Resistive and pulsatile arterial load as predictors of left ventricular mass and geometry the Multi-Ethnic study of Atherosclerosis

Arterial load is composed of resistive and various pulsatile components, but their relative contributions to left ventricular (LV) remodeling in the general population are unknown. We studied 4145 participants enrolled in the Multi- Ethnic Study of Atherosclerosis, who underwent cardiac MRI and radial arterial tonometry. We computed systemic vascular resistance (SVR=mean arterial pressure/cardiac output) and indices of pulsatile load including total arterial compliance (TAC, approximated as stroke volume/central pulse pressure), forward wave amplitude (P_f), and reflected wave amplitude (Pb). TAC and SVR were adjusted for body surface area to allow for appropriate sex comparisons. We performed allometric adjustment of LV mass for body size and sex and computed standardized regression coefficients (β) for each measure of arterial load. In multivariable regression models that adjusted for multiple confounders, SVR (β=0.08; P<0.001), TAC (β=0.44; P<0.001), Pb (β=0.73; P<0.001), and P_f (β=-0.23; P=0.001) were significant independent predictors of LV mass. Conversely, TAC (β=-0.43; P<0.001), SVR (β=0.22; P<0.001), and P_f (β=-0.18; P=0.004) were independently associated with the LV wall/LV cavity volume ratio. Women demonstrated greater pulsatile load than men, as evidenced by a lower indexed TAC (0.89 versus 1.04 mL/mm Hg per square meter; P<0.0001), whereas men demonstrated a higher indexed SVR (34.0 versus 32.8 Wood Units×m²; P<0.0001). In conclusion, various components of arterial load differentially associate with LV hypertrophy and concentric remodeling. Women demonstrated greater pulsatile load than men. For both LV mass and the LV wall/LV cavity volume ratio, the loading sequence (ie, early load versus late load) is an important determinant of LV response to arterial load.