Aortic wave reflection in women and men

Abstract

Augmentation index (AIx), a marker of the number of aortic wave reflections (AWRs), is influenced not only by the magnitude of incident and reflected pressure waves but also by the time of return. A new triangulation method has been developed, enabling us to better quantify AWRs and to determine their sex differences, which may relate to body size or pulse pressure (PP) amplification, measured from the brachial PP-to-carotid PP (B/C) ratio. With the use of pulse wave analysis, AWRs were evaluated in 51 women and 72 men treated for hypertension and studied in relationship to age, blood pressure, and pulse wave velocity. When women were compared with men, AIx (expressed in %PP and adjusted to heart rate) was significantly higher, together with a significant decrease of the B/C ratio and an increase of the reflection magnitude and of the amplitude (but not the timing) of the backward pressure wave. The significance of the amplitude difference between men and women was enhanced after an adjustment to heart rate or pulse wave velocity but was abolished after an adjustment to body height or the B/C ratio. In the overall population, AIx and the reflection magnitude index were positively (r(2) = 0.39) and independently associated, after excluding confounding factors such as drug treatment. In conclusion, when compared with men, women treated for hypertension have increased AIx, related to the increased amplitude, and not timing, of backward pressure waves. This finding relates to sex differences in body size and mostly brachial-carotid PP amplification, a parameter highly related to the sex difference of cardiovascular risk.