Medial region deployment of radially self-expanding stents

Abstract

An apparatus for deploying a radially self-expanding stent includes proximal and distal sleeves respectively containing proximal and distal end portions of the stent in a reduced radius delivery configuration. The sleeves can abut one another and thus contain the entire length of the stent, or may be used in combination with an outer catheter surrounding the sleeves and containing the medial region of the stent. In either event, once the stent and sleeves are positioned at the intended fixation site, the sleeves are moved axially with respect to one another to permit radial self-expansion of the stent only over its medial region, while the sleeves continue to contain the axially outward regions of the stent. Eventually, upon sufficient movement of the sleeves axially relative to one another, the stent becomes totally free of the sleeves, resulting in radial expansion over the entire stent length. The axial relative movement of the sleeves can be controlled by two or more catheters mounted movably with respect to one another, one catheter integral with each of the sleeves. Alternative arrangements for separating the sleeves include an externally threaded inner catheter, and a dilatation balloon or membrane expandable to force the sleeves apart from one another.