INJECTABLE HEART VALVE PROSTHESIS FOR LOW-INVASIVE IMPLANTATION
A heart valve prosthesis may include a cylindrical support extending between axially spaced apart ends thereof, the cylindrical support including a plurality of support features extend generally axially between the opposed ends of the support, adjacent pairs of the support features being interconnected so as to bias the cylindrical support radially outwardly. A valve is mounted within the support to define a supported valve. The supported valve can include a sidewall portion extending between inflow and outflow ends thereof, the inflow and outflow ends of the valve sidewall portion being mounted within the cylindrical support such that ends of the sidewall portion are spaced axially apart from the spaced apart ends of the cylindrical support. The supported valve can also include a valve portion residing within the sidewall portion and configured to provide for substantially unidirectional flow of blood through the supported valve, the supported valve being deformable between a reduced cross-sectional condition and an expanded cross-sectional condition, whereby implantation of the supported valve is facilitated when in the reduced cross-sectional condition.
This application is continuation of U.S. patent application Ser. No. 10/266,380, which was filed Oct. 8, 2002 and entitled HEART VALVE PROSTHESIS AND SUTURELESS IMPLANTATION OF A HEART VALVE PROSTHESIS, which is a continuation-in-part of U.S. patent application Ser. No. 09/973,609, now U.S. Pat. No. 7,510,572, which was filed on Oct. 9, 2001, and entitled HEART VALVE PROSTHESIS AND SUTURELESS IMPLANTATION OF A HEART VALVE PROSTHESIS, which is a continuation-in-part of U.S. patent application Ser. No. 09/659,882, which was filed on Sep. 12, 2000 and entitled VALVULAR PROSTHESIS AND METHOD OF USING SAME. Each of the above-identified applications is incorporated herein by reference.
TECHNICAL FIELDThe invention relates to an implantable prosthetic device and, more particularly, to a heart valve prosthesis that can be implanted via a low-invasive procedure.
BACKGROUNDIt is well known to utilize mechanical heart valves, such as the ball check valve, and natural tissue cardiac valves to replace defective aortic and mitral valves in human patients. One type of natural tissue heart valve typically employs a porcine valve for implantation in a human, as they are very similar to human valves of appropriate size and generally are easy to procure. Typically, the porcine valve is fixed by chemically treating it, such as with an appropriate glutaraldehyde solution. The treated porcine valve further may be mounted into a stent to support the valve at a fixed position.
A stent typically is formed of a resilient material, such as a plastic (e.g., DELRIN). Examples of various stent structures are disclosed in U.S. Pat. No. 3,983,581, U.S. Pat. No. 4,035,849. The stent usually is covered with a fabric material, such as DACRON or a suitable textile material. The fabric material provides structure for securing the valve relative to the stent. The stented heart valve prosthesis may be implanted into a patient for a heart valve replacement.
In order to surgically implant a heart valve into a patient, the patient typically is placed on cardiopulmonary bypass during a complicated, but common, open chest procedure. In certain situations, an individual requiring a heart valve replacement may be sufficiently ill, such that placing the individual on cardiopulmonary bypass may pose too great of risk. Such individuals may correspond to a class of patients who may have a non-functioning pulmonary valve or severe aortic valve insufficiency. In particular, many older patients having a deficient aortic or pulmonic valve may be too ill to survive conventional open-heart surgery.
Patients exhibiting these and other conditions would benefit from an improved heart valve prosthesis that may be implanted by a less invasive and/or more efficient implantation procedure.
SUMMARYThe following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
The invention relates to an implantable prosthetic device and, more particularly, to a heart valve prosthesis, such as can be implanted via a low-invasive procedure.
One aspect of the invention provides a heart valve prosthesis that includes a cylindrical support extending between axially spaced apart ends thereof, the cylindrical support including a plurality of support features extend generally axially between the opposed ends of the support, adjacent pairs of the support features being interconnected so as to bias the cylindrical support radially outwardly. A valve is mounted within the support to define a supported valve. The supported valve can include a sidewall portion extending between inflow and outflow ends thereof, the inflow and outflow ends of the valve sidewall portion being mounted within the cylindrical support such that ends of the sidewall portion are spaced axially apart from the spaced apart ends of the cylindrical support. The supported valve can also include a valve portion residing within the sidewall portion and configured to provide for substantially unidirectional flow of blood through the supported valve, the supported valve being deformable between a reduced cross-sectional condition and an expanded cross-sectional condition, whereby implantation of the supported valve is facilitated when in the reduced cross-sectional condition
To the accomplishment of the foregoing and related ends, certain illustrative aspects of the invention are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed and the present invention is intended to include all such aspects and their equivalents. Other advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings, in which:
The valve portion 12 includes inflow and outflow ends 16 and 18 spaced apart from each other by a length of a generally cylindrical sidewall portion 20. While the inflow and outflow ends 16 and 18 are illustrated as being annular in
The valve portion 12 also includes one or more leaflets 22, 24, and 26 that are attached to and extend from an interior of the sidewall portion 20. In the example illustrated in
The valve portion 12 may be formed of any substantially biocompatible valve apparatus. By way of example, the valve portion 12 may include an animal heart valve (e.g., pulmonic or aortic), a manufactured valve device (e.g., a valve as shown and described in U.S. Pat. No. 4, 759,758 or U.S. Pat. No. 5,935,163) a venous valve (e.g., a bovine or equine jugular venous valve). Those skilled in the art will understand and appreciate that the foregoing list is not intended to be exhaustive but, instead, is intended illustrate a few examples of the types of valves that may be utilized in a valvular prosthesis 10 in accordance with an aspect of the present invention.
