WO2005013857A1

WO2005013857A1 - Implantable venous valve

Info

Publication number: WO2005013857A1
Application number: PCT/US2004/025356
Authority: WO
Inventors: F. Joseph Obermiller
Original assignee: Cook Incorporated
Priority date: 2003-08-05
Filing date: 2004-08-05
Publication date: 2005-02-17

Abstract

Described are frameless grafting prostheses (11) formed of remodelable material (12). Medical products (20) comprising a frameless grafting prosthesis enclosed in a sterile packaging (21, 22) are also described. Further described are methods for attaching a frameless grafting prosthesis to a vein to treat venous insufficiency.

Description

IMPLANTABLE VENOUS VALVE

REFERENCE TO RELATED APPLICATION This application claims the benefit of United States Patent Application Serial No. 60/492,648 filed August 5, 2003, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD OF THE INVENTION The present invention resides generally in the field of medical devices, and, more particularly, relates to grafting prostheses such as those for implantation within the vasculature. BACKGROUND OF THE INVENTION In all vertebrates, blood is transported away from the heart and throughout the body via arteries and returns to the heart through veins . To allow for optimal transport back to the heart and to reduce blood pressure build-up, veins contain various valves within their lumens, which open to permit blood flow to the heart but close to prevent the backflow of blood. Accordingly, venous valves function to provide the unidirectional flow of blood back to the heart. Problems can arise when hese venous valves fail to function properly. For example, venous valves can become incompetent or damaged by disease such that the backflow of blood is not prevented. When this occurs, blood pressure builds up and the veins and their valves become dilated, particularly in the lower extremities. If enough pressure builds up, the condition of venous insufficiency may develop. The severity of this condition is substantial, resulting in swelling, extensive pain, deformities, and, in the most severe cases, the development of ulcers can occur. If these ulcers become infected, amputation may ultimately be necessary to save the patient's life. Currently, there is no proven cure for venous insufficiency. Basic treatments include elevation of the legs or the use of compression stockings. If surgery is determined to be necessary, vein stripping is typically performed, which involves the removal of the incompetent or damaged vein(s). Other surgical methods involve valvular reconstruction or transplantation. Recently, ^' the development of artificial and biological valves has been employed in an attempt to return normal pressure to the veins. There are a variety of these valves described in the art, which are generally designed to allow normal flow of blood back to the heart, while preventing retrograde flow. For example, US Patent No. 6,508,833 discloses a multiple- sided medical device comprising a closed frame of a single piece of wire or other resilient material and having a series of bends and interconnecting sides. The device has both a flat configuration and a second, folded configuration that comprises a self-expanding stent. The device is pushed from a delivery catheter into the lumen of a duct or vessel . A covering of fabric or other flexible material is sutured or attached to the frame to form an artificial valve. The flexible material utilized in the disclosed valves can be comprised of collagenous submucosa obtained from various animals, such as, for example, pigs, cattle, and sheep. This material can be processed and preserved so as to be capable of inducing host tissue proliferation, remodeling, and regeneration of appropriate tissue structures e.g., veins upon implantation in vivo (see, e.g., U.S. Patent No. 6,485,723). The preparation of submucosal material is generally described in U.S. Patent Nos. 4,902,508 and 5,554,389. The submucosal material can be prepared in large, flat sheets, which are subsequently cut and attached to a framing element, for example a stent, for deployment in a vein. Despite work in the area there remain needs for medical products for grafting within the vasculature, and in particular within the venous system, to improve blood flow. The present invention addressed to these needs .

