Associations of aortic and mitral regurgitation with body composition and myocardial energy expenditure in adults with hypertension: the Hypertension Genetic Epidemiology Network study

Abstract

Background: It has been reported that aortic regurgitation, mitral valve regurgitation, or both are associated with lower body mass index, an index of body adiposity. However, the relations of valvular regurgitation to body composition and myocardial bioenergetic expenditure have not been previously investigated in a population-based sample.

Methods: We selected 1496 patients with hypertension who did not have diabetes mellitus to participate in the Hypertension Genetic Epidemiology Network (HyperGEN) study. We excluded participants with severe aortic or mitral stenosis or with known coronary heart disease. Bioimpedance was used to assess body composition. Echocardiography was used to assess left ventricular (LV) structure and function and to calculate myocardial workload (expressed as energy expenditure) from end-systolic stress, ejection time, and stroke volume. The study sample was divided into groups without mitral or aortic regurgitation (control subjects, n = 1175), with mild valvular regurgitation (1+, n = 246), and with at least moderate (>or=2+) mitral or aortic regurgitation (n = 75).

Results: The mean patient age was higher with more severe valvular insufficiency. Sex distribution and blood pressure were similar among the 3 groups. Body mass index and fat mass were significantly lower with more severe valvular regurgitation, whereas fat-free mass was only slightly lower in the group with >or=2+ regurgitation compared with control subjects. Skinfold thicknesses (brachial and subscapular) were lower with more severe valvular regurgitation, whereas self-reported physical activity per week was similar among the 3 groups. LV mass and circumferential end-systolic stress were higher with more severe valvular regurgitation. Noninvasively estimated myocardial energy expenditure was slightly higher in participants with 1+ valvular regurgitation and was significantly higher with >or=2+ regurgitation. Ejection fraction was mildly lower with >or=2+ aortic insufficiency, mitral insufficiency, or both. Midwall shortening and stress-corrected midwall shortening did not differ among groups.

Conclusions: In a population-based sample of adults with hypertension and without diabetes mellitus, known coronary heart disease, or significant valvular stenosis, mitral and aortic regurgitation were associated with higher LV mass and total myocardial biomechanical workload but with lower body fat mass and slightly lower body fat-free mass, which suggests that global myocardial bioenergetic expenditure is elevated by concomitant valvular regurgitation beyond the effect of pressure overload caused by hypertension.