If the valve portion 12 is formed of a natural tissue material, such as an animal heart valve, a venous valve, or a composite valve manufactured of natural tissue, the valve should be chemically fixed, such as in a suitable solution of glutaraldehyde in a closed condition (as is known in the art). The fixation process facilitates closure of the valve 12 under application of back flow pressure, while remaining open during normal forward blood flow through the valve 12. By way of example, the natural tissue valve may be cross-linked with glutaraldehyde and undergo a detoxification process with heparin bonding. The treatment improves biocompatibility of the valve apparatus 12 and mitigates calcification and thrombus formation.
In accordance with an aspect of the present invention, the valve portion 12 exhibits structural memory. That is, if the valve apparatus 12 is compressed, such as to a reduced diameter at the time of being implanted, it will return substantially to its original shape and configuration upon removal of radially inward forces. As a result, the valve apparatus 12 is able to maintain coaptation of the leaflets 22, 24, and 26 even after being deformed. The memory feature of the valve is further improved by mounting it within the stent portion 14.
Turning now to the stent portion 14, such as shown in
According to an aspect of the present invention, the stent 14 may deformable between first and second conditions, in which the first condition has a reduced cross-sectional dimension relative to the second condition.
By way of example, the mesh may be formed of a shape memory alloy material, such as may be formed of a nitinol (nickel-titanium alloy) wire. Shape memory (or thermal memory) is a characteristic in which a deformed part remembers and recovers to a pre-deformed shape upon heating. By forming the stent 14 of a shape memory alloy, the stent is inelastically deformable to new shape, such as a reduced cross-sectional dimension, when in its low-temperature (martensitic) form. For example, the stented valve (
When the stent 14 is heated to its transformation temperature, which may vary according to the alloy composition, it quickly reverts to its high-temperature (austenitic) form. The stented valve may retain the compressed condition by keeping it cooled. Alternatively, the stent and valve may be retained in the compressed position, such as with sutures circumscribing the structure, a cylindrical enclosure around the structure, etc. The prosthesis 10 will then return toward its high-temperature (or original) position upon removal of the retaining element.
It is to be appreciated that, alternatively, the stent 14, in accordance with an aspect of the present invention, could be inelastically deformable so as to require an intervening force to return the deformed stent substantially to a desired configuration. For example, a balloon catheter or spring mechanism could be employed to urge the stent and the valve located therein generally radially outward so that, after being implanted to a desired position, the stent will engage the surrounding tissue in a manner to inhibit movement relative to the surrounding tissue.
Referring back to
As mentioned above, the stent portion 14 may be formed of a shape memory alloy. In this way, the valvular prosthesis 10 may be compressed to a reduced cross-sectional dimension about the axis A and maintained at the reduced dimension while being implanted. Once the valvular prosthesis 10 is at a desired implantation position, the prosthesis may be permitted to return toward its original cross-sectional dimension so as to engage a valve wall or other surrounding tissue at the desired position. The engagement between the stented valvular prosthesis 10 and the surrounding tissue inhibits axial movement of the prosthesis relative to the tissue. In accordance with an aspect of the present invention, lateral extensions or spikes (see, e.g.,
The stent portion 54 in this example is formed of a deformable mesh, which may be substantially identical to that described above with respect to
In accordance with an aspect of the present invention, each of the stent posts 84, 86, 88 may extend radially outwardly an angle Θ relative to the axis A. By way of example, the angle Θ may range from about 10 to about 60 degrees relative to a line drawn through the juncture of each post and the base 82 parallel to the central axis A. The outwardly extending posts 84, 86, and 88 facilitate engagement between each respective post and surrounding tissue when implanted, as the posts (being resilient) tend to urge radially outwardly and into engagement with such tissue.
The stent 80 also includes a plurality of spikes 90 and 92 that extend radially outwardly from the stent. In particular, some outwardly extending spikes 90 are curved generally toward an outflow end of the stent and others 92 are curved generally toward an inflow end of the stent. In addition, a row of spikes 90 may extend outwardly relative to the stent 80 at the inflow end thereof, which spikes also are curved generally toward the outflow end. The varying contour of the spikes 90 and 92 mitigates axial movement of the stent 80 (in both axial directions) relative to tissue engaged thereby, such as after being implanted. It is to be understood and appreciated that, while a single row of spikes is illustrated near the inflow end of the stent in
In accordance with an aspect of the present invention, the prosthesis 100 of
An implantation flange (or sewing ring) 132 may be formed at the inflow end of the prosthesis 100. The implantation flange 132 may be formed of substantially the same material as the outer sheath 140, such as formed from the outer sheath 130 or by attaching a separate flange by other methods. The outer sheath 130 may be attached to the valve 98 and/or to the stent 80 by applying sutures 134 and 136 at the respective inflow and outflow ends of the prosthesis 100. Some of the spikes 90, 92 may extend through the outer sheath 130 so as to mitigate axial movement of the prosthesis 100 relative to surrounding tissue when the prosthesis is implanted. Sutures 134 and 136 may be applied respectively at the inflow and outflow ends to secure the outer sheath relative to the stent 80 and the valve 100. The outer sheath 130 may include an outflow end that conforms to the contour of the outflow end 104 of the valve 100.
The valvular prosthesis 202 is illustrated within the enclosure 208 in a compressed condition, such as described above. That is, the valvular prosthesis 202 within the enclosure 208 has a cross-sectional dimension that is less than its normal cross-sectional dimension, being maintained in such position by the enclosure. Those skilled in the art will appreciate that the orientation of the valvular prosthesis 202 will vary depending upon the direction in which blood is to flow through the valve when implanted.
