U.S. patent application number 10/160885 was filed with the patent office on 2002-10-17 for methods and devices for implanting cardiac valves.
Invention is credited to Garrison, Michi E., Gifford, Hanson S. III, St. Goar, Frederick G..
Application Number | 20020151970 10/160885 |
Document ID | / |
Family ID | 22941221 |
Filed Date | 2002-10-17 |
United States Patent
Application |
20020151970 |
Kind Code |
A1 |
Garrison, Michi E. ; et
al. |
October 17, 2002 |
Methods and devices for implanting cardiac valves
Abstract
The valve implantation system has a valve displacer for
displacing and holding the native valve leaflets open in a first
aspect of the invention. A replacement valve may be attached to the
valve displacer before or after introduction and may be positioned
independent of the valve displacer. In another aspect of the
invention, the valve displacer and valve are in a collapsed
condition during introduction and are expanded to deploy the valve
displacer and valve. The valve is a tissue valve mounted to an
expandable support structure. The support structure may have
protrusions for engaging the valve displacer or barbs for anchoring
the valve displacer to the heart or blood vessel. A temporary valve
mechanism may be used to provide temporary valve functions during
and after deployment of the valve displacer.
Inventors: |
Garrison, Michi E.; (Half
Moon Bay, CA) ; Gifford, Hanson S. III; (Woodside,
CA) ; St. Goar, Frederick G.; (Menlo Park,
CA) |
Correspondence
Address: |
AUDLEY A. CIAMPORCERO JR.
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
22941221 |
Appl. No.: |
10/160885 |
Filed: |
June 3, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10160885 |
Jun 3, 2002 |
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09248911 |
Feb 10, 1999 |
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6425916 |
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Current U.S.
Class: |
623/2.11 ;
623/2.14 |
Current CPC
Class: |
A61F 2220/0016 20130101;
A61F 2/2436 20130101; A61F 2/2418 20130101; A61F 2/2433 20130101;
Y10S 623/904 20130101; A61F 2250/0059 20130101; A61F 2250/006
20130101 |
Class at
Publication: |
623/2.11 ;
623/2.14 |
International
Class: |
A61F 002/24 |
Claims
What is claimed is:
1. A method of implanting a cardiac valve, comprising the steps of:
introducing a valve and a valve displacer into a patient, the valve
and valve displacer being movable from collapsed positions to
expanded positions, the valve and valve displacer being introduced
into the patient in the collapsed position; positioning the valve
displacer between valve leaflets of a native cardiac valve;
expanding the valve displacer to the expanded position after the
positioning step thereby displacing and holding the valve leaflets
in an open position; and securing the valve at a desired location
in the patient.
2. The method of claim 1, wherein: the securing step is carried out
with the replacement valve being secured to the valve
displacer.
3 The method of claim 2, wherein: the securing step is carried out
with the valve interlocking with the valve displacer.
4. The method of claim 2, wherein: the securing step is carried out
with the valve having sharp elements which penetrate the native
valve.
5. The method of claim 1, wherein: the introducing step is carried
out with the valve having a support structure and a valve portion,
the support structure being expandable from a collapsed position to
an expanded position, the introducing step being carried out with
the support structure being in the collapsed position.
6. The method of claim 1, wherein: the securing step is carried out
with the desired valve location being spaced apart from the valve
displacer.
7. The method of claim 6, wherein: the securing step is carried out
with the desired location of the valve being between the coronary
ostia and the brachiocephalic artery.
8. The method of claim 1, wherein: the introducing step is carried
out with the valve displacer being mounted to a catheter.
9. The method of claim 8, further comprising the step of: enclosing
the valve displacer in a flexible sheath during the introducing
step; and uncovering the valve displacer before the expanding
step.
10. The method of claim 8, wherein: the introducing step is carried
out with the catheter passing through a penetration in the aortic
arch.
11. The method of claim 8, wherein: the introducing step is carried
out through the femoral artery.
12. The method of claim 1, wherein: the introducing step is carried
out with the valve being mounted on a catheter.
13. The method of claim 8, wherein: the introducing step is carried
out with the catheter having an expandable member, the valve
displacer being mounted to the expandable member.
14. The method of claim 12, wherein: the introducing step is
carried out with the catheter having a valve mechanism.
15. The method of claim 12, wherein: the introducing step is
carried out with the catheter having a balloon, the balloon being
coupled to a control mechanism for inflating and deflating the
balloon to provide pumping assistance to the patient's heart.
16. The method of claim 1, wherein: the introducing step is carried
out with the valve displacer being mounted on a catheter.
17. The method of claim 16, wherein: the introducing step is
carried out with the catheter having an expandable member, the
valve displacer being mounted to the expandable member.
18. The method of claim 14, wherein: the introducing step is
carried out the valve displacer having an end which flares
outwardly when the valve displacer is in the expanded position.
19. The method of claim 1, wherein: the introducing step is carried
out with the valve displacer having a circumferential recess formed
between the first end and a second end.
20. The method of claim 1, wherein: the securing step is carried
out before the introducing step so that the valve and valve
displacment device are introduced together.
