U.S. patent application number 13/454016 was filed with the patent office on 2012-08-09 for leaflet valve.
Invention is credited to James L. Pokorney, Robert Foster Wilson, Scott Robert Wilson.
Application Number | 20120203334 13/454016 |
Document ID | / |
Family ID | 31978478 |
Filed Date | 2012-08-09 |
United States Patent
Application |
20120203334 |
Kind Code |
A1 |
Wilson; Robert Foster ; et
al. |
August 9, 2012 |
Leaflet Valve
Abstract
A device and method for improving flow through a native blood
vessel valve, such as the aortic valve, are provided. The present
invention allows a miniature valve to be implanted into affected
leaflets percutaneously, obviating the need for coronary bypass
surgery. The method includes the cutting of small holes, on the
order of 4 mm, in the leaflets of a targeted valve, thereby
allowing blood to flow through the newly formed holes. The holes
are used as attachment sites for the miniature valves of the
present invention.
Inventors: |
Wilson; Robert Foster;
(Roseville, MN) ; Wilson; Scott Robert; (Maple
Grove, MN) ; Pokorney; James L.; (Northfield,
MN) |
Family ID: |
31978478 |
Appl. No.: |
13/454016 |
Filed: |
April 23, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12037025 |
Feb 25, 2008 |
8163008 |
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13454016 |
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10651162 |
Aug 28, 2003 |
7335218 |
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12037025 |
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60407414 |
Aug 28, 2002 |
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Current U.S.
Class: |
623/2.11 ;
623/2.17 |
Current CPC
Class: |
A61F 2/2418 20130101;
Y10S 623/904 20130101; A61F 2/2466 20130101; A61F 2/2463 20130101;
A61F 2/2427 20130101 |
Class at
Publication: |
623/2.11 ;
623/2.17 |
International
Class: |
A61F 2/24 20060101
A61F002/24 |
Claims
1. A method of implanting a prosthetic valve assembly into a target
site comprising: inserting at least a portion of the valve assembly
into the target site in a distal direction; allowing a distal
portion of the valve assembly to flare radially such that the
radially flared distal portion engages tissue of the target site;
and releasing a remaining portion of the valve assembly.
2. The method of claim 1 wherein inserting at least a portion of
the valve assembly into the target site in a distal direction
comprises inserting at least a portion of the valve assembly
between leaflets of a target native valve.
3. The method of claim 1 wherein allowing a distal portion of the
valve assembly to flare radially comprises allowing a distal
portion of a deformable housing of the valve assembly to flare
radially.
4. The method of claim 1 further comprising using friction between
the valve assembly and the target site to hold the valve assembly
in place.
5. The method of claim 4 wherein using friction between the valve
assembly and the target site to hold the valve assembly in place
comprises providing a mesh housing material.
6. The method of claim 1 wherein allowing a distal portion of the
valve assembly to flare radially comprises allowing a distal cuff
to flare radially.
7. A fluid control valve, transluminally deliverable via a catheter
to a target site in a patient, comprising: a deformable mesh
housing structure including a radially expandable anchoring
mechanism; and, a flow control mechanism coupled to said deformable
housing structure.
8. The fluid control valve of claim 7 wherein said anchoring
mechanism comprises a cuff.
9. The fluid control valve of claim 7 wherein said radially
expandable anchoring mechanism includes a distal end that, when
said fluid control valve is compressed into a catheter, comprises a
distal end of the fluid control valve.
10. The fluid control valve of claim 7 wherein said flow control
mechanism comprises a sleeve.
11. The fluid control valve of claim 10 wherein said sleeve has a
distal end and a proximal end, said distal end coupled to said
deformable housing structure.
12. The fluid control valve of claim 11 wherein said distal end of
said sleeve is coupled to an inside surface of said deformable
housing structure.
13. The fluid control valve of claim 11 wherein said proximal end
extends proximally out of said deformable housing structure.
14. The fluid control valve of claim 7 wherein said anchoring
mechanism comprises radially self-expanding legs.
15. A system for transluminally delivering a replacement fluid
control valve to a target site in a patient comprising: a delivery
catheter; a radially compressible and expandable mesh cuff having a
compressed state allowing said cuff to be contained within said
delivery catheter and an expanded state that anchors said cuff to a
target site in a patient; a flow control mechanism having a sleeve
and a plurality of valve members, said sleeve having a distal
portion and a proximal portion, said distal portion operably
coupled to and within said cuff.
16. The system of claim 15 wherein said cuff has a distal end that
expands as said cuff exits said delivery catheter.
17. The system of claim 15 wherein said proximal portion of said
flow control mechanism extends proximally out of said cuff.
18. The system of claim 16 wherein said distal end of said cuff
flares outwardly during expansion.
19. The system of claim 15 wherein said cuff has a proximal end
that surrounds said distal portion of said sleeve.
20. The system of claim 16 wherein said distal end of said cuff is
constructed and arranged to expand as said cuff exits said delivery
catheter such that said distal end of said cuff contacts tissue
prior to a remaining portion of said cuff exiting said delivery
catheter.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 12/037,025 filed Feb. 25, 2008 entitled
Leaflet Valve [as amended], which will issue as U.S. Pat. No.
8,163,008 on Apr. 24, 2012; which is a continuation of U.S. patent
application Ser. No. 10/651,162 filed Aug. 28, 2003 entitled
Delivery Device For Leaflet Valve (now U.S. Pat. No. 7,335,218
issued Feb. 26, 2008), which claims benefit of U.S. Provisional
Application Ser. No. 60/407,414, filed Aug. 28, 2002 entitled
Mini-Valve Heart Valve Replacement; all of which are incorporated
herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] Blood vessel valves include flexible tissue leaflets that
passively alternate between open and closed positions as the forces
of a blood stream act upon them. As blood flows in a first
direction, the leaflets are urged apart from each other, and allow
the blood to pass. Between pulses, as the blood attempts to flow in
a reverse direction, the blood acts upon upstream surfaces of the
individual leaflets, causing the leaflets to move inwardly. As the
leaflets move inwardly, the edges of the individual leaflets (two,
in the case of bicuspid valves, and three in the case of tricuspid
valves) abut against each other, effectively blocking the blood
flow in the reverse direction.
[0003] Valves are also present within the heart. The heart contains
four one-way valves that direct blood flow through the heart and
into the arteries. Three of these valves, the aortic valve, the
tricuspid valve, and the pulmonary valve, each have three leaflets.
The fourth valve, the mitral valve, has two leaflets. By defining a
direction in which blood can flow, these valves are responsible for
the resulting pump effect a heart has on blood when the heart
beats.
[0004] A number of diseases result in a thickening, and subsequent
immobility or reduced mobility, of valve leaflets. Valve immobility
leads to a narrowing, or stenosis, of the passageway through the
valve. The increased resistance to blood flow that a stenosed valve
presents eventually leads to heart failure and death.
