Association of anesthesia strategies with outcomes in endovascular treatment for distal and medium vessel occlusions: A propensity score-matched analysis of the MR CLEAN registry and meta-analysis

Background: Recent trials did not demonstrate the benefit of endovascular therapy (EVT) for distal or medium vessel occlusions (DMVOs), raising questions about factors influencing outcomes. Anesthesia choice may play a role, yet its impact remains unclear. This study assessed general anesthesia (GA) versus non-GA in EVT for DMVOs, evaluating procedural, functional, and safety outcomes. Patients and methods: Patients undergoing EVT for AIS due to anterior DMVOs in the middle cerebral artery (MCA-M2, M3, M4) and anterior cerebral artery (ACA-A1, A2, A3) from the MR CLEAN registry between March 2014 and December 2018 were included. They were stratified into GA and non-GA groups, with propensity score matching employed to adjust for differences in baseline risk. Primary outcomes included functional outcomes at 90 days, assessed by ordinal regression analysis of modified Rankin Scale (mRS) scores at 90 days, and recanalization rates measured by Thrombolysis in Cerebral Infarction (TICI) scores. Secondary outcomes included dichotomized mRS scores, death at 90 days, and symptomatic intracranial hemorrhage (sICH). A systematic review and meta-analysis of relevant DMVO studies with a random effects model was performed. This study was registered with PROSPERO (CRD42024607294). Results: Among 5193 patients in the registry, 657 were eligible for our study, with 506 in the non-GA group, and 151 in the GA group. The median age was 73 years (IQR 64–81) in the non-GA group and 73 years (IQR 61–80) in the GA group (p = 0.35). The proportion of male patients was 50.2% in the non-GA group and 57.0% in the GA group (p = 0.15). In the matched cohort (n = 170), recanalization rates were higher in the GA group compared to the non-GA group (excellent recanalization rates (TICI2c/3): 61.0% vs 32.1%; OR 3.31, 95% CI (1.74–6.29), p < 0.001). There were no significant differences in the overall distribution of functional outcomes at 90 days (common OR 0.93, 95% CI (0.54–1.56), p = 0.77). Mortality was comparable between groups (34.1% vs 31.8%; OR 1.11, 95% CI (0.59–2.11), p = 0.74), and there was no significant difference in sICH (12.9% vs 5.9%; OR 0.42, 95% CI (0.14–1.27), p = 0.12). The systematic review and meta-analysis included six studies with a total of 3521 patients. The pooled analysis indicated that GA was associated with significantly lower rates of excellent functional outcomes (mRS 0–1: OR 0.74, 95% CI (0.58–0.94), p = 0.01) and higher mortality (OR 1.36, 95% CI (1.07–1.74), p = 0.01) compared to the non-GA at 90 days. Discussion and conclusion: In the MR CLEAN Registry, GA was associated with higher recanalization rates during EVT, but this technical advantage did not translate into improved 90-day functional outcomes. Our meta-analysis further indicated that non-GA strategies were associated with better functional recovery and lower mortality. These associations, however, warrant cautious interpretation given potential unmeasured confounders, including blood pressure management and conversion from non-GA to GA. Broad categorization of anesthesia as GA versus non-GA overlooks critical factors such as agent selection, physiological targets, and intraoperative monitoring, which may substantially impact cerebral perfusion and outcomes. Further prospective randomized studies with detailed anesthetic data and expert input are needed to refine these findings and guide clinical practice.