SUMMARY OF THE INVENTION In one embodiment, the invention provides a medical product comprising a frameless grafting prosthesis to treat venous insufficiency. The frameless grafting prosthesis is formed of a material effective to remodel tissue from a wall of a vein and comprises at least one shaped valve cusp. The shaped valve cusp includes a relatively narrow base, a relatively wide top edge, and diverging side edges extending from the base edge to the top edge of the shaped valve cusp. The side edges of the valve cusp are configured for attachment to a wall of a vein. The frameless grafting prosthesis can be a premanufactured device provided in sterile packaging, providing a medical product of the present invention. Further, an inventive product line can include a plurality of such medical products, providing grafting prostheses of varying sizes, to suit various patients and/or applications . Further provided by the invention is a method for attaching a frameless grafting prosthesis to a vein. The method comprises providing a grafting prosthesis as described above, and attaching the frameless grafting prosthesis to a wall of a vein. Such methods are useful in medical treatments involving incompetent or damaged venous valves, e.g., venous insufficiency. Additional embodiments as well as features and advantages of the invention will be apparent to those skilled in the art from the descriptions herein. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A provides a perspective view of a sheet of remodelable material from which four frameless grafting prostheses of the invention may be obtained. Figure IB provides a perspective view of one of the frameless grafting prostheses taken from the sheet in Figure 1A. Figure 1C provides a cutaway view of a vein having a frameless grafting prosthesis of the invention attached thereto . Figure 2 shows a medical product of the invention including the frameless grafting prosthesis of Figure IB enclosed within a sterile medical package. Figure 3 provides a cutaway view of a vein having a multi-cuspid frameless grafting prosthesis of the invention attached thereto.

DETAILED DESCRIPTION As disclosed above, the present invention provides medical products, frameless grafting prostheses, and methods involving the use of the same . A preferred embodiment of the invention provides a frameless grafting prosthesis for implantation in a vein to treat venous insufficiency, wherein the frameless grafting prosthesis is formed of a material effective to remodel tissue from a wall of a vein and comprising at least one shaped valve cusp, the shaped valve cusp including a relatively narrow base, a relatively wide top edge, and diverging sides extending from the base edge to the tope edge. The diverging side edges are typically configured for attachment to a wall of the vein. By "configured for attachment to a wall of the vein" is meant that the side edges are sufficiently constructed to allow for secure attachment of a frameless grafting prosthesis of the invention to a vein. The frameless grafting prosthesis of the invention can be adapted to provide a monocusp valve in a vein, or, alternatively, it can be adapted to provide for a multicuspid valve in a vein, wherein the multicuspid valve comprises a plurality of cusps. In this respect, the frameless grafting prosthesis can be adapted to provide a monocuspid valve, a bicuspid valve, a tricuspid valve, or a quadracuspid valve in a vein. When a monocusp leaflet configuration is utilized in the invention, the frameless grafting prosthesis having such a configuration can be dimensioned and attached in such a manner so as to allow the leaflet to extend across the entire lumen of a vein and co-apt with the opposite wall of the vein. Alternatively, two or more monocusp devices can be provided and dimensioned for separate attachment to the wall of the vein so as to co-apt with each other within the vein lumen, e.g. near the middle of the lumen. When a multicusp leaflet configuration is utilized, the frameless grafting prosthesis will comprise at least two leaflets, wherein the at least two leaflets are attached to the vein wall in such a manner so as to allow the leaflets to co-apt within the lumen of the vein, e.g. near the center of the lumen of the vein. Whatever configuration is utilized, it will be understood that blood flow back to the heart will pass through the co-apt line i.e., the point where the monocusp leaflet co-apts with the opposite wall of a vein or where the at least two leaflets co-apt within the lumen of the vein, e.g. near the center of the lumen. On the other hand, blood flow in the opposite direction will be restricted. The frameless grafting prosthesis of the invention can be adapted to provide a shaped valve cusp having any suitable configuration. For example, the shaped valve cusp after implantation can have a non-planar configuration when in a closed condition. Preferably, the shaped valve cusp will have a generally concave/convex configuration when in a closed condition, as shown for example in Fig. 1C . Other configurations are contemplated for use in the invention, and can be designed through routine experimentation so as to allow for optimal blood flow back to the heart . The frameless grafting prosthesis of the invention can be constructed so as to have predetermined dimensions at its base, top edge, and diverging sides, such that the prosthesis is adapted to provide a valve function in a vein or other vessel of a specific diameter. For example, the dimensions of the prosthesis can be selected so as to render the device suitable for providing a valve function in a vein or other vessel having an inner diameter of about 5mm to about 25mm, more typically in the range of about 8mm to about 20mm. Packaged, sterile medical products are also provided by the invention. Such products comprise a frameless grafting prosthesis as described herein contained in sterile packaging. The sterile packaging can contain a single frameless grafting prosthesis, a plurality of frameless grafting prostheses. When more than one frameless grafting prostheses is included in the sterile packaging, the prostheses can each be of substantially the same size and shape, or, alternatively, can vary with respect to size and shape.