[0005] Treating severe valve stenosis or regurgitation has
heretofore involved complete removal of the existing native valve
followed by the implantation of a prosthetic valve. Naturally, this
is a heavily invasive procedure and inflicts great trauma on the
body leading usually to great discomfort and considerable recovery
time. It is also a sophisticated procedure that requires great
expertise and talent to perform.
[0006] Historically, such valve replacement surgery has been
performed using traditional open-heart surgery where the chest is
opened, the heart stopped, the patient placed on cardiopulmonary
bypass, the native valve excised and the replacement valve
attached. More recently, it has been proposed to perform valve
replacement surgery percutaneously, that is, through a catheter, so
as to avoid opening the chest.
[0007] One such percutaneous valve replacement method is disclosed
in U.S. Pat. No. 6,168,614 (the entire contents of which are hereby
incorporated by reference) issued to Andersen et al. In this
patent, the prosthetic valve is collapsed to a size that fits
within a catheter. The catheter is then inserted into the patient's
vasculature and moved so as to position the collapsed valve at the
location of the native valve. A deployment mechanism is activated
that expands the replacement valve against the walls of the body
lumen. The expansion force pushes the leaflets of the existing
native valve against the lumen wall thus essentially "excising" the
native valve for all intents and purposes. The expanded structure,
which includes a scaffold configured to have a valve shape with
valve leaflet supports, is then released from the catheter and
begins to take on the function of the native valve. As a result, a
full valve replacement has been achieved but at a significantly
reduced physical impact to the patient.
[0008] One particular drawback with the percutaneous approach
disclosed in the Andersen '614 Patent is the difficulty in
preventing leakage around the perimeter of the new valve after
implantation. Since it appears that the tissue of the native valve
remains within the lumen, there is a strong likelihood that the
commissural junctions and fusion points of the valve tissue (as
pushed against the lumen wall) will make sealing of the prosthetic
valve around the interface between the lumen and the prosthetic
valve difficult. Furthermore, in some patients, the deflection of
the leaflets against the lumen walls could potentially obstruct the
ostial openings of the lumen.
[0009] Although both the traditional open heart valve replacement
surgery and the newer percutaneous valve replacement surgery
replace a native valve in entirely different ways and both have
their drawbacks, the paradigm of these two approaches is identical:
Render the native valve useless, either through excision (open
heart) or immobilization (percutaneous), and then implant a
completely new replacement prosthetic valve to take over. In other
words, both approaches rely entirely on the premise that the native
valve must be entirely replaced (physically or functionally) by an
entirely new prosthetic valve.
[0010] In contravention of the prior art, the present invention
introduces an entirely different paradigm to valve replacement
surgery, something neither taught nor contemplated by the open
heart approach or the percutaneous approach (e.g., U.S. Pat. No.
6,168,614) and something that largely avoids the drawbacks
associated with both. More specifically, the present invention is
premised on leaving the native valve in place, not on its excision
or immobilization, and then utilizing the native valve as a
platform for actually treating the diseased valve. This is a wholly
new approach to treating diseased valves.
[0011] For example, in one embodiment of the invention, the
physician diagnoses that the patient has a stenotic valve and then
percutaneously mounts a plurality of small "leaflet valves" or
"mini-valves" on one or more of the diseased native valve leaflets.
In other words the native valve and its leaflets are used as a
planar surface or a type of "bulkhead" on which new mini leaflet
valves are mounted. The native valve remains in place but valve
disfunction is remedied due to the presence of these new leaflet
valves. As a result, the diseased valve is successfully treated
without the complication associated with removing the native
valve.
[0012] This leads to a much simpler and safer approach as compared
to the prior art. It avoids the invasive nature of the open heart
approach and avoids the sealing and ostial blockage problems of the
percutaneous approach.
BRIEF SUMMARY OF THE INVENTION
[0013] The present invention relates to the treating of narrowed,
stiff or calcified heart valves. The aforementioned problems with
present treatment methods are addressed by treating the targeted
valve leaflets individually, rather than replacing the entire valve
using an open-heart or a percutaneous procedure. That is, in the
present method, the rigid heart valve leaflet is treated by
introducing small prosthetic valves into the leaflet itself.
[0014] The present invention includes a method of treating the
individual leaflets of a targeted heart valve that includes
installing one or more small, one-way valves into the targeted
leaflets. These smaller valves can be placed in the leaflet using
catheter systems, obviating the need for opening the heart or great
vessels, cardiopulmonary bypass, excision of the diseased valve,
and a thoracotomy. Additionally, multiple small valve placements
might reduce the long-term risks associated with a complete
prosthetic valve, because failure of an individual valve will not
necessarily lead to cardiac failure. The remaining small valves and
remaining healthy native valves might be sufficient to sustain
life.
[0015] One aspect of the present invention provides a method of
placing small valves through a target valve that involves
puncturing the target valve and pushing the miniature valve through
the target valve tissue. The valve is then anchored in place using
a variety of mechanisms including tabs, riveting of the valve
housing, spines, friction placement or the use of a fixation
cuff.
[0016] Another aspect of the present invention provides a variety
of valve implant mechanisms constructed and arranged for placement
in a target valve leaflet. The valve implant mechanisms include a
valve housing that operably houses a valve mechanism such as a
duckbill valve, a tilting check valve, a ball and cage valve, or a
hinged leaflet valve or a valve using tissue leaflets. The valve
implant may also include an anchoring mechanism such as tabs,
spines, threads, shoulders, or a deformable housing.
