Racial Differences in Arterial Stiffness and Microcirculatory Function Between Black and White Americans

• Type of Material: Article
• Authors: Alanna A. Morris, Emory University; Riyaz S. Patel, Emory University; Jose N Binongo, Emory University; Joseph Poole, Emory University; Ibhar Al Mheid, Emory University; Yusuf Ahmed, Emory University; Neli Stoyanova, Morehouse; Viola Vaccarino, Emory University; Rebecca Din-Dzietham, Morehouse; Gary H. Gibbons, National Institutes of Health; Arshed Ali Quyyumi, Emory University
• Language: English
• Date: 2013-04-24
• Publisher: American Heart Association
• Publication Version: Final Published Version
• Copyright Statement: © 2013 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley-Blackwell.
• License: Creative Commons Attribution-Noncommercial 3.0 Unported
• Final Published Version (URL): http://jaha.ahajournals.org/content/2/2/e002154
• Title of Journal or Parent Work: Journal of the American Heart Association
• ISSN: 2047-9980
• Volume: 2
• Issue: 2
• Start Page: 1
• End Page: 8
• Grant/Funding Information: This work was supported by funding from NIH/NHLBI 1 U01 HL079156‐01 (Quyyumi) and 1 U01 HL79214‐01 (Gibbons); NIH, National Center for Research Resources (NCRR) Grant M01‐RR00039 for the Emory Clinical Interaction Unit (ACTSI) and NIH/NCRR 5P20RR11104 for the Morehouse CRC; NIH K24HL077506‐06 (Vaccarino); NIH/NCRR 5U54RR022814 (Din); and the Woodruff Fund (Emory Predictive Health Initiative).
• Keywords: arterial stiffness; reactive hyperemia; racial disparities
• Research Categories: Health Sciences, General; Biology, Biostatistics

Abstract

Background Compared with whites, black Americans suffer from a disproportionate burden of cardiovascular disease (CVD). We hypothesized that racial differences in the prevalence of CVD could be attributed, in part, to impaired vascular function in blacks after adjustment for differences in risk factor burden. Methods and Results We assessed vascular function in 385 black and 470 white subjects (mean age, 48±11 years; 45% male). Using digital pulse amplitude tonometry (EndoPAT) we estimated the reactive hyperemia index (RHI), a measure of microvascular endothelial function, and peripheral augmentation index (PAT‐AIx). Central augmentation index (C‐AIx) and pulse‐wave velocity (PWV) were measured as indices of wave reflections and arterial stiffness, respectively, using applanation tonometry (Sphygmocor). Compared with whites, blacks had lower RHI (2.1±0.6 versus 2.3±0.6, P<0.001), greater arterial wave reflections assessed as both PAT‐AIx (20.4±21.5 versus 17.0±22.4, P=0.01) and CAIx (20.8±12.3 versus 17.5±13.3, P=0.001), and greater arterial stiffness, measured as PWV (7.4±1.6 versus 7.1±1.6 m/s, P=0.001). After adjustment for traditional CVD risk factors, black race remained a significant predictor of lower RHI and higher PAT‐AIx and CAIx (all P<0.001) in all subjects and of higher PWV in men (P=0.01). Furthermore, these associations persisted in a subgroup analysis of “healthy” individuals free of CVD risk factors. Conclusion Black race is associated with impaired microvascular vasodilatory function, and greater large arterial wave reflections and stiffness. Because impairment in these vascular indices may be associated with worse long‐term outcomes, they may represent underlying mechanisms for the increased CVD risk in blacks.