Objective: Widening of pulse pressure contributing to increased prevalence of systolic hypertension in older subjects could result from arterial stiffening, increased peripheral pressure wave reflection and/or an altered pattern of ventricular ejection. We evaluated the roles of these factors in determining changes in pulse pressure during longitudinal follow-up of the Twins UK cohort.

Methods: Non-invasive central blood pressure and flow were obtained by carotid tonometry and Doppler sonography respectively in a total of 329 women at first visit (mean SD, age 58± 8 years) and a follow-up visit approximately five years later (mean age 63± 8 years). Aortic root pulse wave velocity and reflection index (the ratio of the peak of the backward pressure wave over that of the forward pressure wave) were computed from the pressure and flow waves.

Results: Over the five year follow-up period, pulse pressure increased by 9.2%, from 43.7±73 to 47.7±0.78 mmHg (means SE, P < 0.001), PWV increased by 18.5 % from 4.01±0.08 m/s at first visit (P<0.001), the maximum value of flow velocity tended to increase (from 1.13±0.01 to 1.15±0.01 m/s) but reflection index decreased from 0.38±0.01 to 0.32±0.01 (P<0.001).

Conclusions: These results suggest that the increase of pulse pressure is related mainly to an increase in arterial stiffening rather than to an increase in pressure wave reflection.