U.S. patent application number 09/951362 was filed with the patent office on 2002-03-14 for heart valve and apparatus for replacement thereof.
This patent application is currently assigned to Spence, Paul A.. Invention is credited to Ortiz, Mark, Spence, Paul A..
Application Number | 20020032480 09/951362 |
Document ID | / |
Family ID | 23204530 |
Filed Date | 2002-03-14 |
United States Patent
Application |
20020032480 |
Kind Code |
A1 |
Spence, Paul A. ; et
al. |
March 14, 2002 |
Heart valve and apparatus for replacement thereof
Abstract
Apparatus and methods for replacing a heart valve within a
vessel. The apparatus includes a replacement heart valve and a
plurality of commisure stabilizers connected to the commisures of
the heart valve in a removable manner. The commisure stabilizers
position and stabilize the commisures in the proper positions as
the replacement heart valve is secured within the vessel. The
commisure stabilizers may be removed following securement of the
replacement heart valve within the vessel. An expansion or
retraction device of the invention assists in properly positioning
the valve within the vessel.
Inventors: |
Spence, Paul A.;
(Louisville, KY) ; Ortiz, Mark; (Milford,
OH) |
Correspondence
Address: |
WOOD, HERRON & EVANS, L.L.P.
2700 Carew Tower
441 Vine St.
Cincinnati
OH
45202
US
|
Assignee: |
Spence, Paul A.
Louisville
KY
|
Family ID: |
23204530 |
Appl. No.: |
09/951362 |
Filed: |
September 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09951362 |
Sep 13, 2001 |
|
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09310891 |
May 12, 1999 |
|
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6309417 |
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Current U.S.
Class: |
623/2.11 ;
623/2.19 |
Current CPC
Class: |
A61N 1/05 20130101; A61F
2/2412 20130101; A61F 2250/0059 20130101; A61F 2/2427 20130101 |
Class at
Publication: |
623/2.11 ;
623/2.19 |
International
Class: |
A61F 002/24 |
Claims
However, the invention itself should only be defined by the
appended claims, wherein we claim:
1. A replacement heart valve for implantation within a vessel, the
replacement heart valve comprising: an annular base, a plurality of
commisures extending from the annular base at spaced apart
positions, said commisures having proximal ends connected with said
annular base and opposite distal ends, and a flexible fabric
material connecting the distal ends of said commisures and adapted
to be secured to said vessel during implantation.
2. An expandable and collapsible vessel retraction device
comprising: a body movable between expanded and collapsed
conditions such that, in the collapsed condition the body may be
inserted into an open vessel and actuated into the expanded
condition whereby said vessel expands into a shape substantially
corresponding to the natural pressurized shape of the vessel.
3. The vessel retraction device of claim 2, wherein the body is
generally tubular.
4. The vessel retraction device of claim 2, wherein the body is at
least partially formed of a shape memory material.
5. A method of implanting a replacement heart valve including an
annular base and a plurality of commisures extending from spaced
apart positions of the annular base, the method comprising:
inserting said replacement heart valve into a patient, connecting
at least one commisure stabilizer to each of said commisures of
said replacement heart valve either before or after inserting said
replacement heart valve, securing said replacement heart valve
within the patient using said commisure stabilizers to orient the
commisures of the replacement heart valve, and removing said
commisure stabilizers from the patient leaving the secured
replacement heart valve in place.
6. A method of implanting a replacement heart valve including an
annular base and a plurality of commisures extending from spaced
apart positions of the annular base, the method comprising:
connecting three commisure stabilizers of a positioning and
stabilizing device to the respective three commisures of said
replacement heart valve, inserting said replacement heart valve
into a patient, securing said replacement heart valve within the
patient using said commisure stabilizers to orient the three
commisures of said replacement heart valve, and removing said
positioning and stabilizing device from the patient leaving the
secured replacement heart valve in place.
Description
[0001] This application is a divisional of application Ser. No.
09/310,891 filed May 12, 1999 (now pending), the disclosure of
which is fully incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to heart valve
replacement and, more particularly, to replacement heart valves and
apparatus used during their implantation.
