Primary anastomotic bonding in polytetrafluoroethylene grafts?

Abstract

Previous studies have demonstrated that standard knitted and woven fabric grafts are forever dependent on the suture material for anastomotic tensile strength. Clinical experience with polytetrafluoroethylene (PTFE) and double velour knitted grafts have shown that there is extensive fibrous capsular bonding between the graft and the surrounding tissues. This would lead to increased anastomotic tensile strength. To test this theory, 34 mongrel dogs underwent replacement of their infrarenal aortas with grafts made of PTFE (10 dogs), of double velour knitted Dacron (DVD, 11 dogs), of single velour knitted Dacron (SVD, 5 dogs), and of woven Dacron (WD, 8 dogs). One anastomosis was constructed with 5-0 Prolene and the opposite anastomosis was constructed with 5-0 Dexon (average absorption time, 21 days). In five grafts each of PTFE and DVD, as well as in all eight WD grafts, the midgraft was divided and resutured with 5-0 Dexon. All grafts were harvested together with adjacent proximal and distal aorta between 3 and 10 months from the time of implantation. The tensile strength of each anastomosis was measured with a tensiometer. The mean graft-to-artery (absorbable suture) anastomotic tensile strength, in pounds, for PTFE (14.3) and DVD (12.6) was significantly higher than that for SVD (6.9) or WD (7.2) (p < 0.003). Graft-to-graft anastomotic tensile strength for PTFE (mean 17.3) was significantly better than that for DVD (mean 9.0; p < 0.03) or WD (mean 7.9; p < 0.001). Analysis of anastomotic tensile strength as a function of time revealed continued increase in PTFE in contrast to a slow decline with time in DVD. All 10 dogs in the PTFE and WD groups with graft-to-graft anastomosis (Dexon) were alive after 10 months, with intact anastomoses. Three of five dogs with DVD grafts died between 19 and 35 days following operation because of anastomotic disruption. On the basis of tensile strength and survival data, we conclude that there is evidence of improved primary anastomotic bonding in PTFE grafts and DVD grafts when contrasted to single velour knitted and woven Dacron grafts. Graft-to-graft anastomotic bonding appears superior in PTFE grafts when compared with DVD and WD.