Aortic graft and method of treating abdominal aortic aneurysms

• US 6,162,246 A
• Filed: 02/16/1999
• Issued: 12/19/2000
• Est. Priority Date: 02/16/1999
• Status: Expired due to Term

• Current Assignee: Lavant International S.A.
• Original Assignee: Hector Daniel Barone
• Inventors: Barone, Hector Daniel
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): KING, ANTHONY S
• Application Number:
  US09/250,742
• Time in Patent Office: 672 Days
• Field of Search: 623/1.35, 623/1.11, 623/1.51, 623/12, 623/1, 128/898, 606/194, 606/108, 606/191, 606/198, 606/195, 604/96
• US Class Current: 623/1.35
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/89 the wire-like elements comprising two or more adjacent rings flexibly connected by separate members
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2002/065 Y-shaped blood vessels
• CPC Class Codes: A61F 2002/067 modular
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2002/9583 Means for holding the stent on the balloon, e.g. using protrusions, adhesives or an outer sleeve

Abstract

An aortic graft and method for treatment of abdominal aortic aneurysms by inserting into the aorta and into the iliac arteries of the patient the graft in a way to exclude the aneurysm from the blood circulatory system, the graft comprising a tubular hollow fabric material including a trunk portion and at least one leg portion capable of being accommodated to any rotation of the graft resulting from the installation of the graft and to any varying ratio between the diameters of an aortic neck and the iliac arteries, the graft being also adapted to different shapes of the aorta, thus diminishing and even avoiding the risks of misplacing the graft inside the aorta. The trunk also includes an inelastic edge to retain a stent in an expanded condition to attach the trunk and the leg portions together.

Claims

1. An aortic graft for treatment of abdominal aortic aneurysms, the graft comprising a tubular hollow material for intraluminal insertion in the aorta, the aorta having an upper proximal aortic neck and a distal aortic lower portion forming an iliac bifurcation dividing into two iliac arteries, the graft comprising:

a compliant graft main portion having a generally cylindrical shape with an upper end for secure attachment to the aortic proximal neck, and a lower free end constructed so as to wholly reside at a position inside the aneurysm and above the iliac bifurcation, and

at least one compliant graft iliac leg portion having a generally elongated cylindrical shape with a lower end for secure attachment to one of the iliac arteries, and an upper end for secure attachment in fluid communication to the lower end of the graft main portion.

2. The graft of claim 1, wherein the graft leg portion has a diameter slightly larger than the diameter of the graft main portion, the diameter of the graft main portion decreasing towards the lower end thereof to securely receive the upper end of the graft leg portion inside the lower end of the graft main portion.

3. The graft of claim 2, wherein the upper end of the graft leg portion is retained within the lower end of the graft main portion by anchoring means.

4. The graft of claim 3, wherein the anchoring means is fixed into the upper end of the graft leg portion and is securely attached to the graft main portion by a radially expandable balloon removably placed by a catheter, whereby the anchoring means is implantable by expansion against the graft main portion, at an overlap between the lower end of the graft main portion and the upper end of the graft leg portion, both ends being securely retained to each other.

5. The graft of claim 4, wherein anchoring means is fixedly located into the lower end of the graft leg portion and is securely attached to the iliac artery by a radially expandable balloon removably positioned by the catheter, whereby the anchoring means is implantable by expansion against the artery.

6. The graft of claim 2, wherein the upper end of the graft leg portion is retained within the lower end of the graft main portion by a diameter interference.

7. A method of treating abdominal aortic aneurysms with the graft of claim 1, comprising the steps of:

inserting a guide wire in a blood vessel at a site remote to the site of an aorta affected by the aneurysm and moving the guide wire to make it enter the aneurysm by the aortic upper neck,

inserting the graft main portion over the guide wire by means of a positioning device entering the aneurysm by an iliac artery, the positioning device including at least one expandable balloon, with the graft main portion being maintained in a compressed condition inside the positioning device with least the upper end of the graft main portion located over the balloon,

positioning the graft inside the aorta at the site of the aneurysm and deploying the graft main portion by inflating the balloon, whereby the upper end of the graft main portion is securely attached to the proximal upper aortic neck,

