U.S. patent application number 11/959158 was filed with the patent office on 2008-07-31 for systems and methods for unobstructed visualization and ablation.
This patent application is currently assigned to Voyage Medical, Inc.. Invention is credited to Ruey-Feng Peh, Chris A. Rothe, Vahid Saadat, Edmund Tam.
Application Number | 20080183036 11/959158 |
Document ID | / |
Family ID | 39668755 |
Filed Date | 2008-07-31 |
United States Patent
Application |
20080183036 |
Kind Code |
A1 |
Saadat; Vahid ; et
al. |
July 31, 2008 |
SYSTEMS AND METHODS FOR UNOBSTRUCTED VISUALIZATION AND ABLATION
Abstract
Systems and methods for unobstructed, visualization and
ablation, particularly of the pulmonary veins, are described
herein. Such a system may include a deployment catheter and an
attached imaging hood deployable into an expanded configuration as
well as one or more expandable anchors which are temporarily
securable within a respective pulmonary vein while allowing blood
flow to pass through the anchor unimpeded. With the one or more
non-impeding anchors secured within a respective pulmonary vein,
ablation of the tissue surrounding the ostium or several ostia may
be effected with the catheter while the tissue is under direct
visualization.
Inventors: |
Saadat; Vahid; (Saratoga,
CA) ; Rothe; Chris A.; (San Mateo, CA) ; Peh;
Ruey-Feng; (Mountain View, CA) ; Tam; Edmund;
(Mountain View, CA) |
Correspondence
Address: |
LEVINE BAGADE HAN LLP
2483 EAST BAYSHORE ROAD, SUITE 100
PALO ALTO
CA
94303
US
|
Assignee: |
Voyage Medical, Inc.
Campbell
CA
|
Family ID: |
39668755 |
Appl. No.: |
11/959158 |
Filed: |
December 18, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60870598 |
Dec 18, 2006 |
|
|
|
Current U.S.
Class: |
600/104 ;
606/41 |
Current CPC
Class: |
A61B 17/12136 20130101;
A61B 17/12172 20130101; A61B 18/1492 20130101; A61B 1/3137
20130101; A61B 2018/00577 20130101; A61B 1/005 20130101; A61B
1/00089 20130101; A61B 1/018 20130101; A61B 17/12036 20130101; A61B
2018/00982 20130101; A61B 1/00085 20130101; A61B 17/12022 20130101;
A61B 17/1204 20130101; A61B 2018/00357 20130101 |
Class at
Publication: |
600/104 ;
606/41 |
International
Class: |
A61B 1/005 20060101
A61B001/005; A61B 18/14 20060101 A61B018/14 |
Claims
1. An apparatus for treating tissue surrounding a vessel opening,
comprising: a deployment catheter defining at least one lumen
therethrough; a barrier or membrane projecting distally from the
deployment catheter and defining an open area therein, wherein the
open area is in fluid communication with the at least one lumen; an
anchor having a low-profile shape and an expanded shape, wherein
the anchor is sized to be secured at least partially within a
vessel lumen in the expanded shape such that blood flows
unobstructed through or past the expanded shape; and an anchor
member extending from the anchor and through the catheter wherein a
distance of the member between the anchor and the barrier or
membrane is adjustable such that the barrier or membrane is
positionable directly upon the tissue surrounding the vessel
opening.
2. The apparatus of claim 1 further comprising a visualization
element disposed within or along the barrier or membrane for
visualizing tissue adjacent to the open area when the open area is
purged of blood via a transparent fluid.
3. The apparatus of claim 1 further comprising an ablation probe
positionable within the open area of the barrier or membrane.
4. The apparatus of claim 1 further comprising an anchor sheath for
constraining the anchor in its low-profile shape.
5. The apparatus of claim 1 wherein the anchor has a helical
configuration.
6. The apparatus of claim 1 wherein the anchor has a basket
configuration.
7. The apparatus of claim 1 wherein the anchor has a meshed
configuration.
8. The apparatus of claim 1 wherein the anchor comprises a
plurality of balloon members which are offset relative to one
another along an inflation lumen.
9. The apparatus of claim 1 wherein the anchor member extends
through the open area within the barrier or membrane.
10. The apparatus of claim 1 wherein the anchor member extends
through a port defined along the catheter proximal to the barrier
or membrane.
11. An apparatus for treating tissue surrounding a vessel opening,
comprising: a deployment catheter defining at least one lumen
therethrough; a barrier or membrane projecting distally from the
deployment catheter and defining an open area therein, wherein the
open area is in fluid communication with the at least one lumen; a
flap member having a low-profile shape and an extended shape,
wherein the flap is positioned along an inner surface of the
barrier or membrane in its low-profile shape and wherein the flap
is projected distally relative to the barrier or membrane in its
extended shape, and wherein the flap member is sized to be
positioned at least partially within a vessel lumen in the extended
shape such that blood flows unobstructed past the extended flap
with the open area positioned upon a portion of the tissue
surrounding the vessel opening.
12. The apparatus of claim 11 further comprising an inflatable
member positioned between the flap and the barrier or membrane.
13. The apparatus of claim 11 further comprising a visualization
element disposed within or along the barrier or membrane for
visualizing tissue adjacent to the open area when the open area is
purged of blood via a transparent fluid.
14. The apparatus of claim 11 further comprising an ablation probe
positionable within the open area of the barrier or membrane.
15. A method of treating tissue surrounding a vessel opening,
comprising: intravascularly securing an anchor extending from an
anchor member at least partially within a vessel lumen such that
blood flows unobstructed through or past the anchor; adjusting a
distance of the anchor member between the anchor and a barrier or
membrane projecting distally from a deployment catheter such that
an open area defined by the barrier or membrane is placed against
or adjacent to a portion of the tissue surrounding the vessel
opening; displacing blood with a transparent fluid from the open
area; and treating the tissue while visualizing through the
transparent fluid.
16. The method of claim 15 wherein intravascularly securing
comprises advancing the anchor within a lumen of a pulmonary
vein.
17. The method of claim 15 wherein intravascularly securing
comprises expanding the anchor from a low-profile shape to an
expanded shape.
18. The method of claim 15 wherein intravascularly securing
comprises expanding the anchor having a helical shape.
19. The method of claim 15 wherein intravascularly securing
comprises expanding the anchor having a basket shape.
20. The method of claim 15 wherein intravascularly securing
comprises expanding the anchor having a mesh shape.
21. The method of claim 15 wherein adjusting comprises tensioning
the anchor member extending through the open area of the barrier or
membrane.
22. The method of claim 15 wherein adjusting comprises tensioning
the anchor member extending through an opening defined along the
catheter proximal to the barrier or membrane.
23. The method of claim 15 wherein treating comprises ablating the
tissue with an ablation probe advanced into the open area.
24. The method of claim 15 wherein treating comprises
circumferentially ablating the tissue surrounding the vessel
opening.
25. The method of claim 24 wherein circumferentially ablating
comprises ablating the tissue in a continuous line while
visualizing through the transparent fluid.
26. The method of claim 24 wherein circumferentially ablating
comprises ablating the tissue along discrete lesions which overlap
one another surrounding the vessel opening.
27. A method of ablating tissue surrounding a vessel opening,
comprising: positioning an anchor at least partially within a
vessel lumen, wherein the anchor comprises an open structure which
allows unobstructed blood flow through or past the anchor;
positioning a barrier or membrane projecting distally from a
deployment catheter such that an open area defined by the barrier
or membrane is placed against or adjacent to a portion of the
tissue surrounding the vessel opening; purging blood with a
transparent fluid from the open area such that the portion of
tissue is visualized through the transparent fluid; and adjusting a
position of the barrier or membrane relative to the vessel opening
such that the catheter remains tethered to the anchor.
28. The method of claim 27 wherein positioning an anchor comprises
advancing the anchor within a lumen of a pulmonary vein.
29. The method of claim 27 wherein positioning a barrier or
membrane comprises tensioning an anchor member connected to the
anchor and extending through the open area of the barrier or
membrane.
30. The method of claim 27 wherein adjusting a position comprises
circumscribing tissue surrounding the vessel opening while tethered
to the anchor.
31. The method of claim 30 wherein circumscribing tissue further
comprises visualizing the tissue through the transparent fluid
while adjusting the position of the barrier or membrane.
32. The method of claim 27 further comprising treating the tissue
visualized within the open area.
33. The method of claim 32 wherein treating comprises ablating the
tissue visualized within the open area.
34. The method of claim 33 wherein treating comprises
circumferentially ablating the tissue surrounding the vessel
opening.
