A medical device for delivery of a self-expanding stent comprises a
catheter assembly having a catheter shaft and a self-expanding stent
disposed thereabout. A retractable sheath is disposed about the catheter
shaft and the stent. The retractable sheath retains the stent in a
reduced diameter condition prior to delivery. A retractable membrane is
also disposed about the catheter shaft and the stent prior to delivery.
Prior to delivery a first portion of the membrane is positioned between
the stent and the retractable sheath. A second portion of the retractable
membrane extends from the first portion and is positioned radially
external of the retractable sheath. The retractable sheath and the
retractable membrane are independently moveable relative to one another.