downwardly removing the positioning device,

permitting the lower end of the graft main portion to freely rotate relative to the upper end of the graft main portion to unfold/untwist and accommodate any rotation of the upper end generated during deploying and installation of the main graft, whereby the lower end remains in a floating or moving free relaxed condition after the upper end of the main portion has been attached to the aorta, and

introducing the same positioning device or a new positioning device over the guide wire, the positioning device carrying at least one balloon and the graft leg portion in a compressed condition with at least the upper end of the graft leg portion over the balloon of the positioning device, and deploying the graft leg portion by inflating at least one balloon when the upper end of the graft leg portion is inside the lower end of the graft main portion and the lower end of the leg portion is inside a corresponding iliac artery, whereby the ends of the graft leg portion are radially expanded and securely attached against the lower end of the graft main portion and the corresponding iliac artery, with the graft main and leg portions being connected in fluid flow communication.

8. The method of claim 7, wherein the upper end of the graft leg portion is provided with anchoring means capable of being expanded by the balloon and remains in the expanded condition to retain the upper end of the graft leg portion against the lower end of the graft main portion.

9. The method of claim 8, wherein the expansion of the anchoring means at the upper end of the graft leg portion is carried out simultaneously with an expansion of anchoring means located at least at the lower end of the graft leg portion, whereby the lower end of the graft leg portion is implanted within and against one of the iliac arteries simultaneously with the attaching of the upper end of the graft leg portion to the lower end of the graft main portion.

10. The graft of claim 1, wherein anchoring means are provided at the upper end of the graft main portion and at the upper and lower ends of the graft leg portion.

11. The graft of claim 10, wherein the anchoring means are of a resilient self-expanding type.

12. A method of treating abdominal aortic aneurysms with the graft of claim 11, comprising the steps of:

inserting a guide wire in a blood vessel at a site remote to the site of an aorta affected by the aneurysm and moving the guide wire to make it enter the aneurysm by the upper aortic neck,

inserting the graft main portion over the guide wire by means of a positioning device entering the aneurysm by an iliac artery, the positioning device including the graft main portion and a self-expanding anchoring means maintained in a compressed condition inside the positioning device,

positioning the graft main portion inside the aorta at the site of the aneurysm and deploying the graft main portion by permitting the expandable anchoring means to freely expand, whereby the upper end of the graft main portion is securely attached to the proximal aortic neck while the lower end of the graft main portion remains free to rotate,

downwardly removing the positioning device,

permitting the lower end of the graft main portion to rotate relative to the upper end of the graft main portion, to accommodate any rotation of the main portion generated during deployment and installation thereof, whereby the lower end of the main portion remains in a relaxed condition after the upper end of the main portion has been attached to the aorta, and

introducing the same positioning device or a new positioning device over the guide wire, the positioning device being inserted by the iliac artery and carrying the graft leg portion with associated self-expanding anchoring means in a compressed condition, and deploying the graft leg portion by permitting the anchoring means to freely expand when the upper end of the graft leg portion is inside the lower end of the graft main portion and the lower end of the leg portion is inside the iliac artery, whereby the ends of the graft leg portion are radially expanded and securely attached against the lower end of the graft main portion and the iliac artery, with the graft main and leg portions being connected in fluid flow communication.

13. The graft of claim 1, comprising an inelastic woven material, the graft main portion having a generally cylindrical shape with a lower portion tapered towards the lower end of the main portion, the upper end of the leg portion being retained within the tapered lower portion by anchoring means.

14. The graft of claim 1, comprising an inelastic woven material, the graft main portion having a generally cylindrical shape with a lower end of the main portion being a cone-shaped portion the diameter of which decreases towards a lower edge of the main portion, the upper end of the leg portion being retained within the tapered lower end by anchoring means.

15. A method for intraluminally positioning and implanting an aortic graft according to claim 1, by acceding to an aorta through any blood vessel connected to the aorta, preferably an iliac artery, wherein the graft is implanted by first placing a main portion of the graft against an upper proximal aortic neck and then installing a secondary leg portion in the corresponding iliac artery and connecting the main and leg graft portions to each other inside the aorta, whereby the leg portion is attached to the iliac artery and to the main portion once any rotation of the main portion, produced by the deployment and installation of the main portion, has already occurred, whereby no rotation or twisting of the graft main portion is transferred to the graft leg portion.

