Hemodynamics of increased pulse pressure in older women in the community-based age, gene/environment susceptibility-Reykjavik study

Pulse pressure increases with advancing age particularly in women. As a result, women have a higher pulse pressure than men from midlife onward. Higher pulse pressure in older women as compared to men is often attributed to increased aortic wall stiffness and premature wave reflection. To evaluate this hypothesis, we measured central aortic input impedance, pulse wave velocity, and wave reflection in 408 older men and women (age range, 69 to 94 yr, mean 75 yr) participating in the community-based Age, Gene/Environment Susceptibility- Reykjavik Study (AGES-Reykjavik). Women as compared to men had higher pulse pressure (75.8±18.7 versus 69.5±16.8 mm Hg, P<0.001) and smaller aortic diameters (2.74±0.24 versus 2.97±0.28 cm, P<0.001). Augmentation index (AI) was higher (11.0±15.9 versus 7.9±12.9%, P=0.032) in women whereas proximal aortic elastance-wall thickness product (Eh) did not differ (P=0.61). In a stepwise model for pulse pressure that included age and sex and offered aortic diameter, Eh, mean pressure, AI, pulse wave velocity, height, weight, and body surface area as additional covariates, higher pulse pressure was associated with increased wall stiffness, smaller aortic diameter, higher mean pressure, and increased AI (Model R=0.59, P<0.001). The sex difference in pulse pressure (6.6±1.7 mm Hg, P<0.001) persisted after Eh entered the model (6.9±1.5 mm Hg, P<0.001) but not after aortic diameter entered the model (-0.4±1.4 mm Hg, P=0.75). Thus, reduced aortic diameter and impaired matching between diameter and flow accounts for the sex difference in pulse pressure in an unselected community-based cohort of older people.