenosis, but the
results were disappointing. ARIO, due to its mild mode of operation
is a suitable candidate for clearing in-stent restenosis.
[0018] Perforation--Coronary artery perforation is a rare but
important complication of percutaneous revascularization.
Perforation has been reported in lesions treated with PTCA and
Stents and at much higher rate in atherectomy devices. During PTCA
or stenting perforation may occur as a consequence of guidewire
advancement, balloon inflation or balloon rupture. Regardless of
the device, the risk of perforation is increased when complex
lesion is present (chronic total occlusion, vessel bifurcation,
severe tortuosity in artery). Clinically, coronary perforation is
associated with a high incidence of death.
[0019] Total Occlusions (TO) is a formidable obstacle for
physicians. Physicians cannot see the path for the guidewire
through the TO because the flow of the angiography contrast media
is stopped by the blockage. There is a higher risk of perforation
or damaging the vessel than with normal angioplasty. U.S. Pat. No.
6,228,076 to Winston is an example of controlling the path of the
guidewire across a lesion using OCT. Another example for TO
crossing is U.S. Pat. No. 6,120,516 to Selmon.
[0020] Bifurcation: Percutaneous coronary intervention (PCI) in
bifurcation lesions is challenging. It has lower procedural success
and high rates of restenosis compared with non-bifurcation PCI.
[0021] A great part of the problems described above can be solved
if the physician is provided with means for imaging the arteries.
An important and standard imaging modality is angiography. However,
angiography enables the physician to see only a general view of the
arteries, where the details of the plaque are not clear. Several
modalities that can give a detailed image of the plaque have been
suggested. These modalities allow the physician to visualize the
morphology as well as the composition of the plaque. Subsequently,
the physician can position the working head of the intraluminal
catheter at a desired location. This procedure could minimize
remarkably the risk of blood vessel perforation.
[0022] The imaging modalities can be classified in the following
hierarchical manner:
[0023] There are two types of blood vessel imaging techniques,
non-invasive and minimally invasive. The non-invasive modalities
include CT (X-ray Computer Tomography), MRJ (Magnetic Resonance
Imaging), ECBT
[0024] (Electron Beam Computer Tomography), etc. In current
non-invasive technology the resolution of the image is poor and
therefore this type of imaging can be used for a general view of
the arteries. The minimally invasive imaging can be divided into
two classes: The first incorporates an imaging sensor into or on
the catheter. This class is exemplified by U.S. Pat. No. 4,794,931
to Yock, which describes an atherectomy device with ultrasonic
imaging capabilities.
[0025] The second class incorporates a sensor into a guidewire. The
second class can be divided into two sub-classes. The first
sub-class produces a cross sectional image of the lumen e.g., IVUS
(Intravascular Ultrasound)--U.S. Pat. No. 6,459,921 to Belef, OCT
(Optical Coherence Tomography)--U.S. Pat. No. 6,445,939 to Swanson,
MRI (Magnetic Resonance Imaging)--U.S. Pat. No. 6,377,048 to Golan.
This sub-class is relevant to the present invention, as the
operation of the device is based on the fact that the physician can
see a cross sectional view of the lumen.
[0026] The second sub-class does not provide a cross sectional
image of the lumen. It provides other kind of information related
to the lumen e.g., No. 6,228,076 to Winston describes a system
which receives interferometric data from the tissue, etc.
[0027] Prior art describes a device that incorporates an imaging
guidewire that can produce a cross sectional view of the lumen into
an intravascular catheter. U.S. Pat. No. 5,938,609 to Pomeranz
describes an imaging guidewire with an ultrasound sensor. The
movable imaging guidewire includes a fixed guidewire tip attached
to its distal end. The movable imaging guidewire is first
positioned within the vascular system so that its fixed guidewire
tip extends beyond the stenosed region, and than the intravascular
catheter is inserted over the movable imaging guidewire. This mode
of operation renders it suitable for balloons procedures. The
disadvantages of this type of movable imaging guidewire are similar
to the standard guidewire, i.e., the mechanical requirements of
pushability and crossability are high. The operational disadvantage
is high risk of perforating the blood vessel or in case the
occlusion is too severe the guidewire cannot cross it.
SUMMARY OF THE INVENTION
[0028] The present invention is directed to improvements of ARIO.
The unique features of ARIO allow clearing of blocked arteries,
removing vulnerable plaque, clearing in-stent restenosis, opening
totally occluded arteries and removing plaque at bifurcation.
[0029] It is the object of the present invention to provide a
minimally invasive device for removing intraluminal occlusions in a
safe, gentle and controlled manner.
[0030] It is the object of the present invention to provide a
minimally invasive device that is guided by a non-crossing the
lesion imaging guidewire.
[0031] It is the object of the present invention to provide an
imaging guidewire that is not required to cross the lesion by
itself. It crosses the lesion together with the catheter. This
reduces the mechanical requirement of the guidewire. It also eases
the physician's work and reduces blood vessel trauma or
perforation.
[0032] It is another object of the present invention to provide an
atherectomy device that cuts atheroma in a gentle manner, thus
reducing restenosis.
[0033] Another object of the present invention is to provide an
atherectomy device that cuts and remove in-stent restenosis in a
gentle manner.
[0034] It is a further object of the present invention to provide
an atherectomy device that cuts the atheroma safely, reducing the
risk of artery perforation.
[0035] A still further object of the present invention is to
provide an atherectomy device that gives the physician a real time
artery cross-section image.
[0036] A still further object of the present invention is to
provide an atherectomy device which includes balloons for radially
positioning of the working head.
