Increased Wave Reflection Rather Than Central Arterial Stiffness Is the Main Determinant of Raised Pulse Pressure in Women and Relates to Mismatch in Arterial Dimensions : A Twin Study

ObjectivesOur aim was to examine the relative contributions of the first systolic shoulder (P1) and augmentation pressure (ΔPaug) to central pulse pressure (cPP), their relation to central arterial stiffness (pulse wave velocity [PWV]) and arterial diameters, and their respective heritability estimates.BackgroundcPP is augmented above P1 by ΔPaugdue to pressure waves reflected from the periphery of the circulation.MethodsWomen (n = 496) from the Twins UK adult twin registry (112 monozygotic, 135 dizygotic pairs) age 21 to 81 years were studied. cPP, P1, and ΔPaugwere estimated using the SphygmoCor system (Atcor, West Ryde, Australia) from transformed radial waveforms. Carotid-femoral PWV was measured using the same system. Aortic and femoral artery diameters were measured by ultrasonography. Heritability was estimated using structural equation modeling.ResultsP1 and ΔPaugaccounted for 22% and 76%, respectively, of the variance in cPP. After adjustment for mean arterial pressure and heart rate, P1 strongly independently positively correlated with PWV (standardized regression coefficient, β = 0.4, p < 0.0001), whereas ΔPaugdid not independently correlate with PWV but independently negatively correlated with the ratio of the diameter of the femoral to that of the abdominal aorta (β = −0.12, p < 0.001). Estimates of heritability (h2) of cPP, PWV, P1, and ΔPaugwere 0.43, 0.34, 0.31, and 0.62, respectively, after adjustment for mean arterial pressure and heart rate.ConclusionsThese results suggest that, in women, ΔPaugis highly heritable, is associated with the ratio of distal to proximal arterial diameters, and, independent of PWV, is a major determinant of cPP.