U.S. patent application number 10/680075 was filed with the patent office on 2005-04-07 for minimally invasive valve replacement system.
Invention is credited to Myers, Keith E., Nguyen, Tuoc Tan.
Application Number | 20050075728 10/680075 |
Document ID | / |
Family ID | 46599162 |
Filed Date | 2005-04-07 |
United States Patent
Application |
20050075728 |
Kind Code |
A1 |
Nguyen, Tuoc Tan ; et
al. |
April 7, 2005 |
Minimally invasive valve replacement system
Abstract
Methods and systems for minimally invasive replacement of a
valve. The system includes a collapsible valve and anchoring
structure, devices and methods for expanding the valve anchoring
structure, adhesive means to seal the valve to the surrounding
tissue, a catheter-based valve sizing and delivery system, native
valve removal means, and a temporary valve and filter assembly to
facilitate removal of debris material. The valve assembly comprises
a valve and anchoring structure for the valve, dimensioned to fit
substantially within the valve sinus.
Inventors: |
Nguyen, Tuoc Tan; (Irvine,
CA) ; Myers, Keith E.; (Lake Forest, CA) |
Correspondence
Address: |
JONES DAY
555 WEST FIFTH STREET, SUITE 4600
LOS ANGELES
CA
90013-1025
US
|
Family ID: |
46599162 |
Appl. No.: |
10/680075 |
Filed: |
October 6, 2003 |
Current U.S.
Class: |
623/2.17 ;
623/1.26; 623/23.68 |
Current CPC
Class: |
A61F 2/243 20130101;
A61F 2/2418 20130101; A61F 2220/0016 20130101; A61F 2/013 20130101;
A61F 2210/0028 20130101; A61F 2220/0075 20130101; A61F 2210/0019
20130101; A61F 2/2496 20130101; A61F 2220/0008 20130101; A61F
2220/0066 20130101; A61F 2220/005 20130101; A61F 2230/0054
20130101; A61F 2250/0059 20130101; A61F 2/2439 20130101 |
Class at
Publication: |
623/002.17 ;
623/001.26; 623/023.68 |
International
Class: |
A61F 002/24; A61F
002/06 |
Claims
1. A valve assembly comprising: a replacement valve; and a dual
ring anchoring structure; said dual ring anchoring structure
comprising an inflow ring and an outflow ring connected by a
vertical element.
2. The valve assembly of claim 1, wherein said valve is positioned
internally to said anchoring structure.
3. The valve assembly of claim 2, wherein said valve comprises an
inflow annulus, an outflow annulus, and a plurality of
leaflets.
4. The valve assembly of claim 3, wherein said inflow annulus is
scalloped.
5. The valve assembly of claim 1, wherein said vertical element
comprises two posts.
6. The valve assembly of claim 5, wherein said two posts are
configured to slide past each other upon compression of the
anchoring structure.
7. The valve assembly of claim 5, wherein said two posts form a
single vertical element upon compression of the anchoring
structure.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to devices and systems for the
replacement of physiological valves.
BACKGROUND OF THE INVENTION
[0002] The transport of vital fluids in the human body is largely
regulated by valves. Physiological valves are designed to prevent
the backflow of bodily fluids, such as blood, lymph, urine, bile,
etc., thereby keeping the body's fluid dynamics unidirectional for
proper homeostasis. For example, venous valves maintain the upward
flow of blood, particularly from the lower extremities, back toward
the heart, while lymphatic valves prevent the backflow of lymph
within the lymph vessels, particularly those of the limbs.
[0003] Because of their common function, valves share certain
anatomical features despite variations in relative size. The
cardiac valves are among the largest valves in the body with
diameters that may exceed 30 mm, while valves of the smaller veins
may have diameters no larger than a fraction of a millimeter.
Regardless of their size, however, many physiological valves are
situated in specialized anatomical structures known as sinuses.
Valve sinuses can be described as dilations or bulges in the vessel
wall that houses the valve. The geometry of the sinus has a
function in the operation and fluid dynamics of the valve. One
function is to guide fluid flow so as to create eddy currents that
prevent the valve leaflets from adhering to the wall of the vessel
at the peak of flow velocity, such as during systole. Another
function of the sinus geometry is to generate currents that
facilitate the precise closing of the leaflets at the beginning of
backflow pressure. The sinus geometry is also important in reducing
the stress exerted by differential fluid flow pressure on the valve
leaflets or cusps as they open and close.
[0004] Thus, for example, the eddy currents occurring within the
sinuses of Valsalva in the natural aortic root have been shown to
be important in creating smooth, gradual and gentle closure of the
aortic valve at the end of systole. Blood is permitted to travel
along the curved contour of the sinus and onto the valve leaflets
to effect their closure, thereby reducing the pressure that would
otherwise be exerted by direct fluid flow onto the valve leaflets.
The sinuses of Valsalva also contain the coronary ostia, which are
outflow openings of the arteries that feed the heart muscle. When
valve sinuses contain such outflow openings, they serve the
additional purpose of providing blood flow to such vessels
throughout the cardiac cycle.
[0005] When valves exhibit abnormal anatomy and function as a
result of valve disease or injury, the unidirectional flow of the
physiological fluid they are designed to regulate is disrupted,
resulting in increased hydrostatic pressure. For example, venous
valvular dysfunction leads to blood flowing back and pooling in the
lower legs, resulting in pain, swelling and edema, changes in skin
color, and skin ulcerations that can be extremely difficult to
treat. Lymphatic valve insufficiency can result in lymphedema with
tissue fibrosis and gross distention of the affected body part.
Cardiac valvular disease may lead to pulmonary hypertension and
edema, atrial fibrillation, and right heart failure in the case of
mitral and tricuspid valve stenosis; or pulmonary congestion, left
ventricular contractile impairment and congestive heart failure in
the case of mitral regurgitation and aortic stenosis. Regardless of
their etiology, all valvular diseases result in either stenosis, in
which the valve does not open properly, impeding fluid flow across
it and causing a rise in fluid pressure, or
insufficiency/regurgitation, in which the valve does not close
properly and the fluid leaks back across the valve, creating
backflow. Some valves are afflicted with both stenosis and
insufficiency, in which case the valve neither opens fully nor
closes completely.
[0006] Because of the potential severity of the clinical
consequences of valve disease, valve replacement surgery is
becoming a widely used medical procedure, described and illustrated
in numerous books and articles. When replacement of a valve is
necessary, the diseased or abnormal valve is typically cut out and
replaced with either a mechanical or tissue valve. A conventional
heart valve replacement surgery involves accessing the heart in a
patient's thoracic cavity through a longitudinal incision in the
chest. For example, a median sternotomy requires cutting through
the sternum and forcing the two opposite halves of the rib cage to
be spread apart, allowing access to the thoracic cavity and the
heart within. The patient is then placed on cardiopulmonary bypass,
which involves stopping the heart to permit access to the internal
chambers. Such open heart surgery is particularly invasive and
involves a lengthy and difficult recovery period. Reducing or
eliminating the time a patient spends in surgery is thus a goal of
foremost clinical priority.
[0007] One strategy for reducing the time spent in surgery is to
eliminate or reduce the need for suturing a replacement valve into
position. Toward this end, valve assemblies that allow implantation
with minimal or no sutures would be greatly advantageous.
Furthermore, while devices have been developed for the endovascular
implantation of replacement valves, including collapsing,
delivering, and then expanding the valve, such devices do not
configure the valve in a manner that takes advantage of the natural
compartments formed by the valve sinuses for optimal fluid dynamics
and valve performance. In addition, to the extent that such devices
employ a support structure in conjunction with a tissue valve, such
valve constructs are configured such that the tissue leaflets of
the support valve come into contact with the support structure,
either during the collapsed or expanded state, or both. Such
contact is capable of contributing undesired stress on the valve
leaflet. Moreover, such support structures are not configured to
properly support a tissue valve having a scalloped inflow annulus
such as that disclosed in the U.S. patent application Ser. No.
09/772,526 which is incorporated by reference herein in its
entirety.
[0008] Accordingly, there is a need for a valve replacement system
comprising a collapsible and expandable valve assembly that is
capable of being secured into position with minimal or no suturing;
facilitating an anatomically optimal position of the valve;
maintaining an open pathway for other vessel openings of vessels
that may be located in the valvular sinuses; and minimizing or
reducing stress to the tissue valve leaflets. The valves of the
present invention may comprise a plurality of joined leaflets with
a corresponding number of commissural tabs. Generally, however, the
desired valve will contain two to four leaflets and commissural
tabs. Examples of other suitable valves are disclosed in U.S.
patent application Ser. Nos. 09/772,526, 09/853,463, 09/924,970,
10/121,208, 10/122,035, 10/153,286, 10/153,290, the disclosures of
all of which are incorporated by reference in their entirety
herein.
SUMMARY OF THE INVENTION
[0009] The present invention provides systems and devices for the
replacement of physiological valves. In one embodiment of the
present invention, the replacement valve assemblies are adapted to
fit substantially within the valve sinuses. Because the devices and
procedures provided by the present invention eliminate or reduce
the need for suturing, time spent in surgery is significantly
decreased, and the risks associated with surgery are minimized.
Further, the devices of the present invention are suitable for
delivery by cannula or catheter.
[0010] In one preferred embodiment of the present invention a valve
anchoring structure is provided that is dimensioned to be placed
substantially within the valve sinus. In this embodiment, the valve
anchoring structure extends substantially across the length of the
valve sinus region.
[0011] In another preferred embodiment of the present invention a
valve assembly is provided, comprising a valve and anchoring
structure, in which the valve comprises a body having a proximal
end and a distal end, an inlet at the proximal end, and an outlet
at the distal end. The inlet comprises an inflow annulus,
preferably with either a scalloped or straight edge. The outlet
comprises a plurality of tabs that are supported by the anchoring
means at the distal end. In preferred embodiments of the invention,
the plurality of tabs are spaced evenly around the circumference of
the valve.
[0012] In yet another embodiment of the present invention, a valve
assembly is provided in which there is minimal or no contact
between the valve and anchoring structure.
[0013] In still another embodiment of the present invention, a
valve assembly is provided in which the valve is capable of
achieving full opening and full closure without contacting the
anchoring structure.
[0014] In yet another embodiment of the present invention, a valve
assembly is provided in which the vertical components of the
anchoring structure are limited to the commissural posts between
sinus cavities, thereby minimizing contact between mechanical
components and fluid, as well as providing flow to vessels located
in the valve sinus.
[0015] In still another embodiment of the present invention, a
valve is provided that firmly attaches to the valve sinus,
obviating the need for suturing to secure the valve placement.
[0016] In a further embodiment of the present invention, a valve
assembly is provided in which the anchoring structure may be
collapsed to at least fifty percent of its maximum diameter.
[0017] In still a further embodiment of the present invention, an
expansion and contraction device is provided to facilitate
implantation of the valve and anchoring structure.
[0018] In another embodiment, the present invention provides
adhesive means for securing the valve assembly in a valve
sinus.
[0019] In yet another embodiment of the present invention, a valve
sizing apparatus is provided for the noninvasive determination of
native valve size.
[0020] The present invention also provides cutting means to remove
the native diseased valve. One aspect of the cutting means
comprises a plurality of jaw elements, each jaw element having a
sharp end enabling the jaw element to cut through at least a
portion of the native valve. Another aspect of the cutting means
comprises a plurality of electrode elements, wherein radiofrequency
energy is delivered to each electrode element enabling the
electrode element to cut through at least a portion of the native
valve. A further aspect of the cutting means comprises a plurality
of ultrasound transducer elements, wherein ultrasound energy is
delivered to each transducer element enabling the transducer
element to cut through at least a portion of the native valve.
[0021] In yet another embodiment, the present invention provides a
temporary two-way valve and distal protection filter assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows an exemplary valve during operation. FIG. 1A
shows the valve in the open position during peak flow. FIG. 1B
shows the valve in closed position to prevent backflow of the fluid
across the valve.
[0023] FIG. 2 shows a preferred embodiment of the valve of the
present invention. This valve features commissural tabs and a
scalloped inflow annulus.
[0024] FIGS. 3A, B and C are representations of a typical valve
sinus. These figures illustrate the anatomy of the sinus cavities,
commissural posts, leaflets and inflow/outflow annuli.
[0025] FIG. 4 is a schematic representation of the geometry and
relative dimensions of the valve sinus region.