[0037] A still further object of the present invention is to
provide an atherectomy device that allows the physician to control
the longitudinal position and orientation of the working head.
[0038] A still further object of the present invention is to
provide an atherectomy device that allows the physician to control
the lumen's cross sectional area to be excised.
[0039] A still further object of the present invention is to
provide an atherectomy device that enables opening of total
occlusions.
[0040] A still further object of the present invention is to
provide an atherectomy device that enables removal of atheroma at
bifurcation.
[0041] A still further object of the present invention is to
provide an atherectomy device which includes means for aspirating
debris of the atheroma.
[0042] A still further object of the present invention is to
provide an atherectomy device which includes lumen for supplying
therapeutic liquid to the site of atheroma.
[0043] According to these and further objects of the present
invention, which will become apparent as the description thereof is
presented below; the present invention provides an atherectomy
device which includes:
[0044] A catheter assembly having a distal portion and adapted for
insertion into a patient, said catheter assembly including an
actuator and controller/computer unit; a piston located within the
distal portion of the catheter assembly and adapted for
simultaneous longitudinal and rotational movement therein, the
first piston including an endless wave-shaped groove defined in a
circumferential surface thereof; at least one ball retained for
revolving motion in a recess defined in an interior surface of the
distal portion of the catheter assembly, said ball projecting into
and received by said groove to force said piston to rotate about
its longitudinal axis in response to longitudinal movement of said
piston; A working head secured to said piston for simultaneous
longitudinal and rotational movement together with said piston;
positioning balloon located on the circumference of the catheter
distal end; and an imaging guidewire designed and constructed to
position an operative portion of a catheter before a plaque (i.e.
the guidewire does not traverse the plaque).
[0045] The imaging guidewire of this invention is unique in its
mode of operation and its construction. In prior art the imaging
guidewire that can produce a cross sectional image is required to
cross the lesion. This requirement is problematic. Treating more
calcified and/or longer lesions, pose higher risk of causing trauma
to the blood vessel or perforation. ARIO's mode of operation does
not require that the imaging guidewire will cross the lesion by
itself First, the physician inserts the imaging guidewire up to the
lesion and then slides the catheter over the imaging guidewire up
to the distal end of the imaging guidewire. Crossing the lesion is
done by the catheter together with the imaging guidewire. The
catheter advances slowly. The physician can see where he is heading
and can control the radial position of the catheter with the
positioning balloons, prior to operating the working head. This
procedure eases the physician's work and minimizes blood vessel
perforation.
[0046] In regard to the imaging guidewire technical
requirements:
[0047] ARIO's imaging guidewire must withstand the following
requirements:
[0048] 1) Steerability--to allow the physician to direct the
guidewire into the desired branch. A common solution is by
manufacturing the guidewire with a bend at its distal end.
[0049] 2) Flexibility--to allow easy advancement of the guidewire
in curved blood vessel.
[0050] 3) Torqueability--is needed because the distal tip of the
guidewire is rotated from its proximal end. However the fact that
ARIO's mode of operation does not require that the imaging
guidewire will cross the lesion by itself, markedly eases the
pushability (axial force) and crossability (shape of the distal
tip) requirements.
[0051] An additional technical advantage of the non-crossing the
lesion imaging guidewire lies in the fact that the distal tip can
be relatively large. This eases the incorporating of an imaging
sensor in the distal tip. For example the distal tip of this
invention can be 800 microns in diameter, while the rest of the
guidewire is 350 microns in diameter. The larger the diameter of
the sensor, the better is the image quality. Prior art teaches an
imaging guidewire that has a small diameter along its entirety.
U.S. Pat. No. 6,445,939 to Swanson describes an Optical Coherence
Tomography (OCT) imaging guidewire, that is 350 microns (0.014'')
in diameter along its entirety which results in reduced image
quality.
[0052] The present invention further provides a method of removing
intraluminal occlusions which includes the following steps: (a)
inserting an imaging guidewire into the blood vessel up to the
occlusion, without crossing the lesion; (b) sliding the catheter
over the imaging guidewire up to the distal end of the imaging
guidewire; (c) securing proximal end of imaging guidewire to
imaging guidewire motor; (d) connecting therapeutic infusion pump;
(e) connecting debris vacuum pump; (f) operating balloon pumps and
equally pressurizing the positioning balloons; (g) scanning the
blood vessel with the imaging system to produce a cross section
image of the blood vessel; (h) radially positioning the working
head in a desired location by non-equally pressurizing the
positioning balloons: (i) operating the working head; (j) repeating
steps (g) to (i) until the desired result is achieved; (k)
deflating positioning balloons; (I) advancing the catheter
distally; and (m) repeating steps (f) to (l) until the lesion is
crossed.
[0053] Thus, according to one aspect of the present invention there
is provided a method for reducing restriction of blood flow in a
lumen of a blood vessel caused by an intraluminal plaque therein.
The method includes: (a) inserting an imaging guidewire into the
lumen of the blood vessel to the intraluminal plaque, the imaging
guidewire capable of generating a cross-sectional image of the
lumen; (b) propelling a catheter including a working head over the
imaging guidewire towards the intraluminal plaque until the
catheter reaches the distal end of the guidewire; (c) scanning the
lumen with the imaging guidewire to generate the cross-sectional
image of the lumen; (d) radially positioning the catheter in the
lumen by actuating at least one positioning element; (e) monitoring
the cross sectional image to ascertain that the working head is
positioned at a desired location with respect to the proximal end
of the intraluminal plaque; and (f) operating the working head to
remove at least a portion of the intraluminal plaque.
