Enhanced Aortic Reflected Wave Magnitude Accounts for the Impact of Female Gender on Aortic Pressure Augmentation in a Group of African Ancestry.

Abstract

Aortic reflected wave magnitude (RM) may not account for sex-specific differences in aortic pressure augmentation in Caucasians. However, aortic reflected waves are greater in groups of African descent than other ethnic groups. We determined whether RM or alternative factors explain the impact of sex on aortic augmented pressure (Pa) in participants of African ancestry. We assessed aortic function (radial applanation tonometry, SphygmoCor) in 1,197 randomly recruited community participants of African ancestry (age ≥ 16 years). Aortic forward (Pf) and backward (Pb) wave separation was performed assuming an aortic triangular flow wave validated against aortic velocity measurements. Across the adult lifespan, women had greater multivariate-adjusted augmentation index (AIx) and Pa. This was associated with multivariate-adjusted age-related increases in Pb, RM (Pb/Pf), and time to the peak of Pf and decreases in backward wave foot time; but not increases in Pf. With adjustors, Pa was associated with female gender (β-coefficient = 3.81 ± 0.34), a relationship which was markedly attenuated by adjustments for RM (β-coefficient = 1.78 ± 0.31, P < 0.0001 vs. without adjustments for RM), and Pb (β-coefficient = 2.05 ± 0.19, P < 0.0001 vs. without adjustments for Pb), but not by adjustments for Pf, time to the peak of Pf, or backward wave foot time. Similarly, AIx was associated with female gender, a relationship which was markedly attenuated by adjustments for RM, Pb, and backward wave foot time, but not alternative factors. In contrast to reports in alternative populations, the relationship between aortic pressure augmentation and female gender in participants of African descent is accounted for mainly by increases in RM.