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Two way shape memory alloy medical stent

  • US 5,562,641 A
  • Filed: 05/20/1994
  • Issued: 10/08/1996
  • Est. Priority Date: 05/28/1993
  • Status: Expired due to Term
First Claim
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1. A stent for placing in a portion of a tubular organ so as to support the walls of the tubular organ in said portion such that the tubular organ in said portion will have a diameter above a critical diameter, the stent comprising:

  • a spiral coil or cylinder made of a two-way shape memory alloy;

    having a super-elastic scale in which the stent has a first diameter which is at least about the critical diameter but within a physiological range tolerated by said organ; and

    having a soft state in which the stent has a second diameter, after changing to this state from the super-elastic scale, which is less than said critical diameter;

    the shape memory alloy has two transition temperatures being within a range that will not damage biological tissue, of which a first transition temperature, being a temperature which is above body temperature, is a temperature in which said alloy changes from said soft state to said super-elastic state and of which a second transition temperature, being a temperature which is below body temperature, is a temperature in which said alloy changes from said super-elastic state to said soft state, so that after changing into one of the two states, the stent remains in that state at body temperature.

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