Assembly for treating branched vessels

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.