Objective To analyze outcome and its predictors after endovascular treatment (ET) in stroke patients suffering from large vessel occlusion with large pre-treatment infarct cores defined by an Alberta Stroke Program Early CT Score (ASPECTS) <6.

Methods We analyzed data from an industry-independent, multicenter, prospective registry (German Stroke Registry – Endovascular Treatment) which enrolled consecutive patients treated by ET (June 2015–April 2018) with different devices. Multivariate logistic regression analyses identified predictors of independent outcome (IO) defined as a modified Rankin Scale (mRS) 0–2, and mortality at 90 days in patients with ASPECTS <6.

Results Of 1700 patients included in the analysis, 152 (8.9%) had a baseline ASPECTS <6. Of these, 33 patients (21.6%) achieved IO, and 68 (44.7%) were dead at 90 days. A lower age, lower baseline National Institutes of Health Stroke Scale (NIHSS) score, and successful recanalization (defined as modified Thrombolysis in Cerebral Infarction Score, mTICI 2b/3) were predictors of IO. Successful recanalization had the strongest association with IO (OR 7.0, 95% CI 1.8 to 26.8). Pre-treatment parameters predicting IO were age <70 years (sensitivity 0.79, specificity 0.69) and NIHSS <12 (0.57 and 0.94). A higher age, a pre-stroke mRS score >1, and failed recanalization were predictors of death.

Conclusions A substantial proportion of stroke patients with an ASPECTS <6 can achieve independence after thrombectomy, in particular, if they are younger, have only moderate baseline stroke symptoms, and no relevant pre-stroke disability. These results may encourage considering thrombectomy in low ASPECTS patients in clinical practice until randomized trials are available.