Long-term outcome changes after mechanical thrombectomy for anterior circulation acute ischemic stroke

Background and purpose Mechanical thrombectomy (MT) improves early clinical outcome in patients with acute ischemic stroke but insights on determinants of long-term outcome after MT treatment are scarce. Methods Data from stroke patients with anterior circulation large vessel occlusion of a prospective MT registry (01/2014-06/2017) of a large comprehensive stroke center were analyzed regarding clinical outcome between short- (3 months) and long-term (12 months) assessment reflected by a change of modified Rankin scores ( increment mRS). Secondary endpoints included favorable long-term outcome (mRS 0-2). Multi-variable regression analysis was performed to identify determinants of outcome changes and favorable outcome at long term. Results Of 264 patients included, 42.0% showed a favorable long-term outcome. Longitudinal analysis found that some individuals still improved, but no overall mRS difference between short and long-term follow-up was detected [ increment mRS - 0.004 (95% CI - 0.020; 0.013); p = 0.672]. Right hemispheric stroke [ increment mRS 0.286 (0.011; 0.561); p = 0.043] and high NIHSS at discharge [ increment mRS, 0.039 (0.004; 0.074); p = 0.029] were associated with a longitudinal mRS decline. Favorable long-term outcome was associated with successful recanalization (p < 0.0001). Conclusions A significant number of patients with MT experience a favorable long-term outcome. Outcomes remained stable between short- and long-term follow-up, but some individuals may still show improvement beyond short-term rehabilitation. Right hemispheric stroke and clinical stroke severity at hospital discharge may be frail predictors for delayed decline of functional status, whereas successful recanalization remains a positive outcome predictor. Death rarely occurs beyond 3 months after MT treatment.