35. The method of claim 33 wherein treating comprises
circumferentially ablating the tissue in a continuous line while
visualizing through the transparent fluid.
36. The method of claim 33 wherein circumferentially ablating
comprises ablating the tissue along discrete lesions which overlap
one another surrounding the vessel opening.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to U.S.
Prov. Patent Application 60/870,598 filed Dec. 18, 2006, which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to medical devices
used for accessing, visualizing, and/or treating regions of tissue
within a body. More particularly, the present invention relates to
methods and apparatus for intravascularly accessing, visualizing,
and/or treating tissue regions at or around the ostia of the
pulmonary veins of the heart, without obstructing blood flow from
the pulmonary vein.
BACKGROUND OF THE INVENTION
[0003] Conventional devices for accessing and visualizing interior
regions of a body lumen are known. For example, ultrasound devices
have been used to produce images from within a body in vivo.
Ultrasound has been used both with and without contrast agents,
which typically enhance ultrasound-derived images.
[0004] Other conventional methods have utilized catheters or probes
having position sensors deployed within the body lumen, such as the
interior of a cardiac chamber. These types of positional sensors
are typically used to determine the movement of a cardiac tissue
surface or the electrical activity within the cardiac tissue. When
a sufficient number of points have been sampled by the sensors, a
"map" of the cardiac tissue may be generated.
[0005] Another conventional device utilizes an inflatable balloon
which is typically introduced intravascularly in a deflated state
and then inflated against the tissue region to be examined. Imaging
is typically accomplished by an optical fiber or other apparatus
such as electronic chips for viewing the tissue through the
membrane(s) of the inflated balloon. Moreover, the balloon must
generally be inflated for imaging. Other conventional balloons
utilize a cavity or depression formed at a distal end of the
inflated balloon. This cavity or depression is pressed against the
tissue to be examined and is flushed with a clear fluid to provide
a clear pathway through the blood.
[0006] However, such imaging balloons have many inherent
disadvantages. For instance, such balloons generally require that
the balloon be inflated to a relatively large size which may
undesirably displace surrounding tissue and interfere with fine
positioning of the imaging system against the tissue. Moreover, the
working area created by such inflatable balloons are generally
cramped and limited in size. Furthermore, inflated balloons may be
susceptible to pressure changes in the surrounding fluid. For
example, if the environment surrounding the inflated balloon
undergoes pressure changes, e.g., during systolic and diastolic
pressure cycles in a beating heart, the constant pressure change
may affect the inflated balloon volume and its positioning to
produce unsteady or undesirable conditions for optimal tissue
imaging.
[0007] Accordingly, these types of imaging modalities are generally
unable to provide desirable images useful for sufficient diagnosis
and therapy of the endoluminal structure, due in part to factors
such as dynamic forces generated by the natural movement of the
heart. Moreover, anatomic structures within the body can occlude or
obstruct the image acquisition process. Also, the presence and
movement of opaque bodily fluids such as blood generally make in
vivo imaging of tissue regions within the heart difficult.
[0008] Other external imaging modalities are also conventionally
utilized. For example, computed tomography (CT) and magnetic
resonance imaging (MRI) are typical modalities which are widely
used to obtain images of body lumens such as the interior chambers
of the heart. However, such imaging modalities fail to provide
real-time imaging for intra-operative therapeutic procedures.
Fluoroscopic imaging, for instance, is widely used to identify
anatomic landmarks within the heart and other regions of the body.
However, fluoroscopy fails to provide an accurate image of the
tissue quality or surface and also fails to provide for
instrumentation for performing tissue manipulation or other
therapeutic procedures upon the visualized tissue regions. In
addition, fluoroscopy provides a shadow of the intervening tissue
onto a plate or sensor when it may be desirable to view the
intraluminal surface of the tissue to diagnose pathologies or to
perform some form of therapy on it.
[0009] Moreover, many of the conventional imaging systems lack the
capability to provide therapeutic treatments or are difficult to
manipulate in providing effective therapies. For instance, the
treatment in a patient's heart for atrial fibrillation is generally
made difficult by a number of factors, such as visualization of the
target tissue, access to the target tissue, and instrument
articulation and management, amongst others.
[0010] Conventional catheter techniques and devices, for example
such as those described in U.S. Pat. Nos. 5,895,417; 5,941,845; and
6,129,724, used on the epicardial surface of the heart may be
difficult in assuring a transmural lesion or complete blockage of
electrical signals. In addition, current devices may have
difficulty dealing with varying thickness of tissue through which a
transmural lesion desired.
[0011] Conventional accompanying imaging devices, such as
fluoroscopy, are unable to detect perpendicular electrode
orientation, catheter movement during the cardiac cycle, and image
catheter position throughout lesion formation. Without real-time
visualization, it is difficult to reposition devices to another
area that requires transmural lesion ablation. The absence of
real-time visualization also poses the risk of incorrect placement
and ablation of critical structures such as sinus node tissue which
can lead to fatal consequences.
[0012] Thus, a tissue imaging system which is able to provide
real-time in vivo access to and images of tissue regions within
body lumens such as the heart through opaque media such as blood
and which also provides instruments for therapeutic procedures such
as ablation of the ostia around the pulmonary veins are
desirable.
SUMMARY OF THE INVENTION
[0013] A tissue imaging and manipulation apparatus that may be
utilized for procedures within a body lumen, such as the heart, in
which visualization of the surrounding tissue is made difficult, if
not impossible, by medium contained within the lumen such as blood,
is described below. Generally, such a tissue imaging and
manipulation apparatus comprises an optional delivery catheter or
sheath through which a deployment catheter and imaging hood may be
advanced for placement against or adjacent to the tissue to be
imaged.
[0014] The deployment catheter may define a fluid delivery lumen
therethrough as well as an imaging lumen within which an optical
imaging fiber or electronic imaging assembly may be disposed for
imaging tissue. When deployed, the imaging hood may be expanded
into any number of shapes, e.g., cylindrical, conical,
semi-spherical, etc., provided that an open area or field is
defined by the imaging hood. The open area is the area within which
the tissue region of interest may be imaged and which is also
defined in part by the contacted tissue region as well. The imaging
hood may also define an atraumatic contact lip or edge for
placement or abutment, against the tissue region of interest.
Moreover, the distal end of the deployment catheter or separate
manipulatable catheters may be articulated through various
controlling mechanisms such as push-pull wires manually or via
computer control
[0015] The deployment catheter may also be stabilized relative to
the tissue surface through various methods. For instance,
inflatable stabilizing balloons positioned along a length of the
catheter may be utilized, or tissue engagement anchors may be
passed through or along the deployment catheter for temporary
engagement of the underlying tissue.
[0016] In operation, after the imaging hood has been deployed,
fluid may be pumped at a positive pressure through the fluid
delivery lumen until the fluid fills the open, area completely and
displaces any blood from within the open area. The fluid may
comprise any biocompatible fluid, e.g., saline, water, plasma,
Fluorinert.TM., etc., which is sufficiently transparent to allow
for relatively undistorted visualization through the fluid. The
fluid may be pumped continuously or intermittently to allow for
image capture by an optional processor which may be in
communication with the assembly.
[0017] The imaging hood, may be formed into any number of
configurations and the imaging assembly may also be utilized with
any number of therapeutic tools, such as tissue ablation
instruments, which may be deployed through the deployment catheter.
One particular variation may employ an imaging hood having a tissue
anchor deployable therethrough and into a portion of a body lumen
such as the pulmonary vein. Once the anchor has been temporarily
deployed and secured within the pulmonary vein, the hood and
ablation instrument may be articulated around a circumference of
the vein ostium or several ostia where the tissue may be ablated in
a controlled and consistent manner to electrically isolate the
tissue such that a conduction block is created.
[0018] While the imaging hood is moved around the tissue with the
anchor deployed and secured distally within the pulmonary vein, the
imaging hood may be articulated such that blood flow through the
pulmonary vein is unobstructed or uninhibited by the hood.
[0019] The tissue surrounding the ostium may be visualized via the
imaging hood prior to, during, or after the ablation to ensure that
the appropriate tissue is suitably ablated for treating conditions
such as atrial fibrillation. The distally located anchor which
secures a relative position of the imaging hood with respect to the
tissue may be maintained until the procedure is completed. After
completion, the anchor may be at least partially withdrawn into the
imaging hood or reconfigured into a low-profile shape to disengage
the tissue and allow the imaging hood to be removed or repositioned
in the patient body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1A shows a side view of one variation of a tissue
imaging apparatus during deployment from a sheath or delivery
catheter.
[0021] FIG. 1B shows the deployed tissue imaging apparatus of FIG.