BACKGROUND OF THE INVENTION
[0003] A popular option for aortic valve replacement is to retain
the native aortic root and the normal coronary artery attachments
and secure the replacement prosthesis inside the patient's own
aorta. With this procedure, only the valve is replaced and not the
entire root. It is unnecessary to re-attach the coronary arteries
and, should repeat surgery be necessary, a surgeon must only
replace the valve and not an entire section of the aorta. When a
surgeon replaces the aortic valve in this manner, the patient is
first placed on a heart-lung machine and the section of the aorta
having the aortic valve is clamped off to allow access. That
section of the aorta is therefore collapsed and unpressurized
leaving a pressurized section connected to the heart-lung machine.
The unpressurized section of aorta is then opened and the diseased
valve is removed in its entirety, including careful removal of
calcium deposits within the aorta and annulus. The aorta and
sinotubular junction are then sized and the surgeon prepares the
appropriate replacement valve. The surgeon then sutures the inflow
or annular end of the replacement valve into the inside of the
aorta. When these sutures are drawn tight, the valve is pulled
inside the aorta when approximately 20 sutures are then applied
around the annular end. The commisures of the replacement valve,
which extend from the annular end, may or may not need to be
affixed to the aorta as discussed below.
[0004] Two major types of prosthetic or replacement heart valves
exist. The first general type of valve is a mechanical prosthesis
which includes commisures that are self-supporting and do not need
to be affixed to the aortic wall. Mechanical prostheses are
generally formed entirely of artificial material, such as carbon
fiber, titanium, dacron and teflon. While these mechanical
prostheses are durable, relatively quick to implant and generally
easy to manipulate during surgery, they also have certain
disadvantages. For example, due to the artificial materials used in
their construction, blood clots can form on the valve and
subsequently cause valve failure. If the clot dislodges from the
valve, the clot can lodge in a downstream vessel and cause stroke
or organ ischemia. For these reasons, patients with mechanical
heart valves must take anticoagulants for the rest of their lives.
Anticoagulants bring about their own complications in some
patients, including internal bleeding or other side effects.
[0005] The second major type of prosthetic or replacement heart
valve is a biologic valve. This category includes valves harvested
from human cadavers, i.e., allografts or homografts, or animal
tissue generally harvested from cows and pigs. More recently, there
has been increasing effort to develop synthetic biologically
compatible materials to substitute for these natural tissues. Among
their advantages, biologic prostheses generally do not require
lifelong anticoagulation as they do not often lead to clot
formation. These valves are provided in stented or unstented forms.
A stented valve includes a permanent, rigid frame for supporting
the valve, including the commisures, during and after implantation.
The frames can take the form of a wire or other metal framework or
a plastic frame encased within a flexible fabric covering.
Unstented valves do not have built-in commisure support so surgeons
must use their skill and best judgement to determine the optimal
site of implantation inside the patient's native aorta to maintain
valve competence. When securing the valve commisures, obstruction
of the patient's native coronary arteries must be avoided or
myocardial infarction may result.
[0006] There are many limitations to procedures utilizing
permanently stented biologic replacement valves. First, allografts
(human cadaver donor valves) are not generally available with
permanent frames or stents. Second, the frames or stents can take
up valuable space inside the aorta such that there is a narrowing
at the site of valve implantation. This narrowing leads to pressure
gradients and increased loads on the left ventricle and, therefore,
increased incidence of hypertrophy and reduced patient survival.
The frame includes artificial materials which can increase the risk
of new infection or perpetuate an existing infection. It is also
very important to realize that although the permanent frames or
stents guarantee alignment of the commisures, they cause very high
stresses on the commisures when the valve cusps move between open
and closed positions. A patient's natural commisures are not placed
under significant strain during opening and closing of the valve
due to the natural resilience of the aorta. On the other hand,
artificially mounted valves place the commisures under strain
during operation of the valve due to the rigid materials of the
frame. Over time, the valve cusps tend to decay under this strain
and manifest calcification and tears which can lead to valve
failure.