By way of example, the external stent of the valvular prosthesis 202 may be formed of a deformable material, such as a shape memory alloy material (e.g., nitinol), which maintains its shape when cooled. Accordingly, the prosthesis 202 may be cooled (e.g., within a suitable fluid), compressed to a desired reduced cross-sectional dimension so as to fit within the enclosure 208, and then inserted within the enclosure. The prosthesis 202, after the stent being heated (e.g. to an ambient temperature), may desire to expand to its original dimension and configuration. However, the enclosure 208 or another retaining mechanism, such as a suture or other tubular member around the prosthesis, may be used to restrict its expansion. The compression of the valvular prosthesis 202 may be performed just prior to surgery to mitigate undesired permanent deformation of the valvular prosthesis 202. The plunger mechanism may be urged in the direction of arrow 220, such as by activating the trigger 206. Movement of the plunger 210, in turn, causes the prosthesis 202 to also be moved in the direction of the arrow 220. As the prosthesis 202 is urged through the opening 214 and discharged therefrom, the prosthesis may expand. Accordingly, the opening 214 should be positioned at the location where the prosthesis 202 is to be implanted prior to discharge. When the prosthesis 202 expands toward its original condition, the sidewall of the stent and/or spikes associated with the stent may engage and/or be urged into surrounding tissue so as to mitigate axial movement of the prosthesis relative to the surrounding tissue. As a result, the prosthesis may be implanted without sutures to provide an operable valve, such as a heart valve or a venous valve. When a valvular prosthesis is being employed as a heart valve, in accordance with present invention, it will be appreciated that the prosthesis may be implanted either as part of an open chest procedure or the patient's chest may be closed. Additionally, other expandable stent structures also could be utilized in accordance with an aspect of the present invention.
The valvular prosthesis 300 may be implanted in a compressed condition. It is to be appreciated that the valvular prosthesis 300 may be implanted in the aortic position during a conventional open chest procedure or during a closed chest procedure. The valvular prosthesis 300 may be implanted by using a catheter (or other structure) to retain the prosthesis in a compressed condition. The catheter may then be used to position the valve at a desired position, such as by utilizing a suitable imaging technology (e.g., x-ray, ultrasound, or other tomography device) or a direct line of sight. Once at the desired position, the prosthesis 300 may be discharged from its retaining mechanism (e.g., an enclosure) so that it expands toward its original expanded configuration at the desired position within the aorta 306.
It is to be understood and appreciated, though, if the patient has a calcified aortic valve, the patient typically must be put on cardiopulmonary bypass to remove the calcium and implant the valve. Advantageously, a valvular prosthesis 300 in accordance with the present invention may be implanted more efficiently so as to mitigate morbidity and mortality of the patient. In addition, the prosthesis may be implanted without sutures or, alternatively, some sutures may be utilized. For example, sutures may be applied at the inflow end 304 (e.g., at a sewing ring) and/or at the outflow end 308, such as when the prosthesis is configured to have axially extending lobes (see
As mentioned above, the prosthesis 350 is mounted within the enclosure 353 in a compressed condition prior to implantation. The enclosure 353 and the prosthesis 350, for example, may be introduced into the inferior vena cava through the patient's right femoral vein. The prosthesis 350 and enclosure 353 may traverse the vascular system to the inferior vena cava 354 with the assistance of suitable imaging equipment such as x-ray, ultrasound, or other imaging devices. The imaging equipment is utilized to navigate the enclosure 353 and the prosthesis 350 to the desired position. Once at the desired position, such as at the opening to the pulmonary artery 360, the prosthesis 350 may be discharged through a distal opening of the enclosure 353. The valvular prosthesis 350 then expands from its compressed condition to an expanded condition, as illustrated in
Advantageously, the valvular prosthesis 350 may be implanted in the patient without cardiopulmonary bypass. As a result, a significant amount of time may be saved with less stress on the patient, thereby mitigating the risks of morbidity and mortality associated with conventional open-heart surgery typically employed to implant a heart valve prosthesis. Those skilled in the art will understand and appreciate that this process also may be utilized to implant a valvular prosthesis for a venous valve, such as in a patient's lower limb.
The support 400 also includes one or more retaining elements 410 that inhibit radial expansion of the support beyond a certain desired amount defined by the length of the retaining elements 410. For example, the retaining element 410 can be in the form of one or more flexible cords (e.g., sutures) that limit circumferential expansion of the features 406 caused by the biasing elements 408. In the example in
The support 420 also includes retaining features 432 that limit the circumferential expansion of the support to a desired amount. The retaining feature 432 is in the form of a pair of cords (e.g., sutures) having ends connected together to form a loop that is connected at each end 424 and 426 of the support. Each loop 432 is flexible to permit the support to be deformed into a reduced cross-sectional dimension. The loops 432 also inhibit expansion at each of the ends 424 and 426 according to the dimensions of the respective loops. For example, one end 426 (e.g., the inflow end) can have a larger maximum diameter than the other end 424 (e.g., the outflow end) of the intermediate portion 422.
The support 420 further includes members 440 and 442 that extend axially and radially outwardly from the respective ends 424 and 426 of the support. In this example, each of the members 440 and 442 includes a plurality of triangular projections 444. Each projection 444 includes a pair of legs 446 that are connected to the respective ends 440 and 442. The legs 446 extend radially axially and radially outwardly from the respective ends 440 and 442 and terminate in an apex 448 spaced apart from the intermediate portion 422.
In the example in
The valve 472 includes an inflow end 474 and an outflow end 476 at axially opposed ends of the valve, with a sidewall portion 478 extending between the ends thereof. The inflow end 474 of the valve 472 is positioned near an inflow end 426 of the support 420. The sidewall portion 478 can be a tubular valve wall. A plurality of leaflets 480 extend radially inward from the valve wall 478 and coapt along their side edges to provide for substantially unidirectional flow of blood through the valve 472. The outflow end 476 of the valve 472, which is located near the outflow end 424, has a generally sinusoidal contour. The peaks are aligned with commissures between adjacent leaflets 480, with sinuses located between the commissures. The valve 472 can be connected within the support 420 via sutures 124 or other connecting means.
