Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent combined with surgical delivery system
Utility Patent
1999-01-15
2001-01-02
Buiz, Michael (Department: 3731)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent combined with surgical delivery system
C623S001110
Utility Patent
active
06168618
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to delivery systems for implanting endoluminal prostheses—“stents”—to treat narrowing of biological organs or vessels, for example, the coronary arteries, renal arteries and carotid arteries. More particularly, the present invention relates to methods and apparatus for releasing a stent from a contracted delivery state to a deployed state by causing electrolytic erosion of binding straps.
BACKGROUND OF THE INVENTION
In recent years a number of minimally invasive technologies have been developed to treat arterial diseases, such as atherosclerosis, which result in narrowing and stenosis of body lumens, such as the coronary arteries. Specifically, a large number of endoluminal prostheses, often referred to as “stents,” have been developed to maintain the patency of a vessel, following, for example, a balloon dilatation procedure (e.g., angioplasty). These devices generally are inserted percutaneously and transluminally to the site of a constricted region in a contracted delivery state. After being positioned at a desired deployment site, the stents are then permitted to self-expand, or are balloon dilated to support the vessel or body lumen.
A drawback encountered with many previously known stents is the inability to precisely control the placement of the stent during deployment. For example, coiled sheet stents, such as described in U.S. Pat. No. 5,443,500 to Sigwart, are constrained in a contracted delivery state by a locking wire or exterior sheath, and deployed by removing the wire or retracting the sheath proximally. A disadvantage of these deployment mechanisms, however, is that the distal end of the stent expands while the proximal end is still constrained, and may result in cocking or longitudinal movement of the stent during deployment.
Similar types of stent motion may be encountered in deploying helical spring-type stents, such as described in U.S. Pat. No. 4,553,545 to Maass et al. It would therefore be desirable to provide a stent delivery system and methods that enable portions of a stent to be deployed in a predetermined sequence along the length of the stent, thereby minimizing the risk for cocking or displacement of the stent during deployment.
A further disadvantage of retractable-sheath delivery systems is that the exterior sheaths increase the overall diameter of the delivery system and reduce the ability of the delivery system to negotiate tortuous anatomy. It would therefore be desirable to provide a stent delivery system and methods that permit the thickness of an exterior sheath of the delivery system to be reduced or eliminated altogether.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of this invention to provide a stent delivery system and methods of use that enable portions of a stent to be deployed in a predetermined sequence along the length of the stent, thereby minimizing the risk for cocking or displacement of the stent during deployment.
It is another object of the present invention to provide a stent delivery system and methods of use that permit the thickness of an exterior sheath of a delivery system to be reduced or eliminated altogether.
These and other objects of the invention are accomplished in accordance with the principles of the invention by providing a stent delivery system, and methods of use, in which a stent is constrained in a contracted delivery state with binding straps that are electrolytically eroded to deploy the stent.
In accordance with the principles of the present invention, a stent is constrained in a contracted delivery state by one or more metal straps, for example, that encircle the circumference of the stent. The binding straps preferably are attached to a power source to form an anode, and all but a small exposed area of each binding strap is covered with an electrically insulating material. A cathode is disposed adjacent to the exposed area of the binding strap, or separately electrically coupled to an exterior surface of the patient's body. When an electric current is applied, the exposed area of each of the binding straps is electrolytically eroded, thereby causing rupture and allowing the stent to at least partially deploy. The anode (and cathode, if present) and binding straps are then removed from the body.
Electrolytic erosion of the binding straps may be accomplished with an internal anode, exterior cathode, and use of the patient's body fluid as the electrolyte. Alternatively, the anode and cathode may be mounted on the stent adjacent to the exposed areas of the binding straps, with the patient's body fluid again used as the electrolyte. As a yet further alternative, the anode, and the cathode, and the exposed areas of the binding straps may be mounted on the stent adjacent to the exposed areas of the binding straps and enclosed within small balloons containing a conductive fluid.
Methods of deploying a stent by eroding a plurality of binding straps in a predetermined sequence are also provided.
REFERENCES:
patent: 5122136 (1992-06-01), Guglielmi et al.
patent: 5263964 (1993-11-01), Purdy
patent: 5354295 (1994-10-01), Guglielmi et al.
patent: 5360440 (1994-11-01), Andersen
patent: 5423829 (1995-06-01), Pham et al.
patent: 5443500 (1995-08-01), Sigwart
patent: 5540680 (1996-07-01), Guglielmi et al.
patent: 5873907 (1999-02-01), Frantzen
patent: 5984929 (1999-11-01), Bashiri et al.
patent: WO 98/11846 (1998-03-01), None
Buiz Michael
Endotex Interventional Systems, Inc.
Goldberg Jonathan D.
Lyon & Lyon LLP
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