[0026] FIG. 5 shows a valve anchoring structure, in accordance with
a preferred embodiment of the present invention, that is lodged
inside a vessel.
[0027] FIGS. 6A and B are schematics of a valve assembly comprising
a valve and an anchoring structure in which the anchoring structure
features an additional cloth ring along the valve inflow edge that
serves as a gasket. FIG. 6C shows a valve anchoring structure
according to one preferred embodiment of the present invention
featuring a two-ring inflow rim.
[0028] FIG. 7 is a diagrammatic representation of a flat pattern of
a preferred embodiment of an anchoring structure in the expanded
state.
[0029] FIG. 8 is a diagrammatic representation of a flat pattern of
a preferred embodiment of an anchoring structure in the compressed
state.
[0030] FIG. 9 shows a flat valve leaflet of a preferred valve to
which the anchoring structure dimensions can be fitted.
[0031] FIG. 10 illustrates the relative dimensions of a preferred
embodiment of an anchoring structure of the present invention.
[0032] FIG. 11 shows a flared anchoring structure dimensioned to
lodge inside the sinus cavities.
[0033] FIG. 12 shows a different view of the flared anchoring
structure.
[0034] FIG. 13 shows a preferred embodiment of an anchoring
structure lacking an outflow ring, and having support posts
dimensioned to lodge in the sinus commissural posts, providing
cantilevered support for the valve outflow end.
[0035] FIG. 14 shows a preferred embodiment of an anchoring
structure with flared in- and outflow ends and support posts for
lodging in the commissural posts with attachment windows capable of
deflecting inward at back flow pressure.
[0036] FIG. 15A shows a top view of a preferred embodiment of a
valve assembly comprising a valve and an anchoring structure made
of elliptical segments joined together.
[0037] FIG. 15B shows a lateral view of the preferred anchoring
structure without valve.
[0038] FIG. 16A shows the valve assembly comprising a valve and
elliptical segment anchoring structure in expanded form. FIG. 16B
shows the same in compressed form
[0039] FIG. 17 shows the lodging of an elliptical anchoring
structure inside the valve sinus cavities.
[0040] FIG. 18A shows how the elliptical segments of the anchoring
structure may be joined by a double crimp. FIG. 18B shows how the
valve is positioned inside the anchoring structure.
[0041] FIG. 19A shows a double crimp uniquely designed to flexibly
join the elliptical segments. FIG. 19B shows a modified double
crimp.
[0042] FIG. 20A shows how the elliptical segments may be assembled
into the double crimp. FIG. 20B shows the final assembly.
[0043] FIGS. 21A-G show different views of an elliptical segment
anchoring structure further comprising cloth covering including a
gasket cloth cuff at the inflow rim.
[0044] FIGS. 22A and B show different views of an elliptical
segment anchoring structure made from a single piece of tubing.
[0045] FIGS. 23A through D show an elliptical segment anchoring
structure in which the upper segments have been removed and the
ends of the junctions are formed into prongs.
[0046] FIG. 24 shows a preferred valve assembly of the present
invention with an anchoring structure comprising a ring
incorporated into the valve inflow rim.
[0047] FIG. 25A shows an anchoring structure comprising two
undulating rings with inverse wave patterns. FIG. 25B shows an
anchoring structure comprising two such rings connected by vertical
elements.
[0048] FIG. 26 shows a valve assembly comprising an anchoring
structure in which the inflow ring and outflow ring are
structurally unconnected.
[0049] FIG. 27A-C show a tubular anchoring structure.
[0050] FIGS. 28A-D show an anchoring structure comprising an inflow
ring and an outflow ring connected by vertical posts that slide
across one another upon compression.
[0051] FIGS. 29A and B show an anchoring structure comprising an
inflow and outflow ring connected by vertical posts that join to
form a single vertical element upon compression.
[0052] FIGS. 30A and B shows an anchoring structure comprising a
three-member spring aided frame.
[0053] FIGS. 31A and B show a preferred embodiment of an expansion
and contraction device.
[0054] FIGS. 32A and B more particularly shows the angled wires of
the device.
[0055] FIG. 33 shows the positioning of an anchoring structure on
the expansion and contraction device.
[0056] FIG. 34 shows another preferred embodiment of an expansion
and contraction device featuring a wire-spindle mechanism.
[0057] FIG. 35 shows a different perspective of the wire-spindle
expansion and contraction device.
[0058] FIGS. 36A and B show another preferred embodiment of an
expansion and contraction device for self-expanding valve
assemblies.
[0059] FIG. 37A shows a further preferred embodiment of an
expansion and contraction device featuring a rotating plate
mechanism. FIGS. 37B and C more particularly shows the
spiral-shaped rotating plate.
[0060] FIGS. 38A and B show the expansion and contraction device
expanding an anchoring frame.
[0061] FIG. 39 shows another preferred embodiment of an expansion
and contraction device featuring a groove-pin mechanism.
[0062] FIG. 40 shows one preferred embodiment of a valve having an
outer circumferential reservoir containing a sealable fixation
means for securely fixing the valve prosthesis at a desired
location within a vessel or body cavity.
[0063] FIGS. 41A and B show another embodiment of a valve having an
outer circumferential reservoir, wherein the sealabe fixation means
comprises a two component biological adhesive.
[0064] FIG. 42 illustrates a reservoir with thin spots adapted to
rupture when the reservoir is under pressure, thereby releasing the
contents of the reservoir.
[0065] FIG. 43 is a cross-sectional view of the reservoir showing
the thin spots.
[0066] FIG. 44 is a cross-sectional view of a valve reservoir
having two concentric component compartments.
[0067] FIGS. 45A and B depict a minimally-invasive valve
replacement sizer.
[0068] FIG. 46 is a cross-sectional view of a minimally-invasive
valve replacement sizer comprising a guidewire, an intravascular
ultrasound (IVUS) catheter having a transducer, and a balloon
catheter, all positioned within the central lumen of the
catheter.
[0069] FIG. 47 shows a balloon catheter comprising a balloon that
circumferentially surrounds a portion of the catheter at its distal
portion.
[0070] FIG. 48 shows a cross-sectional view of an inflated balloon
with curves forming leaflets to enable fluid to pass.
[0071] FIG. 49 shows one preferred embodiment of a
minimally-invasive valve replacement sizer, wherein the balloon is
inflated with saline.
[0072] FIG. 50 shows a preferred embodiment of a minimally-invasive
valve replacement sizer system, wherein the transducer emits an
ultrasonic signal in a perpendicular direction to an intravascular
ultrasound catheter (IVUS), which is reflected off the outer wall
of the balloon and then received by the transducer and wherein the
radius and diameter of the body cavity is determined by the
auxiliary processor.
[0073] FIG. 51 shows an anchoring structure of the present
invention having ultrasound cutting means.
[0074] FIG. 52 shows an anchoring structure of the present
invention having radiofrequency cutting means.
[0075] FIG. 53 shows an anchoring structure having sharp edge
cutting means.
[0076] FIG. 54 is a partial view of the valve assembly with cutting
means on a partially inflated balloon catheter.
[0077] FIGS. 55A-C show a temporary two-way valve for distal
protection.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0078] The present invention relates to valve replacement systems
and devices. As illustrated in FIG. 1, a valve (1) comprises a
distal or outflow end (2), leaflets (3) and a proximal or inflow
end (4). A typical valve functions similar to a collapsible tube in
that it opens widely during systole or in response to muscular
contraction, to enable unobstructed forward flow across the
valvular orifice (FIG. 1A). In contrast, at the end of systole or
contraction, as illustrated in FIG. 1B, as forward flow
decelerates, the walls of the tube are forced centrally between the
sites of attachment to the vessel wall and the valve closes
completely.
[0079] Replacement Valves
[0080] A preferred valve (5) for use with the systems and devices
of the present invention is illustrated in FIG. 2 and is comprised
of a body having a proximal end or inflow ring (6) and a distal end
or outflow ring (7). The body is comprised of multiple leaflets of
valve tissue joined by seams (8), wherein each seam is formed by a
junction of two leaflets. A commissural tab region (9) extends from
each seam at the distal end of the valve body. The proximal end (6)
has an inflow ring with a peripheral edge that can be scalloped or
straight. The inflow ring (6) of the valve can further comprise a
reinforcement structure (10) that can be stitched to it. In
preferred embodiments of the invention, the inflow edge of the
valve is scalloped. The valve replacement systems and devices of
the present invention are not limited, however, to the specific
valve illustrated in FIG. 2. An important consideration in the
design of valve replacement systems and devices that has received
insufficient attention in previous approaches is the architecture
of valve sinus. Valve sinuses are dilations of the vessel wall that
surround the natural valve leaflets. Typically, each natural valve
leaflet has a separate sinus bulge or cavity that allows for
maximal opening of the leaflet at peak flow without permitting
contact between the leaflet and the vessel wall. Thus, for example,
a two-leaflet valve is surrounded by two sinus bulges, a
three-leaflet valve by three, and a four-leaflet valve by four
sinus cavities. The individual sinus bulges or cavities are
separated by vertical fibrous structures known as commissural
posts. These commissural posts define longitudinal structures with
lesser outward curvature than the sinus cavities, as can be seen in
FIG. 3. FIGS. 3A and B illustrate the reduced curvature of the
commissural posts (11) compared with the curvature of the sinus
cavities (12). FIG. 3C shows a view from outside the vessel of a
commissural post (11) between two sinus cavities (12), while FIG.
3A shows a cross sectional view from the top of a closed valve
within a valve sinus. The areas between the bulges define the
commissural posts (11) and as can be clearly seen in FIG. 3B, the
commissural posts serve as the sites of attachment for the valve
leaflets to the vessel wall (13).
[0081] FIGS. 3B and C also show the narrowing diameter of the sinus
region at both its inflow end (14) and outflow end (15) to form the
inflow and outflow annuli of the sinus region. Thus, the valve
sinuses form a natural compartment to support the operation of the
valve by preventing contact between the leaflets and the vessel
wall, which, in turn, may lead to adherence of the leaflets and/or
result in detrimental wear and tear of the leaflets. The valve
sinuses are also designed to share the stress conditions imposed on
the valve leaflets during closure when fluid pressure on the closed
leaflets is greatest. The valve sinuses further create favorable
fluid dynamics through currents that soften an otherwise abrupt
closure of the leaflets under conditions of high backflow pressure.
Lastly, the sinuses ensure constant flow to any vessels located
within the sinus cavities.
[0082] As shown in FIG. 4, the valve sinus region is characterized
by certain relative dimensions which remain constant regardless of
the actual size of the sinuses. Generally, the diameter of the
sinus is at its largest at the center of the cavities or bulges
(16), while there is pronounced narrowing of the sinus region at
both the inflow annulus (17) and outflow annulus (18). Furthermore,
the height of the sinus (19), i.e. the distance between the inflow
and outflow annuli remains proportional to its overall dimensions.
It is thus apparent that the sinus region forms an anatomical
compartment with certain constant features that are uniquely
adapted to house a valve. The systems and devices of the present
invention are designed to utilize these anatomical features of the
native sinus region for optimal replacement valve function and
position.
[0083] Accordingly, in one preferred embodiment of the present
invention, the replacement valve assembly comprises a collapsible
and expandable anchoring structure adapted to support a valve
distally along the commissural tab region and proximally along the
inflow annulus. FIG. 5 shows a preferred anchoring structure
adapted to support a valve such as that illustrated in FIG. 2. As
seen in FIG. 5, the preferred anchoring structure has a generally
tubular configuration within which the valve is secured. The valve
is secured at its proximal (inflow) annulus by attachment to the
inflow rim (20) of the anchoring structure and at its distal end
via the commissural tabs that are threaded through the axially
extending slots (21), which are formed in the support posts (22)
that extend longitudinally from the inflow rim (20) to the outflow
rim (23) of the anchoring structure. Thus, the distal ends (24) of
the support posts contact the outflow rim (23) of the anchoring
structure, whereas the proximal ends (25) of the support posts
contact the inflow rim (20) of the anchoring structure.