[0054] According to another aspect of the present invention there
is provided a system for reducing restriction of flow in a lumen of
a blood vessel caused by an intraluminal plaque therein. The system
includes: (a) an imaging guidewire insertable in the lumen of the
blood vessel, the imaging guidewire capable of generating digital
data which describe a cross-sectional image of the lumen and
communicating the digital data to a central processing unit (CPU)
and further capable of guiding a catheter to the intraluminal
plaque without traversing the plaque; (b) the catheter including a
working head, the working head designed and constructed to remove
at least a portion of the intraluminal plaque; (c) at least one
positioning element integrally formed with, or attached to, the
catheter, the at least one positioning element designed and
constructed to radially position the working head within the lumen
of the blood vessel, (d) the CPU and (e) the actuators, subject to
control by the CPU and including: (i) at least one positioning
element actuator responsible for the control of the at least one
positioning device. The CPU is designed and configured to: (i)
accept input from a physician; (ii) to receive the digital data
which describe the cross-sectional image of the lumen and transform
the digital data into the cross-sectional image displayable upon a
display device; (iii) operate actuators which control components of
the system; (iv) control operation of the positioning element by
means of at least one of the actuators
[0055] According to further features in preferred embodiments of
the invention described below, the method further includes
iteratively repeating (c) through (f) until the restriction of the
lumen has been reduced to the desired degree.
[0056] According to still further features in the described
preferred embodiments the method further includes repetition of (e)
and (f).
[0057] According to still further features in the described
preferred embodiments the method further includes iteratively
repeated until the restriction of the blood flow in the lumen has
been reduced to the desired degree.
[0058] According to still further features in the described
preferred embodiments the method further includes advancing the
catheter in the lumen.
[0059] According to still further features in the described
preferred embodiments the method further includes iterative
repetition of at least some of the actions until the working head
traverses the intraluminal plaque.
[0060] According to still further features in the described
preferred embodiments the intraluminal plaque is of a type selected
from the group consisting of a primary atherosclerotic lesion, a
lesion caused by restenosis, a lesion residing at least partially
within a previously implanted stent, a lesion situated in close
proximity to a bifurcation of the lumen of the blood vessel, a
vulnerable plaque and a lesion which totally occludes the lumen of
the blood vessel.
[0061] According to still further features in the described
preferred embodiments the working head includes at least one
cutting edge which is operative only when the working head moves
rotationally.
[0062] According to still further features in the described
preferred embodiments the at least one positioning element includes
at least one balloon which circumferentially surrounds at least a
portion of the catheter.
[0063] According to still further features in the described
preferred embodiments the at least one positioning element includes
at least one set of at least three balloons in a single cross
sectional plane of the catheter.
[0064] According to still further features in the described
preferred embodiments the method further includes at least one
additional set of at least three balloons in a single cross
sectional plane of the catheter.
[0065] According to still further features in the described
preferred embodiments the inserting, propelling, scanning, radially
positioning, monitoring and operating are subject to control by a
single central processing unit (CPU).
[0066] According to still further features in the described
preferred embodiments the single computerized control unit is
further subject to input by a physician operator thereof.
[0067] According to still further features in the described
preferred embodiments the operating the working head begins prior
to a traversal of the plaque by the working head.
[0068] According to still further features in the described
preferred embodiments the operating of the working head includes
rotating the working bead at a speed of 1 to 100 RPM, more
preferably at a speed of 5 to 50 RPM, most preferably at
approximately 15 RPM.
[0069] According to still further features in the described
preferred embodiments the CPU is further designed and configured to
perform at least one action selected from the group consisting of:
(i) to rotate the guidewire within the catheter by means of the
actuators; and (ii) control operation of the working head.
[0070] According to still further features in the described
preferred embodiments the CPU further includes at least one item
selected from the group consisting of a display device and a data
input device.
[0071] According to still further features in the described
preferred embodiments the actuators further includes at least one
additional actuator designed and constructed to perform at least
one action selected from the group consisting of: (ii) rotate the
working bead; (iii) advance the catheter within the lumen; and (iv)
rotate the guidewire within the catheter. The actuators are subject
to control of the CPU.
[0072] According to still further features in the described
preferred embodiments the working head operates intermittently as
the catheter traverses the intraluminal plaque. Traversal is
preferably incremental.
[0073] According to still further features in the described
preferred embodiments the working head includes at least one
cutting edge which is operative only when the working head moves
rotationally.
[0074] The present invention successfully addresses the
shortcomings of the presently known configurations by providing
minimally invasive surgical systems and methods of use thereof
which permit traversal of a plaque via sequential removal of
portions thereof, each of the portions selected from a cross
sectional image made prior to the traversal.
[0075] Implementation of the method and system of the present
invention involves performing or completing selected tasks or steps
manually, automatically, or a combination thereof. Moreover,
according to actual instrumentation and equipment of preferred
embodiments of the method and system of the present invention,
several selected steps could be implemented by hardware or by
software on any operating system of any firmware or a combination
thereof. For example, as hardware, selected steps of the invention
could be implemented as a chip or a circuit. As software, selected
steps of the invention could be implemented as a plurality of
software instructions being executed by a computer using any
suitable operating system. In any case, selected steps of the
method and system of the invention could be described as being
performed by a data processor, such as a computing platform for
executing a plurality of instructions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0076] The invention is herein described, by way of example only,
with reference to the accompanying drawings. With specific
reference now to the drawings in detail, it is stressed that the
particulars shown are by way of example and for purposes of
illustrative discussion of the preferred embodiments of the present
invention only, and are presented in the cause of providing what is
believed to be the most useful and readily understood description
of the principles and conceptual aspects of the invention. In this
regard, no attempt is made to show structural details of the
invention in more detail than is necessary for a fundamental
understanding of the invention, the description taken with the
drawings making apparent to those skilled in the art how the
several forms of the invention may be embodied in practice.
