Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent in combination with graft
Reexamination Certificate
1999-07-21
2004-09-14
Pellegrino, Brian E (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent in combination with graft
C623S901000
Reexamination Certificate
active
06790225
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to medical devices and their methods of manufacture, and more particularly to tubular, polytetrafluoroethylene (PTFE) grafts having integral, radially expandable stents, for implantation in cavities or passageways (e.g., ducts or blood vessels) of the body.
BACKGROUND OF THE INVENTION
A. Stents
The prior art has included a number of radially expandable stents which may be initially deployed in a radially collapsed state suitable for transluminal insertion via a delivery catheter, and subsequently transitioned to a radially expanded state whereby the stent will contact and engage the surrounding wall or the anatomical duct or body cavity within which the stent has been positioned. Such stents have been used to support and maintain the patency of blood vessel lumens (e.g., as an adjuvant to balloon angioplasty) and to structurally support and/or anchor other apparatus, such as tubular endovascular grafts, at desired locations within a body cavity or passageway (e.g., to anchor a tubular endovascular graft within a blood vessel such that the graft forms an internal conduit through an aneurysm or site of traumatic injury to the blood vessel wall).
Many stents of the prior art have been formed of individual member(s) such as a wire, plastic, metal strips, or mesh which has been bent, woven, interlaced or otherwise fabricated into a generally cylindrical configuration. These stents of the prior art have generally been classified into two major categories—a) “self-expanding” stents, and b) “pressure expandable” stents.
i) Self-expanding Stents
Self-expanding stents are typically formed of spring metal, shape memory alloy, or other material which is resiliently biased toward its' fully radially expanded Configuration or otherwise capable of self-expanding to its' fully radially expanded configuration without the need for the exertion of outwardly directed radial force upon the stent by some extraneous expansion apparatus (e.g., a balloon or mechanical expander tool). These self-expanding stents may be initially radially compressed and loaded into a small diameter delivery catheter or alternatively mounted upon the outer surface of a delivery catheter equipped with some means for restraining or maintaining the stent in its' radially compressed state. Thereafter, the delivery catheter is inserted into the body and is advanced to a position where the stent is located at or near the site at which it is to be implanted. Thereafter, the stent is expelled out of (or released from) the delivery catheter and allowed to self-expand to it's full radial diameter. Such expansion of the stent causes the stent to frictionally engage the surrounding wall of the body cavity or passageway within which the stent has been positioned. The delivery catheter is then extracted, leaving the self-expanded stent at its' intended site of implantation. Some examples of self-expanding stents of the prior art include those described in U.S. Pat. No. 4,655,771 (Wallsten et al.); U.S. Pat. No. 4,954,126 (Wallsten): U.S. Pat. No. 5, 061, 275 (Wallsten et al.); U.S. Pat. No. 4,580,568 (Gianturco); U.S. Pat. No. 4,830,003 (Wolf et al.); U.S. Pat. No. 5,035,706 (Gianturco et al.) and U.S. Pat. No. 5,330,400 (Song).
ii) Pressure-Expandable Stents
The pressure-expandable stents of the prior art are typically formed of metal wire, metal strips, or other malleable or plastically deformable material, fabricated into a generally cylindrical configuration. The pressure-expandable stent is initially disposed in a collapsed configuration having a diameter which is smaller than the desired final diameter of the stent, when implanted in the blood vessel. The collapsed stent is then loaded into or mounted upon a small diameter delivery catheter. The delivery catheter is then advanced to its desired location within the vasculature, and a balloon or other stent-expansion apparatus (which may be formed integrally of or incorporated into the delivery catheter) is utilized to exert outward radial force on the stent, thereby radially expanding and plastically deforming the stent to it's intended operative diameter whereby the stent frictionally engages the surrounding blood vessel wall. The material of the stent undergoes plastic deformation during the pressure-expansion process. Such plastic deformation of the stent material causes the stent to remain in its radially expanded operative configuration. The balloon or other expansion apparatus is then deflated/collapsed and is withdrawn from the body separately from, or as part of, the delivery catheter, leaving the pressure-expanded stent at it's intended site of implantation.
Some examples of pressure-expandable stents of the prior art include those described in U.S. Pat. No. 5,135,536 (Hillstead); U.S. Pat. No. 5,161,547 (Tower); U.S. Pat. No. 5,292,331 (Boneau); U.S. Pat. No. 5,304,200 (Spaulding) and U.S. Pat. No. 4,733,665 (Palmaz).
B. PTFE Vascular Grafts
Fluoropolymers, such as polytetrafluoroethylene, have been heretofore used for the manufacture of various types of prosthetic vascular grafts. These vascular grafts are typically of tubular configuration so as to be useable to replace an excised segment of blood vessel.
The tubular PTFE vascular grafts of the prior art have traditionally been implanted, by open surgical techniques, whereby a diseased or damaged segment of blood vessel is surgically excised and removed, and the tubular bioprosthetic graft is then anastomosed into the host blood vessel as a replacement for the previously removed segment thereof. Alternatively, such tubular prosthetic vascular grafts have also been used as bypass grafts wherein opposite ends of the graft are sutured to a host blood vessel so as to form a bypass conduit around a diseased, injured or occluded segment of the host vessel.
In general, many tubular prosthetic vascular grafts of the prior art have been formed of extruded, porous PTFE tubes. In some of the tubular grafts of the prior art a PTFE tape is wrapped about and laminated to the outer surface of a tubular base graft to provide reinforcement and additional burst strength. Also, some of the prior tubular prosthetic vascular grafts have included external support member(s), such as a PTFE beading, bonded or laminated to the outer surface of the tubular graft to prevent the graft from becoming compressed or kinked during implantation. These externally supported tubular vascular grafts have proven to be particularly useful for replacing segments of blood vessel which pass through, or over, joints or other regions of the body which undergo frequent articulation or movement.
One commercially available, externally-supported, tubular vascular graft is formed of a PTFE tube having a PTFE filament helically wrapped around, and bonded to, the outer surface of the PTFE tube. (IMPRA Flex™ Graft, IMPRA, Inc., Tempe, Ariz.)
One other commercially available, externally-supported, tubular vascular graft comprises a regular walled, PTFE tube which has PTFE reinforcement tape helically wrapped around, and bonded to,the outer surface of the PTFE tube and individual rings of Fluorinated Ethylene Propylene (FEP) rings disposed around, and bonded to, the outer surface of the reinforcement tape. (FEP ringed ePTFE vascular graft, W. L. Gore & Associates, Inc., Flagstaff, Ariz.)
C. Stented Grafts
The prior art has also included a number of “stented grafts”. These stented grafts typically comprise a self-expanding or pressure-expandable stent which is affixed to or formed within a pliable tubular graft. Because of their radial compressibility/expandability, these stented grafts are particularly useable in applications wherein it is desired to insert the graft into an anatomical passageway (e.g., blood vessel) while the graft is in a radially compact state, and to subsequently expand and anchor the graft to the surrounding wall of the anatomical passageway.
More recently, methods have been developed for introducing and implanting tubular prosthetic vascular grafts wi
Chu Yizi
Clinkenbeard Ronald L.
Kuo Chris
McIntyre John
Shannon Donald T.
Edwards Lifesciences Corporation
Pellegrino Brian E
Yadav Rajiv
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