A sealable vascular system includes an endovascular implant to be delivered in a compressed or folded state to an implantation site. The endovascular implant includes a tubular implant body and a sealable circumferential collar at said tubular implant body and including a variable sealing device and a control lead traversing from said variable sealing device to a user for controlling said variable sealing device by the user, said variable sealing device and said control lead being cooperatively operable to reversibly expand and contract said sealable circumferential collar such that said sealable circumferential collar is circumferentially adjustable during deployment thereof to achieve a repositionable fluid-tight seal between said sealable circumferential collar and the internal walls of the implantation site.