Wherever possible, like reference numerals have been utilized to
identify common elements throughout the figures.
[0077] In the drawings:
[0078] FIG. 1 is a longitudinal sectional view of the distal unit
of ARIO according to one embodiment of the present invention.
[0079] FIG. 2 is a development into a plane view of the closed
wave-shaped groove employed in the present invention.
[0080] FIG. 3 is a cross sectional view taken along lines 3-3 of
FIG. 1.
[0081] FIG. 4a is a planar view of the working head of the present
invention
[0082] FIG. 4b is a cross sectional view taken along lines 4b-4b of
FIG. 4a.
[0083] FIG. 4c is an isometric view of the working head of the
present invention.
[0084] FIG. 5 is a view in longitudinal section of one alternative
embodiment of the distal end of the non-crossing the lesion imaging
guidewire of the present invention.
[0085] FIG. 6 is a view in longitudinal section of an alternative
embodiment of the working head of the present invention.
[0086] FIG. 7 is a diagrammatic illustration showing the way
In-Stent restenosis is removed from inside the stent according to
the present invention.
[0087] FIG. 8 is a diagrammatic illustration showing the way plaque
is removed from a blood vessel that has a diameter substantially
greater then ARIO's diameter, according to the present
invention.
[0088] FIG. 9 is a diagrammatic illustration showing the way plaque
located at bifurcation is removed, according to the present
invention.
[0089] FIG. 10 is view in longitudinal partial section of the
proximal end of ARIO of the present invention.
[0090] FIG. 11 is a detailed view in longitudinal section of the
0-ring region shown in FIG. 10.
[0091] FIG. 12 is a side view of ARIO's actuator of the present
invention.
[0092] FIG. 13 is a top view of ARIO's actuator of the present
invention.
[0093] FIG. 14 is a schematic drawing of the ARIO's
controller/computer unit of the present invention.
[0094] FIG. 15 is an isometric view of an imaging guidewire
according to one embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0095] The present invention is of surgical systems and methods of
use thereof which can be used to increase blood flow in a lumen of
a blood vessel in a way which minimizes the risk of damage to
surrounding portions of the vessel wall. Specifically, the present
invention can be used to provide improved computerized control for
operation of atherectomy instruments which results in improved
methods for intravascular surgery.
[0096] The principles and operation of methods and systems
according to the present invention may be better understood with
reference to the drawings and accompanying descriptions.
[0097] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments or of being practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting.
[0098] ARIO combines two main operational features. First, ARIO is
able to rotate a working head at a very low speed of rotation (less
than 100 RPM) and at high cutting moment. This is in contrast to
previously known devices such as AtheroCath.TM. and the
Rotablator.TM. that rotate at speeds of 190,000, and 2,000 RPM
respectively. Second, ARIO's working head is not forced through the
lesion prior to operation, but is rather slowly advanced by small
increments while cutting the plaque. This prevents stretching the
vessel and resultant damage. As a result of these features, minimal
trauma to the artery is incurred. This is of utmost importance as
medical research has shown that the rate of restenosis is
proportional to the trauma caused to the vessel during the
angioplasty procedure.
[0099] Thus, the present invention includes several improvements
and additions with respect to my own U.S. Pat. No. 5,350,590. The
main improvements and additions are:
[0100] 1) Incorporation of a non-crossing the lesion imaging
guidewire.
[0101] 2) Incorporation of positioning balloons.
[0102] 3) Replacing of the hydraulic power by a pushable shaft in
the manner described in my U.S. Pat. No. 5,806,404, FIG. 5.
[0103] 4) Alternative working head that has a cone shape.
[0104] 5) The pins that protrude in the closed wave-shaped groove
are replaced by balls.
[0105] 6) Alternative construction of the closed wave-shaped
groove.
[0106] For purposes of this specification and the accompanying
claims, the phrase "working head" should be construed in its
broadest possible sense. Thus a working head may include, but is
not limited to, a rotary cutting nose cone, an abrasive nose cone,
a laser energy delivering device, an ultrasound energy delivering
device, a heat delivering device, a blunt dissection device or a
blunt abrasive device. The structural interrelations between the
working head and the catheter may vary depending on the nature of
the working head, so long as effective guidance of the working head
to establish a path across the occlusion during its intermittent
operation is achievable.
[0107] It is expected that during the life of this patent many
relevant minimally invasive medical imaging techniques that can
generate a cross-sectional view of the blood vessel will be
developed and the scope of the terms "image" and "imaging" is
intended to include all such new technologies a priori.
[0108] The ARIO device comprises three main units: The distal unit,
the proximal unit, and two tubes that connect the distal and the
proximal units. ARIO is operated by an actuator that is controlled
by a controller/computer unit (CPU). There are two additional
components that are needed for ARIO's operation: The first is a
vacuum pump for removing atheroma debris and blood clots and the
second is a therapeutic liquid infusion pump. These components are
commercially available and one of ordinary skill in the art will
readily be able to incorporate the commercially available pumps
into the context of the present invention.