[0084] In FIG. 5 the outflow rim (23) of the anchoring structure is
depicted as comprising a plurality of rings that extend between the
support posts (22) generally at or above the axially extending
slots (21) that reside therein. The plurality of rings of the
outflow rim (23) are configured in an undulating or zigzag pattern
forming peaks (26) and valleys (27), wherein the individual rings
remain substantially parallel to one another. The plurality of
rings of the outflow rim comprise a vertical connector element (28)
positioned at the center of the valleys (27) formed by the
undulating or zigzag pattern. This vertical connector element (28)
is designed to stabilize the anchoring structure and to prevent
distortion of the valve during compression and expansion of the
anchoring structure comprising the valve. The vertical element (28)
extends longitudinally in the axial direction of the cylindrical
anchoring structure. In a preferred embodiment, the outflow rim
(23) of the anchoring structure comprises two rings. In a preferred
implementation of this embodiment shown in FIG. 5, the inflow rim
(20) of the support structure comprises a single ring that extends
between the support posts (22).
[0085] Both the inflow (20) and outflow (23) rims of the anchoring
structure are formed with an undulating or zigzag configuration,
although the inflow rim (20) may have a shorter wavelength
(circumferential dimension from peak to peak) and a lesser wave
height (axial dimension from peak to peak) than the outflow rim
(23). The wavelengths and wave heights of the inflow (20) and
outflow (23) rims are selected to ensure uniform compression and
expansion of the anchoring structure without distortion. The
wavelength of the inflow rim (20) is further selected to support
the geometry of the scalloped inflow annulus of a preferred valve
of the present invention. Notably, as shown in FIG. 5, the
undulating or zigzag pattern that forms the inflow rim (20) of the
anchoring structure is configured such that the proximal ends (25)
of the vertical support posts (22) are connected to the peaks (29)
of the inflow rim (20). Similarly, the undulating or zigzag pattern
that forms the outflow rim (23) of the anchoring structure is
configured such that the distal ends (24) of the support posts (22)
are connected to the valleys (27) of the outflow rim (23). Locating
the distal ends (24) of the support posts at the valleys (27) of
the outflow rim (23) will prevent the longitudinal extension of
outflow rim (23) in the direction of the valve secured within the
lumen of the anchoring structure upon compression of the valve
assembly, thereby eliminating any contact between valve and
anchoring structure. Likewise, locating the proximal ends (25) of
the support posts at the peaks (29) of the inflow rim (20) will
prevent longitudinal extension of the inflow rim (20) in the
direction of the valve tissue. Thus, compression of the valve and
anchoring structure does not lead to distortion of or injury to the
valve.
[0086] FIG. 5 further shows that the support posts (22) are
configured generally in the shape of paddle with the axial slot
(21) extending internally within the blade (30) of the paddle. The
blade (30) of the paddle is oriented toward the outflow rim (23) of
the anchoring structure and connects to the outflow rim (23) at a
valley (27) of the undulating or zigzag pattern of the outflow rim
(23). An important function of the support posts (22) is the
stabilization of the valve in general, and in particular the
prevention of any longitudinal extension at points of valve
attachment to preclude valve stretching or distortion upon
compression of the device. The blades (30) of the paddle-shaped
support posts (22) are designed to accommodate the commissural tabs
of the valve. The support posts (22) further comprise triangular
shaped elements (31) extending on each side of the proximal end
(25) of the support post. The triangular shaped elements (31) are
designed to serve as attachments sites for the sewing cuff gasket
and may be designed in different shapes without losing their
function.
[0087] The number of support posts (22) in this preferred
embodiment can range from two to four, depending on the number of
commissural posts present in the valve sinus. Thus, in a preferred
embodiment, the anchoring structure comprises three support posts
for a three-leaflet valve with a sinus that features three natural
commissural posts. The support posts (22) of the anchoring
structure are configured to coincide with the natural commissural
posts of the sinus.
[0088] FIGS. 6A and B show the preferred embodiment of FIG. 5
having a valve secured internally. The valve (32) is secured at its
proximal (inflow) annulus (33) by attachment to the inflow rim (20)
of the anchoring structure and at its outflow or distal end (34)
via the commissural tabs (35) that are threaded through the axially
extending slots (21), which are formed in the support posts (22)
that extend longitudinally from the inflow rim (20) to the outflow
rim (23) of the anchoring structure. Notably, as can be seen in
FIGS. 6A and B, in this preferred embodiment the outflow rim (23)
of the anchoring structure is configured to be longitudinally
displaced from the distal outflow annulus (34) of the valve
leaflets (36) that reside within the lumen of the tubular anchoring
structure, thereby avoiding any contact between the valve leaflets
(36) and the anchoring structure.
[0089] As shown in FIGS. 6A and B, the inflow rim (20) of the
anchoring structure can be secured to the proximal inflow annulus
(33) of the valve via a suitable fabric that may be wrapped around
the circumferential juncture at the inflow end (33) and stitched
into position to form a sewing cuff (37). The fabric may be made of
any suitable material including but not limited to woven polyester,
such as polyethylene terepthalate, polytetrafluoroethylene (PTFE),
or other biocompatible material. Thus, the valve (32) is secured
inside the anchoring structure by sewing a fabric ring (37) around
the inflow rim (20) of the anchoring structure so as to create a
sealing surface around the outer perimeter of valve's inflow
annulus (33). In a preferred embodiment, the fabric ring (37)
comprises two sewing cuff rings as shown in FIGS. 6A and B, with
the second sewing cuff ring (38) having a larger diameter than the
inflow annulus of the native valve sinus to ensure the firm lodging
of the anchoring structure against the inflow annulus of the native
valve sinus, thereby creating a tight, gasket-like seal.
[0090] The positioning of the valve (32) internally to the
preferred anchoring structure with only the fabric of the
commissural mounting tabs (35) of the valve (32) contacting the
support posts (22) at the distal outflow annulus of the valve (34),
while the proximal inflow annulus (33) of the valve is separated
from the inflow rim (20) of the anchoring structure by the sewing
cloth (37), ensures that no part of the valve (32) is contacted by
the anchoring structure during operation of the valve (32), thereby
eliminating wear on the valve (32) that may be occasioned by
contact with mechanical elements.
[0091] In FIGS. 6A, B and C the outflow rim (23) of the anchoring
structure is depicted as comprising a plurality of rings that
extend between the support posts (22) generally at or above the
axially extending slots (21) that reside at their distal ends (24).
The plurality of rings of the outflow rim (23) are configured in an
undulating or zigzag pattern forming peaks (26) and valleys (27),
wherein the individual rings remain substantially parallel to one
another. The plurality of rings of the outflow rim comprise a
vertical connector element (28) positioned at the center of the
valleys (27) formed by the undulating or zigzag pattern. This
vertical connector element (28) is designed to stabilize the
anchoring structure and to prevent distortion of the valve during
compression and expansion of the anchoring structure containing the
valve within. The vertical element (28) extends longitudinally in
the axial direction of the cylindrical anchoring structure. In a
preferred embodiment, the outflow rim of the anchoring structure
comprises two rings.
[0092] FIG. 6C shows another implementation of a preferred
anchoring structure of the present invention. In contrast to the
implementation shown in FIG. 5, wherein the inflow rim (20) of the
anchoring structure comprises a single ring that extends between
the support posts (22), the implementation shown in FIG. 6C
features an inflow rim (20) comprising two rings that are
substantially parallel to each other and are connected by a
vertical connector element (39) positioned at the center of the
peaks (29) formed by the undulating or zigzag pattern. This
vertical connector element (39) is designed to stabilize the
anchoring structure and to prevent distortion of the valve during
compression and expansion of the anchoring structure comprising the
valve. The vertical element (39) extends longitudinally in the
axial direction of the cylindrical anchoring structure. FIG. 6C
also shows that the distal end (24) of the support post (22) may
further comprise suture bores (41) to facilitate the placement of
additional sutures for the securing the valve to the anchoring
structure.
[0093] Because the wavelengths and wave heights of the inflow (20)
and outflow rims (23) are selected to ensure uniform compression
and expansion of the anchoring structure without distortion, a
different wavelength and height may be chosen for the inflow ring
(20) of an implementation of a preferred embodiment of an anchoring
structure featuring an inflow rim (20) with two substantially
parallel undulating rings as shown in FIG. 6C. Thus, the inflow rim
(20) depicted in FIG. 6C may have substantially the same wavelength
and height as the outflow rim (23). Similarly, the support posts
(22) may be modified to comprise a widened proximal end (25) with
an axial slot (40) extending longitudinally from the inflow rim
(20) toward the distal end (24) of the support posts (22) and
centrally through the triangular shaped elements (31). The widening
of the proximal end (25) of the support posts (22) protects the
triangular shaped elements (31) from distortion by the different
collapsed profile of the inflow rim (20) with larger wavelength and
height and ensures that no part of the valve (32) will be contacted
by the anchoring structure during compression.
[0094] FIGS. 7 and 8 show the expansion (FIG. 7) and compression
(FIG. 8) profile of a preferred anchoring structure of the present
invention. In a preferred embodiment of the present invention, the
anchoring structure is collapsible to at least 50% of its expanded
diameter. As shown in FIGS. 7 and 8, the undulating or zigzag
pattern that forms the inflow rim (20) of the anchoring structure
is configured such that the proximal ends (25) of the vertical
support posts (22) are connected to the peaks (29) of the inflow
rim (20). Similarly, the undulating or zigzag pattern that forms
the outflow rim (23) of the anchoring structure is configured such
that the support posts (22) are connected to the valleys (27) of
the outflow rim (23). Locating the distal ends (24) of the support
posts (22) at the valleys (27) of the outflow rim (23) will prevent
the longitudinal extension of outflow rim (23) in the direction of
the valve upon compression of the device, thereby eliminating any
contact between valve and anchoring structure. Similarly, locating
the proximal ends (25) of the support posts (22) at the peaks (29)
of the inflow rim (20) prevents structural interference between the
proximal ends (25) of the support posts (22), in particular the
triangular shaped elements (31) designed to support the scalloped
inflow annulus of the replacement valve, and the undulating pattern
of the inflow rim (20), as well as longitudinal extension of the
inflow rim (20) in the direction of the valve tissue. Thus,
compression of the valve and anchoring structure does not lead to
distortion of or injury to the valve.
[0095] FIG. 8 shows that the support posts (22) connect to the
outflow rim (23) at a valley (27) of the undulating or zigzag
pattern and that during compression, the support posts stabilize
the anchoring structure by preventing any longitudinal extension at
points of valve attachment, that is at the proximal (25) and distal
(24) ends of the support posts. The commissural mounting tabs of
the valve are attached to the anchoring structure by extending
through the axial slots (40) of the support posts to the exterior
of the anchoring structure, while the inflow annulus of the valve
is connected to the inflow rim (20) of the anchoring structure via
a fabric ring. This arrangement allows firm attachment of the
distal or outflow end of valve to the anchoring structure and
ensures the proper positioning of the valve, with the outflow end
being supported such that the leaflets are allowed to open and
close with the movement of fluid across the lumen of the valve. It
should be noted that the particular shapes of the individual
elements of the structures disclosed herein may be modified by a
person of skill in the art to achieve the advantages described
without departing from the scope of the present invention.
[0096] The number of support posts (22) in this preferred
embodiment can range from two to four, depending on the number of
commissural posts present in the valve sinus. Thus, in a preferred
embodiment, the anchoring structure comprises three support posts
(22) for a three-leaflet valve with a sinus that features three
natural commissural posts. The support posts (22) of the anchoring
structure are configured to coincide with the natural commissural
posts of the sinus.
[0097] An advantage of this arrangement is the additional option
for the surgeon of suturing the valve assembly into place, wherein
the anchoring structure provides the surgeon with additional
guidance as to the proper anatomical positioning of the valve
inside the native valve sinuses. Since the anchoring structure is
dimensioned to fit precisely into the valve sinus cavities, the
surgeon's positioning task is simplified to a visual determination
of the location of the commissural posts of the native sinuses and
their alignment with the support posts (22) of the anchoring
structure of the valve. Thus, the present preferred embodiment
takes advantage of the natural features of the valve sinus for the
rapid orientation and attachment of the valve assembly. The ability
of the anchoring structure to emulate the architecture of the valve
sinus thus significantly reduces the surgeon's time spent on
suturing the valve into position, should he so desire.
[0098] The geometry of the preferred embodiment of a valve
anchoring structure further naturally positions it across the
entire longitudinal extension of the native valve sinus, lodging
the anchoring structure firmly against the vessel walls.
Proximally, the inflow rim (20) of the anchoring structure
naturally fits into the native valve sinus at a position near the
inflow narrowing (annulus) of the native valve sinus against which
it is designed to rest, while distally, the outflow rim (23) of the
anchoring structure fits into the sinus at a position near the
outflow narrowing (annulus) of the sinus against which it is
designed to rest.
