Abstract 1321: African Americans Have Worse Arterial Compliance Than Whites, Independent of Risk Factor Burden and Framingham Risk Estimates
Introduction: African Americans (AAs) have greater cardiovascular (CV) mortality than Whites. Since greater arterial stiffness and wave reflections contribute to ventricular afterload and CV events, we hypothesized that AAs would have higher arterial stiffness indices compared to Whites for the same degree of risk factor burden.
Methods: We studied 773 healthy volunteers and community based subjects with risk factors, including 383 AAs (mean age 48±10 years, male 45%) and 390 Whites (mean age 49±11, male 55%). Using radial artery tonometry (Sphygmocor,© Atcor), we measured augmentation index adjusted for heart rate (Aix75) and augmented pressure (cAP) as primary outcome variables. Risk factor burden was assessed as number of risk factors (diabetes, hyperlipidemia, hypertension and smoking) and a calculation of Framingham Risk Score (FRS).
Results: AA males and females had greater Aix75 (both p=0.001) and cAP (both p<0.001) when compared to their White counterparts, after adjusting for differences in age, height, weight, mean arterial pressure, glucose, lipids, CRP and smoking (Figure⇓). FRS was similar in both races for each gender (both p=NS). When grouped by risk factor burden, AAs had higher augmentation indices than Whites after adjusting for the above covariates, with race an independent predictor of Aix75 (p=0.001) and cAP (p=0.003).
Conclusion: AAs have greater systemic arterial stiffness and wave reflections compared to Whites, irrespective of risk factor burden. Standard CV risk scores may underestimate vascular risk in AAs. Whether measures of arterial compliance are better predictors of long term risk in AAs needs to be investigated.