[0109] Referring now to the drawings, FIG. 1 illustrates a
longitudinal sectional view of the distal unit of ARM. It is shown
a blood vessel (21) that has atheroma (22). A pushable shaft (1)
moves back and forth, forcing the piston (2) to reciprocate
longitudinally in a cylinder (12). Balls (3) located in a closed
wave-shaped groove (4) are held in place by holder (10), and force
piston (2) to rotate. The connection of the pushable shaft (1) to
the piston (2) is via a bearing adapter (11) and spherical plain
bearing (5). Spherical plain bearing (5) decouples the pushable
shaft (1) from the rotation movement of the piston (2), i.e., the
pushable shaft (1) is not rotating during the operation. A working
head (6) is fixedly attached to the piston (2) thus performing a
combined longitudinal and unidirectional rotational motion. The
pushable shaft (1) is a flexible tube with enough axial stiffness
to push and pull piston (2). Pushable shaft (1) is located within
torque tube (13). Flexible tube (13) has enough torsion stiffness
to counter the moment created by the working head (6). The outside
diameter of pushable shaft (1) is PTFE coated in order to decrease
friction between it and torque tube (13).
[0110] The working head (6) contains several sharp edge openings
(7) through which the excised atheroma is forced into the cavity
(8). The debris is then removed from the blood vessel by suction of
a vacuum pump via the plenum (9). Torque tube (13) is connected to
cylinder (12). Three positioning balloons (14) are mounted on the
outer circumference of torque tube (13). Lumens (15) in the
circumference of the torque tube (13) enable inflating/deflating
the three positioning balloons (14). The role of the positioning
balloons will be explained in details in FIG. 3 and FIG. 7 to FIG.
9.
[0111] ARIO accommodates a non-crossing the lesion imaging
guidewire (16). Like a standard guidewire it has a body in the form
of an elongated flexible tubular member. The imaging guidewire (16)
has a proximal end and a distal end. Although imaging guidewire
(16) is shown in the drawings to be straight along the catheter,
when the imaging guidewire is outside the catheter its distal end
resembles a standard guide wire (i.e., its distal tip is bent to
allow for steerability).
[0112] The preferred imaging method used in this embodiment is
Optical Coherence Tomography (OCT). OCT uses infra red light waves
that reflect back from the vessel wall to produce a real time
computer processed images cross section. OCT in conjunction with
appropriate software can produce a 3 dimensional image of the blood
vessel. The resolution of the images can reach 10 microns.
[0113] The distal end of imaging guidewire (16) comprises a folding
mirror (17) that is optically coupled to a grin lens (18), and a
preformed curved tip transparent to light energy (20) that
encapsulates the folding mirror (17). In some embodiments of the
invention the folding mirror (17) and the grin lens (18) protrude
in front of the working head. In the preferred embodiment, shown in
FIG. 1, only folding mirror (17) protrudes in front of the working
head. This design minimizes the trauma to the blood vessel. It is
an important feature of the present invention that the angle
between folding mirror (17) and the catheter axis may vary, thus
enabling the image to be taken at cross sections distally or
proximally to the folding mirror (17). In the arrangement shown in
FIG. 1 the angle is 45 degrees and therefore the image is taken at
the section of the folding mirror (17). An optical fiber (19) is
optically coupled to the grin lens (18). The optical fiber (19)
extends, via a central lumen, all over the imaging guidewire (16)
up to the proximal end where it is coupled to an optical connector
(not shown in drawing). For understanding the function of these
elements the reader is referred to U.S. Pat. No. 6,445,939 to
Swanson.
[0114] In order to get an image of the circumference of the blood
vessel wall (21) the imaging guidewire (16) is rotated. The number
of revolutions of the imaging guidewire (16) is dictated by
technical requirements e.g., whether video or still images are
required. It is preferable that surface (27) of the working head
(6), where the imaging guidewire (16) slides, will be Teflon
coated. It is to be noted that while the image is taken, the
catheter is held in place by the positioning balloons (14). This
fact results in a better image.
[0115] It is clear that in order to accurately radially position
the catheter in the lumen by inflating/deflating the balloons (14)
the physician must know the relative orientation between the
folding mirror (17) and the balloons. This can be done either
mechanically or by software. For mechanical orientation the
proximal end of the imaging guidewire has a mechanical key (66),
shown in FIG. 15. The mechanical key (66) can be of various designs
e.g., it may have a "D" shape. Whatever the shape of "key" (66),
its function is to assure that when the imaging guidewire is
located inside the catheter there is a fixed orientation between
the folding mirror and the balloons.
[0116] Alternatively, orientation may be accomplished by software.
In this case the orientation of the folding mirror (17) in regard
to balloons (14) is arbitrary. The balloons are inflated
sequentially. Following each inflation, a cross sectional image of
the lumen is taken. By comparing the images the orientation of the
folding mirror to the balloons can be calculated.
[0117] The rotation of the imaging guidewire inside the catheter
can be exploited to facilitate the movement of the atheroma debris
towards the proximal end. This is in addition to the vacuum force
exerted on the debris. This goal may be achieved, for example, by
incorporating an Archimedes screw into the design of the imaging
guidewire. Archimedes screw (67) is shown in FIG. 1 and also in
FIG. 15. Archimedes screw may extend along the imaging guidewire or
only at a small part of the imaging guidewire. In FIG. 1 it is
shown a screw that extends from working head (6) to the bearing
adapter (H). Screw (67) expedites movement of plaque debris removed
by working head (6) in plenum (9) that is narrow.
