Optimizing thrombectomy in medium vessel occlusion: Focus on vessel diameter

Mechanical thrombectomy for medium vessel occlusion (MeVO) is a challenging field with limited results. In this study, we aimed at evaluating the efficacy and safety of a procedural strategy beginning with occluded vessel diameter measurement and matched aspiration catheter selection. We retrospectively analyzed all sequentially treated patients by mechanical thrombectomy at two comprehensive stroke centers between May 2020 and April 2023, focusing on the occluded vessel diameter. We included patients who underwent thrombectomy for MeVO based on the matching strategy (a procedural approach involving vessel diameter assessment, matching aspiration catheter selection, and firm clot engagement with or without a stent retriever). We evaluated efficacy and safety using the modified Thrombolysis in the Cerebral Infarction Scale (mTICI) and intracranial hemorrhage (ICH) and procedure-related complications. Seventy patients fulfilled the final inclusion criteria. The median occluded vessel diameter was 1.71 mm. We achieved mTICI 2b/2c/3 in 82.9% and mTICI 2c/3 in 51.4% of the cases and did not observe any symptomatic ICH. We detected asymptomatic subarachnoid hemorrhage (SAH) in 24.3% of the cases, that is, 5.6%, 20.0%, and 45.5% in the vessel diameter groups ≥2.0, 1.5-2.0, and ≤1.5 mm, respectively. The SAH incidence was significantly higher in narrower vessel groups. The occluded vessel diameter and the contact method with clots predicted clinical outcomes. Matching strategy-based thrombectomy yields acceptable efficiency and safety results. In narrower vessels, it is optimal to engage matched aspiration catheters and clots without the assistance of conventional stent retrievers.