The Annals of Thoracic Surgery, Vol 27, 173-177, Copyright © 1979 by The Society of Thoracic Surgeons
Changes in the manufacture of expanded microporous polytetrafluoroethylene: effects on patency and histological behavior when used to replace the superior vena cava
WH Heydorn, JW Geasling, WY Moores, LO Lollini and AC Gomez
Polytetrafluoroethylene (PTFE) has been used clinically and experimentally
as a vein substitute. Since its introduction, changes have been made in the
manufacture of the material. This study was designed to evaluate the
effects of pore size (fibril length), PTFE cover, and spiral tube support
on long-term patency and histological behavior when this material is used
as a replacement for the precava in the dog. A graft of 30-mu pore size has
adequate fibroblastic ingrowth, a neointima of 200 mu or less, and the best
long-term patency. The PTFE cover results in less fibroblastic involvement
of the prosthetic graft and prevents late occlusion caused by transmural
fibrosis in the 90-mu graft. The spiral support does not affect patency and
may be indicated when external pressure on the tube must be avoided.
