OVERVIEW ON THROMBOLYSIS IN ACUTE ISCHEMIC STROKE

Objective: to give an overview of the literature on thrombolytic therapy in acute ischemic stroke within the last decade. Inclusion criteria for the studies were that the patients had CT scan done before inclusion and that thrombolytic therapy was started within 48 h of stroke onset. Design: the studies are grouped into those of intra-arterial administration of thrombolytic agents, in which recanalization is documented by angiography, and into those of intravenous administration, which studies may be angiography-based or symptom-based; in the latter case the degree of reperfusion is unknown. Results: in basilar artery occlusion intra-arterial thrombolytic therapy in 111 patients resulted in a rate of recanalization of 60%, the acute mortality was 51%, and good clinical outcome was obtained in 28%. In 41 patients with occlusion of the internal carotid artery the rate of partial recanalization was 56%. The acute mortality was 22% and good clinical outcome was seen in 20%. In 106 patients with occlusion of the middle cerebral artery, which is the most common site of cerebrovascular occlusion, recanalization was obtained in 50%. The acute mortality was 17%, and good clinical outcome was obtained in 43%. Intravenous administration of thrombolytic agents in 203 patients with middle cerebral artery or internal carotid artery occlusions resulted in recanalization in 37%. Acute mortality was 15%, and good clinical outcome was obtained in 44%. In symptom-based studies, intravenous administration of thrombolytic agents was associated with 3 months mortality of 18%. Good clinical outcome was obtained in 43%. The occurrence of parenchymal cerebral hemorrhage ranged from 5% to 18%. Three randomized, placebo-controlled trials comprising 156 patients with carotid territory stroke showed similar rates of intracerebral hemorrhagic complications in thrombolytic treated and placebo treated groups. There was no significant difference in mortality. Good clinical outcome was seen more frequently in actively treated patients than in the controls. Comments: Patients in symptom-based studies may have less severe strokes than patients in angiography-based studies and comparisons between trials are not valid. Intra-arterial application of thrombolytic agents may result in higher recanalization rates than intravenous application. However, no direct comparison of the two treatment modalities has been made, and no placebo-controlled study has yet been performed of intra-arterial administration. The limited data on intravenous application seem to indicate that recanalization occurs more frequently than by spontaneous recanalization. Several large, placebo-controlled, randomized symptom-based studies of intravenous administration of thrombolytic agents are underway.