An endovascular prosthetic system comprises an prosthetic device (10) witha major lumen extending therethrough, a major wall, at least one opening (16,19, 31) in the major wall； at least one branch (18, 20, 40) extending into the majorlumen of the prosthetic device (10) the or each branch having a minor lumen, a minorwall, and a fenestration (15) in the minor wall in communication with the majorlumen； and at least one guide wire (17) extending through the fenestration andout of the prosthesis through the opening.
