Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent combined with surgical delivery system
Reexamination Certificate
1999-10-18
2002-02-26
Milano, Michael J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent combined with surgical delivery system
C623S001230
Reexamination Certificate
active
06350278
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates generally to apparatus and methods for the endoluminal placement of tubular prostheses, such as grafts, stents, and other structures. More particularly, the present invention relates to a delivery catheter for the initial placing and optional repositioning of such intraluminal tubular prosthesis in body lumens such as blood vessels for the treatment of abdominal and other aneurysms.
Vascular aneurysms are the result of abnormal dilation of a blood vessel, usually resulting from disease and/or genetic predisposition which can weaken the arterial wall and allow it to expand. While aneurysms can occur in any blood vessel, most occur in the aorta and peripheral arteries, with the majority of aortic aneurysms occurring in the abdominal aorta, usually beginning below the renal arteries and often extending distally into one or both of the iliac arteries.
Aortic aneurysms are most commonly treated in open surgical procedures where the diseased vessel segment is bypassed and repaired with an artificial vascular graft. While considered to be an effective surgical technique, particularly considering the alternative of a usually fatal ruptured abdominal aortic aneurysm, conventional vascular graft surgery suffers from a number of disadvantages. The surgical procedure is complex and requires experienced surgeons and well equipped surgical facilities. Even with the best surgeons and equipment, however, patients being treated frequently are elderly and weakened from cardiovascular and other diseases, reducing the number of eligible patients. Even for eligible patients prior to rupture, conventional aneurysm repair has a relatively high mortality rate, usually from 3% to 10%. Morbidity related to the conventional surgery includes myocardial infarction, renal failure, impotence, paralysis, and other conditions. Additionally, even with successful surgery, recovery takes several weeks, and often requires a lengthy hospital stay.
In order to overcome some or all of these drawbacks, endovascular graft placement for the treatment of aneurysms has been proposed. Although very promising, many of the proposed methods and apparatus suffer from other problems. In particular, delivery and placement of the endovascular graft within the vasculature can be problematic. Proper positioning and sizing of the endovascular graft is critical to the successful treatment of an aneurysm. With many endovascular graft structures and their associated delivery catheters, however, it is difficult or impossible to retract a partially released graft structure. Thus, improper initial placement of a vascular graft can sometimes require open surgical procedures for correction. Additionally, proper sizing of the graft can require maintenance of a large inventory of graft delivery catheters, where each catheter carries a graft having a different length and/or expansible diameter.
For these reasons, it would be desirable to provide improved apparatus and methods for endovascular placement of intraluminal prosthesis, including both grafts and stents, for treating aneurysms and other conditions. It would be particularly desirable to provide delivery catheters and methods for the placement of endoluminal and other tubular prostheses which permit the repositioning and/or retrieval of partially released prostheses. It would be further desirable if such delivery catheters were able to contain the prosthesis firmly within the catheter until the final release of the prostheses into the blood vessel.
2. Description of the Background Art
Vascular grafts and devices for their endoluminal placement are described in U.S. Pat. Nos. 5,282,824; 5,272,971; 5,242,399; 5,219,355; 5,211,658; 5,201,757; 5,192,297; 5,190,058; 5,158,548; 5,147,370; 5,104,399; 5,092,877; 5,078,726; 5,019,085; 4,990,151; 4,950,227; 4,913,141; 4,886,062; 4,820,298; 4,787,899; 4,617,932; 4,562,596; 4,577,631; and 4,140,126; and European Patent Publications 539,237; 533,511; 518,839; 518,704; 508 473; 505,686; 466 518; and 461 791. Catheters for placing vascular stents are described in U.S. Pat. Nos. 5,192,297; 5,092,877; 5,089,005; 5,037,427; 4,969,890; and 4,886,062. Catheters carding a graft structure in a tube or capsule are described in U.S. Pat. Nos. 5,275,622; 5,104,399; and 4,787,899; and EP466518.
SUMMARY OF THE INVENTION
The present invention provides apparatus and methods for the endoluminal placement of intraluminal prostheses, including both grafts and stents, for the treatment of disease conditions, particularly aneurysms. The intraluminal prostheses will comprise a radially compressible, tubular frame having a proximal end, a distal end, and an axial lumen between said ends. In the case of graft prostheses, an inner liner, typically a fabric, polymeric sheet, membrane, or the like, will line all or most of the surface of the lumen of the tubular frame, usually extending from a near-proximal location to a near-distal location. Suitable graft structures for placement using the catheters and methods of the present invention are described in copending application Ser. No. 08/255,681, the full disclosure of which is incorporated herein by reference.
The intraluminal prostheses of the present invention are suitable for a wide variety of therapeutic uses, including stenting of the ureter, urethra, biliary tract, and the like. The devices and methods will also be useful for the creation of temporary or long term lumens, such as the formation of fistulas. The present invention will find its greatest use, however, in the placement of endovascular grafts into blood vessels for the treatment of abdominal and other aneurysms, vascular stenoses, and the like.
According to the present invention, a delivery catheter for positioning a radially compressible tubular prosthesis comprises an elongate flexible shaft having a proximal end and a distal end. A retaining structure is disposed near the distal end of the shaft and releasably holds the prosthesis to maintain the axial position of the prosthesis on the shaft. A sheath is slidably received over the shaft and radially compresses the prosthesis while the prosthesis remains axially held by the retaining structure. Alternatively, the retaining structure can comprise a separate cover structure which maintains radial compression of the prostheses as the sheath is proximally retracted.
The prosthesis can be partially released from the catheter into a blood vessel or other body lumen by axially retracting the sheath to allow the prosthesis to expand and conform to the interior surface of the lumen being treated. The prosthesis, however, will remain attached to the catheter shaft by the retaining structure, and so long as the prosthesis remains attached, it can be recaptured simply by distally advancing the sheath back over the expanded portion of the prosthesis to radially compress it back on to the underlying shaft. In this way, the prosthesis can be recaptured and optionally repositioned and rereleased. Alternatively, the prosthesis can be withdrawn from the body lumen entirely.
In order to facilitate release and optional recapture of the prosthesis relative to the catheter, the sheath is preferably provided with a flared distal end. In a first particularly preferred design, a mechanism will be provided for reconfiguring the distal end of the sheath between a non-flared configuration (maintained during introduction of the catheter to a target location in the body lumen) and a flared configuration. For example, an inflatable bladder may be provided at the distal end, where inflation of the bladder causes the distal end of the sheath to flare radially outward. Alternatively, the distal end may include a resilient structure having a fixed, outwardly flared configuration. During introduction of the catheter to the body lumen, the resilient flared end may be radially confined, e.g., by a slidable containment sleeve disposed over the sheath or by an axially translatable cap structure which can capture the flared end of the sheath. As yet another alternat
Evans Michael A.
Freislinger Kirsten
Lenker Jay A.
Murphy Richard O.
Ryan Timothy J.
Medtronic AVE Inc.
Milano Michael J.
Sterne Kessler Goldstein & Fox P.L.L.C.
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