21. The method of claim 20, further comprising the step of:
inverting the valve after the introducing step.
22. The method of claim 1, wherein: the valve introducing step is
carried out with the valve having an expandable support structure,
the expandable support structure having at least three posts
extending from the expandable support structure.
23. A device for maintaining a patient's native valve leaflets
open, comprising: a first end; a second end; and a central section
extending between the first and second ends; the first and second
ends being flared outwardly from the central section so that the
central section forms a recess for receiving the native valve
leaflets, the first end, second end and central section forming a
structure which is movable from a collapsed condition to an
expanded condition.
24. The device of claim 23, wherein: the first end, second end and
central section are integrally formed.
25. The device of claim 23, wherein: the structure is substantially
cylindrical in the collapsed condition, the first and second ends
flaring outwardly from the central section when the structure is in
expanded condition.
26. The device of claim 23, wherein: the structure has a
circumferential recess for retaining the native valve leaflets, the
circumferential recess extending around the central section.
27. The device of claim 23, further comprising: a valve portion
attached to at least one of the first end, second end and central
section, the valve portion permitting blood flow therethrough in
one direction and preventing flow in the other direction.
28. The device of claim 27, wherein: the valve portion is a tissue
valve.
29. The device of claim 27, wherein: the valve portion lockingly
engages at least one of the first end, second end and central
section.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention is directed to methods and devices for
implanting replacement cardiac valves. Replacement cardiac valves
are implanted when the patient's native valve exhibits abnormal
anatomy and function due to congential or acquired valve disease.
Congenital abnormalities can be tolerated for years only to develop
into life-threatening problems later. Acquired valve disease may
result from various causes such as rheumatic fever, degenerative
disorders of the valve tissue, and bacterial or fungal
infections.
[0002] Valve dysfunction can be classified as either stenosis, in
which the valve does not open properly, or insufficiency, in which
the valve does not close properly. Stenosis and insufficiency can
occur at the same time and both abnormalities increase the workload
on the heart in pumping blood through the body. The ability of the
heart to function with the increased workload is a major factor in
determining whether the valve should be replaced.
[0003] When the valve must be replaced using conventional methods,
the patient must undergo an invasive, traumatic surgical procedure.
The patient's chest is opened with a median sternotomy or major
thoracotomy to provide direct access to the heart through the large
opening in the chest. The heart is then stopped and the patient is
placed on cardiopulmonary bypass using catheters and cannulae
inserted directly into the heart and great vessels. The heart, or a
great vessel leading to the heart, is then cut open to access and
remove the malfunctioning valve. After removing the valve, the
replacement valve is then sewn into place. After the new valve has
been implanted, the chest is then closed and the patient is weaned
off cardiopulmonary bypass support.
[0004] The conventional open-chest surgery described above is
problematic in that it is highly invasive, traumatic and requires a
lengthy recovery time. These drawbacks to conventional open-chest
surgery prevent some patients from undergoing a valve implantation
procedure even though a new cardiac valve is needed.
[0005] U.S. Pat. No. 5,370,685. U.S. Pat. No. 5,411,552 and U.S.
Pat. No. 5,718,725, which are hereby incorporated by reference,
describe devices and methods for implanting a new cardiac valve
without requiring a median sternotomy or major thoracotomy. Such
devices and methods reduce the pain, trauma and recovery time as
compared to conventional open-chest surgery.
[0006] An object of the present invention is to provide additional
devices and methods which reduce the trauma associated with
conventional open-chest methods and devices for implanting cardiac
valves.
SUMMARY OF THE INVENTION
[0007] In accordance with the object of the invention, a system and
method for implanting a cardiac valve is provided which does not
require a median sternotomy or major thoracotomy. The devices and
methods of the present invention are preferably carried out by
passing the valve through a blood vessel, preferably the femoral
artery, so that the median sternotomy or major thoracotomy is not
required. Alternatively, the systems of the present invention also
permit introduction of the valve through a small incision between
the patient's ribs without cutting the ribs or sternum.
[0008] In a first aspect of the invention, a valve displacer is
used to hold the native valve leaflets open so that the native
valve does not need to be removed. The valve displacer is
preferably introduced into the patient in a collapsed condition and
expanded to displace and hold the leaflets open. The valve
displacer may either be expanded with an expansion mechanism, such
as a balloon, or may be self-expanding. In a preferred embodiment,
the valve displacer has a first end, a second end and a central
section between the first and second ends. The first and second
ends are preferably flared outwardly to form a circumferential
recess around the central portion. The native leaflets are trapped
within the recess when the valve displacer is deployed.
[0009] In another aspect of the invention, the valve is also
introduced into the patient in a collapsed condition and expanded
within the patient. The valve may either be expanded with an
expansion mechanism, such as a balloon, or may be self-expanding.
The cardiac valve may be coupled to the valve displacer or may be
positioned independent from the valve displacer while still
substantially performing the functions of the native valve. For
instance, a replacement aortic valve may be positioned in the
ascending or descending aorta to substantially perform the
functions of the native aortic valve.
[0010] The cardiac valve is preferably delivered separate from the
valve displacer but may also be integrated with the valve displacer
during introduction and deployment. In a preferred embodiment, the
valve has protrusions which engage openings in the valve displacer.