[0017] The present invention also provides a device useable to
remove a section of the target valve, without damaging the
surrounding valve tissue, and inserting a valve implant into the
void left in the target valve. The device is contained within a
catheter such that a valve implant insertion procedure can be
accomplished percutaneously. Preferably, this delivery system is
constructed and arranged to be placed through a 14 French catheter,
traverse the aorta, land on a targeted leaflet such as one of the
leaflets of the aortic valve, puncture the leaflet at a
predetermined spot, cut a hole on the order of 4 mm in diameter,
capture and remove any cut tissue, place a radially compressed
one-way valve including a attachment cuff made of a shape memory
alloy material (e.g., Nitinol) and a stainless steel sizing ring
into the leaflet hole, securely attach the valve assembly to the
leaflet, dilate the hole and the valve assembly to a precise final
diameter, such as 8 mm, using a balloon, and be retracted leaving
the valve assembly in place in the leaflet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view of three valve implants of the
present invention installed in the leaflets of a tricuspid
valve;
[0019] FIG. 2 is a side elevation of two valve implants of the
present invention installed in a stenotic leaflet;
[0020] FIGS. 3a-f are side elevations of various embodiments of the
valve implant of the present invention;
[0021] FIG. 4a is a detailed sectional view of a preferred
embodiment of the valve implant of the present invention in a
compressed or folded state;
[0022] FIG. 4b is a detailed sectional view of the valve implant of
FIG. 4a in an expanded state;
[0023] FIGS. 4c-f are sectional views of alternative configurations
of the preferred valve implant of the present invention;
[0024] FIG. 5a is a sectional view of an embodiment of the delivery
system of the present invention;
[0025] FIG. 5b is a detailed sectional view of the distal end of
the delivery system of FIG. 5a;
[0026] FIG. 6 is a sectional view of the leaflet capture catheter
of the present invention;
[0027] FIG. 7a is a sectional view of the delivery catheter of the
present invention;
[0028] FIG. 7b is a perspective view of an alternative cutter of
the present invention;
[0029] FIG. 8 is a sectional view of the sheath catheter of the
present invention;
[0030] FIG. 9a is a detailed sectional view of the handle of the
delivery system of the present invention;
[0031] FIG. 9b is a side elevation of the handle of FIG. 9a;
[0032] FIG. 10a is a side elevation of the handle of the present
invention in a "Deliver" position;
[0033] FIG. 10b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Deliver" position of FIG. 10a;
[0034] FIG. 11a is a side elevation of the handle of the present
invention in an "Insert" position;
[0035] FIG. 11b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Insert" position of FIG. 11a;
[0036] FIG. 12a is a side elevation of the handle of the present
invention in a "Cut" position;
[0037] FIG. 12b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Cut" position of FIG. 12a;
[0038] FIGS. 13a-e are an operational sequence of the capture
device of FIG. 6 interacting with the cutting drum of FIG. 7a to
remove and capture a section of tissue from a target valve
leaflet;
[0039] FIG. 14a is a side elevation of the handle of the present
invention in a "Distal" position;
[0040] FIG. 14b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Distal" position of FIG. 14a;
[0041] FIG. 15a is a side elevation of the handle of the present
invention in a "Proximal" position;
[0042] FIG. 15b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Proximal" position of FIG. 15a;
[0043] FIG. 16a is a side elevation of the handle of the present
invention in an "Inflate" position;
[0044] FIG. 16b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Inflate" position of FIG. 16a and a balloon of the delivery system
is inflated;
[0045] FIG. 17a is a side elevation of the handle of the present
invention in an "Inflate" position during a deflating
procedure;
[0046] FIG. 17b is a sectional view of the distal end of the
delivery system of the present invention when the handle is in the
"Inflate" position of FIG. 17a and the balloon of the delivery
system has been deflated;
[0047] FIG. 18 is a sectional view of a valve implant of the
present invention in a deployed configuration;
[0048] FIGS. 19A and 19B are cross-sectional views of a valve
implant of the present invention in a deployed configuration;
[0049] FIG. 20 is a cross-sectional view of a portion of a catheter
delivery system in accordance with a preferred embodiment of the
present invention;
[0050] FIG. 21 is a flow chart figure showing a tether retraction
system for use in a catheter delivery system in accordance with the
present invention;
[0051] FIGS. 22A and 22B are top views of a hinged valve in
accordance with another preferred embodiment of the present
invention;
[0052] FIGS. 23A, 23B and 23C are cross-sectional views of a hinged
valve in accordance with the present invention; and,
[0053] FIGS. 24A and 24B are cross-sectional views of a hinged
valve in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0054] Referring now to the Figures, and first to FIG. 1, there is
shown a native tricuspid valve 5 with a valve implant 10 of the
present invention installed in each of the three leaflets 7 of the
tricuspid valve 5. The valve implants 10 are shown in an open
position to demonstrate that blood is allowed to flow through the
valve implants 10, in one direction, even though the native
tricuspid valve 5 remains closed. These valve implants 10 would
similarly work with a native bicuspid valve, unicuspid valve or
quadracuspid valve.
[0055] FIG. 2 demonstrates the positioning of a valve implant 10 in
a native leaflet 7. The leaflet 7 is shown as having calcified
tissue 9, characteristic of a stenosed valve. Notably, the valve
implants 10 have been inserted through the calcified tissue 7. Also
notable is that there may be more than one valve implant 10
inserted into a single leaflet 7 if additional flow capacity is
desired. Alternatively, though not shown, the valve implant 10 may
be installed between the leaflets 7. This configuration is
especially feasible in heavily stenosed valves that have relatively
immovable leaflets. Such leaflets may be fully or partially fused
together. The valve implants generally comprise an anchoring
mechanism 12 and a valve mechanism 14.
[0056] FIGS. 3-5 illustrate several embodiments of the valve
implants 10 of the present invention. In FIGS. 3a-f, a family of
valve implants 10 is provided that are characterized by a rigid
housing 16 with a self-tapping tip 18. The valve implants 10 of
FIGS. 3a-f include a variety of valve mechanisms 14 and anchoring
mechanisms 12.
[0057] The valve implant 10 of FIG. 3a, as well as those of FIGS.
3c and 3d, has a valve mechanism 14 that comprises a single flap
20, hinged on one side, that acts against the rigid housing 16 to
prevent flow in a reverse direction. A benefit of this valve design
is ease of construction. The valve implant 10 of FIG. 3a also uses
the friction between the rigid housing 16 and the native heart
leaflet 7 (FIG. 2) as an anchoring mechanism to hold the valve
implant 10 in place. The pointed tip 18 allows the valve implant 10
to be urged through, or twisted through, the native heart leaflet
without the need for cutting a hole in the leaflet prior to
installing the valve implant 10. Thus, in certain cases, there is
sufficient gripping power between the housing 16 and the leaflet 7
to hold the housing 16 in place. This holding power may be
increased by providing a textured surface (not shown) on the
housing 16, or selecting a housing material, such as a mesh or
stiff fabric, that allows a controlled amount of ingrowth,
sufficient to secure the valve implant 10, but not so much as to
cause a flow hindrance within the valve implant 10.
[0058] The valve implant 10 of FIG. 3b has a valve mechanism 14
that comprises a pair of members constructed and arranged to form a
duckbill valve 22. The duckbill valve 22 operates in a similar way
to a tricuspid or bicuspid valve. When fluid flows through the
valve in a desired direction, each of the members of the duckbill
valve 22 move apart from each other. When the flow reverses, such
as during diastole, the fluid forces the members of the duckbill
valve 22 together, closing the valve 10.
[0059] Also included in the valve implant 10 of FIG. 3b is an
anchoring mechanism 12. The anchoring mechanism 12 generally
comprises a plurality of radially extending posts 24. These posts
24 act against an upstream side 26 (FIG. 2) of the leaflet 7,
thereby counteracting systolic pressure from the blood stream.