[0099] Between the proximal and distal ends of the anchoring
structure the only longitudinal mechanical elements of the
anchoring structure are the support posts (22) which are confined
to the native commissural posts between the sinuses, leaving the
sinus cavities free to create the native fluid currents that
support leaflet closure and valve operation in general. A further
advantage of this preferred embodiment of the present invention is
the ability of the anchoring structure to emulate the natural
compartment formed by the sinus for anchoring the valve. Thus, the
anchoring structure is able to extend completely across the sinuses
without placing mechanical elements into the path of fluid flow and
without obstructing flow to any vessel openings that may be present
in the valve sinuses.
[0100] In a preferred implementation of the present embodiment, the
anchoring structure exerts radial force against the vessel wall so
as to produce a compression fit. This may be accomplished by
oversizing the anchoring structure such that it permanently seeks
to expand to its original size. Thus, both the inflow (20) and
outflow (23) rims are designed to push radially against the sinus
walls near the inflow and outflow annuli of the sinus. The
undulating or zigzag pattern formed by the inflow (20) and outflow
(23) rings further serves to provide tire-like traction against the
sinus wall for anchoring. Thus, the combination of compression fit,
traction and sewing cuff rings (37 and 38) of the anchoring
structure provides a firm anchor for the replacement valve and an
optimal configuration in the native valve sinus.
[0101] In preferred embodiments of the present invention, the
anchoring structure comprises a material that is expandable from a
compressed configuration illustrated in FIG. 8 into the
configuration depicted in FIG. 7. The anchoring structure may be
non-self expanding, i.e. capable of being expanded from a
compressed state using mechanical means, such as a balloon inflated
from within the radial center of the anchoring structure, or using
the expansion and compression devices disclosed herein. The
anchoring structure comprises vertical tab support posts (22) which
are designed to prevent inelastic deformation when the anchoring
structure is collapsed prior to implantation.
[0102] FIG. 9 shows a representative flat valve leaflet (36) before
it is sewn together with a desired number of additional leaflets
(36) to form a three-dimensional replacement valve. The flat
pattern of the leaflet (36) can be used to dimension the anchoring
structure shown in FIG. 10 such that the commissural tabs (35) of
the valve (36) will coincide with the axial slots (21) at the
distal ends (24) of the support posts (22) and the proximal edges
(42) at which the leaflets will be stitched or otherwise attached
to each other to form the inflow annulus of the valve can be
attached to the proximal ends (25) of the support posts (22) of the
anchoring structure via the triangular shaped elements (31).
[0103] FIGS. 9 and 10 also show how an anchoring structure and
valve may be scaled to fit different sizes of valve sinuses while
retaining the proportional dimensions of the valve sinus. For
example, if the width (43) of the leaflet (36) shown in FIG. 9 is
chosen for a certain valve size, then the distance (44) between
support posts (22) of the anchoring structure shown in FIG. 10 will
be determined accordingly. Likewise, the height (45) of the leaflet
(36) in FIG. 9 will determine the length (46) of the support posts
(22) of the anchoring structure in FIG. 10. In this manner, a
person of skill in the art can dimension both the valve and
anchoring structure to fit any size of valve sinus.
[0104] Another preferred embodiment of the present invention,
illustrated in FIGS. 11 and 12, comprises a valve supported by a
flared anchoring structure. The flared anchoring structure
preferably comprises flared-out sections located at both the inflow
(47) and outflow rims (48) to anchor it firmly against the narrowed
inflow and outflow annuli of the valve sinuses. The flared distal
end (48) of the anchoring structure is adapted to support the tab
regions of the valve while the flared proximal end (47) supports
the valve inflow annulus (33). The flared-out feature prevents
contact between the valve tissue and the anchoring structure if the
outflow rim (48) is positioned below the upper edges of the valve
leaflets (36) in the open position, while also allowing the
anchoring structure to secure itself in a sinus cavity of the
vascular passageway. In this embodiment, the outflow rim (48) of
the anchoring structure is comprised of diamond (49) and hexagon
(50) shaped structures which facilitate collapsibility and dynamic
compliance. The commissural tabs (35) of the valve (32) can be
stitched directly to the hexagon shaped elements (50) of the
outflow ring, rather than being secured via slots. The flared
inflow rim (47) of the anchoring structure preferably comprises a
single ring in the form of an undulating or zigzag pattern to which
the valve's fabric ring (37) can be sewn. The inflow ring (47) of
the anchoring structure is connected to the outflow rim (48)
through vertical elements (51) that are positioned to coincide with
the commissural posts of the native sinus region. Thus, the
exemplary embodiment of FIGS. 11 and 12 comprises three vertical
connecting elements (51) for a three-leaflet valve (32). However,
it should be understood that the number of vertical connecting
elements (51) is meant to be adapted to the number of native
commissural posts present in the particular sinus region. The area
between vertical connector elements (51) is thus left free of any
structural elements for the accommodation of vessel openings that
may be present in the particular valve sinus.
[0105] In another preferred embodiment, as illustrated in FIG. 13,
a valve is supported by an anchoring structure comprising a
plurality of posts (52) with a single ring (53) at the inflow rim.
The ring (53) is configured in an undulating or zigzag pattern. In
this exemplary embodiment the plurality of posts (52) number three
for a three-leaflet valve sinus region. The three posts (52) extend
in the distal direction from the single ring (53) located at the
inflow end of the anchoring structure. The proximal end (33) of the
valve is attached to the ring (53) portion of the anchoring
structure so that the ring (53) provides support to the inflow
annulus (33) of the valve. The inflow ring (53) comprises an
undulating or zigzag pattern for tire-like traction against the
vessel wall. The anchoring structure portion surrounding the
proximal end (33) of the valve is preferably flared in an outward
direction to improve anchoring forces against the vascular
wall.
[0106] The three posts (52) extend from the proximal end (33) to
the distal end (34) of the valve and provide cantilevered support
to the tab regions (35) of the valve at the distal end (34). The
three posts (52) are designed to be sufficiently flexible so that
they may deflect inwardly in a controlled motion at back flow
pressures to optimize the fatigue life of the anchoring structure.
The posts (52) comprise a distal end (54) for the attachment of the
valve commissural tabs (35). Below the distal end (54), the posts
(52) comprise a diamond-shaped element (55) for enhanced structural
stability and valve support. As with the previous embodiments of
the present invention, the design according to the present
embodiment creates open space between the proximal (33) and distal
ends of the valve (34). This also ensures that there is no direct
contact between the valve and the anchoring structure and that
vessel openings located within the particular sinus remain
unencumbered. Again, as in the preceding embodiments, the support
posts (52) are configured to spatially coincide with the
commissural posts of the valve sinuses for ease of positioning and
anatomical optimization.
[0107] The anchoring structure embodiment illustrated in FIG. 14
comprises a valve supported by a multi-operational anchoring
structure (56). The multi-operational anchoring structure (56)
comprises a proximal end (57), a distal end (58), posts (59)
extending from the proximal end (57) to the distal end (58), and a
tab attachment window (60) attached to each post (59) at the distal
end (58). The tab attachment windows (60) in the present embodiment
have a triangular geometry that is designed to create an optimal
interference fit between the anchoring structure and the
commissural tabs The post (59) and tab attachment window (60)
construction of the present embodiment allows inward deflection of
the post at back flow pressure, thus providing cantilevered support
to the valve and greater dynamic compliance with the sinus region.
Both the proximal (57) and distal (58) ends of the anchoring
structure are flared out to better secure the valve in the valvular
sinus region. The proximal end or inflow rim (57) of the anchoring
structure also preferably possesses barbs or hooks (61) at the
proximal end (62) of the post (59) for better attachment to the
vascular wall and/or the valve's inflow annulus. In this
embodiment, the flared inflow rim (57) is depicted as featuring two
undulating rings that are substantially parallel to one another,
while the flared outflow rim features three undulating rings.
[0108] Yet another preferred embodiment of a valve anchoring device
according to the present invention is illustrated in FIGS. 15-21.
In this preferred embodiment, an elliptical segment (70) anchoring
structure is used to support the valve (32) as shown in FIG. 15A.
As shown in FIG. 15B, the elliptical segment anchoring structure
(70) comprises a plurality of elliptical segments (71) that are
joined together, either integrally, mechanically, or by adhesive
means. Each elliptical segment (71) is flared outward at the
proximal (72) and distal ends (73) of the anchoring structure and
curved inward at the junctures (74) with the other segments (71)
assuming the shape of a potato chip. When joined together side by
side, the elliptical segments (71) form a tubular structure that is
flared outward at both the inflow (72) and outflow (73) ends. The
junctures (74) of the elliptical segments (71) are located at the
center of a substantially straight area of the elliptical segments
(71) that defines the longitudinal support post elements (75) of
the elliptical segment anchoring structure (70) and also provides a
gap location (75) near which the valve tabs (35) can be secured.
The tab regions (35) extending from the seams of the valve can be
attached to the anchoring structure using any suitable means,
including, sewing, stapling, wedging or adhesive means. The tab
regions (35) are preferably attached to the gaps (75) formed above
the junctures (74) between the elliptical segments (71). The inflow
(72) and outflow (73) rims of the anchoring structure are formed by
the corresponding regions of the elliptical segments (71) that
reside below and above the junctures (74). The inflow annulus of
the valve can be secured at the inflow rim (72) via stitching to
the inflow annulus fabric which also serves as a sealing
gasket.
[0109] As shown in FIG. 16A, the vertical axes (76) of the
elliptical segments (71) are dimensioned to exceed the axial length
(77) of the valve (32), thereby eliminating valve leaflet (36)
contact with the outflow rim (73) of the anchoring structure. FIG.
16B shows how both the valve (32) and anchoring structure (70) of
the present embodiment can be compressed radially to facilitate
implantation. The concave configurations of the elliptical segments
(71) effectively form a radial spring that is capable of being
radially collapsed under pressure for deployment and then expanded
when positioned at the implant site. One advantageous feature of
the instant design is that the region of juncture (74) between the
elliptical segments (71) does not become extended upon compression
of the anchoring structure. The valve (32) and anchoring structure
(70) of the present embodiment can also be compression fit within a
valve sinus cavity to exert radial force against the sinus
walls.
[0110] As shown in FIG. 17, the anchoring structure (70) is
preferably dimensioned to be lodged substantially within a valve
sinus, with the regions of juncture (74) between the elliptical
segments (71) being configured to reside at the location of the
native commissural posts. The elliptical segment anchoring
structure (70) is designed to expand at the proximal end (72)
during peak flow and at the distal end (73) during peak backflow
pressure, thereby maintaining pressure against the vascular wall.
As a result, the valve and anchoring structure (70) of the present
embodiment will remain secure in the valve sinus without sutures. A
metal wire frame made from a metal that exhibits a high modulus of
elasticity and that is biocompatible is preferred, such as Nitinol,
as such materials exhibiting superior compressibility allow the
anchoring structure to be self-expandable.
[0111] A further preferred embodiment of a valve anchoring
structure according to the present invention is illustrated in
FIGS. 18A and B. In the present embodiment, an elliptical segment
anchoring structure (70) is presented in which the elliptical
segments (71) are joined together by a specialized double crimp
(78). FIG. 18B shows that the valve tabs (35) can be secured near
the double crimp (78) that joins the elliptical segments (71). The
tab regions (35) are preferably attached to the gaps (75) between
the elliptical segments (71). The inflow annulus of the valve (33)
can be secured at the inflow rim (72) via stitching to the inflow
annulus fabric which also serves as a sealing gasket.
[0112] FIGS. 19A and B illustrate the double crimp (78) used to
join the elliptical segments (71). As shown in FIGS. 19A and B, the
double crimp (78) comprises two hollow tubes (79), one for each
elliptical segment (71) to be inserted. The hollow tubes (79) of
the double crimp (78) are designed to allow for better motion of
the individual elliptical segments (71) and to minimize material
stresses during expansion and compression of the anchoring
structure. The double crimp (78) further comprises a central
portion (80) joining the two hollow tubes (79). This central
portion (80) comprises one or more holes (81) to facilitate the
attachment of the valve commissural tabs to the anchoring structure
and to reduce the mass of the double crimp (78). Thus, the double
crimp (78) also serves as an attachment site for the valve and
further acts as a stop against backflow pressure on the valve
leaflets.