16. An aortic bifurcated graft for treatment of abdominal aortic aneurysms, the graft comprising a tubular hollow material for intraluminal insertion in the aorta, the aorta having an upper proximal aortic neck and a lower distal portion defining an aortic bifurcation dividing into two iliac arteries, the graft comprising:

a compliant graft trunk portion made of a flexible fabric material, the portion having a generally cylindrical shape with an upper end for secure attachment to the aortic proximal neck, and a lower bifurcated short portion forming two lower side-by-side connecting ends, the connecting ends constructed so as to wholly reside inside the aorta and upwardly and spaced apart from the aortic bifurcation, and

a pair of compliant graft iliac leg portions made of a flexible fabric material, each portion having a generally elongated cylindrical shape with a lower end for secure attachment to one of the iliac arteries, and an upper end for secure connection in fluid communication to a respective one of the lower connecting ends of the lower bifurcated portion of the trunk portion.

17. A method of treating abdominal aortic aneurysms with the graft of claim 16, comprising the steps of:

inserting a guide wire in a blood vessel at a site remote to the site of an aorta affected by the aneurysm and moving the guide wire to enter the aneurysm by the upper aortic neck,

inserting the graft trunk portion over the guide wire by means of a trunk-positioning device entering the aneurysm by an iliac artery and including at least one expandable balloon, with the graft trunk portion being maintained in a compressed condition inside the positioning device with at least the upper end of the graft trunk portion located over the balloon,

positioning the graft trunk portion inside the aorta at the site of the aneurysm and deploying the graft trunk portion by inflating the balloon, whereby the upper end of the graft trunk portion is securely attached to the proximal aortic neck while the lower connecting ends of the graft trunk portion remain inside the aorta and above the aortic bifurcation,

downwardly removing the trunk-positioning device and upwardly moving the guide wire inside the installed graft trunk portion and above the connecting ends,

permitting the lower connecting ends of the graft trunk portion to follow any rotation of the upper end of the graft trunk portion generated by the balloon during inflation thereof, whereby the lower connecting ends remain in a free moving or floating relaxed condition after the upper end of the trunk portion has been attached to the aorta, without the trunk portion being affected by any twisting effect,

introducing the guide wire through one of the connecting ends and making the guide wire enter one of the iliac arteries,

introducing a leg-positioning device over the guide wire passing through the one connecting end of the trunk portion and the one iliac artery, the leg-positioning device carrying at least one balloon and one graft leg portion in a compressed condition with the upper end of the graft leg portion over the balloon of the leg-positioning device, and deploying the graft leg portion by inflating the balloon when the upper end of the graft leg portion is inside the one lower connecting end of the graft trunk portion and the lower end of the leg portion is inside the one iliac artery, whereby at least the upper end of the graft leg portion is radially expanded and securely attached against the one lower connecting end of the graft main portion and the iliac artery, with the graft trunk and leg portions being connected in fluid flow communication,

downwardly removing the leg-positioning device and upwardly removing the guide wire,

introducing a guide wire through the upper end of the installed trunk portion and make the guide wire pass through the other of the connecting ends and enter the other of the iliac arteries,

introducing another leg-positioning device over the guide wire passing through the other connecting end and the other iliac artery, the another leg-positioning device carrying another graft leg portion in a compressed condition with at least the upper end of the graft leg portion over the balloon of the another leg-positioning device, and deploying the graft leg portion by inflating the balloon when the upper end of the graft leg portion is inside the other lower connecting end of the graft trunk portion and the lower end of the leg portion is inside the other iliac artery, whereby at least the upper end of the graft leg portion are radially expanded and securely attached against the other lower connecting end of the graft trunk portion and the other iliac artery, with the graft trunk portion and the other leg portion being connected in fluid flow communication, and downwardly removing the positioning device and upwardly removing the guide wire.

18. The method of claim 17, wherein the upper end of each graft leg portion is provided with anchoring means each capable of being expanded by a balloon and remains in the expanded condition to retain the respective upper end of the graft leg portion against the respective lower connecting end of the graft trunk portion.

19. The method of claim 18, wherein the expansion of the anchoring means at the upper end of each graft leg portion is carried out simultaneously with an expansion, made by the balloon, of anchoring means located at least at the lower end of each graft leg portion, whereby the lower end of each graft leg portion is implanted within and against a respective one of the iliac arteries simultaneously with the attaching of the upper end of each graft leg portion to the respective one of the lower connecting ends of the graft trunk portion.