[0007] In many situations, biologic replacement heart valves are
preferred in the unstented form due to the drawbacks mentioned
above. Such valves are more resistant to infection when implanted
free of any foreign material attachments, such as stents or frames.
Also, the heart valve is more efficient when used without a stent.
Efficiency refers to the pressure gradient across the valve during
use. Natural human valves have almost no pressure gradient. When a
natural heart valve is replaced by a biologic heart valve with a
low pressure gradient, complications such as hypertrophy arise less
often and result in improved patient survival.
[0008] Despite the known advantages of using biologic prosthetic
heart valves without artificial supporting devices such as
permanent stents or frames, relatively few surgeons employ this
surgical technique due to its high level of difficulty. When
unsupported or unstented by artificial devices, such as permanent
stents, biologic replacement heart valves have a flimsy, soft and
flexible nature. That is, the commisures of the heart valve do not
support themselves in the proper orientation for implantation. For
these reasons, it is very difficult to secure the commisures
properly into place. In this regard, the surgeon must generally
suture the individual commisures of the heart valve in exactly the
proper orientation to allow the valve to fully and properly
function.
[0009] During valve replacement surgery, an L-shaped retractor is
placed inside the aorta to pull it open for access purposes. While
this provides exposure, it distorts the aorta and may give the
surgeon an incorrect impression of the correct valve position.
Next, and especially with regard to unstented biologic valve
procedures, the surgeon must guarantee that the commisures pass
straight up the aorta at roughly right angles to the plane of the
annulus. There is very little technology to help the surgeon
correctly place the stentless replacement valve. To help confirm
that the leaflets are correctly spaced at 120.degree. apart,
surgeons may use a disc having markings 120.degree. apart. The
surgeon can use this to roughly estimate the spacing by placing it
near the distal ends of the commisures. However, this provides only
a rough guide. For example, it is possible to equally space the
commisures at the upper end and still have a valve placed in a
skewed position. Finally, the aorta is not a straight tube at the
surgical site, but instead flares outward at the surgical site. The
valve must conform to the flare of the aorta at this location. Once
the surgeon has completed an inspection for these three elements,
i.e., correct spacing at approximately 120.degree. between the
commisures, correct perpendicular position of the commisures
relative to the annulus plane, and appropriate conformation to the
flare of the aorta, the surgeon must suture the commisures to the
wall of the aorta. As this is done, it is necessary to make sure
there is no encroachment on the ostia or origins of the coronary
arteries. After the valve commisures are attached to the aorta and
proper orientation and positioning is confirmed, the surgeon closes
the aorta.
[0010] Following surgery, there is a risk that the aorta will
dilate at the sinotubular junction months or years later and draw
the valve commisures and attached cusps apart from each other. This
will cause insufficiency and failure due to leakage through the
valve. There is a further need for methods to ensure that late
enlargement of the sinotubular junction does not necessitate
reoperation for late valve insufficiency and failure.
[0011] In general, there is an increasing need for devices which
improve the efficiency and reliability of implanting replacement
heart valves. In conjunction with this, there is a need to improve
these procedures so that all surgeons, not just those with the
highest skill levels, can implant heart valves with superior
results.
SUMMARY OF THE INVENTION
[0012] The present invention generally provides apparatus directed
at solving problems, such as those described above, with regard to
replacing a heart valve within a vessel. In one general aspect, the
invention provides a replacement heart valve and a plurality of
temporary commisure stabilizers. More particularly, the replacement
heart valve will generally have an annular base and a plurality of
spaced apart commisures extending from the annular base at spaced
apart positions. The valve may be formed of animal tissue, such as
valves harvested from pigs, cows or human donors. Optionally, the
valve may be formed from synthetic, biologically compatible
material. With the typical aortic valve replacement, there will be
three commisures spaced roughly 120.degree. apart. Each commisure
includes a proximal end connected with the annular base and an
opposite distal end. The plurality of commisure stabilizers are
connected to the commisures in a removable manner. These commisure
stabilizers position and stabilize the commisures of the
replacement heart valve as a surgeon secures the replacement heart
valve in place within the vessel. The commisure stabilizers, in the
instance of an aortic valve replacement, positively orient the
commisures at the 120.degree. spaced apart positions and generally
perpendicular to a plane which contains the annular base of the
heart valve.