By way of illustration, when the prosthesis is to be implanted at the pulmonary position, the valve 472 can be a treated porcine pulmonic valve. When it is to be implanted at an aortic position, the valve 472 can be a porcine aortic valve. For example, the valve can be of the type shown and described in U.S. Pat. Nos. 5,935,163, 5861,028 or 5,855,602. It is to be understood and appreciated that other valve configurations of could be used in accordance with an aspect of the present invention. For example, one or more leaflets of the valve 472 could be mounted within a length of tubular valve wall or other generally cylindrical biocompatible material and operate in a known manner to provide for the unidirectional flow of fluid through the valve from the inflow to outflow ends.
In accordance with an aspect of the present invention, the prosthesis 470 also includes an outer sheath 482 of a substantially biocompatible material. The outer sheath 474 covers at least a substantial amount of exposed portions of the support 420 (including the ends 424 and 426) so as to mitigate contact between the blood and the support when the prosthesis is implanted. In the example of
The support 500 includes a plurality of generally axially extending features 512 (e.g., resilient rods or wires) that are biased to urge adjacent interconnected features circumferentially apart from each other. Because a plurality of such features are interconnected in a cylindrical arrangement, the biasing of the features apart from each other results in radially outward expansion of the cylindrical support 500 according to the dimensions of the retaining cords 506, 508, and 510. In one aspect, biasing elements 514, which can be springs, connect each adjacent pairs of features 512 together at each end of each respective support portion 502 and 504. Each of the cords 506, 508, 510 further interconnect a respective set of biasing elements at a corresponding axial location, with the cord 506 interconnecting biasing elements of both support portions at the intermediate axial location. While substantially identical biasing elements 514 are illustrating throughout the support 500, it is to be understood and appreciated that different types of biasing elements could be used at different locations of the support. Additionally, a separate length of a flexible cord can be used to interconnect adjacent support features, instead of the single loop inserted through an aperture of the respective biasing elements shown and described herein.
In view of the arrangement described above, it is to be appreciated that a length of the cord 506, 508 or 510 that extends between adjacent biasing elements 514 of each support portion 502, 504 and the pair of interconnected adjacent features 512 define a generally triangular structure. A plurality of such triangular structures are interconnected in a circumferential arrangement to define the generally cylindrical sidewalls of the respective support portions 502 and 504. The features 512 of each such triangular structure are urged apart from each other by the interconnecting biasing element 514. The juncture of the support portions 502 and 504 are connected by the connecting element 506 so as to provide radial expansion combined from both of the support portions. As a result, about twice the amount of radial expansive force is provided along the length of the cord 506.
The resulting support 500 thus provides a cage-like structure in which a valve can be mounted in accordance with an aspect of the present invention. The support 500 can be deformed to a reduced cross-sectional dimension, such as by applying a radially inward force to the sidewall portion thereof. Upon removal of the radially inward force, the support will expand to its expanded cross-sectional configuration due to the radial expansion provided by the arrangement of biasing elements 514 and interconnected axially extending features 512.
In accordance with an aspect of the present invention,
The valve 542 illustrated in
By way of illustration, when the prosthesis 540 is to be implanted at the pulmonary position, the valve 542 could be a treated porcine pulmonic valve and a porcine aortic valve when it is to be implanted at an aortic position. For example, the valve can be of the type shown and described in U.S. Pat. Nos. 5,935,163, 5861,028 or 5,855,602. Of course, other types and valve configurations also could be used in combination with the support 500 to form the prosthesis 540 in accordance with an aspect of the present invention.
The prosthesis 540 further includes an outer sheath 550 of a flexible biocompatible material, such as treated and detoxified animal pericardium, as described herein. The outer sheath 550 covers at least some of the exposed support 500, such as the interior of the prosthesis and the ends 552 and 554. The outer sheath 550 can be formed of one or more sheets of the biocompatible material, which are attached to the prosthesis 540 to reduce exposure of the support to blood when implanted in its expanded condition. The outer sheath 550 is sufficiently flexible and resilient so as to facilitate deforming the prosthesis 540 to a reduced cross-sectional dimension and its subsequent expansion to its expanded cross-sectional dimension, as shown in
The sidewall portion of the valve 542 is attached (e.g., by sutures) to the support 500, such as to features and/or biasing elements, so that when the support expands, the valve also expands to its desired expanded configuration. Also, because the valve 542 has been fixed (e.g., in a suitable glutaraldehyde solution) to a desired shape and configuration, the valve maintains its desired shape and coaptation between leaflets when the prosthesis 540 is in its expanded condition.
Prior to implanting the 540, such as by a direct implantation procedure through a blood vessel that provides a generally linear path to the desired implantation site, one or more sutures 554 can be attached to the proximal end 552 of the prosthesis. For example, the suture 554 is applied through loops that form generally diametrically opposed biasing elements 514 at the proximal end 552. The sutures 554 can be used to adjust the relative position of the prosthesis 540 after positioned in the heart in its expanded condition. Additionally or alternatively, the prosthesis 540 could be adjusted to a desired position manually by a surgeon by applying external force to the prosthesis through the heart. Advantageously, the prosthesis 540 can be directly implanted without cardiopulmonary bypass, such as in the pulmonary position or with minimal bypass to the aortic position in accordance with an aspect of the present invention.
Each of the cylindrical portions 572 and 574 includes a plurality of generally axially extending support features 578, such as thin rods, bands, or wire of a substantially resilient material. The features 578, for example, are arranged as a plurality of interconnected triangles in which the features define elongated legs that extend between the intermediate connecting element 576 and additional connecting elements 580 and 582 located at the opposite ends 584 and 586 of the associated cylindrical portions 572 and 574. The connecting element 582 at the inflow end of the valve also can have a greater diameter than the connecting element 580 at the outflow end. The features 578 in each cylindrical portion 572 and 574 are connected by biasing elements 588 that urge each adjacent pair of interconnected features circumferentially apart from each other. Because the features 578 are connected in a circumferential array, the collective forces of the biasing elements result in radially outward expansion of the prosthesis 570 up to a maximum dimension defined by the respective connecting elements 576, 580 and 582.