20. The method of claim 17, wherein the guide wire enters the graft trunk portion through the upper end of the trunk portion, while the positioning devices enter the graft over the guide wire, through the connecting ends, via corresponding femoral arteries.

21. A method of treating abdominal aortic aneurysms with the graft of claim 16, comprising the steps of:

inserting a guide wire in a blood vessel at a site remote to the site of an aorta affected by the aneurysm and moving the guide wire to enter the aneurysm by the upper aortic neck,

inserting the graft trunk portion over the guide wire by means of a trunk-positioning device entering the aneurysm by an iliac artery and including at least one expandable balloon, with the graft trunk portion being maintained in a compressed condition inside the trunk-positioning device with at least the upper end of the graft trunk portion located over the balloon,

positioning the graft trunk portion inside the aorta at the site of the aneurysm and deploying the graft trunk portion by inflating the balloon, whereby the upper end of the graft trunk portion is securely attached to the proximal aortic neck while the lower connecting ends of the graft trunk portion remain inside the aorta and above the aortic bifurcation,

downwardly removing the trunk-positioning device and upwardly moving the guide wire within the installed graft trunk portion and above the connecting ends,

permitting the lower connecting ends of the graft trunk portion to rotate, following any rotation of the upper end of the graft trunk portion, generated during the inflation of the balloon, whereby the lower connecting ends remain in a free moving/floating relaxed condition after the upper end of the trunk portion has been attached to the aorta, without the trunk portion being affected by any twisting effect,

introducing the guide wire through one of the connecting ends and making the guide wire enter one of the iliac arteries,

introducing a leg-positioning device over the guide wire passing through the one connecting end and the one iliac artery, the leg-positioning device carrying at least one balloon and a graft leg portion in a compressed condition with at least the upper end of the graft leg portion over the balloon of the leg-positioning device,

moving the guide wire out of the positioning device and above the connecting ends and simultaneously placing a new guide wire inserted into the leg-positioning device through a rear end of the leg-positioning device, while the leg-positioning device remains inside the trunk portion,

downwardly moving the guide wire through the upper end of the installed trunk portion and making the guide wire pass through the other of the connecting ends and enter the other of the iliac arteries,

introducing another leg-positioning device over the guide wire passing through the other connecting end and the other iliac artery, the another leg-positioning device carrying at least one balloon and another graft leg portion in a compressed condition with at least the upper end of the graft leg portion over the balloon of the positioning device,

deploying the graft leg portions by inflating the balloons when the upper ends of the graft leg portions are inside the corresponding lower connecting ends of the graft trunk portion and the lower ends of the leg portions are inside the iliac arteries, whereby at least the upper end of the graft leg portions are radially expanded and securely attached against the lower connecting ends of the graft trunk portion, with the graft trunk portion and the leg portions being connected in fluid flow communication, and

downwardly removing the leg-positioning devices and the new guide wire, while the guide wire is upwardly removed.

22. The method of claim 21, wherein the upper end of each graft leg portion is provided with anchoring means each capable of being expanded by a balloon and remain in the expanded condition to retain the respective upper end of the graft leg portion against the respective lower connecting end of the graft trunk portion.

23. The method of claim 22, wherein the expansion of the anchoring means at the upper end of each graft leg portion is carried out simultaneously with an expansion, made by one balloon, of anchoring means located at least at the lower end of each graft leg portion, whereby the lower end of each graft leg portion is implanted within and against a respective one of the iliac arteries simultaneously with the attaching of the upper end of each graft leg portion to the respective one of the lower connecting ends of the graft trunk portion.

24. The method of claim 21, wherein the guide wire enters the graft trunk portion through the upper end of the trunk portion and the positioning devices are introduced by the connecting ends, via corresponding femoral arteries.

25. The graft of claim 16, wherein the upper end of each graft leg portion is retained within an associated one of the lower connecting ends of the graft trunk portion by anchoring means.

26. The graft of claim 25, wherein the anchoring means is fixedly located into the upper end of each graft leg portion and is securely attached to the graft trunk portion by a radially expandable balloon removably positioned by a catheter, whereby the anchoring means is implantable by expansion against one associated connecting end of the graft trunk portion, at an overlap between the lower connecting end of the trunk portion and the upper end of the graft leg portion, both ends being securely retained to each other in fluid communication.