1A having an optionally expandable hood or sheath attached to an
imaging and/or diagnostic catheter.
[0022] FIG. 1C shows an end view of a deployed imaging
apparatus.
[0023] FIGS. 1D to 1F show the apparatus of FIGS. 1A to 1C with an
additional lumen, e.g., for passage of a guidewire
therethrough.
[0024] FIGS. 2A and 2B show one example of a deployed tissue imager
positioned against or adjacent to the tissue to be imaged and a
flow of fluid, such as saline, displacing blood from within the
expandable hood.
[0025] FIG. 3A shows an articulatable imaging assembly which may be
manipulated via push-pull wires or by computer control.
[0026] FIGS. 3B and 3C show steerable instruments, respectively,
where an articulatable delivery catheter maybe steered within the
imaging hood or a distal portion of the deployment catheter itself
may be steered.
[0027] FIGS. 4A to 4C show side and cross-sectional end views,
respectively, of another variation having an off-axis imaging
capability.
[0028] FIGS. 4D and 4E show examples of various visualization
imagers which may be utilized within or along the imaging hood.
[0029] FIG. 5 shows an illustrative view of an example of a tissue
imager advanced intravascularly within a heart for imaging tissue
regions within an atrial chamber.
[0030] FIGS. 6A to 6C illustrate deployment catheters having one or
more optional inflatable balloons or anchors for stabilizing the
device during a procedure.
[0031] FIGS. 7A and 7B illustrate a variation of an anchoring
mechanism such as a helical tissue piercing device for temporarily
stabilizing the imaging hood relative to a tissue surface.
[0032] FIG. 7C shows another variation for anchoring the imaging
hood having one or more tubular support members integrated with the
imaging hood; each support members may define a lumen therethrough
for advancing a helical tissue anchor within.
[0033] FIG. 8A shows an illustrative example of one variation of
how a tissue imager may be utilized with an imaging device.
[0034] FIG. 8B shows a further illustration of a hand-held
variation of the fluid delivery and tissue manipulation system.
[0035] FIGS. 9A to 9C illustrate an example of capturing several
images of the tissue at multiple regions.
[0036] FIGS. 10A and 10B show charts illustrating how fluid
pressure within the imaging hood may be coordinated with the
surrounding blood pressure; the fluid pressure in the imaging hood
may be coordinated with the blood pressure or it may be regulated
based upon pressure feedback from the blood.
[0037] FIGS. 11A and 11B show side and end views, respectively, of
a hood and catheter engaging and visualizing the pulmonary vein
ostium while temporarily tethered via a deployable anchor
positioned within the pulmonary vein such that blood flow through
the pulmonary vein is unobstructed.
[0038] FIGS. 12A and 12B show side and end views, respectively, of
the hood and catheter articulated around the pulmonary vein ostium
while ablating and/or visualizing the underlying tissue.
[0039] FIGS. 13A to 13C show end views of the device with the
pulmonary vein anchor acting as a guide to ensure hood stability
while the hood is articulated circumferentially along the pulmonary
vein ostium while leaving the blood flow through the ostium
unimpeded.
[0040] FIGS. 14A and 14B show partial cross-sectional side views of
a helical anchor constrained in its low-profile configuration
within a cylindrical sheath and deployed in its expanded and
unconstrained configuration.
[0041] FIG. 14C shows a partial cross-sectional side view of the
helical anchor temporarily secured within the pulmonary vein while
allowing for blood flow through the vessel to continue unimpeded or
unobstructed.
[0042] FIGS. 15A and 15B show partial cross-sectional side views of
a basket anchor constrained in its low-profile configuration within
a cylindrical sheath and deployed in its expanded and unconstrained
configuration.
[0043] FIG. 15C shows a partial cross-sectional side view of the
basket anchor temporarily secured within the pulmonary vein while
allowing for blood flow through the vessel to continue unimpeded or
unobstructed.
[0044] FIGS. 16A and 16B show partial cross-sectional side views of
a mesh anchor constrained in its low-profile configuration within a
cylindrical sheath and deployed in its expanded and unconstrained
configuration.
[0045] FIG. 16C shows a partial cross-sectional side view of the
mesh anchor temporarily secured within the pulmonary vein while
allowing for blood flow through the vessel to continue unimpeded or
unobstructed.
[0046] FIGS. 17A and 17B show side views of an inflatable balloon
anchor assembly in its low profile configuration and its inflated
configuration, respectively, where the assembly is expandable into
a staggered configuration such that blood may still flow
unobstructed past the inflated balloons.
[0047] FIGS. 18A and 18B show a variation of the tissue
visualization catheter having a reconfigurable flap which is
configured to pivot about the contact lip or edge of the hood from
its low profile configuration to its extended configuration,
respectively.
[0048] FIGS. 19A and 19B show perspective views of the device of
FIGS. 18A and 18B with the flap shown in its low profile and
extended configurations, respectively.
[0049] FIG. 20 shows a side view of the hood having the flap
deployed and engaged along the PV ostium to act as a guide for
articulating the hood circumferentially.
[0050] FIGS. 21A to 21C show end views of the catheter and hood
having the deployed flap engaged along the pulmonary vein ostium
such that the blood flow through the vessel is unimpeded while
circumferentially ablating the underlying tissue under direct
visualization.
[0051] FIG. 22 shows a perspective view of another variation having
an anchor extending from a side port for deployment within the
vessel lumen.
[0052] FIGS. 23A and 23B show perspective and end views,
respectively, of the anchor engaged within a first pulmonary vein
while the tissue around adjacent ostia are ablated in an encircling
lesion to electrically isolate the vessels.
DETAILED DESCRIPTION OF THE INVENTION
[0053] A tissue-imaging and manipulation apparatus described below
is able to provide real-time images in vivo of tissue regions
within a body lumen such as a heart, which is filled with blood
flowing dynamically therethrough and is also able to provide
intravascular tools and instruments for performing various
procedures upon the imaged tissue regions. Such an apparatus may be
utilized for many procedures, e.g., facilitating transseptal access
to the left atrium, cannulating the coronary sinus, diagnosis of
valve regurgitation/stenosis, valvuloplasty, atrial appendage
closure, arrhythmogenic focus ablation, among other procedures.
Further examples of tissue visualization catheters which may be
utilized are shown and described in further detail in U.S. patent
application Ser. No. 11/259,498 filed Oct. 25, 2005, which has been
incorporated hereinabove by reference in its entirety.
[0054] One variation of a tissue access and imaging apparatus is
shown in the detail perspective views of FIGS. 1A to 1C. As shown
in FIG. 1A, tissue imaging and manipulation assembly 10 may be
delivered intravascularly through the patient's body in a
low-profile configuration via a delivery catheter or sheath 14. In
the case of treating tissue, such as the mitral valve located at
the outflow tract of the left atrium of the heart, it is generally
desirable to enter or access the left atrium while minimizing
trauma to the patient. To non-operatively effect such access, one
conventional approach involves puncturing the intra-atrial septum
from the right atrial chamber to the left atrial chamber in a
procedure commonly called a transseptal procedure or septostomy.
For procedures such as percutaneous valve repair and replacement,
transseptal access to the left atrial chamber of the heart may
allow for larger devices to be introduced into the venous system
than can generally be introduced percutaneously into the arterial
system.
[0055] When the imaging and manipulation assembly 10 is ready to be
utilized for imaging tissue, imaging hood 12 may be advanced
relative to catheter 14 and deployed from a distal opening of
catheter 14, as shown by the arrow. Upon deployment, imaging hood
12 may be unconstrained to expand or open into a deployed imaging
configuration, as shown in FIG. 1B. Imaging hood 12 may be
fabricated from a variety of pliable or conformable biocompatible
material including but not limited to, e.g., polymeric, plastic, or
woven materials. One example of a woven material is Kevlar.RTM. (E.
I. du Pont de Nemours, Wilmington, Del.), which is an aramid and
which can be made into thin, e.g., less than 0.001 in., materials
which maintain enough integrity for such applications described
herein. Moreover, the imaging hood 12 may be fabricated from a
translucent or opaque material and in a variety of different colors
to optimize or attenuate any reflected lighting from surrounding
fluids or structures, i.e., anatomical or mechanical structures or
instruments. In either case, imaging hood 12 may be fabricated into
a uniform structure or a scaffold-supported structure, in which
case a scaffold made of a shape memory alloy, such as Nitinol, or a
spring steel, or plastic, etc., may be fabricated and covered with
the polymeric, plastic, or woven, material. Hence, imaging hood 12
may comprise any of a wide variety of barriers or membrane
structures, as may generally be used to localize displacement of
blood or the like from a selected volume of a body lumen or heart
chamber. In exemplary embodiments, a volume within an inner surface
13 of imaging hood 12 will be significantly less than a volume of
the hood 12 between inner surface 13 and outer surface 11.
[0056] Imaging hood 12 may be attached at interface 24 to a
deployment catheter 16 which may be translated independently of
deployment catheter or sheath 14. Attachment of interface 24 may be
accomplished through any number of conventional methods. Deployment
catheter 16 may define a fluid delivery lumen 18 as well as an
imaging lumen 20 within which an optical imaging fiber or assembly
may be disposed for imaging tissue. When deployed, imaging hood 12
may expand into any number of shapes, e.g., cylindrical, conical as
shown, semi-spherical, etc., provided that an open area or field 26
is defined by imaging hood 12. The open area 26 is the area within
which the tissue region of interest may be imaged. Imaging hood 12
may also define an atraumatic contact lip or edge 22 for placement
or abutment against the tissue region of interest. Moreover, the
diameter of imaging hood 12 at its maximum fully deployed diameter,
e.g., at contact lip or edge 22, is typically greater relative to a
diameter of the deployment catheter 16 (although a diameter of
contact lip or edge 22 may be made to have a smaller or equal
diameter of deployment catheter 16). For instance, the contact edge
diameter may range anywhere from 1 to 5 times (or even greater, as
practicable) a diameter of deployment catheter 16. FIG. 1C shows an
end view of the imaging hood 12 in its deployed configuration. Also
shown are the contact lip or edge 22 and fluid delivery lumen 18
and imaging lumen 20.
[0057] The imaging and manipulation assembly 10 may additionally
define a guidewire lumen therethrough, e.g., a concentric or
eccentric lumen, as shown in the side and end views, respectively,
of FIGS. 1D to 1F. The deployment catheter 16 may define guidewire
lumen 19 for facilitating the passage of the system over or along a
guidewire 17, which may be advanced intravascularly within a body
lumen. The deployment catheter 16 may then be advanced over the
guidewire 17, as generally known in the art.
[0058] In operation, alter imaging hood 12 has been deployed, as in
FIG. 1B, and desirably positioned against the tissue region to be
imaged along contact edge 22, the displacing fluid may be pumped at
positive pressure through fluid delivery lumen 18 until the fluid
fills open area 26 completely and displaces any fluid 28 from
within open area 26. The displacing fluid flow may be laminarized
to improve its clearing effect and to help prevent blood from
re-entering the imaging hood 12. Alternatively, fluid flow may be
started before the deployment takes place. The displacing fluid,
also described herein as imaging fluid, may comprise any
biocompatible fluid, e.g., saline, water, plasma, etc., which is
sufficiently transparent to allow for relatively undistorted
visualization through the fluid. Alternatively or additionally, any
number of therapeutic drugs may be suspended within the fluid or
may comprise the fluid itself which is pumped into open area 26 and
which is subsequently passed into and through the heart and the
patient body.
[0059] As seen in the example of FIGS. 2A and 2B, deployment
catheter 16 may be manipulated to position deployed imaging hood 12
against or near the underlying tissue region of interest to be
imaged, in this example a portion of annulus A of mitral valve MV
within the left atrial chamber. As the surrounding blood 30 flows
around imaging hood 12 and within open area 26 defined within
imaging hood 12, as seen in FIG. 2A, the underlying annulus A is
obstructed by the opaque blood 30 and is difficult to view through
the imaging lumen 20. The translucent fluid 28, such as saline, may
then be pumped through fluid delivery lumen 18, intermittently or
continuously, until the blood 30 is at least partially, and
preferably completely, displaced from within open area 26 by fluid
28, as shown in FIG. 2B.
[0060] Although contact, edge 22 need not directly contact the
underlying tissue, it is at least preferably brought into close
proximity to the tissue such that the flow of clear fluid 28 from
open area 26 may be maintained to inhibit significant backflow of
blood 30 bade into open area 26. Contact edge 22 may also be made
of a soft elastomeric material such as certain soft grades of
silicone or polyurethane, as typically known, to help contact edge
22 conform to an uneven or rough underlying anatomical tissue
surface. Once the blood 30 has been displaced from imaging hood 12,
an image may then be viewed of the underlying tissue through the
clear fluid 30. This image may then be recorded or available for
real-time viewing for performing a therapeutic procedure. The
positive flow of fluid 28 may be maintained continuously to provide
for clear viewing of the underlying tissue. Alternatively, the
fluid 28 may be pumped, temporarily or sporadically only until a
clear view of the tissue is available to be imaged and recorded, at
which point the fluid flow 28 may cease and blood 30 may be allowed
to seep or flow back into imaging hood 12. This process may be
repeated a number of times at the same tissue region or at multiple
tissue regions.
[0061] In desirably positioning the assembly at various regions
within the patient body, a number of articulation and manipulation
controls may be utilized. For example, as shown in the
articulatable imaging assembly 40 in FIG. 3A, one or more push-pull
wires 42 may be routed through deployment catheter 16 for steering
the distal end portion of the device in various directions 46 to
desirably position the imaging hood 12 adjacent to a region of
tissue to be visualized. Depending upon the positioning and the
number of push-pull wires 42 utilized, deployment catheter 16 and
imaging hood 12 may be articulated into any number of
configurations 44. The push-pull wire or wires 42 may be
articulated via their proximal ends from outside the patient body
manually utilizing one or more controls. Alternatively, deployment
catheter 16 may be articulated by computer control, as further
described below.
[0062] Additionally or alternatively, an articulatable delivery
catheter 48, which may be articulated via one or more push-pull
wires and having an imaging lumen and one or more working lumens,
may be delivered through the deployment catheter 16 and into
imaging hood 12. With a distal portion of articulatable delivery
catheter 48 within imaging hood 12, the clear displacing fluid may
be pumped through delivery catheter 48 or deployment catheter 16 to
clear the field within imaging hood 12. As shown in FIG. 3B, the
articulatable delivery catheter 48 may be articulated within the
imaging hood to obtain a better image of tissue adjacent to the
imaging hood 12. Moreover, articulatable delivery catheter 48 may
be articulated to direct an instrument or tool passed through the
catheter 48, as described in detail below, to specific areas of
tissue imaged through imaging hood 12 without having to reposition
deployment catheter 16 and re-clear the imaging field within hood
12.
[0063] Alternatively, rather than passing an articulatable delivery
catheter 48 through the deployment catheter 16, a distal portion of
the deployment catheter 16 itself may comprise a distal end 49
which is articulatable within imaging hood 12, as shown in FIG. 3C.
Directed imaging, instrument delivery, etc., may be accomplished
directly through one or more lumens within deployment catheter 16
to specific regions of the underlying tissue imaged within imaging
hood 12.
[0064] Visualization within the imaging hood 12 may be accomplished
through an imaging lumen 20 defined through deployment catheter 16,
as described above. In such a configuration, visualization is
available in a straight-line manner, i.e., images are generated
from the field distally along a longitudinal axis defined by the
deployment catheter 16. Alternatively or additionally, an
articulatable imaging assembly having a pivotable support member 50
may be connected to, mounted to, or otherwise passed through
deployment catheter 16 to provide for visualization off-axis
relative to the longitudinal axis defined by deployment catheter
16, as shown in FIG. 4A. Support member 50 may have an imaging
element 52, e.g., a CCD or CMOS imager or optical fiber, attached
at its distal end with its proximal end connected to deployment
catheter 16 via a pivoting connection 54.
[0065] If one or more optical fibers are utilized for imaging, the
optical fibers 58 may be passed through deployment catheter 16, as
shown in the cross-section of FIG. 4B, and routed through the
support member 50. The use of optical fibers 58 may provide for
increased diameter sizes of the one or several lumens 56 through
deployment catheter 16 for the passage of diagnostic and/or
therapeutic tools therethrough. Alternatively, electronic chips,
such as a charge coupled device (CCD) or a CMOS imager, which are
typically known, may be utilized in place of the optical fibers 58,
in which case the electronic imager may be positioned in the distal
portion of the deployment catheter 16 with electric wires being
routed proximally through the deployment catheter 16.