The prosthesis 570 further includes a heart valve 590 mounted within the support. The valve 590 has an inflow end 592 and an outflow end 594, which are positioned on axially opposed sides of the intermediate cord 576. In particular, the intermediate connecting element 576 and associated biasing elements 588 substantially circumscribe an annular base portion near the inflow end 592 of the valve 590. Because the valve 590 is attached (e.g., by sutures) to the support formed of the cylindrical portions 572 and 574, the radial outward forces provided by the support help maintain the base of valve in a desired annular shape when the prosthesis 570 is in its expanded condition shown in
By way of example, when the prosthesis 570 is to be implanted at the pulmonary position, the valve 590 could be a treated porcine pulmonic valve. A porcine aortic valve can be used for the aortic position. Those skilled in the art will understand and appreciate other types and valve configurations also could be used in the prosthesis 570 in accordance with an aspect of the present invention.
The prosthesis 570 further includes an arrangement of members 598 and 600 that extend axially and radially outwardly from the respective ends 584 and 586 of the prosthesis 570. The members 598 and 600 are operative to help secure the prosthesis 570 to surrounding tissue when it is implanted. The members 598 and 600 include a plurality of triangular projections 602 that extend axially and radially outwardly from the ends. While six substantially symmetrical projections are shown extending outwardly from each of the ends 584 and 586, those skilled in the art will understand and appreciate that any number could be used (e.g., 4, 6, 9, 12, 18, etc.).
Each triangular projection 602 includes a pair of legs 604 that are connected together by an interconnecting biasing element 606. The biasing elements form apices of the triangular projection 602 spaced from the respective ends 584, 586. Adjacent triangular projections 602 also are coupled together and to respective ends 584 and 586 by additional biasing elements 608 located at the ends of the prosthesis 570. The biasing elements 588, 606, and 608 bias the support portion of the prosthesis 570 and valve 590 attached thereto in a radially outward direction toward its fully expanded condition. Additionally, the triangular projections 602 can further engage surrounding tissue when the prosthesis is implanted to help hold the prosthesis at a desired position relative to the surrounding tissue.
The prosthesis 570 also can include an outer sheath 610 of biocompatible material (e.g., animal pericardium) that covers most (or all) of the support structure that would be exposed to blood when implanted. The covering further could be an expansion of the valve wall the contains the leaflets of the heart valve 590. In this example, the outer sheath 610 covers the support between the ends 584 and 586 of the cylindrical portions 572 and 574 and the support features 578 in the interior of the prosthesis 570. The triangular projections 602 are left uncovered, which may facilitate their insertion and integration into surrounding tissue. It is to be understood and appreciated, however, that the projections 602 also could be covered with biocompatible material, similar to the example of
The prosthesis 570 is well suited for direct implantation without cardiopulmonary bypass, such as in the pulmonary position, or direct implantation with minimal bypass to the aortic position in accordance with an aspect of the present invention. Direct implantation with the prosthesis also can be sutureless, although one or more sutures can be applied to further fix the prosthesis at a desired position.
In view of the various arrangements of heart valve prostheses described herein, a simplified and efficient method of using such prosthesis is described below with respect to
For example, the inner diameter of the barrel 704 can range from about 5 mm to about 15 mm, whereas the outer diameter of the heart valve prosthesis 702 (in its expanded condition) typically ranges from about 15 mm to about 35 mm. Thus, the barrel can accommodate a prosthesis 702, which has been deformed to reduced cross-sectional dimension, without compromising the durability and operation of the valve. The exterior of the barrel further can include indicia (e.g., ruler markings) 710 that can help indicate the distance the barrel is inserted into a patient.
Additionally, to facilitate positioning the end 708 of the barrel 704 at a desired position, such as in a patient's heart, the barrel 704 (or at least a distal end portion thereof) can be formed of a flexible, generally resilient material (e.g., a metal or plastic material) that can bend or flex relative to its longitudinal axis A, as indicated at 704′. By way of particular example, the barrel 704 can be formed of helical extension spring, such as formed of a thin wire tightly wound to defines the circular cylindrical barrel in which the heart valve prosthesis can be loaded for implantation. The barrel 704 thus can flex to a curved or bent position 704′, such as to accommodate different angular contours that might be experienced in various passages in the patient's heart as the barrel 704 is guided to a desired implantation position. Such compliant tensile properties of the barrel 704, for example, facilitate gently deflecting the barrel off anatomical structures during implantation, such as the barrel is advanced to its implantation position.
Alternatively or additionally, the barrel 704 can be formed of a deformable material, such as synthetic material (e.g., a polymer) or a metal, that can be deformed to provide a desired curved barrel 704′ for supporting the heart valve prosthesis 702′ for implantation. Accordingly, the barrel 70 can be curved or bent relative to the longitudinal axis A of the implanter 700, as indicated at 704′. For example, Those skilled in the art will understand and appreciate various suitable materials that could be utilized to provide desired flexible and/or deformable properties.
The implanter 700 also includes a handle 712 that extends outwardly from a proximal end 714 of the body portion 706. The handle 712, which may be gripped by a surgeon, facilitates manipulating the barrel 704 along a desired path. A plunger 716 has a distal end 718 that can be urged into engagement with the prosthesis 702 to push the prosthesis from the opening 708 of the barrel 704. The plunger 716 includes an elongated portion that extends from its distal end 718 and terminates in a proximal end portion 718. The proximal end portion 718 operates as a trigger that can be grasped by a surgeon to move the plunger through the barrel 704. Other means to discharge the heart valve also could be utilized in accordance with an aspect of the present invention. Fluid, such as saline, also can be introduced into the barrel 704, such as through an opening (not shown) in the plunger 716, to facilitate the discharge of the prosthesis 702 from the barrel.
