Gender-specific contribution of aortic augmentation index to variations in left ventricular mass index in a community sample of African ancestry

Abstract

Although indices of aortic augmentation derived from radial applanation tonometry are independently associated with adverse cardiovascular effects, whether these relationships are influenced by gender is uncertain. We compared the brachial blood pressure-independent contribution of augmentation index (AIx) to variations in left ventricular mass index (LVMI) in a community sample of 808 participants, 283 of whom were men. Aortic haemodynamics were determined using radial applanation tonometry and SphygmoCor software and LVMI from echocardiography. In men, both AIx derived from aortic augmentation pressure/central aortic pulse pressure (AP/PPc; partial r = 0.17, β-coefficient ± s.e.m. = 0.55 ± 0.20, P < 0.01) and AIx derived from the second peak/first peak (P2/P1) of the aortic pulse wave (partial r = 0.21, β-coefficient ± s.e.m. = 0.42 ± 0.12, P<0.0005) were associated with LVM indexed to body surface area (LVMI-BSA). In contrast, in women, neither AIx derived from AP/PPc (partial r = -0.08, β-coefficient ± s.e.m.=-0.20 ± 0.11, P = 0.08) nor AIx derived from P2/P1 (partial r = -0.06, β-coefficient ± s.e.m. = -0.07 ± 0.05, P = 0.17) were associated with LVMI-BSA. Both the strength of the correlations (P<0.001 and P<0.0005 with z-statistics) and the slope of the AIx-LVMI relationships (P=0.001 and P<0.0005) were greater in men as compared with women. The lack of relationship between AIx and LVMI was noted in both premenopausal (n=285; AP/PPc vs. LVMI-BSA, partial r = 0.01, P = 0.95, P2/P1 vs. LVMI-BSA, partial r = 0.02, P = 0.77), and postmenopausal (n = 240; AP/PPc vs. LVMI-BSA, partial r = -0.06, P = 0.37, P2/P1 vs. LVMI-BSA, partial r = -0.03, P = 0.64) women. Similar differences were noted in the relationships between AIx and LVM indexed to height(2.7) in men and women. In conclusion, radial applanation tonometry-derived AIx may account for less of the variation in end-organ changes in women as compared with men.