Early neurological events after carotid revascularization and estimated whole blood viscosity

Background: This study aimed to investigate the association between preprocedural estimated whole blood viscosity (eWBV) and the 30-day composite outcome of stroke or transient ischemic attack (TIA) following carotid revascularization. Methods: This single-center retrospective cohort study included 247 patients who underwent elective carotid revascularization between 2020 and 2024, comprising 105 patients who underwent carotid endarterectomy (CEA) and 142 who underwent carotid artery stenting (CAS). eWBV at high and low shear rates was estimated using the de Simone equations based on hematocrit and total plasma protein levels measured within 24 h before the procedure. The associations between eWBV and the primary outcome were assessed using separate logistic regression models adjusted for age, sex, diabetes mellitus, symptomatic status, stenosis severity, and procedure type. Results: Stroke or TIA occurred within 30 days after the procedure in 15 of 247 patients (6.1%), including 6 of 105 patients (5.7%) who underwent CEA and 9 of 142 patients (6.3%) who underwent CAS (p=0.839). After adjustment for the prespecified covariates, the odds ratio for the primary outcome was 25.95 (95% confidence interval [CI], 4.37-154.10) per 1-cP increase in high-shear-rate viscosity and 7.57 (95% CI, 2.52-22.75) per 10-cP increase in low-shear-rate viscosity (both p<0.001). Conclusion: Higher preprocedural eWBV was associated with an increased likelihood of neurological events within 30 days after carotid revascularization. However, given the small number of outcome events and the substantial uncertainty reflected in the wide CIs, these findings should be interpreted as exploratory and hypothesis-generating. Prospective studies are needed to validate these associations before eWBV can be considered for clinical use.