[rt-PA in extracardiac thromboembolic vascular occlusions]

Recombinant tissue plasminogen activator (rt-PA) is a thrombolytic agent characterized by elevated but not absolute fibrin specificity. However, its therapeutic dose is high and associated with a variable degree of systemic activation of the fibrinolytic system. Thrombolytic drugs are widely used in acute myocardial infarction and have now begun to be considered for deep vein thrombosis (DVT), pulmonary embolism (PE), and peripheral artery thrombosis (PAT) as well. Although anticoagulant therapy is effective in reducing the immediate complications of venous thromboembolism, thrombolytic therapy has various advantages over anticoagulant therapy, including lysis of thrombi with recanalization of venous circulation, reduction of venous valve damage and prevention of post-phlebitic syndrome. The different dosage regimens of rt-PA recently evaluated (0.71 to 1.76 mg/kg/24 h for 2-4 days) in DVT have caused consistent thrombolysis but also excessive bleeding. The optimal therapeutic range for rt-PA in DVT remains to be determined. Thrombolytic therapy is superior to heparin treatment only in hemodynamically compromised patients with massive PE. The minor systemic fibrinolytic effect and the faster action on thrombi of rt-PA compared with the first generation thrombolytic agents, streptokinase (SK) and urokinase (UK), are very interesting and explain the positive results recently obtained in PE with this drug (50 mg over 2 h, followed, if necessary, by 40-50 mg over 4-5 h) by Goldhaber and Verstraete.(ABSTRACT TRUNCATED AT 250 WORDS)