Coated intraluminal graft

Details Coated intraluminal graft Coated intraluminal graft

1999-07-29

2001-03-27

Truong, Kevin (Department: 3731)

Prosthesis (i.e., artificial body members), parts thereof, or ai

Arterial prosthesis

Having plural layers

C623S001440

Reexamination Certificate

active

06206916

ABSTRACT:

This invention relates to an improved intraluminal graft for use within a body passageway, duct, blood vessel or other cavity and, more particularly, expandable intraluminal grafts for use within a body passageway, duct, blood vessel or other cavity and, more particularly, expandable intraluminal grafts which are particularly useful for repairing blood vessels narrowed or occluded by disease and which graft is at least partially coated with a drug or compound that inhibits biological components capable of causing adverse clinical affects. Here after the terms “graft” and “stent” are interchangeable.
DESCRIPTION OF THE PRIOR ART
Heart disease is still one of the most prevalent medical ailments in the world. Intraluminal endovascular grafting, a type of angioplasty procedure, has been demonstrated by experimentation to present a possible alternative to conventional vascular surgery and is used to treat heart disease. Intraluminal endovascular grafting involves a tubular prosthetic graft and its delivery within the vascular system. Advantages of this method over conventional vascular surgery include obviating the need for surgically exposing, incising, removing, replacing, or bypassing the defective blood vessel. Over 20 million angioplasty or related procedures involving occluded vasculature have been performed worldwide.
Several years ago, a product called a stent was introduced for use in angioplasty procedures. A stent is an expandable metal tubular device that is mounted over an angioplasty balloon and deployed at the site of coronary narrowing. The balloon is inflated to expand the stent so as to physically open and return patency to the body passageway, duct or blood vessel. The balloon is then deflated and the stent is permanently disposed to retain the passageway, duct or blood vessel open. One particular type of stent is disclosed in U.S. Pat. No. 4,733,665. This stent overcame the problem associated with controlled expansion of the stent. In the prior art, there was no control over the final, expanded configuration of the stent. For instance, the expansion of a particular coiled spring-type stent was predetermined by the method of manufacturing, material and delivery system. In the case of self-expanding intraluminal grafts, or prostheses, formed of a heat sensitive material which expands upon exposure to core body temperature, the amount of expansion was predetermined by the heat expansion properties of the particular alloy utilized in the manufacture of the intraluminal graft. Thus, once the foregoing types of intraluminal grafts were expanded at the desired location within a body passageway, such as within an artery or vein, the expanded size of the graft cannot be increased. If the diameter of the desired narrow lumened body passageway had not been determined correctly, the graft might not expand enough to contact the interior surface of the body passageway, so as to be secured thereto. The stent disclosed in the '665 patent overcame the problems associated with these past stent designs.
The stent based upon the '665 patent is currently being used in angioplasty procedures. However, this stent has several shortcomings which contribute to procedural failure rates. The currently used stents are not readily visible under fluoroscopic guidance procedurally. Stent placement is hindered as a result of poor visibility. These stents also shorten longitudinally after radial expansion, which is not desirable for their intended use.
These problems with current stent technology are overcome in my co-pending U.S. patent application Ser. No. 09/273,736 filed Mar. 22, 1999 entitled “Improved Expandable Graft,” which is incorporated herein by reference. My improved stent improves the visibility under fluoroscopy in vivo and retains its longitudinal dimensions from its original pre-expanded configuration to the expanded state.
Several problems can develop after the stent is inserted into a passageway. One problem is known as in-stent restenosis wherein the passageway, which has been previously treated with a stent, renarrows or closes within the stented segment. The renarrowing or closure of the passageway can be caused by a structural failure of the stent due to contractive forces by the passageway on the stent and/or by the passageway growing into the openings in the stent. Other problems can include vascular narrowing and restenosis. Vascular narrowing is defined as a vascular segment that has not been previously treated by any interventional means and eventually closes preventing blood flow. Restenosis is the renarrowing of a previously treated vascular segment not involving a stent. Both of these problems are the result of a passageway that was not treated with an invasive angioplasty, narrowing or closing. Both of the problems result from the insertion of a stent in one portion of the passageway causing vascular narrowing or restenosis in another part of the passageway.
Vascular narrowing, restenosis and in-stent restenosis are caused by biological factors causing the premature closing of vessels. One such agent is platelet derived growth factors, referred to as PDGF. PDGF is an intercellular messenger capable of stimulating proliferation of smooth muscle cells. Smooth muscle cells migrate within the artery and cause a restenotic reaction.
In view of the problems which can result from the insertion of a stent into a passageway, there is a need and demand for a stent that reduces the occurrence of in-stent restenosis and can also reduce the occurrence of vascular narrowing and restenosis in untreated portions of a passageway.
SUMMARY OF THE INVENTION
This invention pertains to an improved intraluminal graft that is designed to meet the present-day needs and demands relating to intraluminal grafts. The present invention includes a geometrically shaped member, having first and second ends and a wall surface disposed between the first and second ends. The wall surface is preferably formed by a plurality of intersecting elongated members, and at least some of the elongated members preferably intersect with one another at a point intermediate to the first and second ends of the tubular shaped member. The tubular shaped member has a first diameter which permits intraluminal delivery of the tubular shaped member into a body passageway having a lumen and a second, expanded diameter. The expansion of the tubular shaped member can be accomplished in a variety of manners. Preferably, the tubular shaped member is expanded to its second diameter by a radially, outwardly extending force that is applied at least partially from the interior of the tubular shaped member. The second diameter of the tubular shaped member is variable and dependent upon the amount of radially outward force applied to the tubular shaped member. Preferably, the tubular shaped member is expandable, to allow expansion of the lumen of the body passageway while retaining its, the tubular shaped member's, original length. At least a portion of the graft is preferably coated with a substance which inhibits the occurrence of in-stent restenosis, vascular narrowing and/or restenosis.
Another feature of the present invention is that the plurality of elongated members include a plurality of wires, and the wires may be fixedly secured to one another where the wires intersect with one another. In one specific embodiment, the tubular member is at least partially made of a wire mesh tube. The wire mesh tube may be utilized as the intraluminal graft. The wire mesh tube can be radially expanded to a second diameter within the body passageway; the second, expanded diameter being variable and determined by the desired expanded internal diameter of the body passageway, duct, blood vessel, etc., whereby the expanded wire mesh tube will not migrate from the desired location within the body passageway, duct, blood vessel, etc., and the expansion of the intraluminal graft does not cause a rupture of the body passageway, duct, blood vessel, etc.
Yet another feature of the present invention is that the plurality of elongated

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