Symptomatic intracranial hemorrhage mediates the association between eosinophils and 90-day outcomes after mechanical thrombectomy for acute ischemic stroke

Abstract

Abstract Background Decreased eosinophil level was associated with poor outcome after mechanical thrombectomy in patients with acute ischemic stroke (AIS), but pathogenesis of this association is elusive. We aimed to assess the mediation effect of intracranial bleeding complications on the aforementioned association. Methods A total of three hundred and twenty-eight consecutive AIS patients experiencing mechanical thrombectomy between May 2017 and March 2021 were analyzed. Hemorrhagic transformation (HT) were categorized as symptomatic intracranial hemorrhage (sICH) and parenchymal hematoma (PH) according to previously published criteria. Regression analysis was used to assess the effect of eosinophils on HT, and its effect on poor outcome. Mediation analysis was utilized to assess the proportion of total effect by HT on the association between eosinophils and poor outcome. Results Multivariater analysis revealed that eosinophils was independently associated with sICH after adjusting for potential confounders (odds ratio, 0.00; 95% CI, 0.00–0.01; P = 0.0141), which is consistent with the result of eosinophils (dichotomous) as a categorical variable (odds ratio, 0.22; 95% CI, 0.11–0.46; P < 0.0001). And the risk of PH in higher eosinophils was 0.36 fold higher than in patients in the low eosinophil group (OR, 0.36, 95% CI, 0.19–0.67; P = 0.0013). Eosinophils was negative associated with poor outcome (odds ratio, 0.00; 95% CI, 0.00–0.02; P = 0.0021). And mediation analysis found that sICH partially mediated the negative relationship between eosinophils and poor outcome (indirect effect=-0.1896; 95%CI: -0.3654 – -0.03, P < 0.001); however, PH did not mediate the association between eosinophils and poor outcome (P = 0.12). Conclusion This study showed an important effect of sICH on the association between eosinophils and poor outcome.