Assembly for treating branched vessels

1. A stent graft assembly comprising:

a. a first prosthesis comprising:

i. a main body formed of biocompatible graft material having a proximal end, a distal end, a length from the proximal end to the distal end, and a main lumen extending between the proximal and distal ends, wherein the main lumen comprises a single lumen extending the length of the main body;

ii. a bifurcated portion extending distally from the main body, the bifurcated portion comprising a first tubular portion defining a first lumen and a second tubular portion defining a second lumen, wherein the first and second lumens are in communication with the main lumen, wherein the bifurcated portion defines a continuous figure eight cross-section from a proximal end of the bifurcated portion to a distal end of the bifurcated portion, wherein the first and second lumens are different sized lumens; and

iii. wherein the main body portion tapers continuously inwardly from the bifurcated portion to a proximal free end of the main body at a first angulation, wherein the proximal free end of the main body defines a proximal most opening;

b. a second prosthesis comprising:

i. a tubular body of biocompatible graft material having a proximal end and a flared distal end portion, the flare tapering outwardly to the distal end at a second angulation;

c. wherein the flared distal end portion of the second prosthesis overlaps with the tapered main body of the first prosthesis to sealingly engage with the tapered main body of the first prosthesis;

d. a third prosthesis configured to receive the second prosthesis in an overlapping relationship comprising:

i. a main body formed of biocompatible graft material having a proximal end and a distal end and a main lumen extending therebetween wherein the main lumen comprises a single lumen extending the length of the main body;

ii. a bifurcated portion including two limbs extending distally from the main body, the bifurcated portion comprising a first tubular portion defining a first lumen and a second tubular portion defining a second lumen, wherein the first and second lumens are in communication with the main lumen, wherein each of the two limbs has a distal end opening; and

iii. wherein a distal end opening of one of the limbs is configured to receive the proximal end of the second prosthesis.

2. The assembly of claim 1 wherein the first angulation of the distal flare of the second prosthesis substantially corresponds to the second angulation of the taper of the main body of the first prosthesis.

3. The assembly of claim 1 wherein the first prosthesis is configured to be deployed in a common iliac artery, wherein the first tubular portion of the first prosthesis is configured to face an ostium of an external iliac artery and the second tubular portion of the first prosthesis is configured to face an ostium of an internal iliac artery.

4. The assembly of claim 1 wherein the first tubular portion of the first prosthesis defines a socket for receiving a first connection stent graft.

5. The assembly of claim 4 wherein the first connection stent graft is adapted for placement in an external iliac artery.

6. The assembly of claim 1 wherein the second tubular portion of the first prosthesis defines a socket for receiving a second connection stent graft.

7. The assembly of claim 6 wherein the second connection stent graft is adapted for placement in an internal iliac artery.

8. A method for treating a diseased vessel comprising an aorta branching into first and second common iliac arteries, the method comprising:

a. introducing a first prosthesis into a patient's vasculature, the first prosthesis comprising:

i. a main body formed of biocompatible graft material having a proximal end and a distal end and a main lumen extending therebetween wherein the main lumen comprises a single lumen extending the length of the main body;

ii. a bifurcated portion including two limbs extending distally from the main body, the bifurcated portion comprising a first tubular portion defining a first lumen and a second tubular portion defining a second lumen, wherein the first and second lumens are in communication with the main lumen, wherein each of the two limbs has a distal end opening;

b. positioning the first prosthesis such that the main body of the first prosthesis resides in the aorta and one or both of the limbs resides in a respective common iliac artery;

c. introducing a second prosthesis into a patient's vasculature, the second prosthesis comprising:

i. a main body formed of biocompatible graft material having a proximal end, a distal end, a length from the proximal end to the distal end, and a main lumen extending between the proximal and distal ends, wherein the main lumen comprises a single lumen extending the length of the main body;

ii. a bifurcated portion extending distally from the main body, the bifurcated portion comprising a first tubular portion defining a first lumen and a second tubular portion defining a second lumen, wherein the first and second lumens are in communication with the main lumen, wherein the bifurcated portion defines a continuous figure eight cross-section from a proximal end of the bifurcated portion to a distal end of the bifurcated portion and defines two different sized lumens; and

iii. wherein the main body portion continuously tapers inwardly from the bifurcated portion to a proximal free end of the main body, wherein the proximal free end of the main body defines a proximal most opening;

d. positioning the second prosthesis in a common iliac artery;

e. introducing a third prosthesis into the patient's vasculature, the third prosthesis comprising a tubular body of biocompatible graft material having a cylindrical proximal end and a flared distal end, the flare tapering outwardly to the distal end;

f. sealingly connecting the tapered main body of the second prosthesis and the flared distal end of the third prosthesis, such that the flared distal end portion of the third prosthesis overlaps with the tapered main body of the second prosthesis to sealingly engage with the tapered main body of the second prosthesis; and

g. sealingly connecting the cylindrical proximal end of the third prosthesis with a limb of the first prosthesis in an overlapping relationship.

9. The method of claim 8 further comprising, prior to the step of introducing the third prosthesis;

a. introducing a first connection stent graft into the internal iliac artery;

b. sealingly connecting a proximal end portion of the first connection stent graft and the second tubular portion of the second prosthesis.

10. The method of claim 9 further comprising:

a. introducing a second connection stent graft into the external iliac artery;

b. sealingly connecting a proximal end portion of the second connection stent graft and the first tubular portion of the second prosthesis.