ePTFE graft with axial elongation properties

摘要

A method of making an ePTFE tubular structure includes the steps of (a) forming a tube of polytetrafluoroethylene; (b) longitudinally stretching the polytetrafluoroethylene tube to form an expanded polytetrafluoroethylene tube, where the expanded polytetrafluoroethylene tube includes fibrils oriented in a longitudinal direction of the tube and nodes oriented in a circumferential direction of the tube; and (c) placing the expanded polytetrafluoroethylene tube circumferentially exterior to a longitudinal foreshortening and radially expanding mechanism, where radial pressure from the foreshortening mechanism radially expands the ePTFE tubular structure and reorients the fibrils non-longitudinally.