Alternatively, the electronic imagers may be wirelessly coupled to
a receiver for the wireless transmission of images. Additional
optical fibers or light emitting diodes (LEDs) can be used to
provide lighting for the image or operative theater, as described
below in further detail. Support member 50 may be pivoted via
connection 54 such that the member 50 can be positioned in a
low-profile configuration within channel or groove 60 defined in a
distal portion of catheter 16, as shown in the cross-section of
FIG. 4C. During intravascular delivery of deployment catheter 16
through the patient body, support member 50 can be positioned
within channel or groove 60 with imaging hood 12 also in its
low-profile configuration. During visualization, imaging hood 12
may be expanded into its deployed configuration and support member
50 may be deployed into its off-axis configuration for imaging the
tissue adjacent to hood 12, as in FIG. 4A. Other configurations for
support member 50 for off-axis visualization may be utilized, as
desired.
[0066] FIG. 4D shows a partial cross-sectional view of an example
where one or more optical fiber bundles 62 may be positioned within
the catheter and within imaging hood 12 to provide direct in-line
imaging of the open area within hood 12. FIG. 4E shows another
example where an imaging element 64 (e.g., CCD or CMOS electronic
imager) may be placed along an interior surface of imaging hood 12
to provide imaging of the open area such that the imaging element
64 is off-axis relative to a longitudinal axis of the hood 12. The
off-axis position of element 64 may provide for direct
visualization and uninhibited access by instruments from the
catheter to the underlying tissue during treatment.
[0067] FIG. 5 shows an illustrative cross-sectional view of a heart
H having tissue regions of interest being viewed via an imaging
assembly 10. In this example, delivery catheter assembly 70 may be
introduced percutaneously into the patient's vasculature and
advanced through the superior vena cava SVC and into the right
atrium RA. The delivery catheter or sheath 72 may be articulated
through the atrial septum AS and into the left atrium LA for
viewing or treating the tissue, e.g., the annulus A, surrounding
the mitral valve MV. As shown, deployment catheter 16 and imaging
hood 12 may be advanced out of delivery catheter 72 and brought
into contact or in proximity to the tissue region of interest. In
other examples, delivery catheter assembly 70 may be advanced
through the inferior vena cava IVC, if so desired. Moreover, other
regions of the heart H, e.g., the right ventricle RV or left
ventricle LV, may also be accessed and imaged or treated by imaging
assembly 10.
[0068] In accessing regions of the heart H or other parts of the
body, the delivery catheter or sheath 14 may comprise a
conventional intra-vascular catheter or an endoluminal delivery
device. Alternatively, robotically-controlled delivery catheters
may also be optionally utilized with the imaging assembly described
herein, in which case a computer-controller 74 may be used to
control the articulation and positioning of the delivery catheter
14. An example of a robotically-controlled delivery catheter which
may be utilized is described in further detail in US Pat. Pub.
2002/0087169 A1 to Brock et al. entitled "Flexible Instrument",
which is incorporated herein by reference in its entirety. Other
robotically-controlled delivery catheters manufactured by Hansen
Medical, Inc. (Mountain View, Calif.) may also be utilized with the
delivery catheter 14.
[0069] To facilitate stabilization of the deployment catheter 16
during a procedure, one or more inflatable balloons or anchors 76
may be positioned along the length of catheter 16, as shown in FIG.
6A. For example, when utilizing a transseptal approach across the
atrial septum AS into the left atrium LA, the inflatable balloons
76 may be inflated from a low-profile into their expanded
configuration to temporarily anchor or stabilize the catheter 16
position relative to the heart H. FIG. 6B shows a first balloon 78
inflated while FIG. 6C also shows a second balloon 80 inflated
proximal to the first balloon 78. In such a configuration, the
septal wall AS may be wedged or sandwiched between the balloons 78,
80 to temporarily stabilize the catheter 16 and imaging hood 12. A
single balloon 78 or both balloons 78, 80 may be used. Other
alternatives may utilize expandable mesh members, malecots, or any
other temporary expandable structure. After a procedure has been
accomplished, the balloon assembly 76 may be deflated or
re-configured into a low-profile for removal of the deployment
catheter 16.
[0070] To further stabilize a position of the imaging hood 12
relative to a tissue surface to be imaged, various anchoring
mechanisms may be optionally employed for temporarily holding the
imaging hood 12 against the tissue. Such anchoring mechanisms may
be particularly useful for imaging tissue which is subject to
movement, e.g., when imaging tissue within the chambers of a
beating heart. A tool delivery catheter 82 having at least one
instrument lumen and an optional visualization lumen may be
delivered through deployment catheter 16 and into an expanded
imaging hood 12. As the imaging hood 12 is brought into contact
against a tissue surface T to be examined, anchoring mechanisms
such as a helical tissue piercing device 84 may be passed through
the tool delivery catheter 82, as shown in FIG. 7A, and into
imaging hood 12.
[0071] The helical tissue engaging device 84 may be torqued from
its proximal end outside the patient body to temporarily anchor
itself into the underlying tissue surface T. Once embedded within
the tissue T, the helical tissue engaging device 84 may be pulled
proximally relative to deployment catheter 16 while the deployment
catheter 16 and imaging hood 12 are pushed distally, as indicated
by the arrows in FIG. 7B, to gently force the contact edge or lip
22 of imaging hood against the tissue T. The positioning of the
tissue engaging device 84 may be locked temporarily relative to the
deployment catheter 16 to ensure secure positioning of the imaging
hood 12 during a diagnostic or therapeutic procedure within the
imaging hood 12. After a procedure, tissue engaging device 84 may
be disengaged from the tissue by torquing its proximal end in the
opposite direction to remove the anchor form the tissue T and the
deployment catheter 16 may be repositioned to another region of
tissue where the anchoring process may be repeated or removed from
the patient body. The tissue engaging device 84 may also be
constructed from other known tissue engaging devices such as
vacuum-assisted engagement or grasper-assisted engagement tools,
among others.
[0072] Although a helical anchor 84 is shown, this is intended to
be illustrative and other types of temporary anchors may be
utilized, e.g., hooked or barbed anchors, graspers, etc. Moreover,
the tool delivery catheter 82 may be omitted entirely and the
anchoring device may be delivered directly through a lumen defined
through the deployment catheter 16.
[0073] In another variation where the tool, delivery catheter 82
may be omitted entirely to temporarily anchor imaging hood 12. FIG.
7C shows an imaging hood 12 having one or more tubular support
members 86, e.g., four support members 86 as shown, integrated with
the imaging hood 12. The tubular support members 86 may define
lumens therethrough each having helical tissue engaging devices 88
positioned within. When an expanded imaging hood 12 is to be
temporarily anchored to the tissue, the helical tissue engaging
devices 88 may be urged distally to extend from imaging hood 12 and
each may be torqued from its proximal end to engage the underlying
tissue T. Each of the helical tissue engaging devices 88 may be
advanced through the length of deployment catheter 16 or they may
be positioned within tubular support members 86 during the delivery
and deployment of imaging hood 12. Once the procedure within
imaging hood 12 is finished, each of the tissue engaging devices 88
may be disengaged from the tissue and the imaging hood 12 may be
repositioned to another region of tissue or removed from the
patient body.
[0074] An illustrative example is shown in FIG. 8A of a tissue
imaging assembly connected to a fluid delivery system 90 and to an
optional processor 98 and image recorder and/or viewer 100. The
fluid delivery system 90 may generally comprise a pump 92 and an
optional valve 94 for controlling the flow rate of the fluid into
the system. A fluid reservoir 96, fluidly connected to pump 92, may
hold the fluid to be pumped through imaging hood 12. An optional
central processing unit or processor 98 may be in electrical
communication with fluid delivery system 90 for controlling flow
parameters such as the flow rate and/or velocity of the pumped
fluid. The processor 98 may also be in electrical communication
with an image recorder and/or viewer 100 for directly viewing the
images of tissue received from within imaging hood 12. Imager
recorder and/or viewer 100 may also be used not only to record the
image but also the location of the viewed tissue region, if so
desired.
[0075] Optionally, processor 98 may also be utilized to coordinate
the fluid flow and the image capture. For instance, processor 98
may be programmed to provide for fluid flow from reservoir 96 until
the tissue area has been displaced of blood to obtain a clear
image. Once the image has been determined to be sufficiently clear,
either visually by a practitioner or by computer, an image of the
tissue may be captured automatically by recorder 100 and pump 92
may be automatically stopped or slowed by processor 98 to cease the
fluid flow into the patient. Other variations for fluid delivery
and image capture are, of course, possible and the aforementioned
configuration is intended only to be illustrative and not
limiting.
[0076] FIG. 8B shows a further illustration of a hand-held
variation of the fluid delivery and tissue manipulation system 110.
