Elevated blood viscosity is associated with delayed cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage

Objectives Delayed cerebral ischemia (DCI) is a contributing factor for poor clinical outcome in aneurysmal subarachnoid hemorrhage (aSAH). Blood viscosity can reflect flow resistance and dehydration status. Our study aimed to analyze the association between blood viscosity and DCI in patients with aSAH. Methods In this retrospective cohort, systolic blood viscosity (SBV) and diastolic blood viscosity (DBV) were measured at admission in patients with aSAH. Receiver operating characteristic curve analysis was used to assess the predictive values of SBV and DBV for DCI after aSAH. Univariate and multivariate logistic regression was performed to analyze the association between blood viscosity and the development of DCI. Results A total of 470 patients with aSAH were included in this study, and 184 (39.1%) patients had DCI. Optimal cut-off values of DBV and SBV were presented as 12.05 (cP) and 3.75 (cP), respectively. In addition, DBV has higher predictable value of DCI than SBV (DBV: area under the curve [AUC] 0.793; standard error [SE] 0.026; 95% CI 0.722–0.864; P < 0.001, and SBV: AUC 0.702; SE 0.040; 95% CI 0.624-0.781; P < 0.001). In multivariate logistic regression analysis, elevated DBV was a predicting factor for development of DCI (odds ratio: 1.60; 95% confidence interval: 1.32-2.58; P = 0.037). Conclusions Blood viscosity is associated with development of DCI in patients with aSAH. Especially, DBV has a higher predictive value for the occurrence of DCI than SBV. Elevated DBV is a potential predicting factor for the occurrence of DCI.