Clinical and vascular outcome in internal carotid artery versus middle cerebral artery occlusions after intravenous tissue plasminogen activator

Background and Purpose - Early reperfusion is a predictor of good outcome in acute ischemic stroke. We investigated whether middle cerebral artery (MCA) occlusions have a better clinical outcome and proportion of recanalization compared with internal carotid artery (ICA) occlusion after standard treatment with intravenous (IV) tissue plasminogen activator (tPA). Patients - In a retrospective analysis of our prospective stroke database between January 7, 1998, and January 30, 2002, we identified 36 consecutive patients who were treated with IV tPA within 3 hours after symptom onset of a stroke in the distribution of a documented ICA or MCA occlusion. The National Institutes of Health Stroke Scale (NIHSS) score was recorded before tPA, at 24 hours, 3 days, and 3 months after stroke. Three-month outcome was recorded by modified Rankin scale. Magnetic resonance angiography or computed tomographic angiography was obtained before tPA. The presence of recanalization was assessed by transcranial Doppler and/or magnetic resonance angiography within 3 days after stroke onset. Results - Nineteen patients had MCA occlusion, and 17 had ICA-plus-MCA occlusion before tPA. Although there was no difference in age and NIHSS at day 0 between the 2 groups, the MCA group had a lower day 3 NIHSS score compared with the ICA group (P=0.006) in an ANCOVA. In addition, patients who had a MCA occlusion had lower day 1 and 3 NIHSS scores compared with the ICA group (P=0.04 and P= 0.03, respectively; Wilcoxon rank sum). Similarly, NIHSS was significantly lower in patients who recanalized on days 1 and 3 (P=0.004 and P=0.003 respectively, Wilcoxon rank sum). When we adjusted for NIHSS score at day 0 in an ANCOVA, the adjusted mean was lower in the group that recanalized compared with the group that did not recanalize (P<0.001). There was a significant difference between the proportion of recanalization in the MCA group (15 of 17 recanalized, 88%) at 3 days after tPA compared with that of the ICA group (5 of 16 recanalized, 31%; P=0.001, Fisher exact test). The 3-month modified Rankin scale was not different between the 2 groups. Conclusions - Despite comparable age and NIHSS scores before IV tPA, MCA occlusions have lower day 1 and 3 NIHSS scores and higher proportion of recanalization compared with ICA occlusions. A combined IV/intra-arterial or mechanical thrombolysis may be needed to achieve early recanalization in ICA occlusions.