The Influence of Supporting Rings on the Healing of the Ringed Expanded Polytetrafluoroethylene Vascular Graft

Abstract

The influence of supporting rings on the healing of the ringed expanded polytetrafluoroethylene (ePTFE) vascular graft (ringed graft) was studied. In 12 dogs (32-42 kgm), a 4cm segment of each common iliac artery was excised and replaced with an equal length of 6mm ePTFE vascular graft. Ringed graft was used on one side and plain on the other. Dogs were sacrificed at intervals of 1, 2, 4, 6, 8 and 12 weeks. All grafts remained patent. The degree of pannus extension and pannus thickness showed no differences between both grafts at each interval. It was covered by a monolayer of endothelial-like cells as seen by scanning electron microscopy. The growth rates of endothelialization measured from the proximal anastomosis were 1.3 and 1.4 mm/week in the plain and ringed grafts, respec tively. Anastomotic intimal hyperplasia (> 50 microns) was noted in 25% and 33% at the proximal and distal anastomoses, respectively, in both grafts. The outer surface was covered by adherent connective tissue particularly encapsu lating the rings without affecting the non-ringed portion in the ringed grafts. We conclude that the supporting rings of the ePTFE graft have no significant influence on the healing and neointimal development.