[0113] FIG. 20A shows the insertion of the elliptical segments (71)
of the preferred anchoring structure embodiment (70) into the
double crimp (78). As with the previous embodiments, the present
embodiment is dimensioned to be lodged substantially within the
valve sinuses, with the joined regions (74) of the elliptical
segments in FIG. 20B configured to align with the commissural posts
of the sinus and the flared inflow (72) and outflow ends (73) of
the anchoring structure configured to rest against the sinus
cavities.
[0114] FIGS. 21A through G show how the elliptical segment
anchoring structure (70) may additionally be covered with cloth
(82), particularly at the inflow end (72) to provide traction and a
gasket-like seal. Thus, this preferred embodiment of the present
invention is dimensioned to follow the sinus architecture and to
lodge into the sinus cavities and against the inflow and outflow
annuli of the sinuses for optimal securing and positioning of the
replacement valve.
[0115] FIGS. 22A and B illustrate a further preferred embodiment
the present invention. This figure shows an elliptical segment
anchoring structure (90) made from one piece of tubing. As
illustrated, the support posts (91) that form the slots (92) for
the valve tabs include a series of small holes (93) on either side
of the slot (92) to facilitate suture or mechanical attachment of
the commissural tabs of the valve. Again, this anchoring structure
(90) is dimensioned to fit substantially within the valve sinuses
with the support posts (91) being configured to reside in the
commissural posts between the individual sinus cavities. The
present embodiment also exerts axial force particularly at the
flared inflow (94) and outflow rims (95) against the sinus walls to
anchor the valve.
[0116] Yet another embodiment of a valve and anchoring structure
according to the present invention is illustrated in FIGS. 23A
through D. In the present embodiment, a claw anchoring structure
(100) is shown in FIG. 23A. This embodiment corresponds to an
elliptical segment embodiment wherein the upper portions of each
elliptical segment have been removed. The ends of the junctures
(101) of the remaining elliptical segments are shaped into prongs
or claws (102). Thus, the claw anchoring structure (100) comprises
a flexible spring frame having a plurality of barbs (102), located
distally just beyond where the valve leaflet tab regions meet the
anchoring structure. The claw anchoring structure (100) preferably
comprises at least one barb (102) for each valve leaflet tab
included in the valve. The barbs (102) are designed to anchor the
valve (32) and anchoring structure (100) to the vascular wall.
[0117] In another preferred embodiment of the invention, an
anchoring structure is provided that lacks vertical support posts.
As shown in FIG. 24, the representative anchoring structure
configuration comprises an inflow ring (110) that is adapted to
being secured to the inflow annulus of the valve (33) via stitching
to the reinforced fabric sewing ring in a manner similar to the
prior representative implementations. The undulating or sinusoidal
pattern of the ring (110) facilitates radial collapse and expansion
and exerts radial force against the vessel wall. The anchoring
structure does not support the outflow annulus (34) of the valve.
Rather, the valve's commissural tabs (35) are attached to the sinus
walls via mechanical means, such as sutures, staples, or wire.
[0118] Another representative embodiment of an anchoring structure
is shown in FIG. 25A. The present embodiment comprises a dual-ring
anchoring structure (120). The dual ring (120) of the present
embodiment may, as in the previous embodiment, be secured to the
inflow annulus of the valve via stitching to the reinforced fabric
sewing ring. The undulating or sinusoidal pattern of the individual
rings (121) is configured such that the peaks (122) of one ring
(121) coincide with the valleys (123) of the other ring and vice
versa, thereby forming a sine-cosine pattern. This pattern
facilitates radial collapse and expansion and exerts radial force
against the vessel wall. As in the previous embodiment, the dual
ring anchoring structure (120) does not support the outflow annulus
of the valve. Rather, the valve's commissural tabs are attached to
the native sinus walls via mechanical means, such as sutures,
staples, or wire, or additionally by the adhesive means disclosed
herein.
[0119] FIG. 25B shows another dual ring embodiment of the present
invention. This anchoring structure is comprised of an upper
(distal) dual ring (130) and a lower (proximal) dual ring (131).
The lower dual ring (131) is connected to the proximal end of the
valve at the inflow annulus while the upper dual ring (130) is
connected to the distal end of the valve at the outflow annulus.
The valve may be connected to the rings (130, 131) via sutures,
clips or any other suitable means for attachment. The valve and the
attached proximal (131) and distal (130) rings can be collapsed and
inserted via a catheter. Once the valve has reached its desired
location in the vascular passageway, the two rings (130, 131) are
expanded to secure the valve in the vascular passageway. As in the
previous embodiment, each dual ring (130, 131) comprises a wire
frame with a circular cross-section and a sinusoidal pattern. The
sinusoidal pattern may be of a sine-cosine shape with a varied
frequency and amplitude. One or more longitudinal rods (132) may be
used to connect the two dual rings (130, 131) and maintain
longitudinal separation and radial orientation. The rods (132) may
be removable so that once the valve is implanted in the vascular
passageway they can be removed.
[0120] In another preferred embodiment, illustrated in FIG. 26, an
upper single ring (140) with an undulating or zigzag pattern
provides support to the tab regions (35) of the valve (32) at the
distal end (34) of the valve whereas a lower single ring (141)
configured in an undulating or sinusoidal pattern provides support
to the inflow annulus (33) at the proximal end of the valve (32).
The inflow ring (141) is stitched to the sewing fabric wrapped
around the circumference of the inflow annulus of the valve, as
described previously. The outflow ring (140) of the anchoring
structure generally resides above the leaflets (36) to avoid
leaflet contact. To improve traction, the inflow or outflow rings
may comprise attachment barbs (142). The structural dissociation
between the rings (140, 141) provides improved dynamic compliance
while retaining the benefits of a two ring design.
[0121] Yet another embodiment of a valve and anchoring structure
according to the present invention is illustrated in FIGS. 27A
through C. In the valve anchoring structure according to the
present embodiment shown in FIGS. 27A and C, the valve (32) is
supported by a tubular anchoring structure (150). The tubular
anchoring structure (150) is preferably made of metal or plastic.
The tubular anchoring structure (150) is also preferably designed
to be expandable. For example, the anchoring structure may be
designed to be self-expandable, balloon-expandable, or
mechanically-expandable. The tab regions (35) of the valve (32) are
preferably attached to the distal end (151) of the tubular
anchoring structure (150) using staples, sutures, wire fasteners,
or any other suitable means. The inflow rim (152) of the tubular
anchoring structure may comprise a plurality of suture bores (153)
to facilitate attachment of the valve (32). The tubular anchoring
structure (150) also comprises vertical support posts (154) with
axial slots (155) for the insertion of the valve tabs (35). The
vertical support posts (154) extend to the distal end (151) of the
tubular anchoring structure (150). In a preferred implementation of
the of the present embodiment, the means of attachment, or an
alternative means, is used to also attach the tab regions (35) of
the valve (32) to the vascular wall thereby securing the valve (32)
and tubular anchoring structure (150) in the valve sinuses. Such
fastening means can also be optionally used at the inflow annulus
to provide additional anchoring.
[0122] Another embodiment of a valve and anchoring structure
according to the present invention is illustrated in FIG. 28. In
the present embodiment, a dual-ring anchoring structure (160) is
shown, as seen in FIGS. 28C and D, with an inflow ring (161) and an
outflow ring (162) connected by a vertical element (163) comprised
of two posts (164). The anchoring structure (160) is designed to be
circumferentially collapsible as can be seen in FIGS. 28A and B. As
shown in FIGS. 28C and D, the anchoring structure (160) is
collapsed by sliding the two posts (164) that are adjacent to each
other in the expanded state (FIG. 28D) past each other to decrease
the circumference of the upper outflow (162) and lower inflow (161)
rings (FIG. 28C). Thus, prior to implantation the anchoring
structure (160) is collapsed and, once the valve is properly
positioned in the valve sinuses, the anchoring structure freely
self-expands to its original dimensions. The self-expanding
behavior of the present embodiment is due to Nitinol's relatively
high modulus of elasticity, which imparts superior spring-like
properties to the anchoring structure. Alternatively, if the
anchoring structure is constructed of a non-self expanding
material, it may be mechanically collapsed and expanded using the
devices disclosed herein.
[0123] Another embodiment of a valve and anchoring structure
according to the present invention is illustrated in FIGS. 29A and
B. In the present embodiment, a dual-ring anchoring structure (170)
is shown, with an inflow ring (171) and an outflow ring (172)
connected by a vertical element (173) comprised of two posts (174).
The inflow rim may further comprise tissue mounting posts (175).
The anchoring structure (170) is designed to be circumferentially
collapsible. FIG. 29A shows how the posts (174) are separated in
the expanded state and FIG. 29B shows how the posts (174) form a
single vertical element (173) in the collapsed state. Thus, prior
to implantation the anchoring structure is collapsed and upon the
positioning of the valve assembly in the valve sinuses, the
anchoring structure (170) freely self-expands to its original
dimensions. As in the previous embodiment, the self-expanding
behavior of the present embodiment is a function of Nitinol's high
modulus of elasticity. Alternatively, if the anchoring structure is
constructed of a non-self expanding material, it may be
mechanically collapsed and expanded using the devices disclosed
herein.
[0124] A further embodiment of a valve and anchoring structure
according to the present invention is illustrated in FIGS. 30A and
B. The present embodiment comprises a spring-aided anchoring
structure (180). The spring aided anchoring structure (180)
preferably comprises three members (181) that are radially
collapsible for implantation into the valve sinuses. The members
(181) comprise peaks (182) that serve as valve attachment points
and valleys (183) that serve to lodge the anchoring structure at
the valve sinus inflow annulus. Following implantation, the
anchoring structure (180) is expanded to its original dimensions by
coil springs (184) that provide an outward radial force on each
member. In a preferred embodiment, shown in FIG. 30B, the spring
aided anchoring structure (180) comprises at least one anchoring
section (185) for selectively securing the anchoring structure
(180) in the valve sinus at the inflow annulus. Although the
present embodiment illustrates three members (181) and three coil
springs (184), it should be appreciated that two or more members
(181) with a corresponding number of coil springs (184) may be
used.
[0125] The anchoring structures of the present invention may be
constructed from superelastic memory metal alloys, such as Nitinol,
described in U.S. Pat. No. 6,451,025, incorporated herein by
reference. Nitinol belongs to a family of intermetallic materials
which contain a nearly equal mixture of nickel and titanium. Other
elements can be added to adjust or modify the material properties.
Nitinol exhibits both shape memory and superelastic properties. The
shape memory effect of Nitinol allows for the restoration of the
original shape of a plastically deformed structure by heating it.
This is a result of the crystalline phase change known as
thermoelastic martensitic transformation. Thus, below the
transformation temperature, Nitinol is martensitic, i.e. easily
deformable. Heating the material converts the material to its high
strength, austenitic condition. Accordingly, prior to implantation,
the valve assembly is chilled in sterile ice water. Upon cooling,
the Nitinol anchoring structure enters its martensite phase. Once
in this phase, the structure is malleable and can maintain a
plastically deformed crushed configuration. When the crushed
anchoring structure comprising the valve is delivered into the
valve sinus, the increase in temperature results in a phase change
from martensite to austenite. Through the phase change, the
anchoring structure returns to its memorized shape, and thus
expands back to its original size.
[0126] The anchoring structures can also be designed to use the
superelasticity properties of Nitinol. With the superelastic
design, the chilling procedure would not be necessary. The
anchoring structure would be crushed at room temperature. The phase
change to martensite would be accomplished by means of the stress
generated during the crushing process. The anchoring structure
would be held in the crushed configuration using force. Force is
removed once the anchoring structure is delivered to the valve
sinus, resulting in a phase transformation of the Nitinol from
martensite to austenite. Through the phase change, the anchoring
structure returns to its memorized shape and stresses and strains
generated during the crushing process are removed. Alternatively,
the anchoring structures of the present invention may be composed
of a non-self expanding suitable material, such as biocompatible
metals, including titanium, and plastics. Whether the valve
assembly is designed to be self-expandable or non-self expandable,
it may be compressed (and expanded, if non-self expandable) for
implantation using the expansion and contraction devices disclosed
herein.
