Intravenous low-dose native tissue plasminogen activator for distal embolism in the middle cerebral artery divisions or branches: A pilot study

OBJECTIVE: We prospectively evaluated the safety and efficacy of an intrave nous infusion of low-dose native tissue plasminogen activator for distal em bolisms in the middle cerebral artery divisions or branches. METHODS: Twenty patients were selected according to the following computed tomographic and angiographic criteria and treated with intravenous infusion of 7.2 mg of tisokinase: 1) no early ischemic changes on the initial compu ted tomographic scan, and 2) embolic occlusion of the middle cerebral arter y divisions or branches without the involvement of the lenticulostriate art eries. For comparison, the records of 12 patients from previous years who m et the above inclusion criteria but underwent no thrombolytic therapy were reviewed retrospectively. The degree of neurological recovery was assessed using the National Institutes of Health Stroke Scale at 24 hours after admi ssion. Major neurological improvement was defined as a decrease in the stro ke score by 4 points or more. RESULTS: There was no significant difference in stroke scores at the time o f admission between the treatment group (mean a standard deviation, 12.8 +/ - 2.8) and the untreated group (14.0 +/- 2.4). In the treatment group, majo r neurological improvement was seen in 17 (85%) of 20 patients, whereas in the untreated group only 5 (41.7%) of 12 patients showed major neurological improvement (P < 0.05). The mean score at 24 hours in the treatment group (3.6 +/- 3.5) was significantly lower than that in the untreated group (9.4 +/- 7.3)(P < 0.05). There was no hemorrhagic complication with neurologica l exacerbation in the treatment group. CONCLUSION: Even with delayed initiation (>3 h after symptom onset), intrav enous infusion of low-dose tisokinase may be safe and effective for small d istal emboli in the middle cerebral artery divisions or branches, when earl y ischemic changes on computed tomographic scans and involvement of the len ticulostriate arteries are absent.