In addition, the sterile packaging can have visible indicia identifying the contained prosthesis as a venous or other vascular valve, and/or can contain or otherwise be associated with printed materials identifying the prosthesis as a venous or other vascular valve and including information concerning its use as a venous or other vascular valve. The sterile packaging can also include visible indicia relating to the dimension of the frameless grafting prosthesis which it contains, and/or relating to the vessel diameter (s) for which the prosthesis is configured. As previously described, each frameless grafting prosthesis of the invention can be constructed so as to have dimensions suited for implantation within a vessel of a given diameter. Also provided within the present invention is a medical valve product line comprising a plurality of packaged, sterile medical products as described above, wherein the plurality of medical products includes packaged prosthesis devices of varying dimensions to suit varying patients or applications, for example the product line including at least 3 differently dimensioned products, e.g. from about 3 to about 20 differently dimensioned products. The frameless grafting prosthesis can be contained in a sterile packaging in any suitable state. Suitable states include, for example, a hydrated or dehydrated state. A frameless grafting prosthesis can be dehydrated by any means known in the art (e.g., lyophilization or air dried) . The present invention further provides methods for attaching a frameless grafting prosthesis of the invention to a vein. Such a method comprises (a) providing a frameless grafting prosthesis of the invention, and (b) attaching the frameless grafting prosthesis to a wall of a vein or other vascular vessel. The frameless grafting prosthesis can be attached to a vein in any suitable manner. Preferably, the frameless grafting prosthesis is attached to a wall of a vein or other vascular vessel surgically. Such a surgical procedure typically comprises suturing or otherwise physically connecting the edges of the at least one shaped valve cusp of the frameless grafting prosthesis to the luminal surface of a vein or other vascular vessel. Other potential surgical attachment procedures include, for example, stapling, bonding or otherwise adhering the edges of the at least one shaped valve cusp of the frameless grafting prosthesis to the luminal surface of a vein or other vascular vessel. Where the inventive prosthesis is to be used to provide venous valve, the prosthesis can be implanted above, below, or at the location of a native venous valve in the patient. Moreover, a plurality of the grafting prosthesis devices can be implanted in a given vein, to treat venous insufficiency or other similar disorders . For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and alterations and modifications in the illustrated device, and further applications of the principles of the invention as illustrated therein are herein contemplated as would normally occur to one skilled in the art to which the invention relates . With reference now to Figures 1A through 1C, illustrated is a first embodiment of the invention comprising a frameless grafting prosthesis 11 for deployment within the vascular system. Frameless grafting prosthesis 11 generally is obtained from a sheet of a remodelable material 12. Frameless grafting prosthesis 11 comprises a top edge 13, a base 14, and diverging sides 15 extending from the base edge to the top edge. Typically, the top edge 13, base 14, and diverging sides 15 are constructed so as to have specific dimensions for optimal performance when attached to a vein. Frameless grafting prosthesis 11 can be attached to a vein 17 so as to allow for antegrade blood flow while restricting retrograde blood flow. The direction of antegrade blood flow is represented by the arrow depicted in Figure 1C . The frameless grafting prosthesis can be stitched 16 along base 14 and diverging sides 15 to a vein wall 18 such that top edge 13 is free to open and close as a result of vascular pressure. As will be understood, a frameless grafting prosthesis such as 11 can be dimensioned for use alone as a monocusp valve, or can be dimensioned for use with one or more additional similar prostheses to provide a