Relations of Microvascular Function, Cardiovascular Disease Risk Factors, and Aortic Stiffness in Blacks: The Jackson Heart Study.

Background Blacks have more severe endothelial dysfunction and aortic stiffening as compared with whites. We aimed to investigate the association between aortic stiffness and microvascular function in the black community. Methods and Results We assessed the association between forearm vascular reactive hyperemia (an indicator of microvascular function) and aortic stiffness in 1458 black participants (N=965 [66% women]; mean age: 66±11 years) in the Jackson Heart Study. We evaluated 2 measures of aortic stiffness: brachial pulse pressure and carotid-femoral pulse wave velocity. Using high-resolution ultrasound and Doppler, we evaluated brachial blood flow at baseline and during reactive hyperemia after 5 minutes of forearm ischemia. Multiple cardiovascular risk factors were significantly related to baseline and hyperemic brachial flow velocity. Women had lower baseline flow across the entire age spectrum. During hyperemia, we observed a significant age-sex interaction for flow velocity ( P=0.02). Female sex was protective against microvascular dysfunction among younger participants, but older women exhibited a greater attenuation of the hyperemic flow reserve. In multivariable models that adjusted for cardiovascular disease risk factors and mean arterial pressure, higher carotid-femoral pulse wave velocity (ß=-0.106±0.033; P=0.001 was related to lower baseline flow. However, during reactive hyperemia, elevated brachial pulse pressure (ß=-0.070±0.031; P=0.03) and carotid-femoral pulse wave velocity (ß=-0.128±0.030; P<0.001) were both related to attenuated brachial flow velocity. Conclusions In a sample of blacks, higher aortic stiffness and pressure pulsatility were associated with lower flow reserve during reactive hyperemia, beyond changes attributable to traditional cardiovascular disease risk factors alone.

Clinical Correlates of Aortic Stiffness and Wave Amplitude in Black Men and Women in the Community.

Background Black individuals have greater risk for cardiovascular disease ( CVD ) than whites. Identifying CVD risk factors associated with abnormal aortic hemodynamics in blacks may optimize CVD prevention and treatment strategies. Methods and Results Jackson Heart Study participants underwent applanation tonometry (2011-2016) with assessment of carotid-femoral pulse wave velocity ( CFPWV ) and forward wave amplitude ( FWA ). CVD risk factors were assessed during examination 3 (2009-2012). We examined the association of risk factors with binary and continuous CFPWV and FWA in multivariable stepwise models. We evaluated for effect modification by sex to determine differential associations of risk factors with aortic hemodynamics in men and women. We examined 1322 individuals (mean age 66±11 years, 66% women). Age was strongly associated with elevated CFPWV (odds ratio, 4.76; 95% confidence interval, 3.84-5.89 [ P<0.0001]) and FWA (odds ratio, 2.30; 95% CI , 1.98-2.69 [ P<0.0001]). Men had greater odds of elevated CFPWV compared with women (odds ratio, 1.54; 95% confidence interval, 1.11-2.13 [ P=0.009]). Heart rate, mean arterial pressure, and use of antihypertensive medications were associated with elevated CFPWV and FWA (all P≤0.02). Additionally, total/high-density lipoprotein cholesterol and fasting glucose were associated with elevated CFPWV (both P≤0.002) and use of diabetes mellitus medications was associated with elevated FWA ( P≤0.0001). We observed a steeper association of age and mean arterial pressure with unfavorable aortic hemodynamics in women than men. Conclusions In blacks in the community, differential CVD risk factors are associated with aortic stiffness and FWA. Future work may determine the impact of risk factor modification on abnormal central aortic hemodynamics and CVD outcomes.