In the examples of
For example, the implanter 700 could be introduced into a blood vessel (e.g., the pulmonary artery) that provides a substantially direct and linear path to the desired implantation position. Further, the procedure can be implemented without cardiopulmonary bypass, such as when the prosthesis is implanted through the pulmonary artery. Alternatively, cardiopulmonary bypass can be used, but for a generally short period of time, such as when the prosthesis is implanted at the aortic position. Bypass generally is required when implanting at the aortic position due to the relatively high blood pressure as well as to facilitate decalcification of the patient's existing heart valve, as needed.
The implanter 700 further can include an aperture 724 (or interconnected apertures) that extend longitudinally through the plunger 716 and the end 718. The aperture 724 provides a passage through which one or more sutures 726 connected to a proximal end 728 of the prosthesis 702 can extend. For example, prior to loading the prosthesis 702 into the barrel 704, the suture 726 can be applied to the end 728 of the prosthesis, such as through generally diametrically opposed biasing elements (e.g., coil springs) at the respective end. Part of the suture 726 extends between the opposed sides of the prosthesis 702. The remaining lengths of the suture 726, which extends from one or both sides of the prosthesis, can be fed through the barrel and aperture 724 to a location external to the implanter 700, such as shown in
The surgeon can then insert the barrel 734 through the opening in the vessel wall 732. Two lengths 738 of the purse string 730 suture extend from the vessel 732 through an elongated cylindrical guide 740 of a generally rigid material, such as rubber, plastic, or metal material. One end 742 of the cylinder 740 engages the vessel wall 732 and/or the barrel 734, and the two lengths 738 of suture extend through the other end 744. By fixing the length of suture relative to the cylinder 740, such as by clamping the sutures to the cylinder by a clamp 745, the vessel wall surrounding the barrel 734 can be kept relatively tight around the barrel so as to mitigate blood loss through the incision. As a result, cardiopulmonary bypass is not required. However, it is to be understood that in certain situations, such as when implanting the prosthesis at the aortic position, some bypass may be necessary, although usually for a much shorter period of time than with conventional procedures.
After the distal end 746 of the barrel 734, which can be flexible or bendable as described herein, has been inserted a desired length into the vessel 732, such as indicated by indicia printed on the barrel, the heart valve prosthesis 748 located in the barrel can be discharged. For example, a plunger 750 positioned for axial movement relative to the barrel 734 can be moved toward the distal end 746 of the barrel and into engagement with the prosthesis 748. The heart valve prosthesis 748 is configured to expand toward its fully expanded condition when it is discharged from the barrel 734 because radial inward forces that maintain the prosthesis at a reduced cross-sectional dimension are removed. In particular, the prosthesis 748 includes a self-expanding support 752 in which an associated heart valve 754 is mounted. In the example of
One or more sutures 762 can be attached to a proximal end 764 of the prosthesis 748 so as to pass through an aperture 766 that extends through at least a substantial portion of the implanter 736. For example, the suture 762 can be applied through the centers of generally opposed circular biasing elements located at the proximal end 764. After the prosthesis 748 is discharged into the patient's heart, a surgeon can grasp the sutures to adjust the position of the prosthesis, such as by urging both ends of the suture in the direction 768, shown in
In view of the foregoing example, those skilled in the art will understand and appreciate that the prosthesis 748 can be implanted without opening the heart and without cardiopulmonary bypass. When the patient's existing valve needs to be removed and or calcium deposits cleaned, such cleaning can be performed through the pulmonary artery or other connecting vessels prior to implanting the prosthesis 748, such as through a trocar and/or by endoscopic means.
In this example, the prosthesis 800 is being implanted through the patient's aorta 804. The prosthesis includes an include an inflow end 806 that is positioned at the aortic annulus 807, with an outflow end 808 of the prosthesis extending into the aorta 804. As described herein, the implantation can be sutureless since the prosthesis 800 includes spikes or other projections 810 that extend outwardly from the prosthesis. Such spikes or protrusions 810 thus engage surrounding tissue, such as the aortic valve wall 804, for inhibiting axial and rotational movement of the implanted prosthesis 800, as described herein.
