Contribution of stroke volume to the change in pulse pressure pattern withage

This study investigated the effect of age on pulse pressure and its underly ing mechanisms in unmedicated hypertensive men with the same level of mean arterial pressure. We included 77 men 17 to 76 years old with daytime mean arterial pressure between 95 and 114 mm Hg. In the supine position, pulse p ressure showed a significant widening in young (<30 years) and older (great er than or equal to 60 years) patients. Pulse pressure decreased in paralle l with stroke index from age >30 to 40 to 49 years. Upright posture, howeve r, eliminated this difference through a larger orthostatic fall in stroke i ndex and pulse pressure in the youngest patients. After age 50 years, pulse pressure exhibited a progressive widening despite the further age-related decrease in stroke index. Supine, upright, and 24-hour pulse pressure fitte d a curvilinear correlation with age (r=0.55, 0.56, and 0.68, respectively, P<0.001), with a transition at age 50 years. Before age 50 years, 24-hour pulse pressure correlated positively with stroke volume (r=0.5, P<0.001) an d negatively with arterial compliance (SV/PP ratio, r=-0.37, P<0.01). In co ntrast, in men greater than or equal to 50 years old, 24-hour pulse pressur e correlated negatively with the SV/PP ratio (r=-0.5; P<0.01), without sign ificant influence of stroke volume. Thus, in hypertensive men, the age-rela ted change in stroke volume significantly accounted for the change in clini c and ambulatory pulse pressure during young adulthood, but its contributio n decreased after the fifth decade.