Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Having variable diameter
Reexamination Certificate
2001-07-03
2004-06-08
Snow, Bruce (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Having variable diameter
C623S001100, C623S001300, C623S001350, C623S001370
Reexamination Certificate
active
06746480
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to vascular grafts, particularly to vascular grafts for end-to-side anastomosis for purposes of bypassing an occluded or diseased section of a blood vessel. More particularly, the present invention is a polytetrafluoroethylene graft having an integral terminal polytetrafluoroethylene flanged cuff section which permits an end-to-side anastomosis with a blood vessel in which the terminal polytetrafluoroethylene flanged cuff section is sutured to the blood vessel and provides a polytetrafluoroethylene-tissue interface between the graft and the blood vessel. The present invention also provides a method and apparatus for forming the flanged polytetrafluoroethylene cuffed section from a tubular polytetrafluoroethylene graft.
2. Description of the Prior Art
The use of cuff grafts for bypassing peripheral vascular occlusive conditions, particularly femoro-crural patch prostheses, is well known in the art. To date, however, either autologous grafts or synthetic grafts with a terminal cuff fashioned from venous tissue at the anastomotic site have been used. Examples of conventional cuffed grafts are the Miller collar described in Miller, J. H.,
The Use of the Vein Cuff and PTFE, VASCULAR SURGICAL TECHNIQUES
2 ed., W. B. Saunders (1989), 276-286 and the Taylor patch described in Taylor, R. S., et al, Improved technique for polytetrafluoroethylene bypass grafting: long-term results using anastomotic vein patches,
Br. J Surg.,
79:348-354 (1992). Both the Miller graft and the Taylor graft are cuff grafts and each employs a polytetrafluoroethylene graft with an autologous venous cuff at the anastomotic site. The Miller collar and the Taylor patch each use venous tissue at the anastomotic site to avoid a compliance mismatch at the polytetrafluoroethylene-tissue interface.
The present invention offers a new type of anastomosis for femoro-crural bypass in which the graft is fabricated in a flared, double-bulb configuration. The inventive graft configuration offers an optimal geometry for the anastomosis as a function of hemodynamic properties. By optimizing blood flow from the bypass prosthesis to the artery, formation of intimal hyperplasia may be reduced with a concomitant increase in graft patency and decreased morbidity.
The present invention also provides an apparatus and method for forming an integral polytetrafluoroethylene distal flange or cuff on an expanded polytetrafluoroethylene (ePTFE) graft. The apparatus consists of an annular mold having a radially extending annular slot forming an expansion port. The inventive flanged cuff graft is made by first forming an unsintered tubular PTFE vascular graft by extruding a PTFE-lubricant mixture into a billet to form a tubular extrudate, placing the extrudate in the annular mold, and forming an annular cuff by either: 1) application of a negative pressure to the expansion port; or 2) application of positive pressure, as by a highly compliant angioplasty balloon, through the tubular extrudate lumen, to radially displace a section of the tubular extrudate, thereby forming a cuffed graft.
Various different approaches have been taken to fabricate branched grafts. As early as 1938, Bowen, U.S. Pat. No. 2,127,903, discloses a bio-absorbable surgically implantable graft made of animal tissue and a binder formed by wrapping strips of the treated animal tissue about a structural form. U.S. Pat. No. 4,909,979, issued Mar. 20, 1990 to Possis, discloses a method of shaping a human umbilical cord for use as a vascular graft. The method employs a mandrel to support and shape the umbilical cord during forming and curing of the cord. The forming and curing process provides a cord with a blood flow restrictor section. PTFE coatings are provide on the mandrel to facilitate mounting the umbilical cord onto the mandrel. A shaping section of the mandrel is provided with a plurality of vacuum openings in the mandrel. The umbilical cord is treated with ethanol and a vacuum applied until the cord is dehydrated. The cord is then exposed to a curative and fixative solution and a vacuum applied until the umbilical cord is cured substantially airtight and circumferentially compressed and compacted around the mandrel forming section. U.S. Pat. No. 4,354,495, issued Oct. 19, 1982 to Bodicky, discloses a method of connecting a PTFE tube to a hub made of a moldable plastic, e.g., polyurethane, acrylics, polyethylene, polycarbonates, etc. The method involves selectively heating a portion of the PTFE tube to form a bulge or protrusion, then inserting the bulge into a mold and molding the moldable plastic hub about the bulge in the mold. Kaneko et al. (U.S. Pat. No. 4,957,508, issued Sep. 18, 1990), disclose an elastomeric medical tube having proximal and distal ends, outwardly flared. The outward flare of the ends is achieved by forming the inner and outer surfaces of the tube to exhibit inverse elastomeric properties, i.e., the inner surface exhibits a dilating force, while the outer surface exhibits a shrinking force. The tube is made of high molecular weight polymers, particularly, polyvinyl halide, polystyrene, polyolefin series polymers, polyester series condensates, cellulose series high polymers, polyurethane series high polymers, polysulfone series resins, polyamides, etc. along with copolymers or mixtures of these. Noshiki et al. (U.S. Pat. No. 5,387,236, issued Feb. 7, 1995), disclose a vascular prosthesis and method of making a vascular prosthesis by providing a vascular prosthesis substrate made of PTFE or other microporous material, and depositing and capturing within the wall of the prosthesis substrate fragments of biological tissue. The biological tissue fragments may be vascular tissues, connective tissues, fat tissues and muscular tissues and/or vascular endothelial cells, smooth muscle cells and fibroblast cells. The impregnation process is conducted by depositing the cellular material on the inner wall of the graft and applying a pressure differential between the luminal and abluminal wall surfaces to drive the tissue fragments into the microporous matrix of the vascular prosthesis. Berry et al. (U.S. Pat. No. 4,883,453, issued Nov. 28, 1989), disclose an aorto-coronary bypass graft and a method of making the graft. The graft consists of a plate portion and at least one tube portion extending from the plate portion. The graft and plate are disclosed as being made of an electrostatically spun fibrous structure. The graft is adhered to the plate by mounting the graft onto a mandrel, applying adhesive to the surface of the plate surrounding an opening in the plate, passing the mandrel through an opening in the plate until the graft contacts the adhesive. The adhesive is any suitable adhesive for the materials forming the plate and the graft. According to the preferred embodiment described in this reference, the graft preferably has a tapered wall thickness, such that the graft wall thickness adjacent the plate is greater than that distant the plate. Hayashi et al. (U.S. Pat. No. 5,110,526, issued May 5, 1992), disclose a process for producing molded PTFE articles. According to this process, unsintered PTFE extrudates are inserted into a sintering mold. The sintering mold has a diameter slightly larger than the outside diameter of the unsintered PTFE extrudate. Clearance between the outside diameter of the unsintered PTFE extrudate and the inside surface of the sintering mold is on the order of 2% of the diameter of the sintering mold. The extrudate is drawn into the sintering mold via a plug, inserted into the terminal lumen of the extrudate and a wire and take-up reel. The PTFE extrudate is cut to match the length of the sintering mold, and the sintering mold is sealed on the cut extrudate end. The assembly is transferred to a sintering oven, and sintered. During sintering, the extrudate expands in contact with the sintering mold and conforms to the shape of the sintering mold. After cooling, the sintered extrudate contracts away from the sintering mold and as
Kruger Ulf
Scholz Hans
Settmacher Utz
Bard Peripheral Vascular, Inc.
Miller Cheryl L
Morrison & Foerster / LLP
Snow Bruce
LandOfFree
Flanged graft for end-to-side anastomosis does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flanged graft for end-to-side anastomosis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flanged graft for end-to-side anastomosis will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3356474