Stent thermoforming apparatus and methods

A stent-assembly apparatus which comprises:

• a stent-assembly mold comprising a first tube including a heat-conductive material and having a seamless inner surface forming a passage;
• a heating unit disposed in proximity and fluidically connected to an outer surface of the mold;
• a housing forming a chamber through which the mold and a second tube extend;
• a temperature sensor disposed within a passage formed within the second tube;
• wherein the heating unit forces a fluid into the chamber to heat the mold and the second tube;
• a conduit having an end fluidically coupled to a stent balloon, the end being positionable between a first location within the passage of the mold and a second location outside of the passage of the mold;
• a valve positioned in proximity to the conduit to control the flow of a fluid through the conduit;
• and
• a dolly that is movable between a third location within the passage of the mold and a fourth location outside of the passage of the mold, wherein the dolly accommodates a portion of the conduit to move the end of the conduit between the first location and the second location,
• wherein the mold is sized to receive a stent assembly that at least partially surrounds a portion of the stent balloon, and the end of the conduit.

A method of increasing retention of an expandable stent assembly on a stent balloon, which comprises:

• disposing an expandable stent assembly about a central portion of a stent balloon in a pre-sized expansion zone;
• heating the stent balloon to a first temperature;
• after heating the stent balloon to the first temperature, inflating the stent balloon to a first pressure to cause the stent balloon to expand and correspond to the pre-sized expansion zone;
• and
• heating the stent balloon to a second temperature that is greater than the first temperature while inflating the stent balloon to the first pressure.

A method of detecting a leak in a stent balloon which comprises:

• disposing a stent balloon in a pre-sized expansion zone;
• heating the stent balloon to a first temperature;
• after heating the stent balloon to the first temperature, inflating the stent balloon in the pre-sized expansion zone to a pressure that expands the balloon;
• isolating the pressure in the stent balloon in situ in the expansion zone;
• determining whether the pressure within the stent balloon recedes below a predetermined threshold pressure over a time period;
• and
• cooling the stent balloon to a second temperature in situ in the expansion zone, while determining whether the pressure within the stent balloon recedes below the predetermined threshold.