In this variation, system 110 may have a housing or handle assembly
112 which can be held or manipulated by the physician from outside
the patient body. The fluid reservoir 114, shown in this variation
as a syringe, can be fluidly coupled to the handle assembly 112 and
actuated via a pumping mechanism 116, e.g., lead screw. Fluid
reservoir 114 may be a simple reservoir separated from the handle
assembly 112 and fluidly coupled to handle assembly 112 via one or
more tubes. The fluid flow rate and other mechanisms may be metered
by the electronic controller 118.
[0077] Deployment of imaging hood 12 may be actuated by a hood
deployment switch 120 located on the handle assembly 112 while
dispensation of the fluid from reservoir 114 may be actuated by a
fluid deployment switch 122, which can be electrically coupled to
the controller 118. Controller 118 may also be electrically coupled
to a wired or wireless antenna 124 optionally integrated with the
handle assembly 112, as shown in the figure. The wireless antenna
124 can be used to wirelessly transmit images captured from the
imaging hood 12 to a receiver, e.g., via Bluetooth.RTM. wireless
technology (Bluetooth SIG, Inc., Bellevue, Wash.), RF, etc., for
viewing on a monitor 128 or for recording for later viewing.
[0078] Articulation control of the deployment catheter 16, or a
delivery catheter or sheath 14 through which the deployment
catheter 16 may be delivered, may be accomplished by computer
control as described above, in which case an additional controller
may be utilized with handle assembly 112. In the ease of manual
articulation, handle assembly 112 may incorporate one or more
articulation controls 126 for manual manipulation of the position
of deployment catheter 16. Handle assembly 112 may also define one
or more instrument ports 130 through which a number of
intravascular tools may be passed for tissue manipulation and
treatment within imaging hood 12, as described further below.
Furthermore, in certain procedures, fluid or debris may be sucked
into imaging hood 12 for evacuation from the patient body by
optionally fluidly coupling a suction pump 132 to handle assembly
112 or directly to deployment catheter 16.
[0079] As described above, fluid may be pumped continuously into
imaging hood 12 to provide for clear viewing of the underlying
tissue. Alternatively, fluid may be pumped temporarily or
sporadically only until a clear view of the tissue is available to
be imaged and recorded, at which point the fluid flow may cease and
the blood may be allowed to seep or flow back into imaging hood 12.
FIGS. 9A to 9C illustrate an example of capturing several images of
the tissue at multiple regions. Deployment catheter 16 may be
desirably positioned and imaging hood 12 deployed and brought into
position against a region of tissue to be imaged, in this example
the tissue surrounding a mitral valve MY within the left atrium of
a patient's heart. The imaging hood 12 may be optionally anchored
to the tissue, as described above, and then cleared by pumping the
imaging fluid into the hood 12. Once sufficiently clear, the tissue
may be visualized and the image captured by control electronics
118. The first captured image 140 may be stored and/or transmitted
wirelessly 124 to a monitor 128 for viewing by the physician, as
shown in FIG. 9A.
[0080] The deployment catheter 16 may be then repositioned to an
adjacent portion of mitral valve MV, as shown in FIG. 9B, where the
process may be repeated to capture a second image 142 for viewing
and/or recording. The deployment catheter 16 may again be
repositioned to another region of tissue, as shown in FIG. 9C,
where a third image 144 may be captured for viewing and/or
recording. This procedure may be repeated as many times as
necessary for capturing a comprehensive image of the tissue
surrounding mitral valve MV, or any other tissue region. When the
deployment catheter 16 and imaging hood 12 is repositioned from
tissue region to tissue region, the pump may be stopped during
positioning and blood or surrounding fluid may be allowed to enter
within imaging hood 12 until the tissue is to be imaged, where the
imaging hood 12 may be cleared, as above.
[0081] As mentioned above, when the imaging hood 12 is cleared by
pumping the imaging fluid within for clearing the blood or other
bodily fluid, the fluid may be pumped continuously to maintain the
imaging fluid within the hood 12 at a positive pressure or it may
be pumped under computer control for slowing or stopping the fluid
flow into the hood 12 upon detection of various parameters or until
a clear image of the underlying tissue is obtained. The control
electronics 118 may also be programmed to coordinate the fluid flow
into the imaging hood 12 with various physical parameters to
maintain a clear image within imaging hood 12.
[0082] One example is shown in FIG. 10A which shows a chart 150
illustrating how fluid pressure within the imaging hood 12 may be
coordinated with the surrounding blood pressure. Chart 150 shows
the cyclical blood pressure 156 alternating between diastolic
pressure 152 and systolic pressure 154 over time T due to the
beating motion of the patient heart. The fluid pressure of the
imaging fluid, indicated by plot 160, within imaging hood 12 may be
automatically timed to correspond to the blood pressure changes 160
such that an increased pressure is maintained within imaging hood
12 which is consistently above the blood pressure 156 by a slight
increase .DELTA.P, as illustrated by the pressure difference at the
peak systolic pressure 158. This pressure difference, .DELTA.P, may
be maintained within imaging hood 12 over the pressure variance of
the surrounding blood pressure to maintain a positive imaging fluid
pressure within imaging hood 12 to maintain a clear view of the
underlying tissue. One benefit of maintaining a constant .DELTA.P
is a constant flow and maintenance of a clear field.
[0083] FIG. 10B shows a chart 162 illustrating another variation
for maintaining a clear view of the underlying tissue where one or
more sensors within the imaging hood 12, as described in further
detail below, may be configured to sense pressure changes within
the imaging hood 12 and to correspondingly increase the imaging
fluid pressure within imaging hood 12. This may result in a time
delay, .DELTA.T, as illustrated by the shifted fluid pressure 160
relative to the cycling blood pressure 156, although the time
delays .DELTA.T may be negligible in maintaining the clear image of
the underlying tissue. Predictive software algorithms can also be
used to substantially eliminate this time delay by predicting when
the next pressure wave peak will arrive and by increasing the
pressure ahead of the pressure wave's arrival by an amount of time
equal to the aforementioned time delay to essentially cancel the
time delay out.
[0084] The variations in fluid pressure within imaging hood 12 may
be accomplished in part due to the nature of imaging hood 12. An
inflatable balloon, which is conventionally utilized for imaging
tissue, may be affected by the surrounding blood pressure changes.
On the other hand, an imaging hood 12 retains a constant volume
therewithin and is structurally unaffected by the surrounding blood
pressure changes, thus allowing for pressure increases therewithin.
The material that hood 12 is made from may also contribute to the
manner in which the pressure is modulated within this hood 12. A
stiller hood material, such as high durometer poly urethane or
Nylon, may facilitate the maintaining of an open hood when
deployed. On the other hand, a relatively lower durometer or softer
material, such as a low durometer PVC or polyurethane, may collapse
from the surrounding fluid pressure and may not adequately maintain
a deployed or expanded hood.
[0085] The imaging hood itself may be formed into any number of
configurations and the imaging assembly may also be utilized with
any number of therapeutic tools, such as tissue ablation
instruments, which may be deployed through the deployment catheter.
One particular variation may employ an imaging hood having a tissue
anchor deployable therethrough and into a portion of a body lumen
such as the pulmonary vein. Once the anchor has been temporarily
deployed and secured within the pulmonary vein, the hood and
ablation instrument may be articulated around a circumference of
the vein ostium or several ostia where the tissue may be ablated in
a controlled and consistent manner to electrically isolate the
tissue such that a conduction block is created.
[0086] Generally, while the imaging hood is moved around the tissue
with the anchor deployed and secured distally within the pulmonary
vein, the imaging hood may be articulated such that blood flow
through the pulmonary vein is unobstructed or uninhibited by the
hood. The tissue surrounding the ostium may be visualized via the
imaging hood prior to, during, or after the ablation to ensure that
the appropriate tissue is suitably ablated for treating conditions
such as atrial fibrillation. The distally located anchor which
secures a relative position of the imaging hood with respect to the
tissue may be maintained until the procedure is completed. After
completion, the anchor may be at least partially withdrawn into the
imaging hood or reconfigured into a low-profile shape to disengage
the tissue and allow the imaging hood to be removed or repositioned
in the patient body.
[0087] Turning now to FIGS. 11A and 11B, which show respective side
and end views of visualization hood 12 placed against and
visualizing a portion of the ostium, e.g., the ostium OS.sub.LS of
the left superior pulmonary vein PV.sub.LS. Placement and movement
of hood 12 about ostium OS.sub.LS may be facilitated by the
deployment and placement of an anchor within the respective
pulmonary vein while tethered to hood 12 or catheter 16. Generally,
the anchor situated within the pulmonary vein may be sufficiently
open such that the anchor does not obstruct blood flow through the
pulmonary vein. Although the examples illustrate placement of the
anchors within the left, superior pulmonary vein PV.sub.LS and
ablation or treatment of the respective left superior ostium
OS.sub.LS, this is intended to be illustrative and anchoring within
the other pulmonary veins and other vessels and/or treatment of the
respective ostia are included within the scope of this
disclosure.
