Futile recanalisation in patients with anterior large vessel occlusion stroke randomised to mechanical thrombectomy

Background: Mechanical thrombectomy (MT) is an effective treatment of large vessel occlusion (LVO) stroke. However, about 50% of patients do not achieve a favourable functional outcome after successful recanalisation by MT, considered as futile recanalisation (FR). We aimed at identifying factors associated with treatment response, vessel recanalisation and clinical outcome in LVO stroke patients randomised to MT and to predict FR to evaluate the effect of single predictors on patient outcome. Methods: We performed a retrospective analysis of the MR CLEAN trial cohort. Ordinal logistic regression with interaction terms between a treatment indicator and patient factors was used to evaluate response to MT in terms of 3-months modified Rankin scale (mRS). In logistic regression, we identified factors associated with vessel recanalisation and FR. We predicted FR in a five-fold cross validation using least absolute shrinkage and selection operator (LASSO) regression. Results: 195 of the 461 included patients were randomised to receive MT. Male sex (OR 0.41, 95% CI 0.21–0.82, p = 0.01) enhanced the treatment effect of MT. Only onset-to-groin time was associated with a technically successful recanalisation (OR 0.99, 95% CI 0.99–1.00, p = 0.01). Higher age (OR 1.05, 95% CI 1.01–1.09, p = 0.02) and worse collateral score (OR 0.05, 95% CI 0.01–0.19, p < 0.01) were associated with FR. Female sex (OR 0.74) and worse collateral status (OR 0.19) showed the best predictive value for FR. Conclusions: Different patient factors seem to be relevant for technical success and clinical success of MT in LVO stroke patients.