[0013] Following securement of the replacement heart valve within
the vessel, the commisure stabilizers are preferably removed to
avert the various disadvantages of permanent stents or frames.
However, there may be situations in which a particular surgeon
desires to leave one or more of the commisure stabilizers in place
and the invention advantageously provides for this option as well.
In the preferred embodiment, the commisure stabilizers are
connected together at spaced apart distal positions, for example,
by a generally annular member. Each commisure stabilizer preferably
comprises at least one elongate member attachable in a manner
allowing removal from the distal end of the respective commisure
following implantation of the heart valve.
[0014] The replacement heart valve can include respective receiving
elements for the commisure stabilizers. These may comprise pockets,
loops or other structure adapted to receive the stabilizers in a
manner allowing removal by a surgeon at the distal end of the
commisures after implantation. The commisure stabilizers may also
be removably affixed to other supporting structure, such as the
generally annular member described above. This, for example, will
allow the surgeon to remove the annular member or other supporting
structure for easier suturing access, while at least temporarily
leaving the commisure stabilizers in place for positioning
purposes. After suturing and/or other securement of the valve, the
commisure stabilizers would be removable to achieve the full
advantages of this invention.
[0015] Each commisure stabilizer may further comprise at least two
spaced apart elongate members or, more preferably, three elongate
members. One or more of these members may curve or flare outwardly
in a lengthwise direction to urge the commisures of the replacement
heart valve against the flared interior wall of the vessel. The
outer elongate members may also angle or curve away from the
central elongate member to extend along opposite edge portions of
the respective commisures.
[0016] In another aspect of the invention, the positioning and
stabilizing device may be formed in a collapsible manner allowing
insertion into the vessel in a collapsed state and subsequent
expansion for positioning and stabilizing the valve commisures
during securement of the valve within the vessel. For example, the
positioning and stabilizing device may be at least partially formed
of a shape memory material allowing the positioning device to be
collapsed and expanded as necessary. This aspect of the invention
may also be practiced in other manners, such as through the use of
hinged or otherwise collapsible and expandible structures.
[0017] In accordance with another aspect of the invention, a
flexible material may connect the distal ends of the three
commisures. This will prevent the commisures from moving radially
apart due to late sinotubular enlargement. This material may also
be secured to the internal wall of the vessel to help prevent the
need for reoperation due to the complications of late enlargement
of the sinotubular junction as described above.
[0018] A method of implanting a replacement heart valve in
accordance with the invention includes inserting the replacement
heart valve into a patient, connecting at least one commisure
stabilizer to each of the commisures of the replacement heart valve
either before or after inserting the replacement heart valve,
securing the replacement heart valve within the patient using the
commisure stabilizers to orient the commisures of the replacement
heart valve, and removing one or more of the commisure stabilizers
from the patient leaving the secured replacement heart valve in
place. Other methods of utilizing apparatus as described herein are
also within the scope of this invention as will be apparent.