[0088] In this example, the pulmonary vein anchor may be configured
as a helical anchor 170 which is attached to an anchor member 172,
e.g., a guidewire, such that helical anchor 170 may be advanced
through delivery catheter 16 in a low-profile configuration and
then slowly expanded when advanced distally out of catheter 16. As
helical anchor 170 expands, anchor member 170 may be advanced
distally within the pulmonary vein until anchor 170 is expanded
into contact against the wall of the pulmonary vein, as shown in
FIG. 11A. Alternatively, a deployment sheath may be advanced
through a working channel of deployment catheter 16, through hood
12, and distally into the pulmonary vein. When the deployment
sheath is desirably situated within the pulmonary vein, helical
anchor 170 may be advanced distally and/or the sheath may be
retracted proximally to deploy and expand the anchor 170. Anchor
170 is described in further detail below.
[0089] With helical anchor 170 secured within the pulmonary vein,
hood 12 may be placed into contact against a portion of ostium
OS.sub.LS by pushing hood 12 along anchor member 172 distally in
the direction towards anchor 170 until hood 12 is pressed against
the tissue surface. Once pressed against the tissue surface, the
transparent purging fluid 28 may be pumped into open area or field
26 to enable direct visualization of the tissue surrounding ostium
OS.sub.LS while surrounded by blood 30.
[0090] As previously mentioned unobstructed blood flow 178 may
continue through the pulmonary vein PV.sub.LS past anchor 170
because of its non-obstructive configuration while the tissue
underlying hood 12 is visualized by imaging element 176, e.g., CCD,
CMOS, or optical fiber, etc., positioned upon or along hood 12 or
within catheter 16. Unlike an anchoring balloon where an entire
inflated balloon potentially blocks the pulmonary vein and deprives
the heart of oxygenated blood from the pulmonary vein, anchor 170
is able to be secured, against the vessel wall without blocking the
vessel lumen. Unobstructed blood flow is further facilitated by
positioning the hood 12 laterally relative to the ostium OS.sub.LS
such that the vessel opening remains minimally obstructed or
completely unobstructed, as shown in FIG. 11B.
[0091] By maintaining contact between hood 12 and the tissue
surrounding OS.sub.LS, an instrument such as ablation probe 174 may
be advanced within hood 12 and placed into contact against or in
proximity to the underlying tissue which may be ablated while under
direct visualization via imaging element 176. Ablation probe 174
may ablate the tissue immediately underlying hood 12 and hood 12
may then be repositioned over an adjacent region of tissue to be
ablated where the process may be repeated. Alternatively, hood 12
may be moved circumferentially about ostium OS.sub.LS while
ablating the underlying tissue in a continuous manner. In either
case, anchor member 172 may act as a guide to ensure that hood 12
stays or tracks circumferentially around ostium OS.sub.LS during
ablation. As shown in the side and end views of FIGS. 12A and 12B,
respectively, an example of how hood 12 may be moved around the
ostium OS.sub.LS during ablation is illustrated where hood 12 is
moved in a counter-clockwise motion relative to ostium OS.sub.LS.
Alternatively, hood 12 may be moved in a clockwise motion as well.
By articulating or translating the hood 12 along the plane of the
ostium OS.sub.LS at an angle away from the pulmonary vein
PV.sub.LS, hood 12 may continue to capture a portion of the ostium
OS.sub.LS as anchor 170 and anchor member 172 may confine the
motion of the hood 12 to the circumference of the ostium
OS.sub.LS.
[0092] As further illustrated in FIG. 12B, a number of discrete
lesions 182 may be formed upon the tissue underlying hood 12.
Repositioning of hood 12 adjacent to the ablated tissue may allow
for the creation of another discrete lesion 182 which may be
overlapped upon one another such that a single continuous lesion
180 is collectively formed. This process may be repeated until the
desired circumference of tissue is ablated. Alternatively, the
continuous lesion 180 may be formed while simultaneously ablating
and moving hood 12 and ablation probe 174 around ostium OS.sub.LS
such that a single continuous line of tissue is ablated. In either
case, the underlying tissue being ablated may be viewed under
direct visualization from imaging element 176.
[0093] FIGS. 13A to 13C illustrate hood 12 and ablation probe 174
being constrained by anchor member 172 coupled to anchor 170 to
follow a circumferential path around the ostium OS.sub.LS as hood
12 is articulated via catheter 16. As previously mentioned,
although hood 12 is illustrated following a counter-clockwise
direction about OS.sub.LS, hood 12 may be articulated to follow a
clockwise direction as well. Moreover, FIGS. 13A and 13B illustrate
ablation probe 174 being used to create a series of overlapping
discrete lesions 182 to create a continuous lesion 180 such that
the entire circumference of tissue surrounding ostium OS.sub.LS is
ablated to completely electrically isolate the ostium OS.sub.LS.
FIG. 13C illustrates the resulting lesion 180 formed by the ablated
tissue once anchor 170 and anchor member 172 have been withdrawn
and hood 12 has been removed from the ostium OS.sub.LS. Although
lesion 180 is illustrated as encircling the entire circumference of
ostium OS.sub.LS one or more discrete portions of the surrounding
tissue may be ablated instead depending upon the desired results.
Moreover, the circumference, or portions, of the circumference, of
ostium OS.sub.LS may be ablated while under direct visualization
within hood 12 while allowing for obstructed blood flow 178 from
the respective pulmonary vein.
[0094] As described above, helical anchor 170 may be advanced
through catheter 16.and through hood 12 in a low-profile
configuration while constrained either by a delivery lumen of
catheter 16 or by an optional anchor sheath 190 advanced through
the delivery lumen while constraining anchor 170. FIG. 14A shows an
example of an optional anchor sheath 190 having helical anchor 170
extending from anchor member 172 constrained within anchor lumen
192 in its low-profile configuration. When helical anchor 170 is to
be deployed from anchor lumen 192, anchor 170 may be advanced
relative to sheath 190 and/or sheath 190 may be retracted relative
to anchor 170 such that helical anchor 170 may be extended beyond
lumen 192 such that anchor 170 is unconstrained and allowed to
expand radially, as illustrated in FIG. 14B.
[0095] Once deployed within the vessel lumen, such as the pulmonary
vein PV.sub.LS, as shown in the partial cross-sectional view of
FIG. 14C, helical anchor 170 may be expanded or reconfigured such
that anchor 176 does not obstruct blood flow 178 within the
pulmonary vein PV.sub.LS. The expanded anchor 170 may provide
engagement and orientation for hood 12 relative to the underlying
tissue surrounding the ostium to conduct direct visualization and
ablation of the tissue surrounding the ostium OS.sub.LS, as
described above. The anchor 170 may secure itself to the vessel
wall by expanding laterally, e.g., perpendicularly relative to a
longitudinal axis of the anchor 170, and applying a radial outward
force upon the tissue walls of the vessel. Fractional contact
between the helical anchor 170 and the tissue surface may provide
additional force to secure the anchor 170 in place. The helical
anchor 170 can be formed from a wire made from a variety of
materials, e.g., shape memory alloys such as Nitinol. When the
helical anchor 170 is retracted back into sheath 190, the anchor
170 may return to its original low-profile shape for repositioning
or for removal from the patient.
[0096] FIGS. 15A and 15B show partial cross-sectional views of
another variation of the anchor for placement within the pulmonary
vein where the anchor is configured as a reconfigurable basket
anchor 200 which is deliverable in its low-profile configuration
where basket anchor 200 is constrained within lumen 192 of sheath
190, as shown in FIG. 15A, and deployable into an expanded or
extended basket configuration, as shown in FIG. 15B.
[0097] Basket anchor 200 may be formed to have several
reconfigurable basket arms or members 206 which are each connected
at a distal connection 202 and at a proximal connection 204. Basket
anchor 200 may extend distally from anchor member 208 such that
distal movement of anchor member 208 (and/or proximal retraction of
sheath 190) may urge basket anchor 200 out of lumen 192 where
basket arms or members 206 may expand laterally into its basket
configuration, e.g., where arms or members 206 reconfigure
perpendicularly relative to the axis of the basket 200, and into
contact against the vessel walls, as shown in FIG. 15C. Fractional
contact between arms or members 206 and the tissue surface in
contact provides additional force to secure the anchor 200 in
place. Even in its expanded configuration, basket anchor 200 may
provide an open pathway for blood flow 178 to continue relatively
unobstructed between the arms or members 206 and through the
vessel.
