Patent ID: 6289568
Filing Date: 2001-09-18
Classification: A61F,A61M,Y10T

Abstract:
A method for making a balloon catheter stent deployment system, comprising the steps of:providing a balloon catheter with an elongated flexible shaft having proximal and distal ends, a hub affixed to the shaft proximal end and having an inflation port, and an inflatable balloon affixed to the shaft near the shaft distal end; the shaft defining an inflation lumen providing fluid communication of an inflation fluid between the hub inflation port and the balloon, such that the balloon is adapted for selective inflation from a deflated state to an inflated state, as well as later deflation; the balloon being formed of a substantially inelastic material; the balloon having a cylindrical working portion with an inflated cross-sectional area located between a pair of conical portions and a pair of leg portions when the balloon is in the inflated state;pleating the balloon in a deflated state into multiple longitudinal pleats and wrapping the pleats around a portion of the shaft;providing a cylindrical phantom stent defining a tubular wall thickness; mounting the phantom stent around the balloon;inserting the balloon and phantom stent into a tubular mold defining a single inner diameter throughout its working length;pressurizing the balloon with a pressurized fluid to a first pressure, and simultaneously heating the balloon, phantom stent and mold;thereby causing the balloon to form a first and second shoulder located immediately proximal and distal of the phantom stent; each balloon shoulder having an initial outer diameter equal to the initial outer diameter of the phantom stent; such that the balloon defines an indented nest shape for the stent in the deflated state;removing the balloon and phantom stent from the mold; removing the phantom stent from the balloon catheter; andproviding a cylindrical medical stent having a wall thickness less than the phantom stent wall thickness; sliding the medical stent over the balloon and crimping the medical stent around the balloon;such that the balloon shoulders have an outer diameter greater than an outer diameter of the crimped medical stent;wherein the balloon is temporarily reformed into a modified shape, and is adapted to inflate and expand the stent to a deployed larger diameter, whereby the balloon forms said cylindrical working portion at above a preselected transition pressure, such that the cylindrical working portion and the portions defining the balloon shoulders in the deflated state have substantially the same diameter in the inflated state; thereby causing said indented nest shape to substantially disappear.