Endothelial cell seeding of expanded polytetrafluoroethylene vena cava conduits: Effects on luminal production of prostacyclin, platelet adherence, and fibrinogen accumulation

The blood-surface interface of 12 mm ID × 5 cm ePTFE vena cava conduits, unseeded (n = 8) and seeded (n = 8) with enzymatically derived autologous endothelial cells, was studied in a canine model at 4 and 12 weeks after graft implantation. Acetylsalicylic acid (325 mg each day) and Coumadin (prothrombin time 1.4 to 1.7 times the control value) were administered preoperatively and continued 4 weeks postoperatively. Platelets labeled with 111In and 125I-labeled fibrinogen were administered 24 hours before graft removal. Luminal platelet adherence, expressed as 106 platelets/cm2 of graft surface, was 8.9 ± 5.6 vs. 56.4 ± 8.0 (p < 0.008) and 4.0 ± 0.9 vs. 12.4 ± 2.3 (p < 0.005) in seeded vs. unseeded grafts at 4 and 12 weeks, respectively. Luminal fibrinogen deposition, expressed in micrograms per square centimeter of graft surface, was 11.8 ± 2.2 vs. 32.0 ± 2.0 (p < 0.06) and 6.1 ± 2.4 vs. 12.4 ± 6.3 (p < 0.005) in seeded vs. unseeded grafts at 4 and 12 weeks, respectively. Cumulative 4- and 12-week luminal production of 6-keto-PGF1α from seeded and unseeded grafts represented 11% and 5%, respectively, of that produced from the native iliac vein. Luminal endothelial cell coverage was 71% ± 22% vs. 33% ± 9% and 79% ± 8% vs. 55% ± 8% (p < 0.05) in seeded and unseeded grafts at 4 and 12 weeks, respectively. Although endothelialization was not complete in seeded vena cava grafts, it is clear that seeded prostheses exhibited improved thromboresistance compared with unseeded conduits.