Method and apparatus for delivery, deployment and retrieval of stents

Claim 1

A catheter for use in delivering a stent, the stent having a reduced diameter for intraluminal delivery and an expanded diameter, greater than the reduced diameter, when heated beyond a transition temperature, the catheter comprising: a first tube having a proximal end, a distal end and a wall defining a first lumen; a balloon sealingly connected to the first tube adjacent the distal end, the balloon defining an interior volume and having an exterior surface defining a stent engagement region, the interior volume of the balloon in communication with the first lumen, so that a heated fluid introduced through the proximal end of the first lumen pressurizes the balloon and heats the stent engagement region.

Claim 15

A method for manufacturing a stent delivery system including a catheter and a stent formed of a shape-memory material, the method comprising steps of: providing a catheter having proximal and distal ends and an inflation lumen; providing a balloon at the distal end of the catheter so that the interior of the balloon is in fluid communication with the inflation lumen, the balloon having a portion defining a stent engagement region; providing at least one aperture in fluid communication with the inflation lumen to permit temperature-controlled fluid to exit the catheter near the balloon; forming a stent having an expanded diameter from a shape-memory material; heating the stent until the shape-memory material transitions to an austenite phase, cooling the stent until the shape-memory material transitions to a martensite phase; positioning the stent over the stent engagement region of the balloon; and compressing the stent onto the stent engagement region to a reduced diameter less than the expanded diameter.

Claim 22

A method for manufacturing a stent delivery system including a catheter and a stent formed of a shape-memory material, the method comprising steps of: providing a catheter having proximal and distal ends and an inflation lumen; providing a balloon at the distal end of the catheter so that the interior of the balloon is in fluid communication with the inflation lumen, the balloon having a portion defining a stent engagement region; providing at least one aperture in fluid communication with the inflation lumen to permit temperature-controlled fluid to exit the catheter near the balloon; forming a stent having an expanded diameter from a shape-memory polymer; physically reducing the diameter of the stent; cooling the stent until the polymer enters the glass phase; positioning the stent over the stent engagement region of the balloon.

Claim 29

A method for introducing and deploying a stent comprising a shape-memory material at an affected site within a vessel of a human body, the method comprising steps of: providing a catheter having proximal and distal ends, a balloon located in the region of the distal end, an inflation lumen communicating between the proximal end and the balloon, and at least one aperture in fluid communication with the inflation lumen to permit temperature-controlled fluid to exit the catheter near the balloon; providing a stent that expands to an expanded diameter when heated beyond a transition temperature; positioning the stent over the balloon in a form having a reduced diameter, the reduced diameter being less than the expanded diameter; inserting the catheter transluminally through a body vessel until the stent is located within an area of the vessel to be treated; providing a bio-compatible fluid at a temperature sufficient to heat the stent above the transition temperature; and injecting the biocompatible fluid into the inflation lumen of the catheter at the proximal end of the catheter to cause inflation of the balloon and a controlled flow of the biocompatible fluid through the at least one aperture, the bio-compatible fluid injected at a rate sufficient to maintain the balloon and the stent in intimate physical and thermal contact during transition of the stent from the reduced diameter to the expanded diameter.

Claim 31

A method for retrieving a stent having an expanded diameter comprising a shape-memory material from an affected site within a vessel of a human body, the method comprising steps of: providing a catheter having proximal and distal ends, a balloon located in the region of the distal end, an inflation lumen communicating between the proximal end and the balloon, and at least one aperture in fluid communication with the inflation lumen to permit temperature-controlled fluid to exit the catheter near the balloon; inserting the catheter transluminally through a body vessel until the balloon is located within the stent within the body vessel; providing a bio-compatible fluid at a temperature effective to cause the stent to contract from the expanded diameter to a reduced diameter less than the expanded diameter; injecting the biocompatible fluid into the inflation lumen of the catheter at the proximal end of the catheter to cause inflation of the balloon and a controlled flow of the biocompatible fluid through the at least one aperture, the bio-compatible fluid injected at a rate sufficient to inflate the balloon into intimate physical and thermal contact with the stent while the stent contracts from the expanded diameter to the reduced diameter; dissipating the fluid in the balloon to allow deflation of the balloon as the stent contracts onto the balloon; and withdrawing the catheter and the stent from the vessel of the human body.