[0118] Alternatively the imaging method can be any of the minimally
invasive modalities mentioned above e.g., Ultrasound. Ultrasound
produces images from back-scattered sounds of the vessel wall. The
general outer shape of the imaging guidewire will be the same as
for OCT, while the inner parts will be different. For understanding
the operation of an ultrasound imaging guidewire the reader is
referred to U.S. Pat. No. 5,095,911 to Pomeranz. It is important to
stress that the requirement that the imaging guidewire rotates
along its axis is not mandatory. Imaging guidewires that can
produce an image without rotation are known, e.g., U.S. Pat. No.
5,947,905 to Hadjicostis which describes an ultrasound transducer
where the signals are received from an array of sensors located all
around the circumference of the imaging guidewire.
[0119] FIG. 2 is a development into a plane view of the closed wave
shaped groove (4). The closed wave shaped groove (4) comprises
three types of sections. A positive slopped section (4a), a
negative sloped section (4b) and a parallel to catheter axis
section (4c). The end points of the positive slopped section (4a)
are located distally to the end points of the negative sloped
section (4b), at a distance that is the length of the parallel to
catheter axis section (4e). The parallel to axis section (4c) is
connecting the end points of the two sloped sections (4a and 4b).
It is the aim of the following discussion to show that the closed
wave shaped groove (4) transforms a reciprocating motion of piston
(2) into a combined reciprocating and uni-directional motion of
piston (2). Let's start with an arbitrary position of ball (3) in
the closed wave shaped groove (4). It is important to understand
that the ball (3) is fixed in the catheter while closed wave shaped
groove (4) slides over it. When distal piston (2) is pulled
proximally it also performs a clock-wise rotation when viewed from
proximal end. This motion continuous until end point (4a-1) reaches
the center of the ball (3). Then if the longitudinal motion of
piston (2) is changed i.e., it is pushed distally, end point (4b-1)
will reach the center of ball (3). This part does not result in
rotation of piston (2). However, if piston (2) continues to be
pushed distally the negative sloped section (4b) will slide over
ball (3) causing piston (2) also to perform a clock-wise rotation
when viewed from proximal end. This motion will continue until end
point (4b-2) reaches the center of ball (3). The above discussion
can be repeated for other apexes of the closed wave shaped groove
(4). Thus, it was shown that the closed wave shaped groove (4)
transforms a reciprocating motion of piston (3) into a combined
reciprocating and uni-directional rotational motion of piston
(3).
[0120] In order to cause piston (2) to rotate in the opposite
direction, (i.e. counter-clock-wise rotation, when viewed from
proximal end), the end points of the positive slopped section (4a)
must be located proximally to the end points of the negative sloped
section (4b), at a distance that is the length of the parallel to
catheter axis section (4c).
[0121] The stroke of the closed wave-shaped groove can vary. For
example, in the device shown in FIG. 1, which is a scaled drawing
of ARIO 2.3 mm(=7 F) the stroke is 2 mm.
[0122] FIG. 3 shows the operation of the positioning balloons (14).
The position of the catheter is a resultant of the forces applied
by the three positioning balloons (14) on the lumen's wall. If the
balloons are inflated by unequal pressures the catheter will move
off axis. In the drawing positioning balloon (14a) is inflated more
then positioning balloons (14b) and (14c). Therefore, the catheter
will move downwards. Positioning balloons (14a-c) can be replaced
by other positioning elements such as mechanical arms that are
located on the outer circumference of the catheter and are pushed
during deployment against the lumen's wall. Also, are shown the
lumens (15) one for each of the positioning balloons (14). An
additional therapeutic lumen (26) is used for injection of
therapeutic liquid to the area of the excised atheroma. The
therapeutic lumen may also serve additional purposes. For example,
it has been observed that there is a substantial attenuation in the
imaging signal resulting from the presence of blood. In order to
overcome this problem injection of saline at the place of imaging
is required. The therapeutic lumen can serve this purpose.
Alternatively, the saline can be injected via an additional lumen
or via the imaging guidewire itself.
[0123] It is to be noted that the three positioning balloons (14)
are connected to a control system (located outside the patient's
body) that measures and regulates the pressure in each of the
positioning balloons (14). The control system assures that the
pressure in any of the positioning balloons (14) will not rise
above a predetermined threshold pressure (e.g., 4 atmospheres).
This is an important feature as it eliminates stressing of the
vessel walls. Balloons can be manufactured from different materials
(PET, latex, silicon etc.). It is preferred to use low pressure
elastomeric balloons, typically made of latex or silicone that
stretch 100-600% when pressure is applied, and return to their
original size when pressure is released.
[0124] An additional embodiment comprises a single positioning
balloon 14. In this case the catheter will always be positioned on
the longitudinal axis of the lumen. However, this embodiment limits
the operation of ARIO. A disadvantage of using one positioning
balloon is that blood cannot flow in the artery when the balloon is
inflated, thus causing pain to the patient. In the case of three or
more balloons, blood can always flow via the gaps between the
balloons. FIGS. 7 to 9 show the operational advantages of using
multiple positioning balloons (14).
[0125] FIGS. 4a, 4b and 4c show the cone shaped working head (6).
It can have one or more openings (7) with sharp edges (25). The
pictured embodiment shows five openings (7). It is the goal of this
design to have a cutter that is safely inserted in the blood vessel
in spite of having very sharp edges. Openings (7) are very narrow,
so that debris of the excised atheroma that enters cavity (8; see
FIG. 1) cannot go outside of working head (6) into the blood
vessel. The opening (7) is manufactured with a cutter (e.g., laser
cutter). Sharp edges (25) are created if the cutter is positioned
so that it cuts perpendicular to a plane passing through the cutter
(6) axis and the cutting pass (7a) is parallel to the contour line
of the cone. When looking on the working head (6) axially towards
the proximal direction, the sharp edges (25) are not seen. This
means that if the working head (6) comes in contact with the
vessel's wall, the wall touches a smooth surface, rather than the
sharp edges. This permits safe insertion of the device into the
blood vessel. The cutting of the atheroma is possible only when
working head (6) rotates.