In another embodiment, the valve has sharp elements or barbs which
either pierce the native valve tissue or engage the sides of the
openings in the valve displacer.
[0011] In yet another aspect of the present invention, the valve
and valve displacer are preferably introduced into the patient with
a catheter system. In a preferred system, the valve displacer is
mounted to a first catheter and the valve is mounted to a second
catheter which passes through and is slidably coupled to the first
catheter. Alternatively, the valve displacer and valve may be
mounted to a single catheter. The term catheter as used herein
refers to any catheter, trocar or similar device for introducing
medical devices into a patient.
[0012] In still another aspect of the present invention, the valve
delivery catheter has a temporary valve mechanism which provides
temporary valve functions after deployment of the valve displacer.
The temporary valve mechanism prevents regurgitation while the
native valve is held open and before deployment of the replacement
cardiac valve. The temporary valve mechanism is preferably a
balloon which is inflated and deflated as necessary to permit
downstream flow and prevent retrograde flow. Although it is
preferred to implant the cardiac valve while the patient's heart is
beating, the devices and methods of the present invention may also
be used with the patient's heart stopped and the patient supported
by a bypass system.
[0013] These and other advantages and aspects of the invention will
become evident from the following description of the preferred
embodiments and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A shows a system for implanting a cardiac valve.
[0015] FIG. 1B shows the system of FIG. 1A introduced through a
femoral vein.
[0016] FIG. 2 shows the system of FIG. 1 with a sheath retracted to
expose the cardiac valve, a valve displacer and a temporary valve
mechanism.
[0017] FIG. 3 shows the valve displacer positioned between the
native valve leaflets prior to expansion.
[0018] FIG. 4 shows the valve displacer expanded by a first
expansion mechanism.
[0019] FIG. 5 shows the valve expanded by a second expansion
mechanism into engagement with the valve displacer.
[0020] FIG. 6 shows the valve displacer and valve implanted in the
native valve position.
[0021] FIG. 7 shows the valve displacer in the collapsed
position.
[0022] FIG. 8 shows the valve displacer in the expanded
position.
[0023] FIG. 9 shows the valve and valve displacer in the expanded
position.
[0024] FIG. 10 shows the valve in a collapsed condition.
[0025] FIG. 11 is a plan view of the valve showing the
leaflets.
[0026] FIG. 12 is a cross-sectional view of the catheter along line
A-A of FIG. 5.
[0027] FIG. 13 shows another system for implanting another cardiac
valve.
[0028] FIG. 14 is a partial cut-away view of the catheter of FIG.
13 with the valve contained in a chamber.
[0029] FIG. 15 is a cross-sectional view of the catheter along line
B-B of FIG. 13.
[0030] FIG. 16 shows another system for implanting a cardiac
valve.
[0031] FIG. 17 shows the system of FIG. 16 with a distal portion of
the valve displacer extending from the catheter.
[0032] FIG. 18 shows the valve displacer fully deployed to hold the
native leaflets open.
[0033] FIG. 19 shows the valve partially expanded with the catheter
manipulated so that the valve engages the valve displacer.
[0034] FIG. 20 shows the valve fully deployed and the catheter
removed.
[0035] FIG. 21 is a partial cut-away view of the catheter of FIGS.
16-19.
[0036] FIG. 22 is a cross-sectional view of the catheter along line
C-C of FIG. 16.
[0037] FIG. 23 shows another system for implanting a cardiac valve
with the valve displacer positioned between the native
leaflets.
[0038] FIG. 24 shows the valve displacer expanded.
[0039] FIG. 25 shows the valve partially deployed within the valve
displacer.
[0040] FIG. 26 shows the valve fully deployed within the valve
displacer.
[0041] FIG. 27 shows the valve displacer holding the native
leaflets open with the valve deployed in the ascending aorta.
[0042] FIG. 28 shows the valve displacer holding the native
leaflets open with the valve deployed in the descending aorta.
[0043] FIG. 29 shows the cardiac valve of FIGS. 23-28 in the
collapsed condition.
[0044] FIG. 30 shows the cardiac valve of FIGS. 23-28 in the
expanded condition.
[0045] FIG. 31 shows another system for delivering a cardiac valve
with the delivery catheter passing through a trocar in the
ascending aorta.
[0046] FIG. 32 shows an expansion mechanism expanding the valve
displacer and the valve.
[0047] FIG. 33 shows sutures being pulled to invert the valve.
[0048] FIG. 34 shows the valve being stored in a preservative
solution.
[0049] FIG. 35 shows the valve inverted and in the expanded
condition.
[0050] FIG. 36 shows the valve and valve displacer in the collapsed
condition before being attached to one another.
[0051] FIG. 37 shows the valve and valve displacer attached to one
another and mounted to the delivery catheter.
[0052] FIG. 38 shows the valve and the valve displacer in the
expanded condition.
