Protection of saphenous vein graft from arterial pressure: an experimental study

Reoperations for bypass surgery increase the need for new grafts. We investigated early changes in both the normal human saphenous vein and in ectatic varicose veins externally supported by PTFE (polytetrafluoroethylene) graft and exposed to arterial pressure in an IN VITRO non-pulsatile flow model.

A total of 24 saphenous vein pieces (11 of them normal, the other 13 with varicosities) with a length of 6 centimeters were divided into equal parts; half of these parts were wrapped in PTFE grafts. All vein parts were placed in a perfusion circuit. Tissue biopsies were obtained from the vein segments. Light and electron microscopy examinations were performed, and endothelial continuity, elastic laminate continuity, medial connective tissue uniformity, medial smooth muscle uniformity, and adventitial connective tissue uniformity parameters were identified.

All parameters in the PTFE protected vein groups were better. The fewest morphological changes among all four groups were detected in the vein walls from normal veins with PTFE protection. There was no significant difference in endothelial continuity and adventitial connective tissue uniformity between the normal vein group and the varicose vein group with PTFE protection.

It is suggested that supporting vein grafts externally with PTFE sufficiently protects the vein walls against damage from exposure to arterial pressure. If varicose veins are used as arterial grafts, supporting them with PTFE may be useful because of the good protection of endothelial and medial connective tissues, resulting in similar parameters to those of normal vein walls.