Abstract 2463: Racial Differences in Vascular Function and Central Hemodynamics Is not Related to Inflammation, Cardiorespiratory Fitness or Body Fat
Black American men have a higher prevalence of hypertension compared with their white peers.
Objectives: to test the hypotheses that
racial differences in vascular function would be mediated by inflammation;
vascular dysfunction in black men would contribute to greater central pulse pressure (PP) when compared to young white men.
Methods: Fifty-five young (23 yrs) healthy men (25 black and 30 white) underwent measures of carotid intimamedia thickness (IMT) and carotid beta-stiffness via ultrasonography, aortic pulse wave velocity (PWV), central pressure, augmentation index (AIx) and wave reflection travel time (Tr) via tonometery and vasodilatory capacity of forearm resistance arteries using reactive hyperemia and strain-gauge plethysmography. C-reactive protein (CRP) was measured from venous samples. Body fat was measured by air displacement plethysmography. Cardiorespiratory fitness was measured using an exercise test with metabolic gas analysis (VO2peak).
Results: Black and white men had similar VO2peak [32(1) vs 30(1) ml/kg/min] and body fat [17(2) vs 21(2) %]. Brachial PP was similar between groups but carotid PP was greater in black men (p<0.05). Black men also had greater CRP [4.6(1) vs 1.4(0.5) mg/L, p<0.05], carotid IMT, carotid beta-stiffness, aortic PWV, AIx and reduced aortic Tr, peak hyperemic forearm blood flow (FBF) (Table 1⇓, p<0.05). Co-varying for CRP, fitness or fatness had no effect on racial differences in vascular function.
Conclusion: Diffuse vascular dysfunction manifesting as carotid hypertrophy, increased stiffness of central arteries, blunted resistance artery dilation and greater arterial wave reflection is present at a young age in black men and is not related to the greater inflammatory burden seen in this population. Young black men have greater central PP despite comparable brachial PP when compared with young white men and conventional brachial PP measurement does not reflect racial differences in vascular burden. Vascular and blood pressure variables
This research has received full or partial funding support from the American Heart Association, Midwest Affiliate (Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, South Dakota & Wisconsin).