Abstract 3848: Common Carotid Artery Diameter Predicts Coronary Heart Disease in Middle-Aged Men and Women: Atherosclerosis Risk in Communities (ARIC) Limited Access Data, 1987–1999
Background: Common carotid artery (CCA) intima medial thickness (IMT) is a useful indicator of the presence and extent of coronary atherosclerosis. CCA diameter is another possible risk indicator. We hypothesized that CCA diameter will predict incident CHD events independently of IMT.
Methods: Of the 15732 men and women in the ARIC Study Limited Access Data (ARICLAD), 10684 (4671 men and 6013 women) had baseline B-mode ultrasound IMT and external diameter measures, were free of baseline MI, and had CHD risk factor data. Median follow up was > 11 years. Incident CHD events (225 in women and 410 in men) were based on ARIC validated, definite or probable MI from hospital surveillance, silent MI on follow-up ECG, or definite fatal CHD. Gender-specific Cox proportional hazards models were used to evaluate the risk associated with standardized units of B-mode right CCA IMT and/or diameter in unadjusted and risk adjusted models. For both men and women, risk adjusted models included age, race, diabetes, systolic BP, fibrinogen, HDL-C, LDL-C, current drinking, and current smoking, while hypertension and BMI were also included for men and glucose was included for women.
Results: For men, in separate unadjusted models, 1 standard deviation of right CCA IMT (HR = 1.25, 95% CI = 1.17–1.33, p < 0.0001) and of CCA diameter (HR = 1.36, 95% CI = 1.24–1.48, p < 0.0001) predicted CHD events. Both CCA measures predicted CHD events in an unadjusted model including both measures (IMT HR = 1.17, 95% CI = 1.09–1.26, p < 0.0001; diameter IMT = 1.27, 95% CI = 1.15–1.40, p < 0.0001) and in separate risk adjusted models (IMT HR = 1.09, 95% CI = 1.02–1.17, p = 0.03; diameter HR = 1.18, 95% CI = 1.07–1.3, p = 0.001). CCA diameter remained significant in risk adjusted models with both measures (diameter HR = 1.16, 95% CI = 1.05–1.28, p = 0.005; IMT HR = 1.06, 95% CI = 0.98–1.14, p = 0.2). For women, CCA diameter was a stronger predictor of incident events (HR = 2.0, 95% CI = 1.75–2.28, p < 0.0001) than CCA IMT (HR = 1.49; 95% CI = 1.38–1.61, p < 0.0001) in separate unadjusted analyses. Both CCA measures predicted events in risk adjusted models that included both vascular measures (diameter HR = 1.20, 95% CI = 1.01–1.42, p < 0.04; IMT HR = 1.12, 95% CI = 1.00–1.25, p < 0.052).
Conclusion: CCA diameter complements IMT as a predictor of CHD events.