In the example of
It is to be appreciated that the valvular prosthesis 800 may be implanted in the aortic position during a conventional open chest procedure or during a closed chest procedure. In the example of
The implantation can be performed in a manner similar to that described above with respect to
It is to be understood and appreciated, though, if the patient has a calcified aortic valve, the patient typically must be put on cardiopulmonary bypass to remove the calcium and implant the valve. Advantageously, a valvular prosthesis 800 in accordance with the present invention may be implanted more efficiently so as to mitigate morbidity and mortality of the patient. In addition, the prosthesis 800 can be implanted without sutures (or, alternatively, some sutures can be utilized. For example, optional sutures (not shown) may be applied near the inflow end 806 and/or at the outflow end 808, such as when the prosthesis is configured to have axially extending lobes (see, e.g.,
In this example, the prosthesis 850 is implanted into the pulmonary artery 864 from a barrel 866 of an implanter, such as a catheter system or other type of implanter described herein. In particular, a distal end 868 of the barrel is inserted through the heart muscle itself, such as through the anterior wall 870 of the right ventricle 872. Once at the desired position, the prosthesis 850 is ejected from the barrel 866 into the outflow of the right ventricle 872, as illustrated in
The support 900 further includes one or more projections or spikes 914 that extend axially and radially outwardly from at least some of the respective end junctures 908, 910 of the support. While a pair of such spikes are illustrated as associated with each end juncture 908, 910, other number of spikes can be implemented, such as single spike or more than two spikes at some or all of the junctures. In the example illustrated in
According to one aspect of the present invention, the support can be formed a shape memory material, such as nitinol. For example, the support can be formed from a small cylindrical tube of the shape memory material, such as via a laser cutting (ablation) process in which the desired sinusoidal sidewall 912 is cut from the tube. In this way, the support features 906, the interconnecting end junctures 908 and 910, and associated spikes 914 can be formed as an integrated structure having a desired shape and size. Additionally, ends of the spikes 914 can have tapered or sharpened tips to facilitate gripping surrounding tissue when implanted. For example, the spikes 914 can be formed by laser cutting from the same tube or, alternatively, they could be welded onto the support 900 at desired positions. The resulting structure can then be heated to its transformation temperature and forced to a desired cross-sectional dimension and configuration (its austentic form), such as shown in
The valve 920, which can be a homograft or xenograft, includes an inflow end 922 and an outflow end 924 at axially opposed ends of the valve, with a sidewall portion extending between the ends thereof. The inflow end 922 of the valve 920 is positioned near an inflow end 904 of the support 900. The prosthesis 920 also can include sidewall portion, which can be a tubular valve wall, such as for a homograft or xenograft valve 920. A plurality of leaflets 926 extend radially inward from the valve wall and coapt along their adjacent edges to provide for substantially unidirectional flow of blood through the valve 920. The outflow end 924 of the valve 920, which is located near the outflow end 902 of the support, has a generally sinusoidal contour, as shown in
It is to be understood and appreciated that various types of valve configurations of could be employed to provide the prosthesis 918 in accordance with an aspect of the present invention. For example, the valve 920 can include one or more leaflets mounted within a length of tubular valve wall or other generally cylindrical biocompatible material and operate in a known manner to provide for the unidirectional flow of fluid through the valve from the inflow to outflow ends. By way of further example, when the prosthesis is to be implanted at the pulmonary position, the valve 920 can be a treated pulmonic valve (e.g., homograft or xenograft). When it is to be implanted at an aortic position, the valve 920 can be a treated aortic valve (e.g., homograft or xenograft). For example, the valve can be of the type shown and described in U.S. Pat. Nos. 5,935,163, 5861,028 or 5,855,602, as well as others mentioned herein or otherwise known in the art.
In accordance with an aspect of the present invention, the prosthesis 918 also includes an outer sheath 930 of a substantially biocompatible material. The outer sheath 930 covers at least a substantial amount of exposed portions of the support 900, such as including the ends 902 and 904, to mitigate contact between the blood and the support when the prosthesis is implanted. The valve 920 further can be attached relative to the sheath 930, such as by sutures along the inflow and outflow ends of the valve. Such sutures (not shown) further can connect the valve 920 and the sheath 930 relative to the support 900. The outer sheath 930 can cover the entire support, such that all non-biological material is completely covered, for example. The outer sheath 930 can be formed of one or more natural tissue sheets (e.g., animal pericardium), although other natural or synthetic biocompatible materials also could be used to provide an outer sheath in accordance with an aspect of the present invention.
The implantation of the prosthesis 950 can be implemented in a manner similar to that show and described with respect to
A small incision or puncture can be made at the center of a purse string 970 that is applied around the location through which the barrel 966 is to be inserted. The surgeon can then insert the barrel 966 through the opening in the vessel wall 952. Two ends 972 of the purse string 970 suture extend from the vessel wall or other tissue and through an elongated hollow guide 974. A distal end 976 of the guide 974 engages the vessel wall 952 and/or the barrel 966, and the two ends 972 extend through the other end 978. The suture can be fixed relative to the guide 974, such as by clamping the sutures to the cylinder by a clamp 980. As a result, the vessel wall (or other tissue) surrounding the barrel 966 can be kept relatively tight around the barrel to mitigate blood loss. Consequently, cardiopulmonary bypass is not required. However, it is to be understood that in certain situations, such as when implanting the prosthesis at the aortic position, some bypass may be necessary, although usually for a much shorter period of time than with conventional procedures.
As mentioned above, the prosthesis 950 includes a self-expanding support 960. Thus, the heart valve prosthesis 950 can expands toward its fully expanded condition when it is discharged from the barrel 966. The projections or spikes 962, in turn, will insert into surrounding tissue to maintain the valve at a desired axial and angular position in the vessel 952, thereby anchoring the prosthesis 950 relative to the valve wall. As the prosthesis 950 is being discharged, the implanter barrel 966 can be concurrently withdrawn from the vessel. While the implantation can be performed completely sutureless, those skilled in the art will understand and appreciate that one or more sutures can be utilized to further help secure the prosthesis 950 relative to the surrounding tissue 952.
What has been described above includes examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” and variants thereof or the term “having” and variants thereof are used in either the detailed description or the claims, each such term is intended to be inclusive in a manner similar to the term “comprising.”
Claims
1. A heart valve prosthesis comprising:
- a cylindrical support extending between axially spaced apart ends thereof, the cylindrical support including a plurality of support features extend generally axially between the axially spaced apart ends of the cylindrical support, adjacent pairs of the support features being interconnected so as to bias the cylindrical support radially outwardly; and
- a valve mounted within the cylindrical support to define a supported valve, the supported valve comprising: a sidewall portion extending between inflow and outflow ends thereof, the inflow and outflow ends of the valve sidewall portion being mounted within the cylindrical support such that ends of the sidewall portion are spaced axially apart from the spaced apart ends of the cylindrical support; and a valve portion residing within the sidewall portion and configured to provide for substantially unidirectional flow of blood through the supported valve, the supported valve being deformable between a reduced cross-sectional condition and an expanded cross-sectional condition, whereby implantation of the supported valve is facilitated when in the reduced cross-sectional condition.
