Endoleak mitigator for aneurysm stent-graft

1. An endoprosthesis for repair of aneurysm in an artery that has an arterial bifurcation for blood to flow downstream from the artery to the bifurcation, the endoprosthesis comprising:

a main body configured to be placed in an artery upstream of the arterial bifurcation, the main body having a cranial end with an anchor portion connected to a fabric portion of the main body, the fabric portion having inner and outer surfaces, the fabric portion being connected to a first plurality of spaced apart stent hoops, the main body extending from the cranial end along a longitudinal axis into two tubular legs wherein each of the legs including respective second and third plurality of spaced apart stent hoops coupled to the fabric portion of each leg;

a leak mitigator stent frame disposed adjacent the anchor portion within the inner surface of the fabric portion such that when the leak mitigator stent frame is in an expanded configuration, the leak mitigator stent frame is disposed on an inner circumferential surface of the fabric portion about the longitudinal axis with a first portion of the leak mitigator stent frame coupled to the fabric portion to allow circumferential movement of the leak mitigator stent frame relative to the fabric portion, the leak mitigator stent frame having a second portion not coupled to the fabric portion so that when the leak mitigator stent frame is in an unexpanded and compressed configuration, the leak mitigator stent frame defines a spiral configuration about the longitudinal axis while confined by the inner surface of the fabric portion; and

in which, the leak mitigator stent frame comprises two side by side circumferential frame rails with a zig-zag member connected to the two side-by-side circumferential frame rails at respective apices of the zig zag member, the two side by side circumferential frame rails are coupled to the fabric portion while moveable circumferentially will respect to the longitudinal axis to allow the leak mitigator stent to expand from the spiral configuration to a fully expanded generally circular configuration.

2. The endoprosthesis of claim 1 , in which the two side by side circumferential frame rails are coupled to the fabric portion via a suture configured to allow for circumferential movement of the leak mitigator stent frame relative to the fabric portion and the longitudinal axis, and to allow the mitigator stent frame to expand from the spiral configuration to a fully expanded generally circular configuration.

3. The endoprosthesis of claim 2 , further comprising a first tubular extension configured for insertion into one of the two legs and a second tubular extension configured for insertion into the other of the two legs.

4. The endoprosthesis of claim 2 , in which the leak mitigator stent frame provides approximately 0.4 N/cm in an outward chronic force and approximately 1.7 N/cm for a radial resistive force.

5. The endoprosthesis of claim 1 , in which the leak mitigator stent frame comprises a shape memory material.

6. The endoprosthesis of claim 5 , in which the shape memory material comprises nitinol.

7. The endoprosthesis of claim 1 , further comprising sutures extending through the fabric portion to secure each of the first, second, and third plurality of spaced apart stent hoops to the graft.

8. The endoprosthesis of claim 1 , in which the first, second, and third plurality of spaced apart stent hoops are not connected to each other by the same material as that of each of the first, second and third plurality of stent hoops.

9. The endoprosthesis of claim 1 , wherein each of the first, second, and third plurality of spaced apart stent hoops are disposed on the inner surface of the fabric portion.

10. The endoprosthesis of claim 1 , in which the first, second, and third plurality of spaced apart stent hoops are not connected to each other by the same material of the first, second, or third plurality of stent hoops or the leak mitigator stent frame.