Common Carotid End-Diastolic Velocity and Intima-Media Thickness Jointly Predict Ischemic Stroke in Taiwan

BACKGROUND AND PURPOSE: In Asian populations, few studies investigated the association between stroke and common carotid artery intima-media thickness (IMT). Our previous case-control studies showed that low end-diastolic velocity (EDV) in common carotid artery, a potential hemodynamic marker of intracranial resistance, was associated with ischemic stroke. Therefore, we investigated the relationship between both EDV and IMT and incident ischemic stroke in an Asian population. METHODS: Baseline data from 3175 adults (30 years or older) in the Cardiovascular Diseases Risk Factor Two-Township Study were linked to incidental ischemic stroke status derived from insurance claims and death certificate records. Hazard ratios for risk of ischemic stroke for high IMT and low EDV values measured in common carotid artery were calculated using Cox proportional hazard models. RESULTS: With 9.85 years (median) of follow-up, 184 persons had ischemic stroke develop. Compared with the first tertile of IMT, hazard ratios were 2.03 (95% confidence intervals, 1.27-3.25) for the second tertile and 3.87 (95% confidence intervals, 2.36-5.69) for the third tertile. Hazard ratios of EDV were 5.31 (95% confidence intervals, 3.52-7.99; first tertile) and 1.94 (95% confidence intervals, 1.21-3.09; second tertile) compared with the third tertile. The individuals with high IMT and low EDV had >2-fold ischemic stroke risk compared to those with low IMT and high EDV (2.10; 95% confidence intervals, 1.35-3.26) after adjusting for age, sex, and traditional cardiovascular risk. CONCLUSIONS: Common carotid IMT and EDV jointly and independently predicted future ischemic stroke in this Taiwanese population. More prospective studies are required in various ethnic groups to understand the significance and implication of the current findings, particularly with respect to EDV.