[The new thrombolytic agents].

Among the new thrombolytic agents, two are or will be available in the near future: plasminogen tissue activator and antistreplase or anysoiled plasminogen-streptokinase activator complex (APSAC). The repermeabilization rate provided by these two thrombolytic agents administered intravenously, is practically identical, close to 70 p. cent, i.e. comparable to that obtained by intracoronary administration of streptokinase. The rate of secondary reobstruction is estimated near 17 p. cent for the tissue plasminogen activator and 10 p. cent for APSAC. Secondary reobstruction would be more frequently observed with thrombolytics with a short half-life (5 to 8 minutes of the tissue plasminogen activator whether it has one or two chains, versus 90 minutes with APSAC). Other factors influence it: persistence of a thrombogenic stimulus at the site of the stenosis, presence of thrombin, platelet activation... Both products have been found to be effective in limiting the size of the myocardial infarction and preservation of the left ventricular function. Finally, both have been shown to be effective on the reduction of the immediate and long-term mortality during extensive multicentric trials. The tissue plasminogen activator, although specific for fibrin, results in haemorrhagic complications which are as frequent as those cause by anistreplase which does not present this specificity for fibrin. The fibrin of pathological thrombi and the fibrin of the haemostatic centrifugate are identical. It is therefore lysed in the same fashion by all thrombolytic agents, whether or not specific of fibrin.