The effect of prolonged blood stasis on a microarterial repair

There is much controversy in the literature about the effect of blood stasis on the patency rate following microvascular repair. Sixty Sprague Dawley rats underwent transection and repair of their femoral arteries. The rats were divided into three groups, which had their repaired arteries clamped for 1 1/2, 2, and 2 1/2 hours. Patency was evaluated by the "stripping test," and the presence of a "flicker" both immediately and on the second day of the experiment. At the time of evaluation on the second day, all arteries in Group I were patent, in Group II two were thrombosed and in Group III, five out of 20 thrombosed. The only significant statistical difference was found between Groups I and III in both immediate (p less than 0.0025) and second day (p less than 0.05) evaluations. Results indicate that the "safe limit" for blood stasis in a repaired artery of 0.8 mm diameter is 1 1/2 hours.