[0053] FIG. 39 shows the catheter passing through the femoral vein,
into the right atrium, and through the intraatrial septum into the
left atrium to access the mitral valve.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] Referring to FIGS. 1A, 1B and 2a system for implanting a
replacement cardiac valve is shown. The present invention is
described in connection with implantation of a replacement aortic
valve but is applicable to any other cardiac valve. The system 2
includes a delivery catheter 4, a cardiac valve 6 and a valve
displacer 8. A protective sheath 10 covers the delivery catheter 4,
cardiac valve 6 and valve displacer 8 during introduction to
prevent contact between the blood vessel and the cardiac valve 6
and valve displacer 8. FIGS. 1A and 1B show the sheath 10 extending
around the cardiac valve 6 and valve displacer 8 and FIG. 2 shows
the sheath 10 retracted to expose the cardiac valve 6 and valve
displacer 8.
[0055] The cardiac valve 6 is preferably introduced through a
peripheral vessel such as the femoral artery (FIGS. 1A and 2) or
femoral vein (FIG. 1B). FIG. 1B shows introduction of the catheter
2 through the femoral vein, into the right atrium, through the
intraatrial septum and into the left atrium to access the mitral
valve. The peripheral vessel is preferably a femoral vessel but may
also be the internal jugular vein, subclavian artery, axillary
artery, abdominal aorta, descending aorta or any other suitable
blood vessel. As will be explained below, the delivery catheter 4
may be introduced by surgical cutdown or percutaneously using the
Seldinger technique. An advantage of passing the catheter 4 through
a peripheral vessel is reduced trauma to the patient as compared to
the conventional open-chest procedure described above. Although it
is preferred to deliver the cardiac valve 6 through a peripheral
vessel, the cardiac valve 6 may also be introduced directly into
the ascending aorta through a small incision between ribs. The
system 2 of the present invention is small enough to deliver
between the patient's ribs so that the advantages of the present
invention over conventional open-chest surgery are provided even
when introducing the catheter through an incision in the chest.
[0056] The valve displacer 8 is expanded within the native valve to
hold the native cardiac valve leaflets 6 open. An advantage of the
system 2 and method of the present invention is that the native
valve does not need to be removed. The replacement cardiac valves
described herein may, of course, also be used when removing the
native valve rather than using the valve displacer 8. Furthermore,
the valve displacer 8 and cardiac valve 6 may be integrated into a
single structure and delivered together rather than separately.
Thus, all features of any valve displacer described herein may also
form part of any of the cardiac valves described herein without
departing from the scope of the invention.
[0057] The valve displacer 8 is shown in the collapsed condition in
FIGS. 3 and 7 and in the expanded condition in FIGS. 4 and 8. When
in the collapsed position, the valve displacer 8 forms a number of
longitudinal slots 12 which form openings 14 in the valve displacer
8 when in the expanded condition. The valve displacer 8 is
substantially cylindrical in the collapsed condition to facilitate
introduction into the patient.
[0058] Referring to FIG. 8, first and second ends 16, 18 of the
valve displacer 8 flare outwardly to form a circumferential recess
24 at a central section 22. The native leaflets are trapped in the
recess 24 when the valve displacer 8 is deployed. The first end 16
has three extensions 20 extending from the central section 22. The
valve displacer 8 may be made of any suitable material and
preferred materials include stainless steel, nitinol, keviar,
titanium, nylon and composites thereof. The valve displacer 8 may
also be coated with an antithrombogenic coating. The valve
displacer 8 is preferably formed from a solid hypotube by etching
or micromachining, machining from a solid material, or welding wire
elements together. Although it is preferred to provide the flared
ends 16, 18, the valve displacer 8 may have any other suitable
shape which holds the leaflets open. The valve displacer 8 may also
have a fabric cover 17 which can trap calcium fragments which might
break free from the valve when the valve displacer is deployed. The
cover 17 is preferably made of a polyesther knit material, such as
dacron, but may be made of any other suitable material.
[0059] The cardiac valve 6 has an expandable support structure 26
which moves from the collapsed position of FIGS. 4 and 10 to the
expanded position of FIGS. 5 and 9. The support structure 26 is
preferably formed with first and second elongate members 28, 30
which are wound to form windings 31, preferably about 12-18
windings 31, around the circumference of the valve 6. The first and
second elongate members 28, 30 are attached to one another at
windings 31 which forms three posts 32 extending from the support
structure 26.
[0060] The support structure 26 has a protrusion 34, preferably
three, extending outwardly to form an interrupted lip around an end
35 of the support structure 26. The protrusions 34 engage the
openings 14 in the valve displacer 8 as shown in FIG. 9 to secure
the cardiac valve 6 to the valve displacer 8. The protrusions 34
are preferably formed by a coil 36 wrapped around the loops 31 in
the elongate member 30. As will be described below, the support
structure 26 may also have barbs to secure the cardiac valve 6 to
the valve displacer 8 or to the blood vessel wall. The cardiac
valve 6 may also engage the valve displacer 8 with any other
suitable connection.