[0098] As above, basket anchor 200 can be fabricated from shape
memory alloy tubing such as Nitinol or from metal wires or ribbons
such as stainless steel, titanium, etc. When retracted proximally
back into sheath 190, the basket anchor 200 may return to its
original low-profile shape for repositioning within the same or
different vessel or for removal from the patient.
[0099] In yet another variation, FIGS. 16A and 16B show partial
cross-sectional side views of an anchor configured as a mesh anchor
210. This mesh anchor 210 variation may anchor itself to the walls
of the pulmonary vein PV.sub.LS by expanding laterally into a
basket-like frame, e.g., perpendicularly relative to the
longitudinal axis of the anchor 210, and applying a radial outward
force on the wails of the vessel. The anchor 210 may generally
comprise multiple wire or ribbon members 216 which are woven,
interwoven, or interlaced with respect to one another to form the
mesh which is connected at a distal connection 212 and a proximal
connection 214 and attached, coupled, or otherwise extending from
anchor member 218. The wire or ribbon members 216 can be formed
from shape memory alloy such as Nitinol or from a polymeric of
plastic material such as PET. When compressed into a low-profile
cylindrical configuration and loaded in the lumen 192 of sheath
190, as shown in FIG. 16A, mesh anchor 210 may return to its
expanded configuration by having wire or ribbon members 216
expanded into the basket-like structure when, deployed from sheath
190, as shown in FIG. 16B. Moreover, when deployed and secured
against the vessel wall, as shown in FIG. 16C, blood flow 178 may
continue relatively unobstructed by flowing between the members
216.
[0100] In yet another variation, the pulmonary vein anchor may be
configured as a balloon anchor assembly 220 having several balloon
members which are inflatable into a staggered pattern for
securement within the vessel. As shown in FIG. 17A, the staggered
balloon assembly 220 may be advanced at least partially within,
e.g., the pulmonary vein PV.sub.LS, while in a deflated or
low-profile configuration. Once desirably positioned, staggered
balloon anchor assembly 220 may be infused with a gas (such as
nitrogen) or fluid (such as saline) via inflation lumen 228 to
expand several balloons positioned in a staggered pattern along the
inflation lumen 228. In this example, first offset balloon 222 may
be positioned distally along lumen 228 while second offset balloon
224 may be positioned proximally and in an offset position relative
to first offset balloon 222. A third offset balloon 226 may be
positioned proximally of second balloon 224 such that it is offset
with respect to second balloon 224 and/or first balloon 222, as
illustrated in FIG. 17B. Although three balloon members are shown
in this example, other variations may utilize two balloons or more
than three balloons. Moreover, rather than having balloon members
offset with respect to one another, balloon members may be
configured into other shapes which still allow for blood flow
through the vessel, e.g., one or more toroidal shaped balloon
members.
[0101] Once the balloon assembly 220 is inflated and secured within
the vessel, blood flow 178 may continue through the pulmonary vein
PV.sub.LS such that the blood is able to meander in an offset flow
pattern 230 past the staggered balloons. The staggered balloons can
be made from a variety of materials typically utilized for
biocompatible inflatable balloons, e.g., medical grade elastomers
such as C-flex, chronoprene, silicone or polyurethane, etc.
[0102] In yet another variation, rather than utilizing a separately
deployable anchor for placement within the vessel lumen. FIGS. 18A
and 18B show a variation of the tissue visualization catheter
having a reconfigurable flap 240 which is configured to pivot about
the contact lip or edge 22 of the hood 12. In its low-profile
configuration, flap 240 may remain folded inwardly along the inner
wall of the hood 12. An inflation lumen 246 may extend from the
catheter 16 along or within the wall of the hood 12 and terminate
proximal to the flap 240 at an inflatable member or balloon 242
positioned between flap 240 and hood 12. Balloon 242 may be
fabricated from a variety of materials, such as C-flex,
chronoprene, polyurethane, etc. and it may be separately attached
to hood 12 or it may optionally be integrated with the material of
hood 12. Upon injecting a fluid or gas through lumen 246, balloon
242 may be inflated such that flap 240 is lifted or rotated in the
direction 244 from its low-profile position along the inner wall of
hood 12, as shown in FIG. 18A, into its extended position, as shown
in FIG. 18B. When the flap 240 is lifted passed an angle of
approximately 25.degree. or more relative to the lining of hood 12,
the flap 240 may be configured to flip open into its extended
configuration. FIGS. 19A and 19B illustrate perspective views of
flap 240 in its low-profile configuration and its extended
configuration, respectively, corresponding to FIGS. 18A and 18B
above.
[0103] In use, flap 240 in its extended position may act as a guide
for the hood 12 to trace the ostium OS.sub.LS to ensure that hood
12 moves along the circumference of the ostium OS.sub.LS. As
illustrated in the side view of FIG. 20, hood 12 may be positioned
in proximity to the vessel and ostium to be treated. In this
example, flap 240 may be extended and hood 12 may be placed
laterally relative to the vessel such that flap 240 is positioned
at least partially along the opening of the pulmonary vein
PV.sub.LS and only a small portion of the vessel opening is covered
such that blood flow 178 through the vessel may continue
unobstructed by the hood 12. In this position, hood 12 is desirably
positioned upon the ostium OS.sub.LS to allow the hood 12 and
ablation probe 174 positioned therewithin to treat the underlying
tissue while under direct visualization through the hood 12.
[0104] As illustrated in FIGS. 21A to 21C, with extended flap 240
positioned at least partially within the vessel and acting as a
guide, hood 12 may be moved circumferentially via catheter 16, or
at least partially, around the ostium OS.sub.LS to create one or
more discrete lesions 182 or a continuous lesion 180. FIG. 21C
illustrates the resulting lesion 180 created circumferentially
about the ostium OS.sub.LS to electrically isolate the tissue
region.
[0105] In other variations for creating lesions about the ostium of
a vessel, FIG. 22 shows a perspective view of an example of a
device utilizing a side port 250 defined along the catheter 16
proximal to the hood 12 for intravascularly creating lesions around
multiple ostia. Although the anchor configuration is illustrated
with helical anchor 170 attached to anchor member 172 extending
through port 250, other anchors which are non-obstructing to the
blood flow through the vessel may be utilized, such as basket
anchors, mesh anchors, staggered, balloons, etc. An anchor deployed
from the side port 250 of the catheter 16 may provide hood 12
additional degrees-of-freedom of controlled motion within the
chamber (such as the left atrium LA) of the heart.
[0106] In use, anchor 170 may be deployed through port 250 proximal
to the hood 12 and advanced into, e.g., pulmonary vein PV.sub.LS,
by advancing anchor member 172 (indicated by the direction of
advancement 252) where it may be secured within the vessel without
obstructing blood flow therethrough, as shown in the perspective
view of FIG. 23A. Hood 12 may then be articulated via catheter 16
(indicated by the direction of articulation 254) while tethered and
guided by anchor member 172 to facilitate the ablation process by
allowing hood 12 to be maneuvered especially when isolating two or
more ostia, e.g., left superior ostium OS.sub.LS and left inferior
ostium OS.sub.LS, within one continuous circumferential lesion, as
shown in FIG. 23B. Other tissue regions may be ablated in the same
manner to create lesion patterns around the various ostia or around
all four ostia within the left atrium LA. Moreover, the side ported
anchor may also provide additional apposition strength for the hood
12 to engage the ablated tissue surface when the anchor 170 is
pulled from the side port 250.
[0107] Another variation may include having two or more side ports
near or at the distal end of the catheter 16 proximal to hood 12,
with each side port deploying a respective anchor. When one anchor
secures itself to the right superior/inferior pulmonary vein while
the other pulmonary vein anchor secures itself within the left
superior/inferior PV, navigation around all four pulmonary vein
ostia and apposition to target tissue surface in the vicinity of
the four pulmonary vein ostia can be achieved. This can be made so
by pulling on each of the two anchor members with varying tension
and by rotating the hood 12 about the axis of the anchor members.
Both linear lesions connecting the pulmonary veins and
circumferential lesions around the respective ostia can be formed
by maneuvering the hood 12 accordingly.
[0108] The applications of the disclosed invention discussed above
are not limited to certain treatments or regions of the body, but
may include any number of other treatments and areas of the body.
Modification of the above-described methods and devices for
carrying out the invention, and variations of aspects of the
invention that are obvious to those of skill in the arts are
intended to be within the scope of this disclosure. Moreover,
various combinations of aspects between examples are also
contemplated and are considered to be within the scope of this
disclosure as well.
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