[0127] Expansion and Contraction Devices
[0128] A preferred embodiment of an expansion and contraction
device for implanting the valve assemblies of the present invention
is illustrated in FIGS. 31-33. As seen in FIGS. 31A and B, the
device of the present embodiment comprises a group of bendable
hollow tubes or wires (200), a grip handle (201), and a circular
element (202) that holds the wires (200) together at their proximal
ends (203). Each wire (200) comprises a proximal end (203), a
distal end (204) and a hollow shaft (205) running from the proximal
end (203) to the distal end (204). The wires (200) are attached to
the grip handle (201) at their proximal ends (203) via the circular
element (202) such that the wires form a circular pattern.
[0129] As shown in FIGS. 32A and B, the expansion and contraction
device further comprises a cylinder (206) having a proximal end
(207) and a distal end (208). The cylinder (206) has holes (209)
drilled along its distal perimeter (208). The holes (209) in the
cylinder (206) are preferably drilled at an outward angle so that
by forcing the wires (200) through the angled holes (209), the
distal ends (204) of the wires (200) are driven radially outward.
As the wires (200) are pushed further through the outwardly angled
cylinder holes (209), the further the wires (200) spread radially,
thereby expanding the anchoring structure that is positioned over
the wires (200). Accordingly, the angle of the cylinder holes (209)
controls the relationship between the longitudinal movement of the
wires (200) and their radial dilation.
[0130] As shown in FIG. 33, a representative anchoring structure
(210) of the present invention is attached to the distal ends (204)
of the hollow wires (200). The cylinder (206) having a proximal end
(207) and a distal end (208) has holes (209) drilled along its
distal perimeter (208). The holes (209) in the cylinder (206) are
drilled at an outward angle so that by forcing the wires (200)
through the angled holes (209), the distal ends (204) of the wires
(200) are driven radially outward. As this figure shows, when the
wires (200) are pushed further through the outwardly angled
cylinder holes (209), they are forced to spread radially, thereby
expanding the anchoring structure (210) that is positioned over the
wires (200) at their distal ends (204). In a preferred embodiment,
a long suture is routed from the proximal end to the distal end of
the wire down its hollow shaft, looped around a segment of the
anchoring structure at the distal end of the wire and then routed
back to the proximal end of the wire, where it is secured. Attached
to the distal ends (204) of the hollow wires, the anchoring
structure (210) contracts and expands radially in response to the
longitudinal motion of the wires (200). Pulling the grip handle
(201) proximally contracts the anchoring structure (210) into a
collapsed state for implantation whereas pushing the grip handle
(201) distally expands the anchoring structure (210). When the
anchoring structure (210) is positioned in a desirable location in
the vessel and expanded to the desired dimensions, the sutures are
severed and removed from the proximal end (203) of the wires (200)
in order to disconnect the anchoring structure (210) from the
device. The device of the present embodiment is removed, thereby
leaving the valve assembly securely situated in the valve
sinus.
[0131] Another expansion and contraction device is illustrated in
FIGS. 34 and 35. As shown in FIG. 34, the device of the present
embodiment comprises a tube (220), multiple wall panels (221),
springs (222) corresponding to the multiple wall panels (221), a
spindle (223) and a plurality of connecting wires (224). The tube
(220) comprises a hollow shaft (225) having a radial center (226),
a proximal end (227), a distal end (228) as shown in FIG. 35, an
interior wall (229) and an exterior wall (230), wherein a hole
(231) corresponding to each wall panel (221) extends through the
interior (229) and exterior wall (230) of the tube (220). In a
preferred embodiment, the perimeter of the exterior wall (230) is
surrounded by adjacent wall panels (221), only buffered by the
springs (222) corresponding to the wall panels (221). The spindle
(223) is attached to the interior wall (229) of the tube (220),
preferably facing the tube's (220) radial center (226). A
connecting wire (224) is attached to each wall panel (221) and
routed through the spring (222) and the corresponding hole (231) in
the tube wall (229, 230) to meet the other connecting wires (224),
preferably at the radial center (226) of the tube (220).
[0132] As shown in FIG. 35, upon meeting at the radial center (226)
of the tube (220), the wires (224) having been wrapped around the
spindle (223), now run parallel to the tube's (220) longitudinal
axis. By pulling the wires (224) proximally, the attached panels
(221) compress the springs (222) against the tube's (220) exterior
wall (230). In this compressed state, a collapsed valve assembly of
the present invention can be placed over the panels (221). Once the
device of the present embodiment, loaded with the valve assembly,
is positioned at the desired location in the valve sinus, the
tension in the wires (224) is relieved to force the wall panels
(221) outward, thereby expanding the anchoring structure and valve.
The length of the uncompressed spring (222) determines the diameter
to which the anchoring structure can be expanded. The anchoring
structure can optionally be secured to the wall panels (221), by
staples, sutures, wire fasteners, or any other suitable means, so
that the valve assembly may be selectively expanded and collapsed
by preferably varying the tension on the connecting wires.
[0133] In FIGS. 36A and B, another preferred embodiment of an
expansion and contraction device of the present invention is
presented. In this embodiment, the anchoring structure (240) is
composed of a shape memory metal or the like having a relatively
high modulus of elasticity, and possessing an outward spring-like
force when in a compressed state. Therefore, spring loaded wall
panels are not necessary in the present embodiment. Instead, the
wires (241) pass through sutures (242) that are threaded through
holes (243) in the tube (244) wall and wrap around portions of the
anchoring structure. Thus, the wires (241) keep the anchoring
structure (240) compressed by pulling the sutures (242) around the
anchoring structure (240) against the tube (244). Alternatively,
the tube structure can be omitted with only the wires (241) and
sutures (242) keeping the anchoring structure (240) in a compressed
state. This would ensure that the valve within the anchoring
structure is not contacted by any mechanical elements, such as a
tube (244). Alternatively, the tube could be made from a cloth- or
tissue-like material. Once the anchoring structure (240) is
positioned in the desired location in the valve sinus, the wires
(241) can be retracted, allowing the anchoring structure (240) to
self-expand such that the tube (244) can be withdrawn, leaving the
anchoring structure (240) securely lodged at the desired location
of implantation. The sutures (242), which will remain wrapped about
the anchoring structure (240), can be made of biodegradable
material and thus will be resorbed by the body within a matter of
days.
[0134] The contraction and expansion device illustrated in FIGS. 37
and 38 represents another preferred embodiment of the present
invention. As illustrated in FIG. 37, each wall panel (250) is
connected to a pin (251) which runs through the corresponding hole
(252) in the tube (253) wall. The pin (251), protruding radially
inward from the tube's interior, is preferably spring-loaded (254)
toward the radial center of the tube (253). In a zero energy state,
the wall panels (250) rest against the exterior wall of the tube
(253) and the collapsed anchoring structure rests against the wall
panels (250). Instead of wires, the present embodiment comprises a
longitudinal shaft (255) running through the radial center of the
tube. The shaft is comprised of a proximal end (256) and a distal
end (257). The distal end (257) is connected to a central plate
(258) having spiral shaped edges (259) as shown in FIGS. 37B and C.
The central plate (258) is located in the tube (253), parallel to
the tube's cross-section and is aligned with the spring-loaded
(254) pins (251). The plate's spiral-shaped edges (259) preferably
cause the distance from the plate's perimeter to the tube's radial
center to vary along the plate's (258) perimeter. When the shaft
(255) is rotated, the edge of the plate (259) pushes against each
pin (251), thereby driving the corresponding panels (250) outward
and expanding the anchoring structure, as FIG. 37C shows.
[0135] FIGS. 38A and B show how rotation of the shaft (255) pushes
the wall panels (250) radially out, thereby expanding the anchoring
structure (260). In a preferred embodiment, the anchoring structure
(260) is sutured to the wall panels (250) to allow expansion and
contraction of the anchoring structure by alternating rotation of
the shaft. The sutures are preferably removable from the shaft's
(255) proximal end to free the valve assembly from the device
following implantation in the valve sinus.
[0136] In still another embodiment, as illustrated in FIG. 39, an
expansion and contraction device similar to the previous embodiment
is presented. Instead of a device comprising a central plate with
spiral-shaped edges of varying dimensions, the present preferred
embodiment utilizes a circular disk (270) with pre-cut
spiral-shaped grooves (271) corresponding to the spring-loaded pins
(272). Preferably, the grooves (271) provide a track of varying
depth for the pins (272) such that the pins (272) are forced
radially outward upon rotation of the disk (270), thereby expanding
the anchoring structure.
[0137] Adhesive Means for Securing Replacement Valves
[0138] In addition to the disclosed features and mechanisms for
securing the valve assembly comprising a valve and anchoring
structure into position, the present invention provides the use of
biocompatible adhesives. A number of adhesives may be used to seal
the valve assembly to the surrounding tissue in the valve sinus.
The following are examples of available adhesives and methods of
use:
[0139] U.S. Pat. No. 5,549,904, the entire contents of which are
incorporated herein by reference, discloses a formulated biological
adhesive composition comprising tissue transglutaminase and a
pharmaceutically acceptable carrier, the tissue transglutaminase in
an effective amount to promote adhesion upon treatment of tissue in
the presence of a divalent metal ion, such as calcium or strontium.
In operation, the two components are mixed to activate the sealable
fixation means for securely fixing the valve assembly to tissue at
a desired valve location.
[0140] U.S. Pat. No. 5,407,671, the entire contents of which are
incorporated herein by reference, discloses a one-component tissue
adhesive containing, in aqueous solution, fibrinogen, F XIII, a
thrombin inhibitor, prothrombin factors, calcium ions and, where
appropriate, a plasmin inhibitor. This adhesive can be
reconstituted from a freeze-dried form with water. It can contain
all active substances in pasteurized form and is then free of the
risk of transmission of hepatitis and HTLV III. In operations, the
one-component tissue adhesive is reconstituted from a freeze-dried
form with water to activate the sealable fixation means for
securely fixing the valve assembly to tissue at a desired valve
location.
[0141] U.S. Pat. No. 5,739,288, the entire contents of which are
incorporated herein by reference, discloses a method for utilizing
a fibrin sealant which comprises: (a) contacting a desired site
with a composition comprising fibrin monomer or noncrosslinked
fibrin; and (b) converting the fibrin monomer or noncrosslinked
fibrin to a fibrin polymer concurrently with the contacting step,
thereby forming a fibrin clot. In operation, the fibrin monomer or
noncrosslinked fibrin is converted to activate the sealable
fixation means for securely fixing the valve assembly to tissue at
a desired valve location.
[0142] U.S. Pat. No. 5,744,545, the entire contents of which are
incorporated herein by reference, discloses a method for effecting
the nonsurgical attachment of a first surface to a second surface,
comprising the steps of: (a) providing collagen and a
multifunctionally activated synthetic hydrophilic polymer; (b)
mixing the collagen and synthetic polymer to initiate crosslinking
between the collagen and the synthetic polymer; (c) applying the
mixture of collagen and synthetic polymer to a first surface before
substantial crosslinking has occurred between the collagen and the
synthetic polymer; and (d) contacting the first surface with the
second surface to effect adhesion between the two surfaces. Each
surface can be a native tissue or implant surface. In operation,
collagen and a multifunctionally activated synthetic hydrophilic
polymer are mixed to activate the sealable fixation means for
securely fixing the valve assembly to tissue at a desired valve
location.
[0143] U.S. Pat. No. 6,113,948, the entire contents of which are
incorporated herein by reference, discloses soluble microparticles
comprising fibrinogen or thrombin, in free-flowing form. These
microparticles can be mixed to give a dry powder, to be used as a
fibrin sealant that is activated only at a tissue site upon
dissolving the soluble microparticles. In operation, soluble
microparticles comprising fibrinogen or thrombin are contacted with
water to activate the sealable fixation means for securely fixing
the valve assembly to tissue at a desired valve location.
[0144] U.S. Pat. Nos. 6,565,549, 5,387,450, 5,156,911 and
5,648,167, the entire contents of which are incorporated herein by
reference, disclose a thermally activatable adhesive. A "thermally
activatable" adhesive is an adhesive which exhibits an increase in
"tack" or adhesion after being warmed to a temperature at or above
the activation temperature of the adhesive. Preferably, the
activation temperature of the thermally activatable adhesive is
between about 28.degree. C. and 60.degree. C. More preferably, the
activation temperature is between about 30.degree. C. and
40.degree. C. One exemplary thermally activatable adhesive is
described as Example 1 in U.S. Pat. No. 5,648,167, which is
incorporated by reference herein. It consists of a mixture of
stearyl methacrylate (65.8 g), 2-ethylhexyl acrylate (28.2 g) and
acrylic acid (6 g) monomers and a solution of catalyst BCEPC (0.2
g) in ethyl acetate (100 g) is slowly added by means of dropper
funnels to ethyl acetate (50 g) heated under reflux (80 degrees C.)
in a resin flask over a period of approximately 6 hours. Further
ethyl acetate (50 g) is added to the mixture during the
polymerization to maintain the mixture in a viscous but ungelled
state. In operation, thermally activatable adhesive is heated to
activate the sealable fixation means for securely fixing the valve
assembly to tissue at a desired valve location.
