The influence of endothelial seeding and platelet inhibition on the patency of ePTFE grafts used to replace small arteries--an experimental study

Previous studies on the influence of endothelial seeding on graft patency have shown that significant improvement has only been achieved with Dacron and an experimental, porous PTFE graft. Methods of assessing patency or showing statistical significance could be questioned in some of these studies. To determine if the combination of endothelial cell seeding and antiplatelet agents would improve patency in small-diameter, commercially available expanded polytetrafluorethylene (ePTFE) grafts, we placed ePTFE grafts into the left carotid position in two groups of mongrel dogs. All grafts were 4 mm internal diameter and 60 mm long, and were interposed in an end-to-end fashion. Both groups received aspirin (80 mg daily) and dipyridamole (25 mg daily) for 14 days, beginning immediately prior to surgery. In Group I (n = 12), the grafts were seeded with enzymatically harvested autogenous endothelium just prior to implantation; in Group II (n = 10) the grafts were not seeded. All grafts were removed at 30 days. Seven of 12 (58%) seeded grafts, but only one control graft (10%) remained patent (P = 0.03). Six of the seven seeded grafts exhibited surface endothelium, but the single patent control graft did not. The inner capsule of the seeded grafts consisted of a monolayer of endothelium and a thin acellular subendothelial matrix with an average thickness of 8 mu. We conclude that a 14-day course of anti-platelet agents combined with endothelial seeding of ePTFE resulted in significantly improved patency compared to controls, with most patent, seeded grafts developing an endothelial lining in 30 days.