Safety and efficacy of endovascular thrombectomy for primary and secondary MeVO

Background: Medium-vessel occlusions (MeVO) are emerging as a new target for endovascular treatment (EVT). Primary MeVO occur de novo, while secondary MeVO arise from large vessel occlusion (LVO) through clot migration or fragmentation -spontaneously, following intravenous thrombolysis or EVT. We aimed to evaluate efficacy and safety of EVT in primary and EVT-induced secondary MeVO.Methods: Retrospective single-center study on consecutive EVT-treated acute ischemic stroke, from 2019-to -2021. We considered: (1) exclusive-LVO, patients with LVO and - in case of residual distal occlusion - no rescue endovascular procedure; (2) primary MeVO: initial A2, A3, M2 non-dominant, M3, P2, P3 occlusions; (3) EVT-induced secondary MeVO, presenting LVO with subsequent (treated) EVT-induced MeVO. We compared (univariable/multivariable logistic regression) EVT efficacy (eTICI >= 2b, 3-month modified Rankin Scale [mRS] 0-2) and safety (EVT-complications [vessel dissection, perforation, persistent-SAH], symptomatic ICH) in all MeVO versus exclusive-LVO, primary MeVO versus exclusive-LVO, EVT-induced secondary MeVO versus exclusive-LVO and EVT-induced secondary MeVO versus primary MeVO.Results: We included 335 patients: 221 (66.0 %) exclusive-LVO and 114 (34.0 %) MeVO (55 [48.2 %] primary, 59 [51.8 %] secondary). Compared to exclusive-LVO, primary MeVO had higher rates of EVT complications (aOR 3.77 [95%CI 1.58-9.00],p=0.003), lower rates of eTICI >= 2b (aOR 0.32 [95%CI 0.12-0.88],p=0.027) and mRS 0-2 (aOR 0.28 [95%CI 0.13-0.63],p=0.002). EVT-induced secondary MeVO had no major differences in efficacy and safety outcomes compared to exclusive-LVO, but a better mRS 0-2 (aOR 8.00 [95%CI 2.12-30.17],p=0.002) compared to primary MeVO.Conclusions: Primary and EVT-induced secondary MeVO showed different safety/efficacy EVT-related profiles. Dedicated randomized data are needed to identify the best acute reperfusion strategy in the two categories.

Automated summary

This study aimed to evaluate the efficacy and safety of endovascular treatment (EVT) in primary and EVT-induced secondary medium-vessel occlusions (MeVO). The results showed that primary MeVO had poorer outcomes in terms of complications, EVT efficacy, and the proportion of patients with a modified Rankin Scale (mRS) of 0-2 at 3 months compared to exclusive large-vessel occlusion (LVO). However, EVT-induced secondary MeVO showed similar safety and efficacy outcomes as exclusive LVO and had better outcomes in terms of mRS 0-2 compared to primary MeVO.