Expandable vascular prosthesis
First Claim
Patent Images
1. A vascular prosthesis comprising:
- an inner tube made of ePTFE;
an outer tube made of PTFE and having an outer tube diameter; and
a stent formed of a wire and having a cylindrical configuration with a stent diameter, said stent having a relaxed state in which said stent diameter is larger than said outer tube diameter;
said stent being encapsulated between said inner and outer tubes, said inner and outer tubes cooperating to stress said stent radially inwardly from said relaxed state to a stressed state whereby said prosthesis is biased to a predetermined shape by said stent.
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Abstract
A method is disclosed for making vascular prostheses from ePTFE said prostheses having a diameter which is larger, and a wall thickness which is smaller than previously achievable using ram extrusion techniques. The method consists of extruding a PTFE tube, finish processing the tube into an ePTFE tube, laterally dilating it by expansion in incremental steps, calendering the tube after each dilating step, while the tube is being maintained at an elevated temperature. Once the tube is dilated it can be sintered with another tube to form a laminate. Alternatively, a wire stent may be joined with one or more tubes, thereby biasing the laminate to a cylindrical configuration.
69 Citations
13 Claims
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1. A vascular prosthesis comprising:
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an inner tube made of ePTFE;
an outer tube made of PTFE and having an outer tube diameter; and
a stent formed of a wire and having a cylindrical configuration with a stent diameter, said stent having a relaxed state in which said stent diameter is larger than said outer tube diameter;
said stent being encapsulated between said inner and outer tubes, said inner and outer tubes cooperating to stress said stent radially inwardly from said relaxed state to a stressed state whereby said prosthesis is biased to a predetermined shape by said stent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification