Experimental venous reconstructive surgery in rat and piglet models

Although it seems possible to treat deep venous insufficiency with transplantation of a venous segment with valves, experimental data is still lacking. One of the reasons is that the dog model has some severe disadvantages. In this study venous segments were transplanted in rats and piglets. Fifteen rats were primarily used as a training model. Venous segments, diameter varying from 0.3 to 1.2 mm, were transplanted to the femoral position. The animals were sacrificed after a mean of 10.26 weeks. Of 24 segments, 19 were open; 53 anastomoses had been at risk, and 39 of those were open: a patency of 74%. Pigs have not been used before, but offer several similarities with the human species. Eleven piglets, age varying from 2 to 4 months were operated upon. In some animals running sutures were used, and in others single monofilament sutures were applied. Before sacrifice, at least one ascending phlebogram to access patency was performed under general anesthesia. The animals were sacrificed after a mean of 35.6 days. One piglet died two weeks after operation, due to intestinal obstruction. Before sacrifice the segments were explored, and tested in vivo for patency and valve competence. In ten animals, five segments were patent. Since one segment proved to be postthrombotic, an actual patency of only 40% was achieved. Valve competence was hard to prove, but it seemed to equal patency rates. These preliminary results show, that the piglet model after microvascular training on rats, is suitable for evaluation of venous reconstructions, and is challenging because of its thrombogenic tendency.