Patent ID: 8562667

Claim:
An apparatus that is implantable in the vasculature of a subject to treat a vascular aneurysm, said apparatus, comprising: at least one expandable stent having fenestrations, said expandable stent comprising a substantially cylindrical body member located between first and second ends, said cylindrical body member having at least one circumferential element between said first and said second ends defining an internal lumen in communication with said first and second ends; wherein said at least one expandable stent is expandable between a first diameter D and a second diameter D′ wherein D′ is larger than D; and a reactive material applied to some but not all of the stent, said reactive material having a first state of protonation prior to implantation in the body and undergoing a change to a second state of protonation after implantation in the body, said change in the state of protonation resulting in expansion of the reactive material and resulting in a decrease in the size of some of the fenestrations such that blood flow through those fenestrations is lessened.