[0061] The posts 32 support a valve portion 38 which performs the
functions of the patient's malfunctioning native valve. Referring
to FIGS. 10 and 11, the valve portion 38 is preferably a stentless
tissue valve such as a tri-leaflet 39 stentless porcine valve. The
valve portion 38 has a base 41 which is secured to the support
structure 26 with sutures (not shown). The valve portion 38 may be
stored separately from support structure 26 and attached to the
support structure 26 before the procedure. Although it is preferred
to provide a tissue valve for the valve portion 38, the valve
portion 38 may also be made of a flexible, synthetic material. For
example, the valve portion 38 may be made of polyurethane similar
to the valves described in "A Tricuspid Polyurethane Heart Valve as
Alternative to Mechanical Prostheses or Bioprostheses." by Lo et
al., Trans Am Society of Artificial Internal Organs, 1988; 34:
pgsvalve displacer 839-844, and "Evaluation of Explanted
Polyurethane Trileaflet Cardiac Valve Prostheses," Journal Thoracic
Cardiovascular Surgery, 1988; 94: pgs 419-429.
[0062] Referring to FIGS. 2-4, the delivery catheter 4 has a
temporary valve mechanism 40 which provides temporary valve
functions during and/or after deployment of the valve displacer 8.
The temporary valve mechanism 40 ensures proper blood flow
regulation when the leaflets are held open by the valve displacer 8
to provide time for accurate positioning and deployment of the
valve 6. The temporary valve mechanism 40 is preferably a balloon
44 coupled to an inflation mechanism 47 controlled by a control
system 42. The control system 42 senses the patient's heartbeat to
time balloon inflation and deflation to permit and prevent flow in
the same manner as the native valve. Similar systems for
synchronizing inflation and deflation of a balloon with the
patient's heartbeat are known in balloon pump technology and are
described in U.S. Pat. Nos. 5,817,001, 5,413,549 and 5,254,097
which are hereby incorporated by reference. The balloon 44 is
preferably inflated with a gas for quick inflation and deflation.
The temporary valve mechanism 40 is preferably the balloon 44 but
may also be a passive mechanical valve which automatically opens
and closes due to blood flow forces.
[0063] The catheter 4 may also include an elongate balloon 45 to
help pump blood through the patient's body like a blood pump. The
balloon 45 is also coupled to an inflation mechanism 49 controlled
by the control system 42 which inflates and deflates the balloon 45
to provide pumping assistance to the patient's heart. Balloon pump
technology is described in the above-mentioned patents. The
elongate balloon 45 may be replaced by any other suitable blood
pump, such as a centrifugal pump having an impeller, without
departing from the scope of the invention.
[0064] The temporary valve mechanism 40 and balloon 45 are, of
course, only necessary when implanting the valve with the patient's
heart beating. If the patient's heart is stopped and the patient is
supported by a bypass system during the valve implantation
procedure, the temporary valve mechanism 40 and/or balloon 45 may
be used after the procedure for emergency valve functions or
pumping assistance. The balloon 44 is preferably positioned in the
ascending or descending aorta and the balloon 45 is preferably
positioned in the descending aorta.
[0065] Referring to FIGS. 3-6, the delivery catheter 4 also has
first and second expandable members 46, 48 which deploy the valve
displacer 8 and cardiac valve 6, respectively. The expandable
members 46, 48 are preferably balloons 50, 52 but may also be
mechanically actuated devices. The balloons 50, 52 are coupled to
inflation lumens 54, 56 through which inflation fluid is delivered
from sources of inflation fluid 58, 60, respectively. The balloon
50 expands greater at the ends to form the flared ends 16, 18 of
the valve displacer 8.
[0066] The delivery catheter 4 includes a first catheter 62, which
carries the valve displacer 8, and a second catheter 64, which
carries the cardiac valve 6. Referring to FIGS. 2 and 12, the
second catheter 64 has a passageway 66 which receives the first
catheter 62. A hemostasis valve 68 permits slidable movement
between the first and second catheters 62, 64. The first catheter
62 has lumen 54 for inflating balloon 50 and the second catheter 64
has lumen 48 for inflating balloon 52. The second catheter 64 also
has a lumen 51 for inflating balloon 44 and a lumen 53 for
inflating balloon 45. The first catheter 62 also has a main lumen
70 which receives a guidewire 72.
[0067] The slidable connection between the first and second
catheters 62, 64 permits introduction of the first catheter 62 over
the guidewire 72 with the second catheter 64 being advanced over
the first catheter 62 after the valve displacer 8 is in the
ascending aorta. In this manner, the first catheter 62 may be
advanced more easily over the guidewire 72 and through the
patient's vasculature, such as around the aortic arch, as compared
to a single, multichannel catheter having all features of the first
and second catheters 62, 64. The first and second catheters 62, 64
may be wire-reinforced (not shown) catheters constructed in the
manner described in Published PCT Application WO 97/32623 entitled
"Cannula and Method of Manufacture and Use" which is hereby
incorporated by reference.
[0068] A method of implanting a cardiac valve 6 in accordance with
the present invention is now described in connection with FIGS.
1-6. Although the method is described in connection with the system
described above, the method may be practiced with other suitable
devices, including the devices and systems described below, without
departing from the scope of the invention. Furthermore, the method
is described in connection with replacing the aortic valve,
however, the method may also be applied to other other cardiac
valves such as the mitral, tricuspid and pulmonary valves.
