Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Bifurcated
Reexamination Certificate
1999-04-06
2003-02-25
Isabella, David J (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Bifurcated
C623S001160
Reexamination Certificate
active
06524336
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to medical devices and more particularly to grafts for repairing aneurysms.
BACKGROUND OF THE INVENTION
The endovascular approach to aneurysms of the abdominal aorta is a new technique for the therapy of aneurysms by the placement of grafts which are transferred to the position of placement by means of the vascular lumen from easily anatomically approachable regions, thus avoiding the need for open surgical operations. For the effective therapy of an aneurysm by this technique, it is necessary to have good circumferential application (contact) of the endovascular graft with the healthy, nondistended part of the blood vessel, so as to have complete exclusion of the distended arterial lumen by the pressure of the systemic arterial circulation, since the blood will now come out through the graft which substitutes for the vascular lumen. Furthermore, the endovascular graft must have a small initial diameter, which will allow its easy introduction and advancement from the entrance blood vessel to the position of placement, as well as its easy technical positioning. In abdominal aortic aneurysms there usually is a central neck region of the healthy blood vessel having a normal diameter underneath the renal vessels (at the point where the graft is surgically attached even by the classical operation). However, often the aortic distention is peripherally extended to the point of the aortic bifurcation at the two iliac arteries. This fact excludes the possibility of placing an endovascular tube graft due to the absence of a healthy peripheral contact point (neck). This often creates the necessity for the placement of endovascular grafts which can be attached to healthy regions of the iliac arteries more peripherally positioned to the distended aortic bifurcation with the simultaneous branching of the aortic blood flow to two cylinders of effluence. The systems that till now have been presented for the placement of aortic stent grafts are composed , first off, of a stent graft or of grafts comprised of two parts that are often complicated in their placement, have a large compressed size, and have imperfections in their support mechanisms and at their point of contact with the vascular wall. These result in the appearance of immediate or future complications or in the inability of placement for a sufficient number of circumstances.
Furthermore, it is a device that, when combined with the fact that it has a limited number of parts, can serve a large number of circumstances of different anatomical dimensions.
SUMMARY OF THE INVENTION
In one aspect of the invention, the graft arrangement comprises a main graft having a proximal end and a distal end, the main graft further having a proximal orifice to be located in and when expanded to be supported by a vascular vessel the main graft also having at least one distal orifice which when expanded serves to receive a proximal end of at least one expandable peripheral artery graft, wherein the main graft and the at least one expandable peripheral artery graft each comprises an expandable stent and at least one cover over and/or in the expandable stent; and wherein a cross-sectional area of one of the at least one distal orifice and the proximal end of a second at least one expandable peripheral artery graft, when expanded is sufficiently less than that second another cross-sectional area of the at least one distal orifice and the proximal end of the at least one expandable peripheral artery graft so as to form a seal between the grafts.
In another aspect, the distal end of the main graft has a part which is extended to form an iliac artery graft. Another part of the main graft has a distal opening or orifice which has a short inclined extension subtended in a distal direction so as to enable an iliac artery graft to be located therein when the short extension has been expanded. Such iliac artery graft has a proximal end which when expanded forms a seal with the short extension.
In another aspect, the distal end of the main graft has first and second or a pair of short extensions, one extension having the at least one distal orifice of the main graft, and the other extension having another distal orifice for the receipt of a respective iliac artery graft. Each of the iliac artery grafts will have a stent expandable to a cross-sectional area sufficiently greater than the cross-sectional area(s) of the distal orifices so that effective seals are formed.
In still another aspect, the graft arrangement includes an additional graft endovascularly inserted into the part of the aorta adjacent to the renal arteries, wherein the additional graft has, when expanded, a distal orifice region of cross-sectional area(s) less than that of the proximal orifice region so as to provide reinforcement and support for the proximal end of the main graft. The additional graft includes an expandable stent and at least one cover over and/or in the stent. Furthermore, the stent(s) of the additional part includes spikes, barbs, or hooks to facilitate securement to the part of the aorta adjacent to renal arteries. By way of example, the reinforcement is provided by folds in an internally folded cover to provide an increased fitness of cover material. The external cover has a proximal extension on the outer member of each seal whereby the extension is designed to be folded over the proximal end of the outer member and entering the proximal end of the internal member of each seal. As a result, such folded-over cover provides an extra sealing benefit.
The main graft can be selected to be of a length to extend from the said part to the bifurcation region where the aorta joins the iliac arteries. Alternatively, the main graft can be of a length such that it extends only across the said part. The part of the main graft in the region of the distal orifice is reinforced in order to support the iliac artery grafts when expanded. It is preferred for these stents to be self expanding. The cover at the distal end of the main graft preferably extends beyond the distal orifice so that after the iliac grafts have been inserted and expanded, the extension to the cover enters the interior of the iliac grafts and forms an extra seal therewith. The stent of the main graft can comprise spikes, hooks, or barbs designed to enter the wall of the said part in order to assist in the attachment of that graft to the said part.
REFERENCES:
patent: 5609627 (1997-03-01), Goicoechea et al.
patent: 5632763 (1997-05-01), Glastra
patent: 5632772 (1997-05-01), Alcime et al.
DeBruyne Michael P.
DeFord John A
Papazolgou Konstantinos O.
Rasmussen Erik E.
Cook Incorporated
Godlewski Richard J.
Isabella David J
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