Influence of topical heparin on stasis‐induced thrombosis of microvascular anastomoses

Abstract
An experiment was done to determine whether topical heparin and the association of anastomoses with dependent tissue (free flaps) exert any influences on stasis-induced microvascular thrombosis. Rat femoral vessel anastomoses with or without free flap construction were used in a total of 50 male Sprague-Dawley rats. Saline either with or without heparin was used for intralumenal irrigation during the anastomosis. Following anastomotic repair, the femoral vessels were reclamped, inducing stasis for either 2 or 4 hr. Our results showed that static blood had little adverse effect on thrombosis at the arterial anastomosis when reclamped for up to 4 hr in both standard and flap-associated anastomoses. Topical heparin significantly reduced the incidence of stasis-induced thrombosis of venous anastomoses. The venous patency rates in standard anastomoses were lower than those in flap-associated anastomoses after both 2 and 4 hr of stasis. From these results, we conclude the following. (1) Arteries may be reclamped for up to 4 hr without detriment despite static blood being in contact with the anastomotic site. (2) Topical heparin may be helpful in increasing the patency rate of venous anastomoses after a period of blood stasis. (3) Free flap construction may play a role in decreasing stasis-induced microvascular thrombosis. © Wiley-Liss, Inc.