Sex differences in noninvasive estimates of left ventricular pressure energetics but not myocardial oxygen demand in young adults

Background: Sex differences in arterial stiffness and wave reflections may lead to disproportionate increases in afterload and myocardial work in women. We examined sex differences in arterial stiffness, pressure from wave reflections, measures of left ventricular (LV) energetics and myocardial work. Methods: 99 Healthy adults participated in this study 84 were selected (42 females, 42 males) to be matched for potential confounders of central hemodynamic burden such as age, BMI, and mean arterial pressure. Aortic pressure waves were derived from the radial artery using a generalized transfer function. Pulse contour analysis and wave separation analysis were used to obtain: pulse wave velocity (PWV) as a measure of aortic stiffness, augmentation index (AIx) and reflection index (RIx) as measures of global wave reflections, LV pressure effort (δE_w) as a measure of LV energy required to overcome wave reflections and the subendocardial viability ratio (SEVR) as a proxy of myocardial work. Results: Women exhibited higher δE_w (p<0.05), heart rate corrected AIx (p<0.05) and RIx (p<0.01), and lower PWV (p<0.001) compared to men. Pressure from wave reflections (Pb) was significantly associated with δE_w in women (r=0.81, p<0.001), but not in men (r=0.14, p>0.05). There were no sex differences for SEVR (p=0.4). Conclusion: Women had higher pressure from wave reflections which was associated with greater LV pressure effort compared to men. Although women had increased LV pressure effort, proxies of myocardial perfusion and work were not affected.