Carotid characteristics of black South Africans with five-year sustained hypertension

• Published in: Cardiovascular Journal of Africa Vol. 27; no. 4; pp. 262 - 269
• Main Authors: Huisman, Hugo W., Van Rooyen, Johannes M., Fourie, Carla M.T., Schutte, Aletta E., Maritz, Melissa
• Format: Journal Article
• Language: English
• Published: South Africa Clinics Cardive Publishing 01.07.2016
• Subjects: African Continental Ancestry Group - psychology; Aged; Biomarkers - blood; Blood Pressure; Cardiovascular Topics; Carotid Arteries - diagnostic imaging; Carotid Arteries - physiopathology; Carotid Artery Diseases - blood; Carotid Artery Diseases - diagnostic imaging; Carotid Artery Diseases - ethnology; Carotid Artery Diseases - physiopathology; Carotid Intima-Media Thickness; Case-Control Studies; Central pressure; Distensibility; Elastic Modulus; Ethnicity; Female; Health Behavior - ethnology; Humans; Hypertension; Hypertension - diagnosis; Hypertension - ethnology; Hypertension - physiopathology; Hypertension - psychology; Inflammation Mediators - blood; Large artery; Lipids - blood; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Pulse Wave Analysis; South Africa - epidemiology; Stiffness; Surveys and Questionnaires; Time Factors; Vascular Stiffness
• ISSN: 1995-1892; 1680-0745
• DOI: 10.5830/CVJA-2016-059

Introduction: An important feature of hypertension is a reduction in large artery distensibility, which may be due to structural and functional adaptations. Black populations are particularly prone to the development of hypertension. We therefore compared the carotid characteristics between five year sustained hypertensive and normotensive black South Africans, and investigated how carotid characteristics relate to cardiometabolic risk factors, inflammation, endothelial activation and health behaviours. Methods: We included HIV-free black South Africans who were either consistently hypertensive (n = 351) or normotensive (n = 241) from 2005 to 2010. We assessed carotid characteristics, including intima-media thickness (IMT), distensibility and lumen diameter with B-mode ultrasound, and calculated Young's elastic modulus, cross-sectional wall area and beta-stiffness index. We measured the carotid dorsalis pedis pulse-wave velocity, brachial and central systolic blood pressure (cSBP) and determined metabolic, inflammatory and endothelial activation markers from blood samples. Health behaviours were reported in questionnaires. Results: The hypertensive group presented with higher brachial and central blood pressure, thicker IMT and stiffer carotid arteries (all p < 0.001). However, after adjustment for cSBP but not mean arterial pressure (MAP), all significant differences in carotid characteristics were lost. The carotid thickness measurements did not differ after adjustment for MAP. After adjustment, metabolic, inflammatory and endothelial activation markers did not differ between the two groups. Conclusion: Our results suggest that besides structural changes, functional adaptations are also involved in deterioration of the carotid wall characteristics of hypertensive black South Africans. These results highlight the importance of proper hypertension control in Africa.