From the experimental myocardial infarction to the clinical acute myocardial infarction: limitations of thrombolytic therapy

Early administration of thrombolytic agents in acute myocardial infarction lowers mortality and preserves left ventricular function. Currently, only one third of infarct patients receive this treatment, the vast majority being excluded because of restrictive criteria and delayed hospital admission. When correctly administered, thrombolytic therapy achieves reperfusion in 50-85% of occluded vessels. Five to 15% of these initially recanalized vessels eventually reocclude. Possible mechanisms of failure of thrombolytic therapy to induce stable coronary reperfusion include thrombus formation during thrombolysis, platelet activation by thrombolysis, fibrin deposition during thrombolysis, and resistance to thrombolysis. Bleeding complications including intracranial haemorrhage remain a major complication. New therapeutic regimens, new thrombolytic agents and more effective anti-thrombotic drugs, together with intervention strategies that anticipate the time of treatment, promise a significant increase of the overall benefits obtainable with thrombolysis in acute myocardial infarction.