[0069] Before implanting the cardiac valve 6, it may be desirable
to perform valvuloplasty to break up pathologic adhesions between
the native valve leaflets. Breaking up adhesions ensures that the
valve displacer 8 expands fully to provide a large blood flow path.
Valvuloplasty is preferably performed with a balloon which is
inflated to open the leaflets and break the adhesions. The native
cardiac valve and annulus are also sized to determine the proper
size valve displacer 8 and cardiac valve 6. Sizing may be carried
out using fluoroscopy, intravascular ultrasound or with any other
suitable device during or after the valvuloplasty. Size parameters
to consider include the cross-sectional profile through the valve,
the length and size of the valve leaflets and position of the
coronary ostia.
[0070] The delivery catheter 4 is preferably introduced into the
patient by surgical cutdown in the femoral artery but may also be
introduced percutaneously using the Seldinger technique. As
mentioned above, the delivery catheter 4 may also be introduced
into any other suitable vessel or through a small incision in the
chest. The first and second catheters 62, 64 are advanced into the
artery through the cutdown a short distance. The guidewire 72 is
then advanced ahead of the first and second catheters 62, 64 up the
descending aorta, around the aortic arch, into the ascending aorta
and across the aortic valve. The first catheter 62 is then advanced
over the guidewire 72 to the ascending aorta with the sheath 10
covering the first catheter 62 to prevent contact between the valve
displacer 8 and the blood vessel or native valve. The second
catheter 64 is then advanced over the first catheter 62 to position
the cardiac valve 6 in the ascending aorta. The sheath 10 also
prevents contact between the cardiac valve 6 and vessel wall when
advancing the second catheter 64. The sheath 10 is then retracted
as shown in FIG. 2 to expose the valve displacer 8 and the cardiac
valve 6.
[0071] The valve displacer 8 is then introduced between the valve
leaflets as shown in FIG. 3 and the balloon 50 is inflated to
expand the valve displacer as shown in FIG. 4. The valve displacer
8 holds the native valve leaflets open so that the native valve
does not have to be removed. When the valve displacer 8 has been
deployed, the temporary valve mechanism 40 provides temporary valve
functions by inflating and deflating the balloon 44 at appropriate
times to permit and block flow in the same manner as the native
valve. The balloon 45 may also be inflated and deflated to provide
pumping assistance to the patient's heart during the procedure.
Although the above-described method is performed with the patient's
heart beating, the procedure may also be performed on a stopped
heart with the patient supported by a bypass system.
[0072] The second catheter 64 is then advanced until the valve 6 is
positioned adjacent the valve displacer 8. Although FIG. 5 shows
the first catheter 62 extending into the left ventricle, the first
catheter 62 may also be designed to be withdrawn into the
passageway 66 of the second catheter 64 so that the first catheter
62 does not extend beyond the second catheter 64. The balloon 52 is
then partially inflated so that the distal end of the valve 6
having the protrusions 34 expands. The second catheter 64 is then
manipulated until the protrusions 34 engage the openings 14 in the
valve displacer 8. The balloon 52 is then inflated further to
expand the rest of the support structure 26. The catheters 62, 64
are then removed leaving the cardiac valve 6 in place.
[0073] Referring to FIGS. 13 and 14, another system 2A for
implanting a cardiac valve 6A is shown wherein the same or similar
reference numbers refer to the same or similar structures. The
cardiac valve 6A is similar to the cardiac valve 6 described above,
however, the cardiac valve 6A is self-expanding and, therefore,
does not require an independent expansion mechanism. The support
structure 26A is made of a resilient material to naturally bias the
support structure 26A to the expanded position. The support
structure 26A may be made of any suitable material and preferred
materials are stainless steel or shape-memory alloys such as
nitinol. Delivery catheter 4A has the expandable member 46, which
is preferably the balloon 50, for expanding the valve displacer
8.
[0074] The cardiac valve 6A is contained within an outer wall 74 of
the delivery catheter 4A. The cardiac valve 6A is advanced out of a
chamber 76 in the delivery catheter 4A by advancing a rod 78 having
a pusher element 80 attached thereto. The pusher element 80 engages
the posts 82 on the cardiac valve 6A to move the cardiac valve 6A
out of the chamber 76. The rod 78 has threaded connections 80, 82
with a tip 84 and the pusher element 80 to facilitate assembling
the delivery catheter 4A and loading the cardiac valve 6A in the
chamber 76. The rod 78 has a guidewire lumen 86 for receiving the
guidewire 72. Referring to the cross-sectional view of FIG. 15, the
catheter 4A has a first lumen 88 coupled to the balloon 50, a
second lumen 90 coupled to the balloon 44 and a third lumen 91
coupled to the balloon 45. The second and third lumens 88, 90 are
coupled to the inflation mechanisms 47, 29 which are controlled by
the control system 42 described in connection with FIGS. 1 and 2.
The system 2A preferably includes the sheath 10 which prevents
contact between the blood vessel and the valve displacer 8 when the
catheter 4A is advanced through the blood vessel.