[0060] The valve implant 10 of FIG. 3c includes a single flap 20
valve mechanism 14 and an anchoring mechanism 12 that includes a
plurality of angled barbs 28. The barbs 28 are located near the
upstream side of the valve implant 10 and are angled back toward
the downstream side. The angled barbs 28 may provide increased
gripping power, especially if more than one row, such as shown in
FIG. 3c, are provided. Because one or more of the rows of barbs 28
will be located within the leaflet 7 when the valve implant is in
place, the barbs 28 provide resistance to movement in both
directions, and may stimulate ingrowth.
[0061] The valve implant 10 of FIG. 3d provides a combination of
many of the features already discussed. The valve 10 has an
anchoring mechanism 12 that includes both posts 24, on the
downstream side to prevent valve movement in the upstream
direction, and angled barbs 28 on the upstream side of the valve
10. The valve mechanism 14 demonstrates another valve design. The
valve mechanism is an outside-hinged dual flap valve 30. The
individual flap members rotate about their outer edges when
influenced by fluid flow.
[0062] FIG. 3e shows a valve implant 10 with a valve mechanism 14
that uses an inside-hinged dual flap valve 32, with individual flap
members that rotate about their inner edges when influenced by
fluid flow. The valve implant 10 combines upstream posts 24 with
upstream-angled barbs 28 on the downstream side of the valve
implant 10.
[0063] The valve implant 10 shown in FIG. 3f combines a single flap
20, as a valve mechanism 14, with an anchoring mechanism 12 that
uses an external helical thread 34 to anchor the valve implant 10
to a valve leaflet 7. The helical thread 34 provides resistance to
movement in both the upstream and downstream directions. The
helical thread 34 also provides a self-tapping action when the
valve implant 10 is being screwed into place in a leaflet 7.
[0064] One skilled in the art will realize that any of the
aforementioned anchoring mechanisms 12 and valve mechanisms 14 may
be combined in a single valve implant 10. For example, the valve
implants 10 shown in FIG. 2 include upstream and downstream posts
24 as well as upstream and downstream angled barbs 28.
[0065] A preferred embodiment of the valve implant 10 of the
present invention is shown in FIGS. 4a and 4b. The valve implant 10
is expandable from the compressed configuration shown in FIG. 4a,
to the expanded configuration shown in FIG. 4b. The valve implant
10 is constructed and arranged to fit within a catheter when in the
compressed configuration. Compression may be accomplished radially,
helically, longitudinally, or a combination thereof. Preferably,
the compression of the valve implant 10 is radial.
[0066] Like the aforementioned embodiments of the valve implants
10, the valve implant 10 of FIG. 4 generally includes an anchoring
mechanism 12 and a valve mechanism 14. The anchoring mechanism 12
generally comprises a cuff 36 and a sizing ring 38. The cuff 36 is
preferably constructed of Nitonol and has a middle portion 40 a set
of radially expanding distal legs 42 and a set of radially
expanding proximal legs 44.
[0067] In the compressed state, the legs 42 and 44 are somewhat
aligned with the middle portion 40 to allow the cuff 36 to be
compressed into a catheter, preferably a 14 French catheter. The
cuff 36 is either expandable or self-expanding. Upon release from
the catheter, the legs 42 and 44 fold outwardly until they radiate
from the middle portion 40 at approximately right angles to the
longitudinal axis of the cuff 36. The legs 42 and 44 are designed
to act against the upstream and downstream sides, respectively, of
a valve leaflet, sandwiching the leaflet therebetween and anchoring
the cuff 36 to the leaflet.
[0068] The anchoring mechanism 12 of the valve implant 10 shown in
FIGS. 4a and 4b also includes a sizing ring 38. The sizing ring 38
is preferably a stainless steel stent that circumjacently surrounds
the middle portion 40 of the cuff 36. The sizing ring 38 is
constructed and arranged to expand with the cuff 36 until a
predetermined size is reached. Once the predetermined size is
reached, the sizing ring 38 prevents further expansion by the cuff
36. Over expansion of the cuff 36 could render the valve mechanism
14 inoperable, cause calcified tissue to break away from the
stenosed valve and become released into the blood stream, tear the
leaflet tissue, or weaken the cuff 36.
[0069] The valve mechanism 14 includes a sleeve 46 and one or more
valve members 48. The sleeve 46 may be rigid or flexible, but it is
preferably flexible. More preferably, the sleeve 46 is constructed
of any sufficiently flexible material capable of withstanding the
environment to which it will be subjected, including but not
limited to, any mammalian tissue, including human or pig tissue,
vertebrate tissue, or a polymer or other synthetic material. The
valve members 48 are shown as being duckbill valves but may be any
of the aforementioned discussed valve designs.
[0070] Most preferably, the valve mechanism 14 comprises an intact
harvested valve from an animal, such as pig, and is taken from an
appropriate location such that the expanded, original size is
suitable for use in the leaflets of the stenotic valve being
treated. The harvested valve is sutured or otherwise attached to
the inside surface of the cuff 36. In operation, the valve implant
10 is compressed such that it can be placed in a small catheter for
percutaneous delivery. At the time of delivery, the valve implant
10 is attached to a stenotic leaflet and radially expanded to its
functional diameter. Prior to, or during expansion, the distal and
proximal legs 42 and 44 expand radially, allowing the cuff 36 to
create a strong bulkhead-like fitting on both sides of the leaflet.
After attachment is made to the leaflet, the cuff 36, sizing ring
38, and the valve mechanism 14 are radially expanded to the
functional diameter of the valve implant 10. During this expansion,
the sizing ring 38 exhibits plastic deformation until it achieves
the maximum diameter, at which point the sizing ring 38 resists
further expansion.
[0071] FIGS. 4c-4f depict alternative configurations for the
preferred valve implant 10. The valve implant 10 in FIG. 4c has a
sleeve 46 attached to the anchoring mechanism 12 with two rows of
sutures 166 and is configured so an upstream edge 168 of the sleeve
46 is roughly aligned with the distal legs 42 of the anchoring
mechanism 12. The valve implant 10 in FIG. 4d has a sleeve 46
attached to the anchoring mechanism 12 with one row of sutures 166
and is configured so the upstream edge 168 of the sleeve 46 is
roughly aligned with the proximal legs 44 of the anchoring
mechanism 12. The valve implant 10 in FIG. 4e has a sleeve 46
attached to the anchoring mechanism 12 with two rows of sutures 166
and is configured so the downstream edge 170 of the sleeve 46 is
roughly aligned with the proximal legs 44 of the anchoring
mechanism 12. The valve implant 10 in FIG. 4f has a sleeve 46
attached to the anchoring mechanism 12 with one row of sutures 166
and is configured so the downstream edge 170 of the sleeve 46 is
roughly aligned with the distal legs 42 of the anchoring mechanism
12. The sleeve 46 may comprise a scaffold to which valve members 48
are attached, or the entire valve mechanism 14 may be a harvested
tissue valve such as an aortic valve.
