Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis
Reexamination Certificate
1998-06-05
2001-10-30
Milano, Michael J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
C623S001360, C623S001390
Reexamination Certificate
active
06309411
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to medical devices, and more specifically to an improved implantable stent apparatus for the treatment of stenoses in coronary or peripheral vessels in humans.
BACKGROUND OF THE INVENTION
Cardiovascular disease, including atherosclerosis, is the leading cause of death in the U.S. The medical community has developed a number of methods and devices for treating coronary heart disease, some of which are specifically designed to treat the complications resulting from atherosclerosis and other forms of coronary arterial narrowing.
An important development for treating atherosclerosis and other forms of coronary narrowing is percutaneous transluminal coronary angioplasty, hereinafter referred to as “angioplasty” or “PTCA”. The objective in angioplasty is to enlarge the lumen of the affected coronary artery by radial hydraulic expansion. The procedure is accomplished by inflating a balloon within the narrowed lumen of the coronary artery. Radial expansion of the coronary artery occurs in several different dimensions, and is related to the nature of the plaque. Soft, fatty plaque deposits are flattened by the balloon, while hardened deposits are cracked and split to enlarge the lumen. The wall of the artery itself is also stretched when the balloon is inflated.
Unfortunately, while the affected artery can be enlarged, in some instances the vessel restenoses chronically, or closes down acutely, negating the positive effect of the angioplasty procedure. In the past, such restenosis has frequently necessitated repeat PTCA or open heart surgery. While such restenosis does not occur in the majority of cases, it occurs frequently enough that such complications comprise a significant percentage of the overall failures of the PTCA procedure, for example, twenty-five to thirty-five percent of such failures.
To lessen the risk of restenosis, various devices have been proposed for mechanically keeping the affected vessel open after completion of the angioplasty procedure. Such endoprostheses (generally referred to as “stents”), are typically inserted into the vessel, positioned across the lesion or stenosis, and then expanded to keep the passageway clear. The stent overcomes the natural tendency of the vessel walls of some patients to restenose, thus maintaining the patency of the vessel.
Various types of stents are currently under development, although to date none has proven completely satisfactory during testing. U.S. Pat. No. 4,655,771 to Wallsten describes a stent comprising a tube of stainless wire braid. During insertion, the tube is positioned along a delivery device, such as a catheter, in extended form, making the tube diameter as small as possible. When the stent is positioned across the lesion, it is expanded, causing the length of the tube to contract and the diameter to expand. Depending on the materials used in construction of the stent, the tube maintains the new shape either through mechanical force or otherwise.
U.S. Pat. No. 4,733,665 to Palmaz describes a stent comprising a slotted stainless steel cylinder that forms a mesh when expanded. The stent is delivered to an affected area by a balloon catheter, and is then expanded to the proper size by inflating the balloon.
A drawback of such previously known stents, however, is the tendency of such stents to migrate downstream from the initial placement area. For example, due to irregularity in the vessel diameter or underexpansion of the stent, such stents have been observed to migrate downstream from the initial placement area. Thus, not only is the objective of the stent implantation not achieved, but the migrating stent may cause injury elsewhere in the vascular system.
These and other complications have resulted in a low level of acceptance for such stents within the medical community for certain procedures, and to date stents have not been accepted as a practical method for treating many chronic restenosis conditions.
It would therefore be desirable to provide methods and apparatus, useful for treating chronic restenosis conditions, that retain an endoprosthesis in its area of initial placement, and which reduce the risk of migration of the endoprosthesis.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide methods and apparatus for treating chronic restenosis conditions that retain an endoprosthesis in its area of initial placement, and which reduce the risk of migration of the endoprosthesis.
The stent surface anchor constructed in accordance with this invention provides an improved endoprosthesis or stent having an expandable, generally cylindrical body portion defining an inside surface and an outside surface. In accordance with the present invention, the inside surface is preferably regular and smooth to yield a low coefficient of friction, while the outside surface is modified to yield a relatively high coefficient of friction with the vessel surface, includes a macroscopic surface modification to engage the vessel surface, or includes an adhesive coating that bonds with the vessel surface.
The deployment methods for implanting a stent constructed in accordance with the present invention include balloon expansion, self-expansion, self-retraction and mechanical expansion. Some of the intended uses include PTCA type stenting, PTA type stenting, graft support, graft delivery, INR use, GI tract use, drug delivery, and biliary stenting.
REFERENCES:
patent: 4577631 (1986-03-01), Kreamer
patent: 4655771 (1987-04-01), Wallsten
patent: 4733665 (1988-03-01), Palmaz
patent: 4776337 (1988-10-01), Palmaz
patent: 4938740 (1990-07-01), Melbin
patent: 4955859 (1990-09-01), Zilber
patent: 5015253 (1991-05-01), MacGregor
patent: 5019090 (1991-05-01), Pinchuk
patent: 5052998 (1991-10-01), Zimmon
patent: 5100429 (1992-03-01), Sinofsky et al.
patent: 5167614 (1992-12-01), Tessmann et al.
patent: 5167714 (1992-12-01), Tessmann et al.
patent: 5236446 (1993-08-01), Dumon
patent: 5292331 (1994-03-01), Boneau
patent: 5423885 (1995-06-01), Williams
patent: 5549635 (1996-08-01), Solar
patent: 5628788 (1997-05-01), Pinchuk
patent: 5653747 (1997-08-01), Dereume
patent: 5718713 (1998-02-01), Frantzen
patent: A 61333/90 (1991-02-01), None
patent: 0 497 620 A2 (1992-08-01), None
patent: 0 539 237 A1 (1993-04-01), None
patent: 0 797 963 A2 (1997-10-01), None
patent: 0 850 604 A2 (1998-07-01), None
patent: WO 89/07916 (1989-09-01), None
patent: WO 92/06734 (1992-04-01), None
patent: WO 95/13033 (1995-05-01), None
Papanicolaou, et al., “Insertion of a Biliary Endoprosthesis Using a Balloon Dilatation Catheter,”Gastrointestinal Radiology, 1985; 10:394-396.
Rosch, et al., “Modified Gianturco Expandable Wire Stents in Experimental and Clinical Use,”Annales De Radiologie,1988; 31:2:100-103.
Boneau Michael D.
Jendersee Bradley
Lashinski Robert
Medtronic Ave Inc.
Milano Michael J.
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