multicusp valve. With reference now to Figure 2, shown is a medical product 20 of the invention including frameless grafting prosthesis 11 sealed within sterile medical packaging. In particular, medical product 20 has packaging including a backing layer 21 and a front film layer 22 (shown partially drawn away from backing layer 21) . Frameless grafting prosthesis 11 is sealed between backing layer 21 and film 22 utilizing a boundary of pressure-adhesive 23 as is conventional in medical packaging. A cut-out 24 may be provided in the backing layer 21 to assist a user in separating the film layer 22 from the backing layer 21. The final, packaged product is provided in a sterile condition. This may be achieved, for example, by irradiation, ethylene oxide gas, or any other suitable sterilization technique, and the materials and other properties of the medical packaging will be selected accordingly. With reference to Figure 3, shown is a cutaway view of a vein or other vascular vessel having a multicusp frameless valve of the invention attached therein. In particular, shown is a frameless tricuspid valve 30, generally having cusps 31, 32 and 33. Valve 30 can be provided in the vessel as a single, integral piece having material constituting cusps 31, 32 and 33 and slits in appropriate locations to provide the illustrated tricuspid orifice, or can be provided with multiple pieces of the remodelable material, e.g. three pieces with a separate piece providing each of cusps 31, 32, and 33. It will be understood that similar considerations will apply to other multicusp valves of the invention, including bicusp, quadricusp, etc., valves. As well, it will be understood that any suitable method of attaching the edges of the prosthesis to the vessel wall may be used, including for example those disclosed hereinabove. The remodelable material used in the invention is a biocompatible material. Suitable remodelable materials may be made from natural or synthetic polymers, and preferred materials comprise collagen. Thus, in general, the remodelable material may comprise a material such as synthetic biocompatible polymers such as cellulose acetate, cellulose nitrate, silicone, polyethylene teraphthalate, polyurethane, polyamide, polyester, polyorthoester, polyanhydride, polyether sulfone, polycarbonate, polypropylene, high molecular weight polyethylene, polytetrafluoroethylene, or mixtures or copolymers thereof; polylactic acid, polyglycolic acid or copolymers thereof, a polyanhydride, polycaprolactone, polyhydroxy-butyrate valerate, polyhydroxyalkanoate, or another biodegradable polymer. In certain embodiments of the invention, the remodelable material is comprised of a naturally- derived or synthetic collagenous material, and especially an extracellular matrix material. Suitable extracellular matrix materials include, for instance, submucosa (including for example small intestinal submucosa, stomach submucosa, urinary bladder submucosa, or uterine submucosa) , renal capsule membrane, dura mater, pericardium, serosa, peritoneum or basement membrane materials, including liver basement membrane. These layers may be isolated and used as intact natural sheet forms, or reconstituted collagen layers including collagen derived from these materials or other collagenous materials may be used. For additional information as to submucosa materials useful in the present invention, and their isolation and treatment, reference can be made to U.S. Patent Nos. 4,902,508, 5,554,389, 5,993,844, 6,206,931, and 6,099,567. Medical products and frameless grafting prostheses of the invention are desirably adapted for deployment within the vascular system, and in particularly preferred embodiments, medical products and frameless grafting prostheses of the invention are adapted for deployment within the venous system. Accordingly, preferred prostheses, such as prosthesis 11, is adapted as a venous valve, for example, for attachment within veins of the legs or feet, to treat venous insufficiency. While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. In addition, all publications cited herein are indicative of the abilities of those of ordinary skill in the art and are hereby incorporated by reference in their entirety as if individually incorporated by reference and fully set forth.

