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Updated: Nov 17, 2025

Optimized Management of Endovascular Treatment for Acute Ischemic Stroke
Published on: January 18, 2018
Does Intravenous Thrombolysis Within 4.5 to 9 Hours Increase Clot Migration Leading to Endovascular Inaccessibility?
Jeremy C Lim1, Leonid Churilov2, Andrew Bivard3
1Department of Radiology, Royal Melbourne Hospital, Australia (J.C.L., R.J.D., P.J.M.).
Background And Purpose:
Distal clot migration is a recognized event following intravenous thrombolysis (IVT) in the setting of acute ischemic stroke. Of note, clots that were initially retrievable by endovascular thrombectomy may migrate to a distal nonretrievable location and compromise clinical outcome. We investigated the incidence of clot migration leading to clot inaccessibility following IVT in the time window of 4.5 to 9 hours.
Methods:
We performed a retrospective analysis of the EXTEND trial (Extending the Time for Thrombolysis in Emergency Neurological Deficits) data. Baseline and 12- to 24-hour follow-up clot location was determined on computed tomography angiogram or magnetic resonance angiogram. The incidence of clot migration leading to a change from retrievable to nonretrievable location was identified and compared between the two treatment groups (IVT versus placebo).
Results:
Two hundred twenty patients were assessed. Clot migration from a retrievable to nonretrievable location occurred in 37 patients: 21 patients (19.3%) in the placebo group and 16 patients (14.4%) in the IVT group. No significant difference was identified in the incidence of clot migration leading to inaccessibility between groups (P=0.336).
Conclusions:
Our results did not show increased clot migration leading to clot inaccessibility in patients treated with IVT.
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