Recanalization after intravenous thrombolysis: does a recanalization time window exist?

To evaluate the time course of major vessel recanalization under IV thrombolysis in relation to functional outcome in acute ischemic stroke.

A total of 99 patients with an acute anterior circulation vessel occlusion who underwent IV thrombolysis were included. All patients had a standardized admission and follow-up procedure. Color-coded duplex sonography was performed on admission, 30 minutes after thrombolysis, and at 6 and 24 hours after onset of symptoms. Recanalization was classified as complete, partial, and absent. Functional outcome was rated with the modified Rankin Scale on day 30.

Complete recanalization occurred significantly more frequently in patients with multiple branch occlusions compared to those with mainstem occlusion (OR 5.33; 95% CI, 2.18 to 13.05; p < 0.0001) and was associated with lower NIH Stroke Scale (NIHSS) scores (p < 0.001). Not the specific time point of recanalization at 6 or 24 hours after stroke onset, but recanalization per se within 24 hours (OR 7.8; 95% CI 2.2 to 28.2; p = 0.002) was significantly associated with a favorable outcome. Multivariate analysis revealed recanalization at any time within 24 hours and NIHSS scores on days 1 and 7 together explaining 75% of the functional outcome variance 30 days after stroke.

Complete recanalization up to 24 hours after stroke onset is significantly associated with the short-term clinical course and functional outcome 30 days after acute stroke.