[0019] These and other objects, advantages, and features of the
invention will become more readily apparent to those of ordinary
skill in the art upon review of the following detailed description
of the preferred embodiments, taken in conjunction with the
accompanying drawings and as more generally set forth in the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a partially fragmented perspective view of an
aorta undergoing a valve replacement operation with an unstented
biologic replacement valve in the process of insertion;
[0021] FIG. 2 is a view similar to FIG. 1, but showing the initial
removable attachment of a positioning and stabilizing device having
commisure stabilizers constructed in accordance with one embodiment
of the invention;
[0022] FIG. 3 is a perspective view similar to FIG. 2, but showing
the positioning and stabilizing device fully inserted and the
properly positioned and stabilized commisures being sutured in
place;
[0023] FIG. 4 is a perspective view similar to FIG. 3, but showing
the fully implanted heart valve;
[0024] FIG. 4A is a cross sectional view taken along line 4A-4A of
FIG. 4;
[0025] FIG. 5 is a perspective view showing an alternative
embodiment of a positioning and stabilizing device being removed
from a replacement heart valve following implantation;
[0026] FIG. 6 is a perspective view of another alternative
positioning and stabilizing device constructed in accordance with
the invention;
[0027] FIG. 6A is a cross sectional view taken along line 6A-6A of
FIG. 6;
[0028] FIG. 7 is a perspective view of another alternative
embodiment of a positioning and stabilizing device;
[0029] FIGS. 8A and 8B are perspective views of another alternative
positioning and stabilizing device respectively shown in collapsed
and expanded conditions;
[0030] FIG. 9 is a perspective view of an alternative replacement
heart valve and removable positioning and stabilizing device
constructed in accordance with the invention;
[0031] FIG. 9A is a perspective view of the apparatus shown in FIG.
9 with the positioning and stabilizing device removed;
[0032] FIG. 9B is a fragmented and enlarged view of the positioning
and stabilizing device of FIGS. 9 and 9A showing the separable
parts thereof;
[0033] FIG. 10 is a perspective view of another alternative
replacement heart valve and removable positioning and stabilizing
device constructed in accordance with the invention;
[0034] FIG. 11 is a perspective view of an aortic expansion device
constructed in accordance with the invention;
[0035] FIG. 12 is a perspective view of an alternative aortic
expansion device;
[0036] FIG. 13A is a top view of the expansion device illustrated
in FIG. 12, but shown in a collapsed condition; and
[0037] FIG. 13B is a top view of the expansion device shown in FIG.
12 in an expanded condition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] FIG. 1 illustrates an aorta 10 which a surgeon has incised
to create an opening 12 after a patient has been placed on a
heart-lung machine. One or more retractors 14 may be used by
assistants to gain access to opening 12. Aorta 10 may be partially
incised as shown or it may be fully incised across its transverse
dimension. During this procedure, the patient's heart 16, disposed
below the surgical site, is normally in an arrested state due to
the use of the heart-lung bypass machine and cardioplegia.
[0039] An unstented replacement valve 20 is further shown within
aorta 10 in an initial flimsy, unsupported condition. In this case,
a fabric covering 22 is stitched on the outside of the biologic
tissue 24, which may be human or other animal tissue or synthetic
material. Replacement valve comprises typically three commisures
26, 28, 30 extending from an annular base 32. Replacement valve 20
has been inserted within aorta 10 such that annular base 32 is
disposed at the annulus 34 of aorta 10. Conventional sutures 36 may
be used as shown to pull replacement valve within aorta 10 until it
resides on annulus 34 in a known manner.
[0040] As further shown in FIG. 4A, a plurality of sutures 54 are
typically placed around the annular base 32 and into annulus 34.
Replacement valve 20 must be disposed within aorta 10 so as not to
occlude orifices 38, 40 communicating with the left and right
coronary arteries (FIG. 2). As additionally shown in FIG. 4A, the
typical aortic replacement valve includes three cusps 42, 44, 46,
respectively connected with the three commisures 26, 28, 30 for
movement between open and closed positions as the heart beats to
pump blood into the aorta. Sealing lines of contact 48, 50, 52 are
formed between the respective cusps 42, 44, 46. To maintain an
effective seal along lines 48, 50, 52, commisures 26, 28, 30 must
be positioned and secured within aorta 10 in a precise manner. In
this regard, each commisure should preferably extend in a
relatively perpendicular, non-skewed manner along the interior
aortic wall 10a, and in a manner that is essentially perpendicular
to annular base 32. If this is not done, strain will be placed on
commisures 26, 28, 30 and an effective seal between cusps 42, 44,
46 may eventually be lost. Undue strain on commisures 26, 28, 30
can cause decay and calcification and eventually lead to valve
failure and either death or a second surgical operation.