[0075] The cardiac valve 6A is implanted in substantially the same
manner as the cardiac valve 6 and the discussion of implantation of
the cardiac valve 6 is also applicable here. The delivery catheter
4A may be introduced in any manner described herein and FIG. 13
shows the catheter 4A extending through the femoral artery with the
valve displacer 8 positioned between the valve leaflets prior to
expansion. The valve displacer 8 is expanded in the manner
explained above to hold the leaflets open. After the valve
displacer 8 has been expanded, the catheter 4A is retraced a
predetermined amount so that the protrusions 34 are exposed outside
the distal end of the catheter 4A. The catheter 4A may then be
manipulated as necessary so that the protrusions 34 engage the
openings 14 in the valve displacer 8. The valve 6A preferably
remains coupled to the catheter 4A while the protrusions 34 are
exposed for manipulation of the valve 6A until the valve 6A engages
the valve displacer 8. After the valve 6A has engaged the valve
displacer 8, the rod 78 is then advanced far enough to completely
release the cardiac valve 6A.
[0076] Referring to FIGS. 16-22, another system 4B for implanting
the cardiac valve 4A is shown wherein the same or similar reference
numbers refer to the same or similar structure. The system has the
self-expanding cardiac valve 4A described above. The valve
displacer 8B is similar to the valve displacer 8 described above,
however, the valve displacer 8B is also self-expanding and,
therefore, does not require an independent expansion mechanism. The
valve displacer 8B is made of a resilient material to naturally
bias the valve displacer 8B to the expanded position. The valve
displacer 8B may be made of any suitable material and preferred
materials are stainless steel and shape-memory alloys such as
nitinol.
[0077] The valve displacer SB and cardiac valve 6A are contained
within an outer wall 74 of the delivery catheter 4B as shown in
FIG. 21. The valve displacer 8B and cardiac valve 4A are advanced
out of a chamber 76B in the delivery catheter 4B by advancing a rod
78B having first and second pusher elements 80B. 81B attached
thereto. The rod 78B has threaded connections 79B. 82B, and 83B
with the tip 84 and the first and second pusher elements 80B. 81B
to facilitate assembling catheter 4B and loading the valve
displacer 8B and cardiac valve 6A in the chamber 76B. The rod 78B
has the guidewire lumen 86 for receiving the guidewire 72 (FIG.
14). Referring to FIG. 16 and the cross-sectional view of FIG. 22,
the catheter 4B has a lumen 90 coupled to the balloon 44 which
serves as the temporary valve mechanism 40 and a lumen 93 which is
coupled to the balloon 45. The lumen 90 and lumen 93 are coupled to
the inflation mechanisms 47, 29 which are controlled by the control
system 42 (FIGS. 1A, 1B, and 2).
[0078] Another method of implanting a cardiac valve is now
described with reference to FIGS. 16-20 wherein the same or similar
reference numbers refer to the same or similar struture. The method
describes use of the delivery catheter 4B and cardiac valve 6A,
however, the method may be practiced using other suitable
structures. The delivery catheter 4B is introduced in any manner
described above and is preferably introduced through the femoral
artery. The guidewire 72 is advanced ahead of the catheter 4B into
the ascending aorta and the delivery catheter 4B is advanced over
the guidewire 72. The delivery catheter 4B is then advanced between
the valve leaflets. A distal end of the valve displacer 8B is then
advanced out of the chamber 76 and the catheter 4B is retracted
until the valve displacer 8 contacts the valve opening. The
catheter 4B is then retracted while the rod 78B is maintained in
the same position so that the valve displacer 8B emerges from the
chamber 76B as shown in FIG. 18. The catheter 4B is then advanced a
predetermined amount and the rod is advanced to force a distal end
of the valve 6A from the chamber 76B. The catheter 4B is then moved
as necessary so that the protrusions 34 engage the openings 14 in
the valve displacer 8 as shown in FIG. 19. The catheter 4B is then
withdrawn further so that the support structure 26A expands to the
fully deployed position of FIG. 20. The catheter 4B is then removed
leaving the cardiac valve 6A as shown in FIG. 20 During the
procedure described above, the temporary valve mechanism 40
provides temporary valve functions while the balloon 45 provides
pumping assistance as described above.
[0079] Referring to FIGS. 23-30, another system 2C for implanting a
cardiac valve 6C is shown. The system 2C includes the valve
displacer 8 and delivery catheter 4 described above. The delivery
catheter 4 has the balloon 50 for inflating the valve displacer 8,
the balloon 52 for inflating a cardiac valve 6C, the temporary
valve mechanism 40 and the balloon 45. The cardiac valve 6C is
similar to the cardiac valves 6, 6A except that the cardiac valve
6C has barbs 100 which extend outwardly from the cardiac valve 6C
in the expanded condition of FIG. 30. The barbs 100 secure the
cardiac valve 6C to the valve displacer 8 or directly to the vessel
wall. The cardiac valve 6C has depressions 102 so that the barbs
100 are recessed from an outer surface 104 of the cardiac valve 6C
when in the collapsed position of FIG. 29. The depressions 102
prevent the barbs 100 from interfering with smooth retraction of
the sheath 10. When the cardiac valve 6C is expanded, the
depressions 102 and barbs 100 rotate and move outwardly to engage
the valve displacer 8 or vessel wall.