[0072] In one preferred embodiment, the valve implant 10 can be
configured to include commissural support structure like a wireform
stent as sometimes found in known standard sized prosthetic tissue
valves. In such a configuration, the valve material will comprise a
biologic tissue such as human pericardium or equine pericardium or
small intestine submucousal tissue. In the present invention, the
material must be thin enough to be compressed and perhaps folded so
as to fit the valve implant 10 within the delivery system
(described below). In a preferred embodiment, such tissue has a
thickness of around 180 microns or less.
[0073] In another alternative embodiment, the cuff mechanism could
be a torroidal shaped sack (not shown), similar in shape to a
deflated inner tube, attached to the exterior surface of the base
of the valve implant 10 and connected to a UV curable liquid
polymer reservoir contained within the delivery catheter. The sack
material is composed of an elastic material that can be radially
expanded by a balloon angioplasty catheter or by the injection of
the liquid polymer. The liquid adhesive contained within the sack
can be transformed to a solid polymer through UV light activated
cross-linking
[0074] This sack, essentially empty, can be manipulated by the
delivery catheter to straddle both sides or surfaces around the
hole cut in the leaflet for receiving the valve implant 10. Once
located, the sack can be enlarged by an underlying balloon
catheter. Then, UV curable liquid polymer can be injected into the
sack through the delivery catheter. Once filled with an adequate
amount of a polymer and adjusted distally/proximally to form
sufficient bulges on both sides of the valve leaflet, a UV light
emission source, located within the delivery catheter near the bag
is activated to wash the adhesive filled bag with UV curing light.
Once hardened by the UV effect, the cuff maintains its enlarged
size without balloon support.
[0075] Referring to FIGS. 22A-24B, yet another embodiment of a
valve implant 10 of the present invention is shown, this embodiment
being a hinged valve. In this embodiment, the valve implant 10
comprises a valve "poppet" 221 that is connected to a valve leaflet
7 by an attachment mechanism 220 that operates much like a hinge.
The valve poppet 221 pivots between a sealed and an unsealed
condition around the pivot point of the attachment mechanism 220
according to the flow of blood (FIGS. 24A and 24B).
[0076] The poppet 221 or "mini-leaflet" can be comprised of any
material sufficiently flexible to allow for the described movement
yet sufficiently durable to withstand the environment. For example,
the poppet 221 may made from materials such as biologic tissue, a
polymer or a carbon based material. Moreover, the poppet 221 could
be coated with tissue prom the patient, e.g., tissue from a
patient's vein wall. The poppet material may include supporting
internal structure and/or an outer ring to ensure the structural
integrity of the poppet 221 during operation. The poppet can have a
curved in order to better conform the poppet 221 to the contour of
the native leaflet 7.
[0077] In this regard, after a hole is created in the leaflet 7
(discussed below), the poppet 221 is pushed or screwed into the
leaflet. It may be retained there by barbs or screw threads or by
hooks or other types of retaining mechanisms.
[0078] The attachment mechanism 220 (FIGS. 22A-22B and 24A-24B), in
a preferred embodiment, is a hinge. The hinge may fabricated from
such materials as a polymer strip, a biologic tissue strip, a metal
(e.g., stainless steel) strip or a pryolytic carbon material.
Referring to FIGS. 24A and 24B, the hinged mechanism may be
attached to the leaflet 7 tissue using a barbed spike 240.
[0079] In an optional embodiment of the invention shown in FIGS.
22A-24B, the valve implant 10 may also include a support ring 222
that is disposed around the inside perimeter of the hole that is
cut in the leaflet 7 to receive the valve implant 10. The support
ring 222 may serve to limit embolization and to enhance leaflet
integrity (thereby avoiding prolapse). The support ring 222 could
be deployed into the hole either with an expanding balloon or it
could be mechanically deployed using a mechanical spreader.
[0080] Referring to FIGS. 23A-24B, the optional support ring 222
may include struts 224, 225 that serve to capture the edges of the
leaflet 7 in the hole so as to support and retain the support ring
220 at the site.
[0081] Catheter Delivery System
[0082] Referring now to FIGS. 5a and 5b, there is shown a preferred
embodiment of a catheter delivery system 50 of the present
invention. The catheter delivery system 50 generally comprises a
leaflet capture catheter 52, a delivery catheter 54, a catheter
sheath 56, and a handle 58. The catheter delivery system 50 is
preferably constructed and arranged for use with a guidewire
60.
[0083] As best seen in FIG. 6, the leaflet capture catheter 52
includes a cutter die 62 connected to a hemostatic hub 64 with a
cannula 66. The cutter die 62 may be of unitary construction and
includes a conical distal end 68 that increases in radius
proximally until a flat 70 is reached. Proceeding proximally, the
flat 70 ends abruptly to form a capture groove 72. At the proximal
end of the capture groove 72, the cutter die 62 returns to
approximately the same diameter as the flat 70. The purpose of the
cutter die 62 is to "grab" tissue that resiliency "pops" into the
capture groove 72. Once in the capture groove 72, the tissue is
held in place as a cutter 90 (explained below) cuts through the
tissue.
[0084] One skilled in the art will realize that alternatives could
be used instead of a cutter die 62. For example, the cutter die 62
could be replaced with a balloon, constructed and arranged to be
inflated on the upstream side of the leaflet 7 (or both sides of
the leaflet to capture the tissue) and sized to fit within the
cutter 90. A second balloon could also be arranged to be inflated
on the downstream side of the leaflet, such that the leaflet is
captured between the two balloons. The balloon concept, though
arguably more complicated and expensive, may prove useful in
situations where a cut needs to be made in tissue that has lost the
resiliency needed to "pop" into the capture groove 72 of the cutter
die 62. Other devices, such as barbs and clamps, are also
envisioned to act in this manner.
[0085] The cannula 66 connects with the cutter die 62 and the
hemostatic hub 64. At the distal end of the cannula 66 is a needle
tip 74. The needle tip 74 is angled to form a sharp point usable to
puncture tissue. The cannula 66 includes a lumen 76 extending the
length thereof. This lumen 76 is used to accommodate a guidewire 60
(FIG. 5).
[0086] The hemostatic hub 64 allows the leaflet capture catheter 52
to be removably attached to the handle 58. The hemostatic hub 64
includes a body 78, a threaded knob 80, and an elastomeric seal 82.
The body 78 defines an interior cavity 84 that is shaped to receive
and hold a cannula hub 86 that is attached to a proximal end of the
cannula 66. The interior cavity 84 is also shaped to receive the
elastomeric seal 82, which is compressed between the threaded knob
80 and the body 78. The interior cavity 84 is partially internally
threaded to receive the external threads of the threaded knob 80.