[0041] FIGS. 2 and 3 illustrate one embodiment of a positioning and
stabilizing device 60 constructed in accordance with the invention.
Generally, positioning and stabilizing device 60 may be used in a
temporary manner while securing commisures 26, 28, 30 to aortic
wall 10a. Positioning and stabilizing device 60, in this
embodiment, includes an annular portion 62 connected with a
plurality of stabilizers 64, 66, 68, each taking the form of a
single elongate member. Each stabilizer 64, 66, 68 preferably bows
outwardly along its length so as to generally conform to a flared
region 70 of the aortic root. As one of many possible temporary
securement methods, each stabilizer 64, 66, 68 is slipped between
fabric covering 22 and biologic tissue 24 of replacement valve 20.
In the case of a valve which does not have a fabric covering, other
securing structure such as suture loops, hooks, etc., may be used
to attach stabilizers 64, 66, 68. This temporary connection may be
made before replacement valve 20 is inserted into aorta 10 or after
valve 20 is inserted within aorta 10. In the preferred embodiments,
assembly of a positioning and stabilizing device and replacement
valve, such as device 60 and valve 20, is felt to be best
accomplished prior to surgery to allow for insertion as a unit. As
shown in FIG. 3, once replacement valve 20 and positioning and
stabilizing device 60 have been secured within aorta 10, with
stitches 54 already placed at annulus 34, suturing of commisures
26, 28, 30 can begin. This may be accomplished using a typical
needle 72 and suturing thread 74 manipulated by a gripping
implement 76. The surgeon places sutures 78 in this manner along
the entire periphery of each commisure 26, 28, 30. It will be
appreciated that other manners of securing replacement valve 20 to
aorta 10 may be used in accordance with the invention and, for
example, include gluing, stapling or other mechanical fasteners.
FIG. 4 illustrates the completely secured replacement valve 20
implanted within aorta 10. It will be appreciated that, in this
embodiment, once positioning and stabilizing device 60 has been
removed from the pockets formed between fabric covering 22 and
biologic tissue 24, the distal ends 26a, 28a 30a may be stitched to
the aortic wall 10a.
[0042] FIG. 5 illustrates one alternative embodiment of a
replacement valve 20' useful in accordance with the invention.
Replacement valve 20 includes pockets 80 on the outside of each
commisure 26, 28, 30 for receipt of an alternative positioning and
stabilizing device 90. Like the first embodiment, positioning and
stabilizing device 90 can include an annular portion 92 and a
plurality of three stabilizers 94, 96, 98. In this embodiment, each
stabilizer further comprises multiple elongate members adapted to
be removably inserted within pockets 80. More specifically, each
stabilizer 94, 96, 98 comprises respective elongate members 94a-c,
96a-c and 98a-c. As will be appreciated from stabilizer 96, outer
elongate members 96a, 96c curve outwardly from the middle elongate
member 96b. In this manner, outer members 96a, 96c extend within
respective pockets 80 along the outer curved edges 28b, 28c of
commisure 28. The remaining stabilizers 94, 98 function in a
similar manner. It will be further appreciated that each stabilizer
94, 96, 98 bows outwardly, as in the first embodiment, to conform
to the flare 70 at the aortic root. Stabilizers 94, 96, 98 are
flexible enough to be withdrawn, as shown in FIG. 5, from pockets
80 after suturing of each commisure 26, 28, 30 as previously
described. Positioning and stabilizing device 90 may be formed from
various materials and in various configurations for this purpose.
These may include metals, super elastic alloys, or plastics.
[0043] FIGS. 6 and 6A illustrate another alternative positioning
and stabilizing device 100 constructed in accordance with the
invention. In this embodiment, an annular portion 102 is removable
from a plurality of commisure stabilizers 104, 106, 108. In this
manner, positioning and stabilizing device 100 may be used as
described above with respect to devices 60 and 90, except that
annular portion 102 may be removed for easier suturing access or
other securement access when securing commisures 26, 28, 30 (FIG.
