Abstract Background and aims Achieving near-complete or complete reperfusion after a single thrombectomy attempt, referred to as first-pass effect (FPE), has been associated with improved clinical outcomes. Despite its relevance, determinants of first-pass recanalization are not fully understood. Methods We performed a retrospective observational analysis of patients undergoing MT for AISdue to LVO in two tertiary stroke centers. FPE was defined as achievement of eTICI grade 2c or 3 after the first attempt. Thrombectomy techniques were categorized as aspiration-based, stent-retriever–based, or combined approaches. Use of different stent-retrievers (SR)s as well as contact aspiration only was analyzed. Angiographic occlusion phenotypes were classified using established criteria. Univariable and multivariable logistic regression analyses were performed to identify factors associated with FPE. Results FPE was achieved in 72/479 patients (15.0%). On univariable analysis, meniscus and tram-track occlusion signs were more frequently associated with first-pass recanalization (p=0.006 and p=0.036), while contact aspiration was associated with lower rates (14/147, 9.5%; p=0.024). Among stent retrievers, Embotrap (140/479) showed higher first-pass recanalization (31.4%, p0.001) compared with Aperio 6/72 (8.3%, p=0.071) and Solitaire 7/90 (7.8%, p=0.026). In multivariable analysis, Embotrap use was independently associated with FPE (adjusted OR 8.3, 95% CI 3.61–19.23; p0.001), with no independent associations for occlusion phenotypes, procedural factors, or other stent retrievers. Conclusions The use of the Embotrap SR was independently associated with first-pass recanalization, whereas angiographic occlusion phenotypes were not independently predictive after adjustment. These findings support further investigation of procedural strategies aimed at improving early reperfusion. Conflict of interest Matthew Zidan: nothing to disclose
Zidan et al. (2026) studied this question.