Effect of complete hydration of expanded polytetrafluoroethylene graft on improved antithrombogenicity: an experimental study
Higashidate, M.; Takanashi, Y.; Imai, Y.
Nihon Kyobu Geka Gakkai 35(1): 13-19
1987
ISSN/ISBN: 0369-4739 PMID: 3572117 Document Number: 292498
The influence of the pores filled with water on the patency rate of expanded polytetrafluoroethylene (EPTFE) graft was experimentally investigated. EPTFE grafts were pretreated with pure ethylalcohol followed by immersion in distilled water in order to completely fill pores of the wall with water (wet-type). The wet-type grafts were compared with conventional dry-type ones without pretreatment regarding thrombogenicity in this acute experiment. EPTFE grafts of both types, 4 mm in diameter and 4 cm in length, were implanted in different sides of the femoral veins in the same dog. These grafts were inserted into the venous lumen and fixed in place by simple ligatures to eliminate difference in suturing technique. Although all the 6 dry-type grafts were obliterated by clot within 30 minutes, in the wet-type, 4 out of 6 grafts remained patent without serious plasma leakage 5 hours later. These results suggest that the wet-type graft is superior to the dry-type ones in prevention of early thrombotic occlusion. It was found that serous fluid leakage was caused by filling the graft with saline or water under high pressure and this high pressure resulted in enlargement of the pores of EPTFE grafts. However, in our wet-type graft the pores were filled gently with distilled water by replacing alcohol simply by diffusion, no significant leakage of plasma was seen. To minimize possibility of the fluid leakage, forceful instillation of solution into the graft under high pressure should be avoided. Measurement of blood flow through EPTFE graft by an electromagnetic flowmeter has been difficult, since the pores of the graft wall containing air bubbles interfered with electrical conduction. The wet-type EPTFE grafts, of which pores were filled with water, became electrically conductive and blood flow through the graft could be measured accurately by the electromagnetic flowmeter in this experiments.