[0145] FIG. 40 shows a preferred embodiment, wherein an outer
circumferential reservoir (401) is located at an outermost radius
of a valve anchoring structure (400) when the anchoring structure
(400) is in an expanded state, wherein the reservoir is filled with
a sealable fixation means for securely fixing the valve assembly
(400) at a desired location within a body cavity. FIG. 40 further
illustrates one embodiment of the reservoir (401) comprising a
sealable fixation means, wherein the sealable fixation means may
comprise a one-component biological adhesive. The sealable fixation
means may be activated by exposing the biological adhesive to blood
or heat.
[0146] FIG. 41 illustrates another preferred embodiment wherein the
sealable fixation means may comprise a two-component biological
adhesive. The sealable fixation means may be activated by mixing
the two components. Thus, for example, if one reservoir (402)
contains microparticles that are activated by contact with water,
the second reservoir (403) would contain the water for the
activation of the microparticles. This figure also shows that the
reservoirs may be arranged concentrically as shown in FIG. 41B or
adjacent to each other as shown in FIG. 41A.
[0147] FIG. 42 illustrates an exemplary reservoir (401) which may
be attached to the valve anchoring structure by its inner wall
(404) by sutures, glue, staples or some other appropriate method.
FIG. 42 further illustrates a thin spot (405) on the outer wall
(406) of the reservoir (401). The thin spots (405) are areas on the
reservoir (401) that are adapted to rupture when placed under
certain levels of pressure. The pressure is exerted on the thin
spots (405) as the reservoir (401) is expanded along with the valve
anchoring structure. The thin spots (405) are unable to withstand
the pressure and therefore rupture releasing the contents of the
reservoir (401) or reservoirs. In a preferred embodiment, the
reservoir (401) is made of an elastic material that expands along
with the expansion of the valve anchoring structure.
[0148] FIG. 43 illustrates a cross sectional view of the reservoir
(401). The reservoir (401) may contain a lumen (407) which extends
along at least a portion of the circumference of the reservoir. The
reservoir (401) has one or more thin spots (405) along its
outermost circumference, wherein the thin spots (405) are sized and
configured to rupture when the reservoir (401) is expanded to an
appropriate diameter. When the anchoring structure comprising the
valve is fully expanded, the pressure exerted upon the expanded
thin spots (405) causes them to rupture. In still another preferred
embodiment, the reservoir (401) is made of a biodegradable material
adapted for erosion or rupture to release the content of the
reservoir (401) and activate the sealable fixation means in a
desired timeframe after implantation. In a further preferred
embodiment, a circumferentially outermost portion is pressure
sensitive to rupture, wherein the contents of the reservoir (401)
are released when the reservoir (401) is compressed against the
sinus cavities during expansion and implantation of the valve
assembly.
[0149] FIG. 44 shows a cross-sectional view of another preferred
embodiment, illustrating thin spots (405) on a reservoir having two
concentric component compartments, an inner compartment (408) and
an outer compartment (409). Component A in an inner compartment
(408) and component B in an outer compartment (409) are to be mixed
to form adhesive for sealing the valve assembly against the valve
sinuses. The inner compartment (408) has a plurality of thin spots
(405) along its outermost circumference, wherein the thin spots
(405) are sized and configured to rupture when the reservoir (401)
is expanded to an appropriate diameter. The outer compartment (409)
also has a plurality of thin spots (405) along its innermost
circumference. The thin spots (405) of the inner compartment (408)
and the thin spots (405) of the outer compartment (409) may be
located adjacent to each other. In one preferred embodiment, the
space between the adjacent pair of thin spots (405) on the inner
(408) and outer (409) compartment may comprise a piercing element
that is activated to rupture the thin spot or the pair of adjacent
spots when the reservoir is expanded to an appropriate diameter or
a predetermined diameter. Other embodiments of reservoir
configuration, for example, two parallel compartments
circumferentially or longitudinally, and suitable activation
mechanism for the sealable fixation means are also within the scope
of the present invention.
[0150] The present invention further comprises methods and devices
for the sizing of native valves that require replacement.
[0151] Methods and Apparatus for Valve Sizing
[0152] Intravascular ultrasound (IVUS) uses high-frequency sound
waves that are sent with a device called a transducer. The
transducer is attached to the end of a catheter, which is threaded
through a vein, artery, or other vessel lumen. The sound waves
bounce off of the walls of the vessel and return to the transducer
as echoes. The echoes can be converted into distances by computer.
A preferred minimally invasive valve replacement sizer is shown in
FIGS. 45A and B. For purposes of this application, the distal end
or portion refers to the area closer to the body while the proximal
end or portion refers to the area closer to the user of the valve
replacement sizer. The device comprises a guidewire (500), an
intravascular ultrasound (IVUS) catheter (501) having a transducer
(502), and a balloon dilatation catheter (503) all positioned
within the central lumen of a catheter. The transducer (502) is
positioned in the IVUS sizing window (504) of the balloon catheter.
The guide wire (500) advances and guides the catheter (501) to the
appropriate location for valve sizing. FIG. 45A shows the catheter
in deflated form, whereas in FIG. 45B the balloon dilatation
catheter (503) has inflated the balloon (505).
[0153] In a preferred embodiment, shown in FIG. 46, the catheter
(510) contains multiple lumens (511) in order to house a guidewire
(512), an IVUS catheter (513), and a balloon dilatation catheter
(514). FIG. 46 illustrates a cross sectional view. One of the
separate lumens (511) contains the guidewire (512), another
contains the IVUS catheter (513), and another contains the balloon
dilatation catheter (514). The balloon dilatation catheter (514)
has a balloon (515) attached circumferentially surrounding the
balloon dilatation catheter (514) as well as a portion of the
catheter (510).
[0154] FIG. 47 shows a balloon dilatation catheter (516) comprising
a balloon (517) that circumferentially surrounds a portion of the
catheter (518) proximal to its distal portion (519). More
specifically, the balloon (517) comprises an outer wall (520) that
circumferentially surrounds a portion of the catheter (518) near
its distal portion (519). The balloon (517) also has a distal end
(521) and a proximal end (522). In a preferred embodiment, within
the area encompassed by the balloon, a transducer (523) is located
on the IVUS catheter (524). Directly over the transducer (523) a
sizing window (525) is placed on the IVUS catheter (524) to enable
signals to be transmitted and received by the transducer (523)
without interference. In a preferred embodiment, the sizing window
(525) is simply an empty space. However, the sizing window (525)
could be made from any substance which does not interfere with the
signals emitted and received by the transducer (523).
[0155] Preferably, the balloon (517) is round but other shapes are
possible and contemplated for use with the valve sizing apparatus.
In particular, FIG. 48 shows a cross section of an inflated balloon
(530) with curves forming leaflets (531) to enable fluid (532) to
pass through the vessel while the balloon (530) is in its inflated
state and the outer edges (533) of the leaflets (531) are in
contact with the vessel wall (534) to measure the diameter. The
balloon may further be made from compliant or non-compliant
material.
[0156] FIG. 49 shows a preferred embodiment wherein the balloon
(540) is inflated with saline (541). Preferably, the saline is
pumped into the balloon (540) through the balloon dilatation
catheter. Alternatively, the balloon (540) may be inflated with a
gas or any other suitable substance. The balloon (540) is inflated
to a chosen pressure by the person using the valve replacement
sizer. When the balloon (540) has been inflated, the outermost
portion of the outer wall (542) will be in contact with the vessel
wall (543) or other lumen at the location where the replacement
valve is to be placed. When the balloon (540) is completely
inflated, the farthest radial points of the balloon's outer wall
(542) will be equidistant to the center of the catheter (544). This
distance is labeled as R. The transducer (545) may or may not be at
the centermost point of the inflated balloon (540). Any deviation
from the centermost point by the transducer (545) may be accounted
for when calculating the diameter of the vessel lumen. However, the
signal emitted by the transducer (545) preferably intersects the
balloon (540) at its greatest radius.
[0157] FIG. 50 shows a preferred embodiment, wherein a transducer
(550) emits an ultrasonic signal (556) in a perpendicular direction
to the IVUS catheter (551). The signal is then reflected off the
outer wall (552) of the balloon (540) and received by the
transducer (550). The transducer (550) then transmits the data to
the auxiliary processor (553) to determine the radius and diameter
of the vessel lumen. Alternatively, an infrared light may be
emitted and received by the transducer (550) to determine the
radius and diameter of the vessel lumen. The diameter is calculated
by knowing the speed of the signal and the time it takes for the
signal to be reflected off the balloon wall (552) back to the
transducer (550). The known speed is multiplied by the time to
determine the radius of the balloon (540). The radius may be
adjusted if the transducer (550) was not located at the centermost
point of the catheter.
[0158] The present invention further provides devices and methods
to remove the native diseased valves prior to implantation of the
replacement valve assembly. In one embodiment of the present
invention, the valve removing means is provided by the replacement
valve assembly. In another embodiment, the valve removing means is
provided by a valve sizing device of the present invention.
[0159] Valve Assemblies with Native Valve Removing Capabiliy
[0160] The present invention further provides valve assemblies
comprising native valve removing capabilities. Thus, in a preferred
embodiment, a valve anchoring structure having cutting means
located at the annulus base for cutting a native valve is provided.
Accordingly, when passing the valve assembly comprising the valve
and anchoring structure through the vessel with the anchoring
structure in a collapsed state, the cutting means can be advanced
against the native valve with the anchoring structure in a
partially expanded state. In this manner, the anchoring structure
comprising the cutting means cuts at least a portion of the native
valve by deploying the cutting means, before the valve assembly is
secured to the desired valve location with the anchoring structure
in the expanded state.
[0161] It is one object of the present invention to provide a valve
assembly of the preferred embodiment having a tissue valve and an
anchoring structure, which permits implantation without surgery or
with minimal surgical intervention and provides native valve
removing means for removing a dysfunctional native valve, followed
by valve replacement. The native valve removing means on the
anchoring structure is selected from a group consisting of: a
plurality of sharp edge elements, each sharp edge element having a
sharp end enabling the element to cut through at least a portion of
the native valve; a plurality of electrode elements, wherein
radiofrequency energy is delivered to each electrode element
enabling the electrode element to cut through at least a portion of
the native valve, and a plurality of ultrasound transducer
elements, wherein ultrasound energy is delivered to each transducer
element enabling the transducer element to cut through at least a
portion of the native valve.
[0162] Percutaneous implantation of a valve prosthesis is achieved
according to the invention, which is characterized in that the
valve anchoring structure is made from a radially collapsible and
re-expandable cylindrical support means for folding and expanding
together with the collapsible replacement valve for implantation in
the body by means of catheterization or other minimally invasive
procedure. Catheters and catheter balloon systems are well known to
those of skill in the art, for example, U.S. Pat. No. 6,605,056
issued on Aug. 23, 2003.
[0163] Accordingly, in one preferred embodiment of the invention
shown in FIG. 51, the anchoring structure (600) comprises at least
one ultrasound transducer (601) at the distal end portion of the
lower ring (602), wherein each ultrasound transducer is sized and
configured with ultrasound energy as cutting means for cutting a
native valve. Ultrasound energy is delivered through conductor
means (603) to each transducer element (601) enabling the
transducer element (601) to cut through at least a portion of the
native valve. In one embodiment, the conductor (603) passes through
a delivery means and is connected to an external ultrasound energy
generator. The ablative ultrasound delivery means and methods are
well known to one skilled in the art, for example, U.S. Pat. No.
6,241,692 issued on Jun. 5, 2001.
[0164] FIG. 52 shows another preferred embodiment of a native valve
removal system comprising a valve assembly having radiofrequency
cutting means. In this preferred embodiment, the anchoring
structure comprises at least one radiofrequency electrode (610) at
the distal end portion of the lower ring (602), wherein each
radiofrequency electrode (610) is sized and configured with
radiofrequency energy as cutting means for cutting a native valve.