The threaded knob 80 defines a guidewire port 88 that aligns with
the interior cavity 84 and the lumen 76 of the cannula 66 so that a
continuous port is available for the guidewire 60 to extend the
length of the leaflet capture catheter 52. When a guidewire 60 is
inserted through the guidewire port 88, the threaded knob 80 and
the elastomeric seal 82 act together as a hemostatic valve. When
the threaded knob 80 is rotated to compress the elastomeric seal
82, the elastomeric seal 82 swells inwardly, until it forms a
blood-tight seal around the guidewire 60. The cannula 66 and the
hub 64 are constructed and arranged to carry the tensile force
generated during a hole cutting procedure, discussed in detail
below.
[0087] The leaflet capture catheter 52 is slidingly and coaxially
contained within the delivery catheter 54. The delivery catheter 54
is best shown in FIG. 7a, and includes a cutter 90, a balloon
catheter 92, and a delivery catheter hub 94. The cutter 90 is
constructed and arranged to act with the cutter die 62 (FIG. 6) to
cut tissue. The cutter 90 includes a cutter drum 96 that is a
sharpened cylindrical blade having a cutting tip 98. The cutter tip
98, as shown in FIG. 7a, lies in a plane that is substantially
perpendicular to a longitudinal axis of the delivery catheter.
However, an alternative embodiment of the cutter drum 96, shown in
FIG. 7b, may provide increased cutting power. The cutter drum 96 in
FIG. 7b has a curved, non-planar cutting tip 98. Preferably, the
cutter drum 96 is sized to cut a hole having a diameter of
approximately 4 mm through a leaflet. The cutter drum 96 has a
cutter bulkhead 100 at its proximal end that is attached to the
balloon catheter 92 with an adhesive 102. Other suitable attachment
means for attaching the cutter drum 96 to the balloon catheter 92
include threads, welds, unitary construction and the like. To cut
tissue, the cutter die 62 is pulled within the cutter drum 90.
Thus, the balloon catheter 92, and the adhesive 102 fixing the
bulkhead 100 to the balloon catheter 92, must be able to carry the
compressive force that results from opposing the equal and opposite
tensile force applied to the leaflet capture catheter 52.
[0088] The balloon catheter 92 generally includes an inner tube 104
extending distally and proximally from within an outer tube 106. A
balloon 108 is connected at a distal end to the outside of the
inner tube 104 and at a proximal end to the outside of the outer
tube 106. The outside diameter of the inner tube 104 is smaller
than the inside diameter of the outer tube 106, such that a fluid
passageway is formed therebetween for inflation of the balloon 108.
A flexible valve stop 110 is attached to the outer tube 106 just
proximal of the proximal end of the balloon 108. The valve stop 110
has a flexible sleeve 112 that extends distally over the proximal
end of the balloon 108. The function of the valve stop 110 is to
prevent proximal movement of the valve implant 10 during delivery.
The valve implant 10, as will be seen below, will be placed over
the balloon 108, distal of the valve stop 110. The flexible sleeve
112 allows the balloon to inflate while maintaining a desired
positioning of the valve implant 10. The inner tube 104 has an
inner diameter large enough to accommodate the cannula 66 of the
leaflet capture catheter 52. A proximal end of the balloon catheter
92 is attached to the catheter hub 94.
[0089] The catheter hub 94 includes a catheter hub body 114 that
defines an inner cavity 116 and a balloon inflation port 118. The
proximal-end of the inner cavity 116 has internal threads to
receive an externally threaded knob 120. An elastomeric seal 122
resides between the threaded knob 120 and the catheter hub body
114. The threaded knob 120 defines a capture catheter port 124 that
aligns with the interior cavity 116 of the body 114 and the
interior of the balloon catheter 92 so that the leaflet capture
catheter 52 may pass therethrough.
[0090] The balloon catheter 92 is attached to the catheter hub 94
in such a manner that fluid introduced into the balloon inflation
port 118 will flow between the outer tube 106 and the inner tube
104 to inflate the balloon 108. The outer tube 106 is attached at
its proximal end to the distal end of the interior cavity 116 of
the catheter hub body 114. Preferably, an adhesive 126 is used to
connect the outer tube 106 to the interior cavity 116 of the
catheter hub body 114 at a position distal of the balloon inflation
port 118. The inner tube 104 extends proximally from the proximal
end of the outer tube 108. The proximal end of the inner tube 104
is also attached to the interior cavity 116 of the catheter hub
body 114. However, this connection is made at a position proximal
of the balloon inflation port 118, preferably with an adhesive 128.
Thus, fluid entering the balloon inflation port 118 is blocked from
flowing in a proximal direction by the proximal adhesive 128. It is
also blocked from traveling in a distal direction on the outside of
outer tube 106 by the distal adhesive 126. Instead, the fluid is
forced to flow between the inner tube 104 and the outer tube 106 in
a distal direction toward the interior of the balloon 108.
[0091] The leaflet capture catheter 52 and the delivery catheter 54
are slideably contained within the sheath catheter 56. Referring
now to FIG. 8, it can be seen that the sheath catheter 56 includes
a large diameter sheath 130 attached to a distal end of sheath
tubing 132, which is attached at a proximal end to a sheath hub
134. The sheath hub 134 secures the sheath catheter 56 to the
handle 58. The sheath hub 134 includes a tab 154, the function of
which will be explained below. The sheath 130, sheath tubing 132,
and the sheath hub 134, all define a delivery catheter port 136
that extends throughout the length of the sheath catheter 56. The
large diameter sheath 130, is preferably a 14 French catheter, and
sized to accommodate the cutter drum 96.
[0092] Referring now to FIGS. 9A and 9B, there is shown a preferred
embodiment of the handle 58 of the present invention. The handle 58
includes a handle body 138 that defines at a bottom portion a
figure grip 140. An actuator 142 is pivotally attached to the
handle body 138 with a pivot pin 164. At the top of the actuator
142, is a leaflet capture catheter bracket 144. The leaflet capture
catheter bracket 144 is constructed and arranged to hold the
leaflet capture hemostatic hub 64. At a top portion of the body 138
there is defined a slotted chamber 146. The slotted chamber 146 is
constructed and arranged to hold the delivery catheter hub 94 as
well as the sheath hub 134. The slotted chamber 146 includes
external threads 148 around which the sheath retraction nut 150
rides. At the top of the slotted chamber 146 there is defined a
slot 152 through which the balloon inflation port 118 of the
delivery catheter hub 94 and a tab 154 of the sheath hub 134
extend. Below the slotted chamber 146, a sheath retraction
indicator 156 extends distally from the handle body 138.
Preferably, the handle 58 includes a safety button 158 that
prevents a physician from unintentionally depressing the actuator
142.
[0093] The handle 58 is thus constructed and arranged to slide the
leaflet capture catheter 52 in a proximal direction relative to the
sheath catheter 56 and the delivery catheter 54 when the actuator
142 is squeezed toward the finger grip 140, thereby pulling the
hemostatic hub 64 in a proximal direction. The handle 58 is also
constructed and arranged to slide the sheath catheter 56 proximally
over the leaflet capture catheter 52 and the delivery catheter 54
when the sheath retraction nut 150 is rotated proximally. The
operation of the handle 58 and the rest of the delivery system 50
are explained in more detail below.
