Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Stent in combination with graft
Reexamination Certificate
1998-12-03
2002-04-09
O'Connor, Cary E. (Department: 3732)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Stent in combination with graft
C623S001340, C623S001350
Reexamination Certificate
active
06368345
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed generally to methods and apparatus for positioning an intraluminal graft. More specifically the present invention is related to methods and apparatus for positioning an intraluminal graft into a bifurcating vessel such as an artery.
2. Discussion of Related Technology
An artery or other vessel that is weakened by disease, injury, or congenital defect, can become distended due to the pressure of blood or other fluid flowing through the weakened area. In the vasculature, this distended weakening is called an aneurysm. An aneurysm typically occurs in the arterial vessels of the head, chest, or abdomen. The distension may cause the vessel to rupture, which can have serious, even life-threatening consequences.
Aneurysms in the abdominal aorta are typically distended around the circumference of the aorta and tapered at both ends. Most aneurysms of the abdominal aorta are caused by atherosclerotic weakening of a segment of the wall. Abdominal aneurysms may cause backache and severe pain, and may be visible as a throbbing swelling. If an abdominal aorta ruptures, it is seriously life threatening.
Traditionally, aneurysms have been treated by radical surgical graft replacement. This approach is risky for the patient and is sometimes not feasible due to other pre-existing disease states of the patient. More recently, aneurysms have been treated by placement of an intraluminal or endovascular graft. These intraluminal or endovascular grafts may be of various types, including grafts having stents, wireforms, or other attachment means attached to or integrated into the graft structure.
In general, intraluminal grafts and their respective support and/or attachment means fall into two major categories, self-expanding and pressure expandable. Self-expanding intraluminal grafts, are supported and/or attached via resilient or shape-memory material such as spring steel or Nitinol™. Self-expanding material is capable of being formed in a configuration from which it may be compressed to a radially compact diameter for placement within a damaged vessel. At the time of use, the memory feature of these materials causes them to self-expand from the radially compact diameter to the expanded operative diameter.
Pressure-expandable intraluminal grafts are supported and/or attached via plastically deformable material such as stainless steel that is initially formed in its radially compact diameter. This type of material does not have memory, and will remain in the radially compact diameter until manually expanded. Typically, outwardly directed pressure is exerted upon the graft through use of a balloon so as to cause radial expansion and resultant plastic deformation of the material to its operative diameter.
Careful positioning and firm implantation of the intraluminal graft is critical to the successful treatment of the underlying medical condition. This is particularly difficult to accomplish when the aneurysm extends from an artery into one or more divergent arteries. A “trouser graft” has been suggested for use in a first main artery and a pair of divergent arteries by White et al. in PCT Application Nos. WO 97/17910; WO 97/17911; WO 97/18006; WO 97/26936; and WO 97/26938; all of which are hereby incorporated herein by reference in their entireties. A trouser graft comprises a first tubular body that bifurcates into two smaller tubular bodies. In the referenced disclosures, the first tubular body is placed in first artery and the two smaller tubular bodies are placed so as to extend within the two divergent arteries.
Not with standing the important teachings of the foregoing references, features of the aforementioned device have recognized shortcomings that make them less than complete solutions to the treatment of aneurysms in the vasculature, or to the treatment of similar damage to other vessels. The present invention provides substantial improvements to the methods and apparatus of the prior art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved intraluminal graft and method for placement of same that diminishes deleterious kinking and twisting of the graft during and after placement thereof in a vessel.
It is another object of the present invention to provide an improved intraluminal graft and method for placement of same that provides control over inadvertent longitudinal movement within a vessel.
Another object of the present invention is to provide an improved intraluminal “trouser” graft and method for placement of same that precludes inadvertent separation of the legs of the trouser.
These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
To achieve the forgoing objects, and in accordance with the invention as embodied and broadly described herein, the present invention relates to new and useful apparatus and methods for placing a bifurcated graft at the site of a damaged vessel. In a preferred embodiment, the methods and apparatus of the present invention are directed to placement of a bifurcated graft within an aneurysm located in the abdominal aorta downstream of the renal arteries. Preferably, placement of the graft is through the right femoral artery of a patient.
An introducer assembly is provided which is configured for placement over a guidewire and for facilitating the advancement of various catheter assemblies required in connection with the practice of the invention. The introducer assembly includes a sheath, valve head, and a dilator. The sheath is preferably cylindrical in shape and is formed so as to have an appropriate flexibility and an outer diameter suitable for placement at the location of an aneurysm to be repaired. The valve head permits insertion and removal of various catheters during the method of the present invention without significant loss of blood from the femoral artery. The proximal end of the valve head is provided with a threaded connector which facilitates connection of the valve head to other catheters. The dilator, which includes a tapered tip, is placed during use through the valve head and the sheath so that the tapered tip portion protrudes from the sheath. The dilator tip portion is capable of being advanced gently through the tortuous pathway of the vasculature without causing undue trauma or a perforation, yet is also sufficiently stiff to cause the blood vessels to assume a less tortuous path.
Another component of the present invention is a bifurcated aortic graft. The preferred bifurcated aortic graft includes both self-expanding and balloon-expandable wireforms along its length. The balloon-expandable wires permit precision in placement of the aortic graft. The self-expanding wires open within the vessel immediately upon deployment from the main catheter assembly, which allows insertion of other modular components, opens a removal path for the inflatable balloons, and reduces kinking. The self-expanding wires also increase the anchoring force between the bifurcated graft and modular extension grafts used to extend the bifurcated graft into communication with non-distended vessel walls.
One of the self-expanding wireforms is located at a septum region of the bifurcated graft. The septum region separates an ipsilateral leg from a contralateral leg (“ipsilateral” and “contralateral” referring to opposite lateral sides of the patient depending on the surgical approach). This septum wire prevents and helps eliminate the kinks that are typically encountered with conventional bifurcated grafts. In addition, the self-expanding wireform at the septum region includes crimps functioning as radiopaque markers generally pointing to the septum region, which aids in identifying the location of the septum under fluoroscopy. Two additional self-expanding wireforms are located at the ends of each leg of the bifurcated graft. These wireforms facilitate opening the legs immedi
Dehdashtian Mark
White Geoffrey H.
Yu Weiyun
Canter Bruce M.
Edwards Lifesciences Corporation
Gluck Peter Jon
O'Connor Cary E.
Vascular Therapies Technologies
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