27. The graft of claim 26, wherein anchoring means is also fixedly located into at least the lower end of each graft leg portion and is securely attached to the respective iliac artery by a radially expandable balloon removably positioned by a catheter, whereby the anchoring means is implantable by expansion against the artery.

28. The graft of claim 16, wherein anchoring means are provided at the upper end of the trunk portion and at the upper and lower ends of the leg portions.

29. The graft of claim 28, wherein the anchoring means are of a resilient self-expandable type.

30. A method of treating abdominal aortic aneurysms with the graft of claim 29, comprising the steps of:

inserting a guide wire in a blood vessel at a site remote to the site of an aorta affected by the aneurysm and moving the guide wire to enter the aneurysm by the upper aortic neck,

inserting the graft trunk portion over the guide wire by means of a trunk-positioning device with the graft trunk portion and associated self-expanding anchoring means being maintained in a compressed condition inside the trunk-positioning device,

positioning the graft trunk portion inside the aorta at the site of the aneurysm and deploying the graft trunk portion by permitting the anchoring means to radially expand, whereby the upper end of the graft trunk portion is securely attached to the proximal aortic neck while the lower connecting ends of the graft trunk portion remain inside the aorta and at a position above the aortic bifurcation,

downwardly removing the trunk-positioning device and upwardly moving the guide wire within the installed graft trunk portion and above the connecting ends,

permitting the lower connecting ends of the graft trunk portion to follow any rotation of the upper end of the graft trunk portion, generated by the expansion of the anchoring means, whereby the lower connecting ends remain in a relaxed condition after the upper end of the trunk portion has been attached to the aorta,

introducing the guide wire through one of the connecting ends and making the guide wire enter one of the iliac arteries,

introducing a leg-positioning device over the guide wire passing through the one connecting end and the one iliac artery, the leg-positioning device carrying one graft leg portion with associated self-expanding anchoring means in a compressed condition,

moving the guide wire out of the positioning device and above the connecting ends and simultaneously placing a new guide wire inserted into the leg-positioning device through a rear end of the leg-positioning device, while the leg-positioning device remains inside the trunk portion,

downwardly moving the guide wire through the upper end of the installed trunk portion and make the guide wire pass through the other of the connecting ends and enter the other of the iliac arteries,

introducing another leg-positioning device over the guide wire passing through the other connecting end and the other iliac artery, the another leg-positioning device carrying another graft leg portion with associated self-expanding anchoring means in a compressed condition,

deploying the graft leg portions by permitting the expandable anchoring means to freely expand the upper ends of the graft leg portions when they are inside the lower connecting ends of the graft trunk portion and the lower ends of the leg portions are inside the iliac arteries, whereby at least the upper end of the graft leg portions are radially expanded and securely attached against the lower connecting ends of the graft main portion, with the graft trunk portion and the leg portions being connected in fluid flow communication, and

downwardly removing the leg-positioning devices and the new guide wire, while the guide wire is upwardly removed.

31. The graft of claim 16, wherein each graft leg portion has a diameter slightly larger than the diameter of the corresponding lower connecting end of the trunk portion, whereby the upper end of a leg portion can be expanded and tightly sealably received inside a corresponding lower connecting end of the trunk portion.

32. The graft of claim 16, wherein the upper end of each graft leg portion is retained within an associated one of the lower connecting ends of the graft trunk portion by diameter interference.

33. The graft of claim 16, comprising an inelastic woven material, the graft trunk portion having a generally cylindrical shape with the lower connecting ends tapered by the diameter of each connecting end downwardly decreasing, the upper end of each leg portion being retained within the tapered lower connecting end of the trunk portion by anchoring means.

34. A method for intraluminally positioning and implanting an aortic bifurcated graft according to claim 16, by acceding to an aorta through a blood vessel, preferably a femoral artery, wherein the bifurcated graft is implanted by first placing a main trunk portion of the graft against an upper proximal aortic neck and then installing two leg portions in corresponding iliac arteries and connecting the main trunk portion to the leg portions, the trunk and leg portions being installed by inflating respective balloons to expand the portions, whereby each leg portion is attached to the trunk portion once any rotation and twisting of the trunk portion, produced by inflation of the balloon during the deployment and installation of the trunk portion, had already disappeared, whereby no rotation or twisting of the graft trunk portion is transferred to the graft leg portions.