[0126] FIG. 5 shows an imaging guidewire (16) that has the same
diameter (e.g., 350 microns) along its entire length. This small
diameter guidewire includes a small diameter lens (18), as
described in U.S. Pat. No. 6,445,939 to Swanson. This construction
allows only a small part of the imaging guidewire (16) to protrude
in front of working head (6). This minimizes the trauma to the
blood vessel. The part that protrudes includes folding mirror (17)
that is located in preformed curved tip transparent to light energy
(20). Also are shown lens (18) and optical fiber (19). Imaging
guidewire (16) rotates on a sliding surface (27). A ring (28) is
fixed to distal end of imaging guidewire (16), thus preventing
imaging guidewire (16) from being pulled back beyond sliding
surface (27).
[0127] FIG. 6 shows an alternative embodiment of the working head
(6). The working head (6) has opening (7) on its distal surface.
The distal end of imaging guidewire (16) is substantially bigger
then its other parts. In order to reduce the part of the imaging
guidewire (16) that extends in front of working head (6) a recess
(29) is done in the front face of working head (6). This
construction minimizes the trauma to the blood vessel. The part
that protrudes out of working head (6) front face includes only
folding mirror (17) that is located in preformed curved tip
transparent to light energy (20). Imaging guidewire (16) rotates on
a sliding surface (27). Also are shown lens (18) and optical fiber
(19). This embodiment has advantages when used for clearing total
occlusions (22).
[0128] FIG. 7 shows the struts of a stent (30) that is deployed off
blood vessel axis. This phenomenon can happen either during the
deployment of the stent or subsequently. In order to excise the
in-stent Restenosis (31), without damaging the stent (30), the
catheter (32) must be positioned on the stent axis rather then on
the blood vessel axis. The radial positioning is achieved by
positioning balloons (14).
[0129] FIG. 8 shows a catheter (32) that has a diameter that is
significantly smaller than the diameter of the blood vessel. In
minimally invasive procedures it is preferred to use a small
diameter catheter (e.g., no more then 2.3 mm=7 F), so that only a
small incision in the groin is needed to introduce the catheter
(32). Nonetheless, this small diameter catheter (32) must remove
the atheroma that may completely traverse the cross section of the
blood vessel (21). The positioning balloons enable the physician to
move the catheter radially all over the cross section of the blood
vessel. The physician can define an imaginary border line (33) in
which he wants the atheroma to be removed. The border line (33)
diameter is smaller then the inside diameter of the blood vessel
(21), thus reducing the risk of blood vessel perforation. It is
clear, from geometric considerations, that initial atheroma (22)
can never be totally removed in this procedure. Two sequential
positions of the catheter (32) and (32a) are shown in the drawing.
Some protrusion of atheroma (22a) will always be left. The
protrusion (22a) can be defined by its height, as shown in the
drawing. In order to make the protrusion height smaller, and thus
making the inner surface of blood vessel (21) smoother, more
sequential catheter positioning with closer distances between their
centers must be done. The sequential radial positioning of the
catheter can be done either manually or automatically.
[0130] FIG. 9 shows how positioning balloons (14) are used to
remove atheroma (22) at bifurcation. In this case the positioning
balloons are used to position the catheter (32) not only off axis
but also at an angle to the axis of the blood vessel (21). This can
be done if an additional array of 3 positioning balloons (14d, 14e,
14f) (14f is not shown in drawing) is added along the catheter
(32). If positioning balloon (14a) is inflated more than
positioning balloon (14d), catheter (32) will be forced to move
towards the atheroma (22). Although my U.S. Pat. No. 5,697,459
shows a similar arrangement of 6 balloons, their main purpose is to
enable the drill to be self propelled. Therefore, that earlier work
depicts 3 balloons located on the device body and 3 other balloons
located on the working head. According to the present invention
(ARIO) all the positioning balloons are all located on the catheter
body.
[0131] FIG. 10 shows the proximal end of ARIO. The distal end of
ARIO is shown for reference only. It shows a proximal piston (35)
that moves back and forth in a proximal cylinder (36). The stroke
of this movement corresponds to stroke of the closed wave-shaped
groove (4) shown in FIGS. 1 and 2. The velocity of proximal piston
(35) can be very low. In the preferred embodiment it is 1 mm/sec.
This velocity is transformed at the distal end of ARIO to 15 RPM of
the working head (6).
[0132] Proximal cylinder (36) is fixedly attached to torque tube
(13). An infusion connector (37) is mounted on proximal cylinder
(36). Infusion connector (37) is opened to therapeutic lumen (26;
see FIG. 3). An infusion pump is connected to the infusion
connector (37) to deliver therapeutic liquid, via therapeutic lumen
(26; see FIG. 3), to the site of the atheroma. Infusion pumps
suited for use in the context of the present invention are
commercially available. One of ordinary skill in the art will be
easily able to incorporate such a commercially available device
into the present invention. Three balloon connectors (38) (for
clarity only one is shown) are connected to proximal cylinder (36).
Balloon connectors (38) are opened to balloon lumen (15; see FIG.
3). Proximal cylinder (36) includes a groove (39) on its
circumference. Groove (39) is used to mount proximal cylinder (36)
on ARIO actuator (It is explained in FIG. 12 and FIG. 13).