Radiofrequency energy is delivered through conductor means (611) to
each electrode element (610) enabling the electrode element to cut
through at least a portion of the native valve. In one embodiment,
the conductor (611) passes through delivery means and is connected
to an external radiofrequency energy generator. The ablative
radiofrequency delivery means and methods are well known to one
skilled in the art, for example, U.S. Pat. No. 6,033,402 issued on
Mar. 7, 2000.
[0165] FIG. 53 shows another embodiment of an anchoring structure
having sharp edge cutting means (620). In one preferred embodiment,
the anchoring structure comprises a set of sharp edge cutting
elements (621) at the distal end portion of the cutting means (620)
of the lower ring (602) of the anchoring structure, wherein each
cutting element (621) has a cutting tip (622), and wherein each
cutting element (621) of the cutting means is sized and configured,
optionally with radiofrequency energy, as cutting means for cutting
a native valve. In one embodiment, sharp edge cutting means on the
delivery apparatus is rotatable, enabling the cutting element (621)
to cut through at least a portion of the native valve. Sharp edge
cutting means, with optionally ablative radiofrequency delivery
means and methods, are well known to one skilled in the art, for
example, U.S. Pat. No. 5,980,515 issued on Nov. 9, 1999.
[0166] FIG. 54 shows a partially inflated balloon catheter. A
balloon catheter (630) is introduced in the vessel. The balloon
means (632) of the balloon catheter (630) is led out of the
protection cap (633) at the catheter tip (634) and is partly
inflated through a fluid channel (635), which is led to the surface
of the patient. In one embodiment, the balloon (632) is partially
expanded and the sharp end (636) of the cutting means of the valve
anchoring structure (637) is advanced to cut and remove at least a
portion of the native valve. In another embodiment, the valve
anchoring structure (637) comprises an ultrasound or radiofrequency
cutting means (638). In one embodiment, the support structure is
expanded at about 30 to 95% of full expansion for cutting the
native valve. More preferably, the support structure is expanded at
about 50 to 90% of the full expansion. In another embodiment, the
balloon catheter (630) comprises a central channel (639) with
respect to a central axial line (640) to receive a guide wire (641)
which is used in a way known for viewing the introduction of the
catheter through fluoroscopy.
[0167] Some aspects of the present invention provide a method of
endovascularly implanting a valve through a vessel, comprising the
steps of providing a collapsibly expandable valve assembly that
comprises an anchoring structure according to the present invention
with an annulus base and a collapsible valve connected to the
anchoring structure, the collapsible valve being configured to
permit blood flow in a direction and prevent blood flow in an
opposite direction, the anchoring structure having cutting means
located at the annulus base for cutting a native valve, passing the
valve assembly through the vessel with the anchoring structure in a
collapsed state, advancing the cutting means against the native
valve with the anchoring structure in a partially expanded state,
cutting at least a portion of the native valve by deploying the
cutting means, and securing the valve assembly to the desired valve
location with the anchoring structure in the expanded shape.
[0168] In operations, a method of implanting a valve assembly
according to the present invention is given below: a valve assembly
made of an anchoring structure of the present invention and a
collapsible valve, as described above, is placed on a deflated
balloon means and is compressed thereon, either manually or by use
of the expansion/compression devices of the instant invention; the
balloon means and the valve assembly are drawn into an insertion
cover; a guide wire is inserted into a vessel through the central
opening of the balloon catheter under continuous fluoroscopy; the
insertion cover conveys the guide wire to a point in the channel in
the immediate vicinity of the desired position of the valve
assembly; the balloon means is pushed out of the protection cap and
the valve assembly is positioned in the desired position if
necessary by use of further imaging means to ensure accurate
positioning; the balloon means is inflated partially; the valve
assembly is advanced with its cutting means cutting at least a
portion of the native valve; the balloon means is further inflated
to position the valve at a desired site, preferably against the
truncated valvular annulus; the balloon means is deflated; and the
balloon means with entrapped tissue and debris inside the filter
means, the guide wire, and the protection cap are drawn out and the
opening in the channel, if any, wherein the valve prosthesis is
inserted can be closed.
[0169] The present invention also provides for devices and methods
to prevent the release of debris during removal of the native
diseased valves from traveling to distant sites where such debris
may cause undesirable physiological effects.
[0170] Distal Protection Assembly
[0171] As described above, removal or manipulation of diseased
valves may result in dislodgment of parts of the valve or deposits
formed thereon which may be carried by the fluid to other parts of
the body. Thus, the present invention provides for specialized
filters that capture material and debris generated during valve
replacement procedures. The distal protection devices of the
present invention are also effective in trapping material that may
be released during other percutaneous interventional procedures,
such as balloon angioplasty or stenting procedures by providing a
temporary valve and filter in the same device.
[0172] In one preferred embodiment, shown in FIGS. 55A and B, the
present invention provides for a temporary valve (700), which may
be deployed at a desired location in a collapsed state and then
expanded and secured to the walls of the passageway. The temporary
valve (700) comprises two concentric one-way valves, an outer valve
(701) and an inner valve (702) disposed within the outer valve
(701), that open in opposite directions as shown in FIG. 55B. The
outer valve (701) opens in response to positive fluid flow
pressure, thereby regulating blood flow in substantially one
direction. The inner valve (702) opens in the opposite direction of
the outer valve (701) to facilitate the insertion of catheter based
equipment (703) as shown in FIGS. 55C and functions as a seal
through which such equipment may be passed. The pressure required
to open the individual valves may be manipulated to facilitate
positive fluid flow, while precluding or minimizing retrograde flow
that might otherwise occur as a result of back flow pressure.
Hence, it is contemplated that the inner valve (702) be configured
or constructed to open with relatively more pressure than that
required to open the outer valve.
[0173] The outer (701) and inner valves (702) of the temporary
valve (700) may be coupled together by radial support members. In
one embodiment, the radial support members couple the inner surface
of the outer valve to the outer surface of the inner valve. The
length of the radial support means depends upon the dimension of
the blood vessel or body cavity within which the temporary valve is
to be deployed.
[0174] The temporary valve may be constructed from material that is
capable of self-expanding the temporary valve, once it is deployed
from the collapsed state at the desired location. Once expanded,
catheter based equipment required for the particular surgical
procedure may be passed through and movably operated in relation to
the temporary valve.
[0175] In another embodiment of the present invention, the
temporary valve may be combined with a filter that extends distally
from the temporary valve to capture debris material. In this
embodiment, the temporary valve-filter device is preferably
configured such that the open proximal end is secured to the
temporary valve and the closed distal end comprises an opening or a
third valve to facilitate the passage of the catheter equipment
through the distal end of the bag and out of the temporary valve.
Additional valves may also be positioned in the filter to coincide
with one or more branching arteries.
[0176] In yet another preferred embodiment of the present
invention, the temporary valve-filter device may include one or
more traps within the filter bag to trap debris material within the
bag to reduce the likelihood of debris material leaving the filter
when the catheter equipment is being passed through the filter bag.
The filter traps may be comprised of one or more valves disposed
within the filter bag that are configured to open with retrograde
pressure. Alternatively, the traps may be comprised of flaps that
extend inwardly from the perimeter of the bag to create a cupping
effect that traps particulate matter and directs it outwardly
toward the perimeter of the filter bag. The filter traps may be
constructed of material that is capable of facilitating and
filtering antegrade fluid flow, while retaining the debris material
within the filter bag.
[0177] The valve-filter assembly previously described may also
incorporate multiple valves. In this arrangement, debris may be
better and better entrapped, and thus reduces the chance of debris
coming out of the valve-filter assembly. The present invention is
particularly useful while performing an interventional procedure in
vital arteries, such as the carotid arteries and the aorta, in
which critical downstream blood vessels can become blocked with
debris material.
[0178] One benefit of the current invention is that it provides
fast, simple, and quick deployment. One may deploy both the filter
and temporary valve simultaneously. The valve-filter assembly may
also include a cannulation system at the downstream end of the
filter to remove particles and debris. The valve-filter assembly
may also include a grinder for cutting up or reducing the size of
the debris. This debris, in turn, may be removed by a cannulation
system or be allowed to remain in the filter.
[0179] The valve-filter assembly is well-suited for use in
minimally invasive surgery where the valve-filter may be placed in
the aorta between the aortic valve and the innominate branch or the
braciocephalic branch. In such a configuration, the valve-filter
may be put in place before the start of surgery and function as a
valve. The valve-filter may further collect debris and particles
during removal and clean up of the old valve. The valve-filter may
also stay in place while the new valve is put in place and until
the end of the procedure to function as protection and as a valve.
A vascular filter system is well known to one skilled in the art,
for example, U.S. Pat. No. 6,485,501 issued on Nov. 26, 2002.
[0180] In all of the embodiments described above, the invention may
be part of a catheter. The invention may also be assembled onto a
separate catheter. The valve-filter may also be part of a
non-catheter device, placed directly into a blood vessel or other
lumen. In both the catheter and non-catheter embodiments, the
valve-filter may be introduced into the body by the ways described
in the following non-inclusive list: femoral artery, femoral vein,
carotid artery, jugular vein, mouth, nose, urethra, vagina,
brachial artery, subclavian vein, open sternotomies, partial
sternotomies, and other places in the arterial and venous
system.
[0181] Furthermore, in all of the embodiments described above, the
filter mesh of the valve-filter may be of any size and shape
required to trap all of the material while still providing
sufficient surface area for providing satisfactory flows during the
use of the filter. The filter may be a sheet or bag of different
mesh sizes. In a preferred embodiment, the mesh size is optimized
taking the following factors into consideration: flow conditions,
application site, size of filter bag, rate of clotting, etc.
[0182] Radiopaque markers and/or sonoreflective markers, may be
located on the catheter and/or the valve-filter assembly. An
embodiment of the valve-filter catheter is described having an
aortic transillumination system for locating and monitoring the
position and deployment state of the catheter and the valve-filter
assembly without fluoroscopy.
[0183] Additionally, visualization techniques including
transcranial Doppler ultrasonography, transesophageal
echocardiograpy, transthoracic echocardiography, epicardiac
echocardiography, and transcutaneous or intravascular
ultrasoneography in conjunction with the procedure may be used to
ensure effective filtration.
[0184] Alternatively, or additionally, the material of the filter
screen in each embodiment of the filter catheter may be made of or
coated with an adherent material or substance to capture or hold
embolic debris which comes into contact with the filter screen
within the valve-filter assembly. Suitable adherent materials
include, but are not limited to, known biocompatible adhesives and
bioadhesive materials or substances, which are hemocompatible and
non-thrombogenic. Such material are known to those having ordinary
skill in the art and are described in, among other references, U.S.
Pat. Nos. 4,768,523, 5,055,046, 5,066,709, 5,197,973, 5,225,196,
5,374,431, 5,578,310, 5,645,062, 5,648,167, 5,651,982, and
5,665,477. In one particularly preferred embodiment, only the
upstream side of the elements of the filter screen are coated with
the adherent material to capture the embolic material which comes
in contact with the upstream side of the filter screen after
entering the filter assembly. Other bioactive substances, for
example, heparin or thrombolytic agents, may be impregnated into or
coated on the surface of the filter screen material or incorporated
into an adhesive coating.
[0185] In a preferred method, blood is filtered during cardiac
surgery, in particular during percutaneous valve surgery, to
protect a patient from embolization. In this method, the
valve-filter is positioned in the aorta between the aortic valve
and the inominate branch, where it filters blood before it reaches
the carotid arteries, brachiocephalic trunk, and left subclavian
artery. The valve contains the embolic material and foreign matter
dislodged during the surgery and also provides a temporary valve
for use during valve surgery. Such a method may be utilized both on
and off pump. Such a method may also be utilized for aortic,
mitral, and pulmonary valve surgery and repair.
[0186] Although this invention has been exemplified for purposes of
illustration and description by reference to certain specific
embodiments, it will be apparent to those skilled in the art that
various modifications and alterations of the illustrated examples
are possible. Numerous modifications, alterations, alternate
embodiments, and alternate materials may be contemplated by those
skilled in the art and may be utilized in accomplishing the present
invention. Any such changes which derive directly from the
teachings herein, and which do not depart from the spirit and scope
of the invention, are deemed to be covered by this invention.
* * * * *