ABSTRACT NUMBER: ESOC2026A636 TANDEM LESION STROKES: TO STENT OR NOT TO STENT, INSIGHTS FROM A DECADE OF EXPERIENCE AT A COMPREHENSIVE STROKE CENTER IN ARGENTINA

Abstract Background and aims Tandem lesion strokes (TLS), defined as simultaneous intracranial large-medium-vessel LVO/MeVO) and cervical internal carotid artery (ICA) stenosis or occlusion, represent 10–20% strokes. They are associated with poorer outcomes, reduced recanalization rates, higher disability and increased mortality. We aim to assess the safety and efficacy of eCAS versus MTa approach in patients presenting with anterior circulation TLS at a single comprehensive stroke center in Argentina. Methods Retrospective, observational, cross-sectional study analyzed consecutive patients with anterior circulation TLS <24 hours of symptoms onset treated between 2015-2025. Primary efficacy outcomes: ordinal shift in 90-day mRS score, mRS 0–1 and mRS 0–2 at 90 days. Secondary efficacy outcome: TICI 2b or higher. Primary safety outcomes: sICH, in hospital mortality and at 90 days. Secondary safety outcomes: early neurological deterioration (increase of 4 NIHSS points within 24 hours) and in hospital ipsilateral recurrent ischemic stroke. Results A total of 111 patients were included (mean age 71.2 ± 12.6 years; 68.5% male), of whom 74 (67%) underwent eCAS and 37 (33%) received MTa. Baseline features were similar in both groups. Efficacy and safety outcomes are presented in Table 1. Shift in mRS scores at 90 is represented Figure 1 Conclusions In this single-center experience, eCAS during MT for TLS was associated with higher reperfusion rates and improved functional outcomes without increased sICH or mortality. These findings support eCAS as a feasible and safe strategy in selected patients and highlight the need for prospective RCT. Conflict of interest Julieta Rosales: nothing to disclose Table 1 - belongs to Results Figure 1 - belongs to Results