[0133] Proximal piston (35) is fixedly attached to pushable shaft
(1). A vacuum connector (40) is mounted on proximal piston (35).
Vacuum connector (40) is opened to passage (41) that is connected
to plenum (9) shown in FIG. 1. A vacuum pump (not shown here) is
connected to vacuum connector (40) for aspirating the atheroma
debris via passage (41) and plenum (9) (see FIG. 1). Proximal
piston (35) includes a groove (42) on its circumference. Groove
(42) is used to mount proximal piston (35) on ARIO actuator. (It is
explained in FIG. 12 and FIG. 13). An imaging guidewire nut (43) is
attached to the proximal end of proximal piston (35).
[0134] FIG. 11 is an enlargement of detail 11 shown in FIG. 10.
Imaging guidewire nut (43) has a central passage (44) through which
imaging guidewire (16) passes. When imaging guidewire nut (43) is
tightened it squeezes on an O-ring (45) thus keeping the proximal
piston passage (41) vacuum tight. O-ring (45) allows imaging
guidewire (16) to rotate, while keeping the vacuum tight. The
rotation of imaging guidewire (16) is needed for the imaging
process.
[0135] FIGS. 12 and 13 describe ARIO's actuator. FIG. 12 is a side
view of the actuator and FIG. 13 is a top view of the actuator. A
base (48) is fixed to the patient bed. A linear slide (49) is
attached to an advancement linear actuator (50). Both are mounted
on base (48). They serve for advancing ARM in the blood vessel. The
advancement is incremental with a movement that is preferably less
then the stroke of the closed wave-shaped groove (4) (see FIG. 2).
A bracket (51) is mounted on top of linear slide (49). Groove (39)
of proximal cylinder (36) (see FIG. 10) fits into bracket (51) and
secured in place by clamp (52). Linear slide (54) is attached to a
reciprocating linear actuator (55). Both are mounted on bracket
(51). An adapter (60) is mounted on top of linear slide (54).
Groove (42) of proximal piston (35) (see FIG. 10) fits into adapter
(60) and secured in place by clamp (53). Back and forth motion of
reciprocating linear actuator (55) causes reciprocation of proximal
piston (35) and pushable shaft (1) and eventually results in
longitudinal and rotational movement of working head (6) (see FIG.
1).
[0136] FIG. 13 also depicts a balloon inflating/deflating system.
It comprises a syringe pump (56) that is connected to balloon
connector (38) (see FIG. 10). Syringe pump (56) is operated by
balloon linear actuator (58). A pressure transducer (57) measures
the pressure in syringe pump (56). This pressure is monitored by a
controller/computer unit (see FIG. 14 and explanation hereinbelow).
For clarity, only one balloon inflating/deflating system is shown,
but the actual system may, for example, contain three or six
balloons which are independently regulated.
[0137] ARIO's actuator comprises also an imaging guidewire motor
(59). The imaging guidewire (16) is secured to motor (59). In order
to take a circumferential scan of the artery the imaging guidewire
must rotate. This is done by imaging guidewire motor (59). The
signals of the scanning are sent to the computer via optical fiber
(19).
[0138] FIG. 14 is a schematic drawing of ARIO's control system. It
comprises a controller/computer unit (63) and a display (64). The
controller/computer unit (63) governs all the functions of the
system. The inputs to the controller/computer unit are: a) balloon
pressure b) imaging data c) physician inputs: advancement velocity,
reciprocation velocity, maximum balloon pressure, balloon
positioning, cutting border line (33) (see FIG. 8). The outputs
from the controller/computer unit (63) are directed to: a)
advancement linear actuator (50); b) reciprocating linear actuator
(55); c) imaging guidewire motor (59); d) balloon linear actuator
(58) and e) processed optical image of the blood vessel to the
display. The controller/computer unit (63) controls the movement of
balloon linear actuator (58) in such a way that while one of the
positioning balloons (14) moves in a desired direction, the
pressure in the other positioning balloons does not exceed a
predetermined threshold pressure (e.g., 4 Atmospheres). During the
operation the physician sees a real time cross sectional images of
the blood vessel. It is clear that the computer can construct a 3
dimensional image from the cross sections. The physician can see
the atheroma in 3 dimensional image before and after operation. He
can find out how much volume of atheroma was removed, calculate the
surface roughness after the operation etc.
[0139] The operation of ARIO can be done automatically from the
step that ARIO is positioned proximally to the lesion. However, the
physician can always take control of the operation. Physician
control may be either by direct physical manipulation of components
of the system, or via input to the CPU.
[0140] The system further includes safety provisions, e.g., the
electrical current of the advancement linear actuator (50) is
limited so that no excessive force is applied on the blood vessel
during advancement. The same applies to reciprocating linear
actuator (55), so that the moment applied by working head is
limited etc. The physician will be notified visually and/or audibly
of any problem in the system.
[0141] FIG. 15 illustrates clearly an imaging guidewire (16) with a
mechanical key (66) and Archimedes screw (67). These features are
illustrated within catheter (32) in FIG. 1, described
hereinabove.
[0142] It is appreciated that certain features of the invention,
which are, for clarity, described in the context of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention, which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable
subcombination.
[0143] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims. All
publications, patents and patent applications mentioned in this
specification are herein incorporated in their entirety by
reference into the specification, to the same extent as if each
individual publication, patent or patent application was
specifically and individually indicated to be incorporated herein
by reference. In addition, citation or identification of any
reference in this application shall not be construed as an
admission that such reference is available as prior art to the
present invention.
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