Sex Differences in Left Ventricular Wall Stress in Apparently Healthy Adults with Similar Cuff-Measured Blood Pressure

Abstract

Outcome-based evidence shows that women have a higher risk of heart failure than men at a similar level of blood pressure. Left ventricular wall stress (Ó) or afterload is an important determinant of myocardial performance. Thus, it might play a key role in determining the sex differences in heart failure.

The Ó at the beginning of aortic valve opening (Ó-AVO), the systolic peak value of the Ó (Ó-peak), and the Ó at the end systole (Ó-ES) were determined using transthoracic echocardiography combined with cuff-measured brachial blood pressure in 990 age- and heart rate- and cuff-measured blood pressure-matched apparently healthy adults (495 men). The sex differences in the aortic pressure, the ratio of left ventricular wall volume to cavity volume (V_W/V_C), and Ó were analyzed.

Compared with men, women demonstrated higher aortic systolic blood pressure (106.7 versus 101.7 mmHg), smaller V_W/V_C (1.12 versus 1.25 for the end-diastole V_W/V_C, 3.49 versus 3.82 for the end-systole V_W/V_C), and greater Ó (340.0 versus 315.6 for Ó-AVO, 471.9 versus 412.5 for Ó-peak, and 256.2 versus 230.3 kdynes/cm² for Ó-ES) (all P < 0.001).

At the same level of cuff-measured blood pressure, women have a greater Ó or afterload than men in consequence of the sex differences in left ventricular geometry and pulse pressure amplification. The evidence indicates that non-sex-specific categories of blood pressure factitiously impose a relatively higher afterload on the left ventricle in women and may therefore increase potential risk of heart failure in women.