Claims

WHAT IS CLAIMED IS: 1. A medical product, comprising: a frameless grafting prosthesis for implantation in a vein to treat venous insufficiency, the grafting prosthesis formed of a material effective to remodel tissue from a wall of the vein and comprising at least one shaped valve cusp, the shaped valve cusp including a relatively narrow base, a relatively wide top edge, and diverging side edges extending from said base edge to said top edge, said side edges configured for attachment to a wall of the vein; and sterile packaging containing said frameless grafting prosthesis.

2. The medical product of claim 1, wherein the frameless grafting prosthesis is adapted to provide a monocusp valve in said vein.

3. The medical product of claim 1, wherein the frameless grafting prosthesis has a plurality of said cusps, and is adapted to provide a multicuspid valve in the vein.

4. The medical product of claim 3 , wherein the frameless grafting prosthesis is adapted to provide a bicuspid valve in the vein.

5. The medical product of claim 3, wherein the frameless grafting prosthesis is adapted to provide a tricuspid valve in the vein.

6. The medical product of claim 3, wherein the frameless grafting prosthesis is adapted to provide a quadracuspid valve in the vein.

7. The medical product of any of claims 1-6, wherein the remodelable material is an extracellular matrix material .

8. The medical product of any of claims 1-7, wherein the shaped valve cusp is adapted to provide a non-planar configuration in a closed condition.

9. The medical product of claim 8, wherein the shaped valve cusp is adapted to provide a generally concave/convex configuration in a closed condition.

10. The medical product of any of claims 1-9, wherein said at least one shaped valve cusp is dimensioned for a vein having a predetermined inner diameter, and wherein the sterile packaging comprises visible indicia of the predetermined inner diameter.

11. A product line containing a plurality of medical products of any of claims 1-10, said plurality of medical products including prosthesis devices of varying dimensions .

12. A frameless grafting prosthesis for implantation in a vein to treat venous insufficiency, wherein the frameless grafting prosthesis is formed of a material effective to remodel tissue from a wall of the vein and comprising at least one shaped valve cusp, the shaped valve cusp including a relatively narrow base, a relatively wide top edge, and diverging side edges extending from said base edge to said top edge, said side edges configured for attachment to a wall of the vein.

13. The frameless grafting prosthesis of claim 12, wherein the frameless grafting prosthesis is adapted to provide a monocusp valve in said vein.

14. The frameless grafting prosthesis of claim 12, wherein the frameless grafting prosthesis has a plurality of said cusps, and is adapted to provide a multicuspid valve in the vein.

15. The frameless grafting prosthesis of claim 14, wherein the frameless grafting prosthesis is adapted to provide a bicuspid valve in the vein.

16. The frameless grafting prosthesis of claim 14, wherein the frameless grafting prosthesis is adapted to provide a tricuspid valve in the vein.

17. The frameless grafting prosthesis claim 14, wherein the frameless grafting prosthesis is adapted to provide a quadracuspid valve in the vein.

18. The frameless graf ing prosthesis of any of claims 12-17, wherein the remodelable material is an extracellular matrix material.

19. The frameless grafting prosthesis of any of claims 12-18, wherein the shaped valve cusp is adapted to have a non-planar configuration in a closed condition.

20. The frameless grafting prosthesis of claim - 19, wherein the shaped valve cusp has a generally concave/convex configuration in a closed condition.

21. The frameless grafting prosthesis of any of claims 12-20, wherein the prosthesis is adapted for implantation within a vein having an inner diameter of about 5mm to about 25mm.

22. A method for attaching a frameless grafting prosthesis to a vein, comprising: (a) providing a medical product of any of claims 1-11, (b) removing the frameless grafting prosthesis from the sterile packaging of the medical product, and (c) attaching the frameless grafting prosthesis to a wall of a vein.

23. A method for attaching a frameless grafting prosthesis to a vein, comprising: (a) providing a frameless grafting prosthesis of any of claims 12-21, and (b) attaching the frameless grafting prosthesis to a wall of a vein.

24. The method of claim 22 or 23, wherein the frameless grafting prosthesis is attached to a wall of a vein surgically.

25. The method of claim 24, wherein the surgical attachment of the frameless grafting prosthesis to a vein comprises suturing the edges of the at least one shaped valve cusp to the luminal surface of the vein.

26. The method of any of claims 22-25, wherein the frameless grafting prosthesis comprises a monocusp leaflet configuration and is dimensioned and attached in such a manner so as to allow the leaflet to extend across the entire lumen of the vein and co-apt with the opposite wall of the vein.

27. The method of claim 26, wherein the frameless grafting prosthesis comprises a multicusp leaflet configuration having at least two leaflets, wherein the at least two leaflets are attached in such a manner so as to allow the leaflets to co-apt within the lumen of the vein.

28. The method of claim 27, wherein the multicusp leaflet configuration comprises four leaflets, wherein the four leaflets are attached in such a manner so as to allow the leaflets to co-apt within the lumen of the vein.