Sex differences in the impact of ventricular-arterial coupling on left ventricular function in patients with hypertension.

Abstract

Increased arterial stiffness elevates aortic load, which can have adverse impacts on left ventricular (LV) function and contribute to the onset of heart failure. This impact is known to be more pronounced in women. Optimal coordination between ventricular contraction and the arterial system is required to maintain efficient cardiac function. This study aimed to investigate sex differences in the impact of ventricular-arterial coupling (VAC) on LV function in patients with hypertension at rest and after handgrip exercise. Echocardiographic indexes of LV volumes, systolic function, and diastolic function were obtained in the usual way. Effective arterial elastance (EA) and index (EAI) were calculated from stroke volume measured using LV outflow waveform. Effective LV end-systolic elastance (ELV) and index (ELVI) were obtained using the single-beat method. Central aortic pressure waveform was recorded using the applanation tonometry. Characteristic impedance (Zc) of aortic root and reflection magnitude (RM) was calculated after Fourier transformation of both aortic pressure and flow waveforms. Sixty-four patients (31 women and 33 men) with hypertension were enrolled. Women showed higher ELVI (1.33±0.34 vs. 1.10±0.29 mmHg/ml∙m2, P = 0.004) and EAI (1.14±0.25 vs. 0.93±0.26 mmHg/ml∙m2, P = 0.001), but VAC was not different (women: 0.88±0.17 vs. men: 0.85±0.11, P = 0.431). Zc and RM were not different between women and men. After handgrip exercise, an increase in ELVI (P = 0.021) and a decrease in VAC (P = 0.035) were observed specifically in men, with no corresponding changes noted in women. In women, VAC was significantly associated with E' velocity (beta -0.344, P = 0.029) and left ventricular global longitudinal strain (beta 0.470, P = 0.012) after adjustment, but in men, no association was found. Hypertensive women demonstrated greater stiffness in both the left ventricle and arterial systems, along with impaired LV contractile reserve in response to handgrip exercise, as compared to men. The ventricular-arterial mismatch had a notable impact on LV diastolic and systolic dysfunction only in women, but not in men.