4) to aortic wall 10a. One of many possibilities for facilitating
this function is shown in FIG. 6 and FIG. 6A in the form of
connectors 110, 112, 114. Each of these connectors may receive a
stabilizer 104, 106, 108 in a removable fashion with a slight
interference fit. As best shown in FIG. 6A, an end portion 104a of
stabilizer 104 may be received with a slight interference fit
against a resilient tab 116. The other stabilizers 106, 108 may
have a similar structure, as exemplified by end 108a shown in FIG.
6. Many other fastening structures are possible other than this
schematically illustrated example.
[0044] FIG. 7 illustrates another alternative positioning and
stabilizing device 120 having a generally similar construction and
function to device 90 shown in FIG. 5. Device 120 may be formed
from a single length of wire, for example, and includes portions
122, 124, 126 analogous to the previously described annular
portions. A connector 128 may be provided to connect opposite ends
of the wire. Stabilizers 130, 132, 134 are formed with three
sections each for purposes previously described in connection with
FIG. 5. These sections 130a-c, 132a-c, 134a-c serve similar
functions to position and stabilize the commisures of a replacement
heart valve, and device 120 may be removed from the heart valve in
previously described manners.
[0045] FIGS. 8A and 8B illustrate another alternative positioning
and stabilizing device 140 constructed from a shape memory material
such as Nitenol. As shown in FIG. 8A, device 140 may be collapsed
in each a detached form with respect to a heart valve, as shown, or
while connected to a replacement heart valve for insertion within
the patient's aorta as a unit. Upon the application of heat or
electric current once inserted within the aorta, device 140 expands
to the position shown in FIG. 8B and may then be used as previously
described to position and stabilize the heart valve commisures
during implantation. As shown in FIGS. 8A and 8B, one illustrative
example of this device also includes an annular portion 142 and
respective three-legged commisure stabilizers 144, 146, 148.
[0046] FIGS. 9 and 9A illustrate another heart valve replacement
apparatus 160 constructed in accordance with the invention. In this
embodiment, a replacement heart valve 162 may include a flexible
material 164, optionally part of the fabric covering 166 of valve
162, which secures the three commisures 168, 170, 172 together at
their respective distal ends 168a, 170a, 172a. It will be
appreciated that flexible material 164 may be stitched to the
interior aortic wall in conjunction with commisures 168, 170, 172.
Thus, material 164 will prevent distal ends 168a, 170a, 172a from
expanding away from one another as occurs during late sinotubular
enlargement of the aorta. Therefore, this prevents valve failure as
a result.
[0047] As further shown in FIGS. 9, 9A and 9B, an alternative
embodiment of a positioning and stabilizing device 180 includes an
annular portion 182 constructed from separate sections 182a, 182b,
182c, and a plurality of three stabilizers 184, 186, 188.
Stabilizer 184, 186, 188 again are shown as three-legged structures
for purposes previously described. In this embodiment, however,
stabilizers 184, 186, 188 are retained within loops 190, which may
be suture loops sewn into fabric 166. It will be appreciated that
other types of retaining structure may be used to at least
temporarily retain stabilizers 184, 186, 188. In this embodiment,
connectable end portions 192, 194, formed respectively as male and
female portions, may be used to make various connections and
disconnections on device 180. For example, lower ends of adjacent
stabilizers 184, 186, 188 may be connected at a junction 196 as
shown in FIG. 9. This may provide more consistent support along the
edges of commisures 168, 170, 172. As further shown in FIG. 9B,
stabilizers 184, 186, 188 may be completely disconnectable from
annular portion 182 while also allowing selective disconnection of
sections 182a, 182b, 182c. This may be accomplished through the use
of connecting elements 198 having respective female connecting
portions 198a for engaging male connecting portions 192. It will be
understood that many alternative connectors and structures may be
substituted for those shown while retaining the basic function and
general concepts expressed herein.
[0048] FIG. 10 illustrates a heart valve replacement apparatus 200
comprised a replacement heart valve 202, which may be formed from
biological tissue or synthetic biologically compatible material.