2. The prosthesis of claim 1, further comprising biasing elements that interconnect each adjacent pair of the support features, each biasing element urging support features that are interconnected by respective biasing element apart from each other as to bias the cylindrical support radially outwardly.
3. The prosthesis of claim 2, the biasing elements further comprising springs arranged in a generally circular array at the axially spaced apart ends of the cylindrical support, the springs interconnecting adjacent support features to bias the cylindrical support radially outwardly.
4. The prosthesis of claim 3, the support features and the springs being formed of a continuous length of a resilient material to provide a cage-like support.
5. The prosthesis of claim 3, further comprising projections biased to extend radially outwardly from at least one of the axially spaced apart ends of the cylindrical support.
6. The prosthesis of claim 5, the projections further comprising a plurality of triangular projections interconnected at the axially spaced apart ends of the cylindrical support at the biasing elements, each of the triangular projections being configured to extend axially and radially outwardly from the respective opposed ends beyond a radially outer extent of the cylindrical support.
7. The prosthesis of claim 1, further comprising a flexible connecting element attached to the cylindrical support to inhibit radial outward expansion of at least part of the cylindrical support beyond a predetermined amount.
8. The prosthesis of claim 1, the cylindrical support further comprising at least two generally cylindrical support portions having adjacent ends connected substantially coaxially together, the axially spaced apart ends of the cylindrical support define axially opposed inflow and outflow ends of the cylindrical support, the valve including an inflow end and an outflow end spaced apart from each other on axially opposed sides of a juncture between the at least two support portions.
9. The prosthesis of claim 8, further comprising an intermediate connecting element that connects the support portions at the juncture between the at least two support portions.
10. The prosthesis of claim 8, further comprising a plurality of biasing elements that interconnect adjacent support features in each of the support portions, the biasing elements urging the interconnected support features apart from each other to provide radial outward expansion of the respective at least two sidewall portions.
11. The prosthesis of claim 10, the biasing elements being connected by flexible connecting elements in a generally circular arrangement at the axially spaced apart ends of each respective support portion, the connecting elements inhibiting radial expansion of the cylindrical support at the respective ends of the support portions beyond a predetermined amount.
12. The prosthesis of claim 8, further comprising projections extending axially and radially outwardly from the axially opposed inflow and outflow ends of the cylindrical support.
13. The prosthesis of claim 12, the projections further comprising triangular-shaped projections connected at each of the axially opposed inflow and outflow ends of the cylindrical support in a circular arrangement and configured to extend axially and radially outwardly from the respective axially opposed inflow and outflow ends of the cylindrical support.
14. The prosthesis of claim 1, further comprising an outer sheath of a substantially biocompatible material that covers at least a substantial portion of an exposed part of the cylindrical support.
15. The prosthesis of claim 1, wherein the valve portion has an axial length defined by a distance between the spaced apart ends of the valve portion, the axial length of the valve portion being less than the axial length of the cylindrical support and the valve portion is connected to remain near a central axial position of the cylindrical support such that the ends of the valve portion are spaced axially apart from respective ends of the cylindrical support.
16. The prosthesis of claim 15, wherein, in the expanded cross-sectional condition, a cross-sectional dimension of the cylindrical support at an axial position between an outflow end of the valve and an outflow end of the cylindrical support is less than a cross-sectional dimension of the cylindrical support and the valve portion at an axial position where the valve portion resides.
17. The prosthesis of claim 16, wherein, in the expanded cross-sectional condition, a cross-sectional dimension of the cylindrical support at an axial position between an inflow end of the valve portion and an inflow end of the cylindrical support is less than a cross-sectional dimension of both the cylindrical support and the valve portion at an axial position where the valve portion resides.
18. The prosthesis of claim 1 in combination with an implanter, the combination comprising:
- the implanter comprising: a body portion; and an elongated cylindrical member extending from the body portion to terminate in a distal end thereof that is spaced apart from the body portion, the distal end having an opening to a passage that extends through at least a portion of the cylindrical member, at least a distal end portion of the cylindrical member proximal the distal end thereof being flexible to permit flexing or bending of the distal end portion; and
- the prosthesis being mounted within the cylindrical member in the reduced cross-sectional condition.
19. A heart valve prosthesis comprising:
- a cylindrical support extending between axially spaced apart inflow and outflow ends thereof, the cylindrical support including a plurality of support features extend generally axially between the axially spaced apart inflow and outflow ends of the cylindrical support, adjacent pairs of the support features being interconnected so as to bias the cylindrical support radially outwardly; and
- a valve mounted within the cylindrical support to define a supported valve, the supported valve being configured to provide for substantially unidirectional flow of blood through the supported valve, the valve having inflow and outflow ends that are spaced axially apart from the respective inflow and outflow ends of the cylindrical support, the supported valve being deformable between a reduced cross-sectional condition and an expanded cross-sectional condition,
- wherein, in the expanded cross-sectional condition, a cross-sectional dimension of the cylindrical support at an axial position between an outflow end of the valve and an outflow end of the cylindrical support is less than a cross-sectional dimension of the cylindrical support and the valve at an axial position where the valve resides. 20. The prosthesis of claim 19 in combination with an implanter, the combination comprising:
- the implanter comprising: a body portion; and an elongated cylindrical member extending from the body portion to terminate in a distal end thereof that is spaced apart from the body portion, the distal end having an opening to a passage that extends through at least a portion of the cylindrical member, at least a distal end portion of the cylindrical member proximal the distal end thereof being flexible to permit flexing or bending of the distal end portion; and
- the prosthesis being mounted within the cylindrical member in the reduced cross-sectional condition.
Type: Application
Filed: Jun 11, 2009
Publication Date: Oct 1, 2009
Inventor: SHLOMO GABBAY (Boca Raton, FL)
Application Number: 12/482,781
International Classification: A61F 2/24 (20060101);