[0080] The system 2C is introduced into the patient in any manner
described above and FIG. 23 shows the delivery catheter 4 passing
through the femoral artery. The valve displacer 8 is deployed in
the manner described above wherein the valve displacer 8 is
introduced into the valve leaflets and expanded with the balloon 50
to hold the native leaflets open as shown in FIG. 24. The delivery
catheter 4 may then be advanced so that the cardiac valve 6C is
expanded in the valve displacer 8 with the barbs 100 passing into
the openings 14 to secure the cardiac valve 6C to the valve
displacer 8 as shown in FIGS. 25 and 26. The barbs 100 may be long
enough to pierce and anchor in the native valve leaflets or may be
designed to merely pass into and engage the sides of the openings
14.
[0081] The term "cardiac valve" as used herein refers to a valve
which substantially replaces the function of the patient's
malfunctioning cardiac valve. The valve may be positioned in the
native valve position or may be positioned in a different location
while still substantially performing the functions of the native
valve. For example, a replacement aortic valve may be positioned
superior to the coronary ostia, in the aortic arch or in the
descending aorta. Such a replacement valve will substantially
function like the patient's native aortic valve. Referring to FIGS.
27 and 28 the cardiac valve 6C is deployed in the ascending and
descending aorta with the barbs 100 securing the cardiac valve 6C
directly to the vessel wall.
[0082] Referring to FIGS. 31-38 another system 2D for introducing a
valve 6D is shown wherein similar or the same reference numbers
refer to similar or the same structure. The valve 6D is coupled to
a valve displacer 8D prior to introduction into the patient. The
valve 6D has an expandable support structure 26D which is movable
from the collapsed position of FIGS. 36 and 37 to the expanded
position of FIGS. 34 and 35. The support structure 26D has flexible
joints 106 which bend to radially collapse the support structure
26D. The support structure 26D has protrusions 34D which engage
holes 108 in the valve displacer 8D. The valve 6D and valve
displacer 8D may engage one another in any other suitable
manner.
[0083] The valve 6D is inverted before being attached to the valve
displacer 8D as shown in FIG. 35. A number of sutures 110,
preferably three, are then passed through the valve 6D. The sutures
110 are used to invert the valve after introduction into the
patient as will be explained below. The valve 6D may be any of the
valves described herein or any other suitable valve without
departing from the scope of the invention. A circumferential ring
111 extends around the support structure 26D. The ring 111 is
preferably made of stainless steel or shape-memory alloy such as
nitinol and provides circumferential support of the valve against
the aortic wall for hemostasis.
[0084] The valve displacer 8D is mounted to a delivery catheter 4D
having a balloon 112 for expanding the valve displacer 8D and valve
6D. The balloon 112 is coupled to a source of inflation fluid 114
(FIG. 31) for inflating the balloon 112. The catheter 4D passes
through a trocar 116 having a hemostasis valve 117. The sutures 110
and the catheter 4D pass through the hemostasis valve which permits
slidable movements of the sutures 110 and catheter 4D.
[0085] The valve 6D is preferably stored in a preservative solution
until just before the procedure as shown in FIG. 34. The valve is
then inverted as shown in FIG. 35 and the sutures 110 are passed
through the valve 6D. The valve 6D is then attached to the valve
displacer 8D as shown in FIG. 37 and mounted to the delivery
catheter 4D.
[0086] The valve 6D may be delivered in any manner described above
and is preferably introduced through an incision in the patient's
chest. Referring to FIGS. 31 and 32, the trocar 116 is introduced
into the ascending aorta through purse-string sutures (not shown).
The trocar 116 may have a chamber (not shown) in which the valve 6D
is positioned when the trocar 116 is introduced into the ascending
aorta. The sheath 10 (see FIGS. 1A, 1B and 2) described above may
also be used to prevent contact between the valve and trocar and
between the valve and the aortic wall. The valve 6D is preferably
introduced with the patient's heart beating but may also be
implanted with the patient's heart stopped and the patient
supported by a bypass system. Although system 2D does not show the
balloons 40 and 45, it is understood that the balloons 40, 45 may
also be used with system 2D without departing from the scope of the
invention.
[0087] After introduction of the trocar 116, the valve 6D is
advanced until the valve 6D is between the native valve leaflets.
The balloon 112 is then inflated to expand the valve 6D and valve
displacer 8D. The catheter 4D is then removed and the sutures 110
are pulled to invert the valve 6D as shown in FIG. 33. An end of
each suture 110 is then pulled to remove the sutures 110. The
trocar 116 and catheter 4D are then removed leaving the valve 6D
(FIG. 38).
[0088] Although the foregoing invention has been described by way
of illustration and example of preferred embodiments for purposes
of clarity and understanding, changes and modifications to the
preferred embodiments may be incorporated without departing from
the scope of the invention. For example, the native valve may be
removed rather than held open with the valve displacer, the
replacement cardiac valve may be a completely synthetic or
mechanical valve, and the expansion mechanism may be a mechanical
mechanism rather than a balloon.
* * * * *