Heart valve 202 is again illustrated with three commisures 204,
206, 208, as is typical for replacement aortic valves. A
positioning and stabilizing device 210 is fastened to the outside
of valve 202, for example, by suture loops 211. This embodiment of
the invention does not have any connection between the distal ends
204a, 206a, 208a of commisures 204, 206, 208 or at the distal end
of positioning and stabilizing device 210. Also, in this embodiment
positioning and stabilizing device 210 is formed in three sections
212, 214, 216 removably connected together at junctions 218, 220,
222. These connections may be similar to those shown in FIG. 9B.
Other types of connections may be used as well. Use of this
embodiment of the invention will be similar to the previous
embodiments, except that sections 212, 214, 216 may be removed
individually from heart valve 202 following completion of its
securement within the aorta. Sections 212, 214, 216 are preferably
formed of a highly flexible plastic or metal which is
biocompatible. This embodiment provides certain advantages, such as
allowing one or more of the sections 212, 214, 216 to remain in
place following surgery and providing additional room for a surgeon
to access commisures 204, 206, 208 while suturing or otherwise
securing commisures 204, 206, 208 to the aortic wall. It will be
appreciated that other configurations and numbers of legs and
sections may be utilized by those of ordinary skill.
[0049] FIG. 11 illustrates an expansion device 240 useful for
expanding a vessel, such as the aorta, during valve replacement
procedures. In this embodiment, expansion device may be formed as a
collapsible and expandable structure, such as by being formed of
shape memory material as described with respect to FIGS. 8A and 8B.
It will be appreciated that FIG. 11 shows the expanded condition
only. Expansion device 240 may have three extensions 242, 244, 246
of a desired length for disposition between the respective
commisures of an aortic replacement valve. Device 240 need not be
attached to heart valve commisures, but may be used to expand the
collapsed aorta to the proper flared shape thereby assisting the
surgeon during a heart valve replacement procedure. This device
overcomes the drawbacks of typical retractors which tend to distort
the shape of the collapsed aorta and mislead the surgeon as to the
correct position and orientation of the heart valve. Device 240 may
be formed in various manners to be collapsible and selectively
expandable, such as through the use of mechanically expandable
portions or, preferably, expandable shape memory portions.
[0050] FIGS. 12, 13A and 13B illustrate an alternative collapsible
and expandable retraction device 250. This device may be formed
from a mesh or screen material and includes edge portions 252, 254
which allow expanding and contracting of the device. An upper end
256 is formed with a greater diameter than a lower end 258 in the
expanded, operative position shown in FIGS. 12 and 13B. This allows
a surgeon to have greater access into and through the device to
manipulate and, for example, suture a replacement heart valve in
place below device 250 within the aorta. In use, and referring back
to FIG. 1, a surgeon will insert the device 250 in the collapsed
form shown in FIG. 13A through opening 12 such that lower end 258
is situated within aorta 10 and upper end 256 is exposed. The
surgeon will then allow device 250 to expand through its own
resilience or through a shape memory property to the position shown
in FIG. 13B. Alternatively, other activation structure or means may
be provided for attaining the expanded condition. Once expanded,
aorta 10 generally assumes a natural, pressurized shape allowing
placement and implantation of replacement valve 20 in a more
efficient and accurate manner. It will be understood that the
expansion devices shown in FIGS. 11 through 13B are illustrated in
the simplest currently contemplated forms. It is further
contemplated that additional handles or other support and actuation
structure may be added while achieving the same general advantages
of these embodiments.
[0051] While the present invention has been illustrated by a
description of a preferred embodiment and while this embodiment has
been described in some detail, it is not the intention of the
Applicants to restrict or in any way limit the scope of the
appended claims to such detail. Additional advantages and
modifications will readily appear to those skilled in the art. The
various features and concepts of the invention may be used alone or
in numerous combinations depending on the needs and preferences of
the user. This has been a description of the present invention,
along with the preferred methods of practicing the present
invention as currently known.
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