[0094] Referring to FIGS. 19A, 19B and 20, in one embodiment of the
present invention, the catheter delivery system 50 includes a
tether 190 looped around the proximal legs 44 of the valve implant
10. The tether extends from the proximal legs 44 all the way
through the catheter until both ends of the tether 190 are joined
at a connector 192 that resides outside the catheter delivery
system 50 near the handle. The tether 190 allows the user to
retract the valve implant 10 from the valve placement site after it
has been deployed from the catheter if it is determined that the
deployment was improper or in the event a complication arises with
after deployment.
[0095] For example, if after deployment, it is determined that
placement of the valve implant 10 is incorrect, the physician can
pull on the tether and retract the valve implant 10 as shown in
FIG. 19B. If, on the other hand, it is determined that placement of
the valve implant 10 has been successful, then the physician simply
cuts the tether and pulls the free end out of from the proximal
legs 44 and out of the delivery device as shown in FIG. 19A.
[0096] Operation
[0097] Referring now to FIGS. 10-19, the operation of the present
invention is explained. Each of the following figures will include
two drawings, a drawing that shows the position of the handle 58,
and a drawing of the corresponding catheter configuration.
[0098] Referring now to FIG. 10, the first step a physician takes
in using the delivery device 50 to place a valve implant 10 in a
leaflet of a native valve is to use a guidewire 60 to locate the
site of the native valve. The guidewire 60 is thus threaded through
the necessary blood vessels to the site of the native valve. For
example, if it were desired to place the valve implant 10 in, or
between, the leaflets of the aortic valve, the guidewire 60 would
be placed percutaneously in the femoral artery, or other suitable
arterial access, advanced up the aorta, around the arch, and placed
above the target leaflet of the aortic valve. Once the guidewire 60
is in place, the catheter delivery system 50 is advanced along the
guidewire 60.
[0099] In FIG. 10a, it can be seen that the target leaflet 7 has
been located with the guidewire 60 and the catheter delivery system
50 has been advanced along the guidewire 60 the target leaflet 7.
Positioning the catheter delivery system 50 on the target leaflet 7
may be aided using imaging methods such as fluoroscopy and/or
ultrasound. FIG. 10a shows that when this step is performed, the
sheath retraction nut 150 is in the "Deliver" position as shown on
the sheath retraction indicator 156. In the "Deliver" position, the
sheath 130 covers the capture groove 72 of the cutter die 62. The
cutter 90 remains retracted proximal of the capture groove 72.
Also, the conical distal end 68 of the cutter die 62 extends from
the distal end of the sheath 130.
[0100] In this regard, it is helpful to note that the target
leaflet may actually include two leaflets if the leaflets are
calcified together. For example, with reference to FIG. 1, if two
leaflets have become calcified together along their edges or lines
of coaptation, the present invention contemplates cutting a hole in
a manner that traverses the leaflet edges and thereafter inserting
a valve (as explained below) across both leaflet edges.
[0101] Once satisfied that the target site has been reached with
the catheter delivery system 50, the next step is to traverse the
tissue of the target valve leaflet 7. However, before the cutter
die 62 is advanced through the leaflet tissue 7, the sheath
catheter 56 must be retracted until the "Insert/Cut" position has
been achieved. This is accomplished by rotating the threaded sheath
retraction nut 150 until the nut 150 is aligned with the
"Insert/Cut" marking on the sheath retraction indicator 156.
Rotating the sheath retraction nut 150 causes the nut 150 to act
against the tab 154 of the sheath hub 134.
[0102] Referring now to FIGS. 11a and 11b, it can been seen that
the target valve leaflet 7 has been punctured by either the
guidewire 60, in the event that a sufficiently sharp guidewire is
being used, or more preferably, the needle tip 74 of the leaflet
capture catheter 52. When the needle tip 74 of the leaflet capture
catheter 52 is used to puncture the leaflet, the guidewire 60 is
first retracted so that it does not extend through the needle tip
74.
[0103] In one embodiment, the needle may be configured to have a
hollow sharp shaft followed by a conical shank (not shown). This
will allow the needle to create an initial penetration of the
tissue followed by a more traditional puncturing action from the
conical shank A needle configured in this manner will also assist
in positioning the delivery device over each leaflet.
[0104] The cutter die 62 is advanced through the leaflet 7 until
the leaflet 7 snaps into the capture groove 72. The conical distal
end 68, as it is being advanced through the leaflet 7, will provide
an increasing resistance that is tactily perceptible to the
physician. Once the leaflet 7 encounters the flat portion 70, the
physician will detect a decreased resistance and can expect a snap
when the resilient tissue snaps into the capture groove 72. The
guidewire 60 is then re-advanced into the ventricle (assuming the
aortic valve is the target valve).
[0105] In this regard, it is notable that in one embodiment of the
invention, the guidewire could be fabricated to include a
transducer at its distal end (not shown). The guidewire could then
be used to measure ventricular pressure (e.g., left ventricular
pressure when treating the aortic valve) and thus provide the
physician greater ability to monitor the patient during the
procedure.
[0106] Once the physician is convinced that the leaflet 7 has
entered the capture groove 72, the cutting step may commence.
Referring now to FIGS. 12a and 12b, the cutting step is
demonstrated. Cutting is performed by depressing safety button 158
and squeezing the actuator 142. After the safety button 158 and the
actuator 142 are squeezed, the spring loaded safety button on 158
will travel from a first hole 160 in the actuator 142 to a second
hole 162. When the safety button 158 reaches the second hole 162,
it will snap into the second hole 162, thereby locking the actuator
142 in place. This ensures that the cutter die is retracted into
the cutter 90, but that excess pressure is not placed on either the
cutter die 62 or the cutter 90. When the actuator 142 is squeezed,
cutting is effected because the actuator 142 rotates, relative to
the handle body 138, around the pivot pin 164. This action causes
the leaflet capture catheter bracket 144 to move in a proximal
direction thereby pulling the hemostatic hub 64 with it. Pulling
the hub 64 causes the cannula 66 and the cutter die 62 attached
thereto, to be pulled in a proximal direction relative to the
delivery catheter 64. The cutter die 62 enters the cutter 90,
thereby cutting the tissue. The clearance between the cutter die 62
and the cutter drum 96 is sufficiently minimal to prevent the
occurrence of hanging "chads" in the cut. Additionally, the
sharpened cutting tip 98 of the cutter 90 may be cut at an angle,
or even include a point, such that the entire cut does not have to
be initiated around the entire circumference of the cutter drum 96
simultaneously.
