Methods for crimping a polymeric stent onto a delivery balloon

摘要

A medical device- includes a polymer stent crimped to a catheter having an expansion balloon. The stent is crimped to the balloon by a process that includes heating the stent to a temperature below the polymer's glass transition temperature to improve stent retention without adversely affecting the mechanical characteristics of the stent when later deployed to support a body lumen.

主权项

1. A method for making a medical device, comprising the steps of:
forming a scaffold from a tube comprising a polymer, the tube having a tube diameter and the polymer having a lower end of a glass transition temperature (Tg-low); heating the scaffold to a temperature of between Tg-low and 15 degrees below Tg-low; crimping the heated scaffold to a balloon including reducing a scaffold diameter to a final crimp diameter that is at least 2.5 times smaller than the tube diameter; the balloon is a 3.0 mm balloon and the scaffold is made from a tube having a thickness of between 0.1 mm and 0.18 mm; the scaffold includes a circumferential series of closed cells having a W-shape and link struts connecting the W-shape cells; and the scaffold further including rings formed by ring struts, wherein prior to crimping a pair of ring struts adjoined at a crown are each orientated at an angle of between 20 and 30 degrees with respect to an axis perpendicular to a longitudinal axis of the scaffold, and an angle of between 120 and 130 degrees spans between the adjoined ring struts.