Thrombolysis in microvascular surgery using tissue-type plasminogen activator.

Thrombosis at the microanastomotic site is the primary cause of free flap failure. Tissue-type plasminogen activator, a potent thrombolytic agent, effectively lyses vessel thromboses. This study examined the efficacy of tissue-type plasminogen activator in a microvascular model using a modified vascular inversion graft in rabbits. Seventeen rabbits underwent this procedure with formation of thromboses in all but one inversion graft. Ten rabbits were locally infused with 1 mg of tissue-type plasminogen activator over a period of 4 hours; 6 control rabbits received normal saline infusions. Blood flow across the graft was reestablished in all 10 rabbits receiving tissue-type plasminogen activator and in none of those with normal saline infusions. Systemic fibrinolysis was not significantly altered. We conclude that local infusion of tissue-type plasminogen activator is effective in lysing thromboses that may occur at the venous microvascular anastomotic site without significant activation of systemic fibrinolysis.