ABSTRACT NUMBER: ESOC2026A1716 PREDICTORS OF SUCCESSFUL REPERFUSION AND CLINICAL BENEFIT IN DISTAL MEDIUM VESSEL OCCLUSIONS

Abstract Background and aims Distal-medium vessel occlusions (DMVO) represent 25-40% of acute ischemic strokes (AIS). Recent trials showed no benefit of endovascular therapy (EVT) over medical management in DMVO, suggesting the need for refinement of selection criteria. First-pass reperfusion (FPR) in large-vessel occlusion stroke associates with favourable outcomes. This study evaluated predictors and clinical outcomes of FPR in EVT-treated DMVO. Methods We retrospectively analysed DMVO-AIS patients submitted to EVT and/or intravenous thrombolysis at our comprehensive stroke centre (May 2016 - March 2025). DMVO was defined by CT angiography as an isolated occlusion of ACA, PCA, M2 (dominant/non-dominant), M3 and M4 segments of MCA. FPR was defined as TICI 2b-3 after one pass. Univariate and multivariable logistic regression analyses identified predictors and outcomes associated with FPR. Results Among 658 patients, 82.2% were submitted to EVT, using aspiration as first technique in 97.4%, achieving FPR in 50.5%. M2 occlusions predominated (80.8%; 53.6% dominant). Intracranial haemorrhage occurred in 28.4% (subarachnoid haemorrhage in 9.2%, intracerebral hemorrhage (ICH) in 24.4%, symptomatic ICH in two patients). 90-day mRS 0-2 was achieved in 43.8%. FPR was associated with lower NIHSS at 24h (p<0.001), any ICH (p=0.017) and lower mRS at 90 days (p<0.001), including in the sensitivity analysis excluding dominant M2 occlusions. Aspiration as first technique (OR=4.06, 95% CI [1.10, 14.96], p=0.035) and shorter onset-to-puncture time (OR=1.02 per 30-minute reduction, 95% CI [1.00, 1.05], p=0.047) independently predicted FPR. Conclusions In EVT-treated DMVO, FPR associates with better clinical outcomes. Shorter time to treatment and aspiration as first EVT technique predicted FPR. Conflict of interest Nothing to disclose