The efficacy and safety of tissue plasminogen activator in acute ischemic strokes

Over the past decade there has been an increasing use of thrombolytic agents in the treatment of coronary artery disease, pulmonary embolism, and thromboembolic strokes. The use of thrombolytic agents has been most successful in treating acute myocardial infraction. When treatment with intravenous streptokinase or tissue plasminogen activator (tPA) is initiated within the first 3 to 4 hours from the onset of symptoms, the rate of reperfusion ranges from 60% to 90%, as compared to a rate of 13% to 21% for placebo control. Both streptokinase and tPA have been extensively studied as therapies for acute myocardial infarction, and in general, a higher initial rate of reperfusion is achieved in tPA-treated patients than in streptokinase-treated patients, although the final arterial patency rate may not be different in the two groups due to a higher rate of reocclusion in the tPA-treated population. Furthermore, time dependency for efficacy from the onset of symptoms to the initiation of treatment is less for tPA than for streptokinase. However, the role of thrombolytic agents in the treatment of thromboembolic strokes is more experimental than clinical at the present time. Of all agents, tPA is the most promising and the most extensively studied. This paper will review the experimental data on the use of tPA in acute thromboembolic strokes as well as the existing clinical data on stroke reperfusion.