35. An aortic graft for treatment of abdominal aortic aneurysms, the graft comprising a tubular hollow material to be intraluminally inserted in the aorta, the aorta having an upper proximal aortic neck and a distal aortic lower portion forming an iliac bifurcation dividing into two iliac arteries, the graft comprising:

a graft main portion having an upper end to be securely attached to the aortic proximal neck, and a lower end hanging free at a position inside the aneurysm an above the iliac bifurcation, and

at least one graft iliac leg portion having a generally elongated cylindrical shape with a lower end to be securely attached to one of the iliac arteries, and an upper end to be securely connected in fluid flow communication to the lower end of the graft main portion,

at least the main graft portion being made of a compliant, elastic knitted material, and

the main portion terminating in an inelastic lower edge, whereby the upper end of the leg portion may be retained within the lower portion of the main portion by anchoring means, with the inelastic edge encircling the upper end of the graft leg portion and at least part of the anchoring means remaining within the graft main portion upwardly of the inelastic edge.

36. The graft of claim 35, wherein the inelastic edge is formed by an inelastic thread passing through the elastic knitted material of the graft main portion, whereby all the graft main portion is elastic except the inelastic edge of the lower end.

37. The graft of claim 36, wherein a thread is threaded around the upper end of the graft main portion, the thread being loosely threaded so that the upper end of the graft main portion keeps its elastic characteristics to be securely attached against the aortic proximal neck by an expandable anchoring means implanted therein by and expandable balloon and a catheter.

38. A method for treating abdominal aortic aneurysms by installing inside the aorta the graft according to claim 36, the method comprising the steps of:

making a knot in free ends of the thread passing through the knitted material at the lower inelastic edge to define a predetermined maximum diameter of the inelastic edge,

placing the main graft portion inside the aorta whereby the portion is firmly retained against the upper aortic neck with a lower edge of the graft main portion freely moving inside the aneurysm,

inserting the upper end of the leg portion inside the lower portion of the main graft portion, and

expanding the anchoring means of the leg portion once the anchoring means are at least partially inside the lower portion of the graft main portion, whereby the anchoring means defining, in the expanded condition and in at least a section thereof upwardly the thread knotted in the lower inelastic edge, a maximum diameter larger than the predetermined maximum diameter of the inelastic edge, whereby the upper end of the leg portion may be retained within the lower portion of the main portion by the anchoring means, with the inelastic edge encircling the upper end of the graft leg portion and the anchoring means remaining, at least partially, within the graft main portion upwardly of the inelastic edge.

39. The graft of claim 35, wherein the graft is a bi-iliac graft with the graft main portion having a generally cylindrical bifurcated shape, assembling a pair of pants with two pending legs.

40. The graft of claim 39, wherein the inelastic edge is formed by an inelastic thread passing through the elastic knitted material of the graft main portion, at a lower edge of one of the legs of the pants, an additional inelastic thread passing through the knitted material in the other leg at a point of bifurcation of the two pending legs of the pants, whereby the other pending leg of the pants may be closed to the blood flow to convert the bifurcated graft into one monoiliac aortic graft.

41. The graft of claim 35, wherein the graft main portion has a generally cylindrical shape with the lower portion thereof being tapered towards the lower edge of the main portion.

42. A method for treating abdominal aortic aneurysms by installing inside the aorta the graft of claim 35, the method comprising the steps of:

placing the main graft portion inside the aorta whereby the portion is firmly retained against the upper aortic neck with a lower edge of the graft main portion freely moving inside the aneurysm,

inserting the upper end of the leg portion inside the lower portion of the main graft portion, and

expanding the anchoring means of the leg portion once the anchoring means are at least partially inside the lower portion of the graft main portion, whereby the anchoring means defining, in the expanded condition, and in at least a section thereof upwardly the inelastic edge, a maximum diameter larger than the predetermined maximum diameter of the inelastic edge, whereby the upper end of the leg portion may be retained within the lower portion of the main portion by the anchoring means, with the inelastic edge encircling the upper end of the graft leg portion and the anchoring means remaining, at least partially, within the graft main portion upwardly of the inelastic edge.