Impact of Hypertension on Left Ventricular Geometry and Diastolic Function in Africa: Results from the Population-Based TAnve Health (TAHES) Cohort Study

Abstract

High blood pressure leads to morphologic changes and functional alterations of the myocardial structure. Transthoracic echocardiography is of great clinical interest to evaluate these alterations, using reference values proposed by the American Society of Echocardiography/European Association of Cardiovascular Imaging, largely based on studies in Caucasian Whites. We aimed to assess the impact of hypertension on echocardiographic parameters in a sub-Saharan African community, using ethnic-specific reference values. This study is part of the TAnve HEalth Study, a population-based prospective cohort study initiated in 2015 in the district of Tanve, Republic of Benin. Hypertension was defined as systolic blood pressure ≥140mm Hg and/or diastolic blood pressure ≥90mm Hg and/or currently taking antihypertensive medications. All participants had a transthoracic echocardiography. The patterns of diastolic dysfunction and left ventricular (LV) geometry were defined from 486 subjects in the cohort, free from cardiovascular disease, diabetes, and hypertension. Of all participants, 318 (65% women, median age 48years) had hypertension. Systolic blood pressure correlated significantly (p <0.0001) with LV mass (r = 0.28), wall thickness (r = 0.25), isovolumic relaxation time (r = 0.27), E/A ratio (r = -0.35), lateral e' velocity (r= -0.41), and E/E' ratio (r = 0.39). Ventricular geometry was normal in only 22% of participants with hypertension when using the American Society of Echocardiography/European Association of Cardiovascular Imaging reference values, versus 69% with ethnic-specific reference ranges. The severity of hypertension was associated with ventricular geometry abnormalities. The prevalence of diastolic dysfunction was 14.5% (confidence interval 10.6% to 18.4%), including relaxation impairment (9%) and pseudonormal pattern (6%). Thus, correct assessment of the repercussions of hypertension on LV geometry in Black Africans requires ethnic-specific reference values.