[0107] A more detailed view of the cutting action of the cutter die
62 and the cutter 90 is shown in FIGS. 13a-13e. In FIG. 13a, the
needle tip 74 of the cannula 66 has just reached the leaflet 7. The
sheath 130 has been retracted to the "Insert/Cut" position as
indicated by the exposed capture groove 72 of the cutter die 62. In
FIG. 13b, the cutter die 62 is being advanced through the target
leaflet 7 such that the target leaflet 7 has reached the conical
distal end 68 of the cutter die 62. In FIG. 13c, the conical distal
end 68 and the flat portion 70 of the cutter die 62 have passed
completely through the target leaflet 7, and the target leaflet 7
has snapped into the capture groove 72. Additionally, the guidewire
60 has been re-advanced through the leaflet capture catheter 52 so
that it extends beyond the needle tip 74. The guidewire 60 will be
used to retain the position of the hole cut through the leaflet 7
after the cutter die 62 is retracted. In FIG. 13d, the physician
has begun to cut by squeezing the actuator 142 (FIG. 12a), as
evidenced by the advancement of the cutter 90. The cutting tip 98
of the cutter 90 has been advanced mid-way through the target
leaflet 7. This movement is relative to the position of the cutter
die 62. More accurately, the cutter die 62 is being retracted into
the cutter 90, bringing with it the tissue of the leaflet 7. The
movement of the cutter die 62 is evidenced by arrow 172.
[0108] In FIG. 13e, the cut is complete as the actuator 142 has
been squeezed enough so that the safety button 158 has found the
second hole 162 (FIG. 12a), as evidenced by the position of the
cutter die 62. The cutter die 62 is retracted enough such that the
capture groove 72 is completely housed within the cutter drum 96.
Notably, the cut tissue of the leaflet 7 remains trapped between
the capture groove 72 and the cutter drum 96. The trapping of this
tissue prevents the tissue from traveling downstream through the
blood vessel and causing damage.
[0109] Referring now to FIGS. 14a and 14b, once the hole in the
tissue 7 is cut, the step of placing the valve implant 10 begins.
First, the entire delivery system 50 is moved distally deeper into
the patient such that the distal legs 42 pass through the newly
formed hole in the tissue 7. It is important that at least the
distal legs 42 are located on the upstream (ventricle) side of the
tissue 7 prior to deploying the valve implant 10. Once the
physician is confident that the distal legs 42 extend beyond the
valve leaflet tissue 7, the sheath 130 may be retracted to release
the distal legs 42. This is accomplished by rotating the sheath
retraction nut 150 until the sheath retraction nut 150 aligns with
the "Distal" marking on the sheath retraction indicator 156. Doing
so causes the sheath retraction nut 150 to act against the tab 154
thereby withdrawing the sheath 130 until just the distal legs 42
are exposed. The distal legs 42 are preloaded such that they spring
outwardly, as shown in FIG. 14b, when uncovered by the catheter
sheath 130. The distal legs 42 are long enough to extend beyond the
radius of the sheath 130, such that they may act against the valve
leaflet tissue 7. Once the sheath retraction nut 150 has been
rotated to the "Distal" position on the indicator 156, the
physician may pull the catheter delivery system 50 in a proximal
direction until he or she feels the distal legs 42 catch or act
against the valve leaflet tissue 7. Notably, the actuator 142
remains locked in the position it was placed in during the cutting
procedure. Leaving the actuator 142 in this position ensures that
the valve leaflet tissue trapped between the cutter die 62 and the
cutter drum 96 is not released.
[0110] The next step is illustrated in FIGS. 15a and 15b. The
physician maintains the contact between the distal legs 42 and the
valve leaflet tissue 7. While maintaining this contact, the sheath
retraction nut 150 is rotated to the "Proximal" position as
indicated on the marker of the sheath retraction indicator 156.
Rotating the sheath retraction nut 150 again acts against the tab
154 causing the sheath 130 to retract further. When the proximal
position has been achieved, the sheath will be retracted enough to
release the proximal legs 44. Like the distal legs 42, the proximal
legs 44 will spring outwardly when released by the sheath 130. The
proximal legs 44 act against the opposite side (aorta side) of the
valve leaflet tissue 7 sandwiching the valve leaflet tissue 7
between the distal legs 42 and the proximal legs 44. The valve
implant 10 is now attached to the patient.
[0111] The next step is to inflate the balloon 108 thereby
expanding the valve implant 10. This step is best shown in FIGS.
16a and 16b. The physician further rotates the sheath retraction
nut 150 to the "Inflate" position on the indicator 156. The sheath
retraction nut 150 again acts against the tab 154 thereby
retracting the sheath 130 to a point where the valve stop 110 is at
least partially exposed and the flexible sleeve 112 of the valve
stop 110 is completely exposed.
[0112] Once the sheath 130 has been retracted to the "Inflate"
position on the indicator 156, the balloon 108 may be inflated.
This is accomplished by injecting fluid into the balloon inflation
port 118. Fluid is injected until the sizing ring 38 has achieved
its maximum diameter. The physician will feel resistance against
further inflation by the sizing ring 38. Additionally, the sizing
ring 38 or other parts of the anchoring mechanism 12 may be
constructed of a radiopaque material such that monitoring can be
accomplished using X-ray equipment. The use of the sizing ring 38
is not required for the practice of the invention. It is, however,
preferred in the preferred embodiments of the invention.
[0113] Once the inflation of the balloon 108 is complete, the next
step involves deflating the balloon 108. This is illustrated in
FIGS. 17a and 17b. Deflating the balloon involves simply
withdrawing fluid through the balloon inflation port 118. As is
shown in FIG. 17b, when the balloon 108 is deflated, the valve
implant 10 retains its inflated proportions. These inflated
proportions allow easy retraction of the catheter delivery system
through the valve implant 10. As is best seen in FIG. 18, once the
delivery system 50 has been retracted, the valve implant 10 remains
attached to the valve leaflet tissue 7.
[0114] As discussed above with reference to FIGS. 19A, 19B and 20,
one embodiment of the catheter delivery device 50 and the valve
implant 10 includes the use of a tether 190 to allow the physician
to retract the valve implant 10 in the event of improper
deployment. With reference to FIG. 21, the operation of the tether
190 under both proper deployment and improper deployment is
disclosed.
[0115] On the left side of FIG. 21, it is seen that the valve
implant 10 has been properly deployed in the valve leaflet. As a
result, the physician cuts the tether 190 and pulls the tether away
from the catheter handle from the proximal legs 44 of the cuff.
[0116] On the right side of FIG. 22, it is seen that the valve
implant 10 has been improperly deployed insofar as the legs of the
cuff have not adequately grasped the edge of the hole in the
leaflet. As a result, the physician may retract the valve implant
10 by pulling on the tether 190 and thus removing the valve implant
10 from its improperly deployed location
* * * * *