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 (∆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 [∆mRS − 0.004 (95% CI − 0.020; 0.013); p = 0.672]. Right hemispheric stroke [∆mRS 0.286 (0.011; 0.561); p = 0.043] and high NIHSS at discharge [∆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.