Thrombolytic intervention in acute thrombotic and embolic stroke.

Stroke is one of the leading causes of death in the industrial nations of the world. Up to now, there has been no therapeutic strategy available which has been proven by controlled clinical trials. In the majority of acute stroke patients acute thrombosis contributes to carotid and vertebrobasilar arterial occlusions. Therefore, significant interest has focused on the possible value of fibrinolytic therapy in acute stroke. The principal goal is the rapid lysis of occluding thrombus with a minimum risk of intracranial or systemic hemorrhage. Clinical investigations on thrombolysis in cerebrovascular ischemia included different plasminogen-activators such as urokinase, streptokinase, and tissue plasminogen activator, either given systemically or locally via an intraarterial catheter. The pivotal trials conducted so far have revealed a wide range of recanalization rates, an acceptable safety and, also, encouraging effects on neurologic outcome. Thrombolysis itself carries the risk of intracranial bleeding, a practical limitation of this approach in acute stroke. On the other hand, hemorrhagic infarction and parenchymatous hematoma are natural consequences of thromboembolic stroke, possibly as a result of persistent occlusion of an artery. Hemorrhage following thrombolysis seems to show the same features seen in untreated patients and with an incidence similar to that in untreated patients. Future developments in thrombolysis in acute stroke should include improved early recruitment of patients, evaluation of noninvasive techniques in the pretreatment assessment of patients, the evaluation of advanced invasive techniques for delivery of the thrombolytic agent and assessment of combined treatment strategies. Clinical studies evaluating these strategies are currently under way.