A method of implanting a prosthesis in a patient at a treatment site includes providing a prosthesis delivery system with an inner sheath and an outer sheath. The prosthesis is loaded inside the inner sheath. The inner sheath containing the prosthesis is loaded within the outer sheath. The outer sheath is advanced in a patient towards the treatment site up to a given position at a distance from the treatment site. While retaining the outer sheath in the given position, the inner sheath is advanced out from the outer sheath to the treatment site to align the prosthesis with the treatment site and the inner sheath is retracted to at least partially implant the prosthesis at the treatment site. Upon completion of prosthesis implantation, both of the inner and outer sheaths are retracted from the patient.