Application of thrombolytic therapy in vascular occlusive disease. A surgical view

The use of fibrinolytic agents to control the fibrinolytic enzyme system and lyse pathologic fibrin deposits or thrombus has now assumed a position with anticoagulants and vascular surgery in the physician's therapeutic armamentarium. The principal exogenous activators that are used clinically are streptokinase, urokinase, and tissue plasminogen activator. Acute arterial occlusions are more likely than chronic occlusions to respond to thrombolytic therapy, especially if treatment is instituted within a few hours of onset of symptoms and if the disease is due to embolic material rather than in situ thrombosis. Since the duration of drug infusion necessary to lyse arterial thrombus cannot be predicted, patients in whom tissue viability cannot be determined or in whom ischemia cannot be tolerated during the drug infusion interval are not candidates for intraarterial fibrinolytic drug infusion. In treating patients with venous occlusion, thrombolytic therapy is more effective against proximal clots than in calf thrombosis. No protective effect from pulmonary embolism has been noted in trials comparing heparin with streptokinase. Fifty percent of patients with an initial episode of deep venous thrombosis treated within 72 hours of onset will have complete resolution of thrombus with preservation of valve function.