Arterial compliance abnormalities in isolated systolic hypertension

Arterial compliance measurements using intraarterial pulse contour analysis and a modified Windkessel model were carried out in 19 patients with isola ted systolic hypertension (greater than or equal to 160/less than or equal to 90 nim Hg) and compared to measurements in 29 patients with essential hy pertension (diastolic blood pressure [BP] greater than or equal to 95 mm Hg r) and 47 normotensive control subjects. Arterial capacitive compliance was significantly lower in isolated systolic hypertension than in essential hy pertension (P < .0002) and significantly lower in essential hypertension th an in normotensive control subjects (P < .0001). Although the isolated syst olic hypertension group was older than the essential hypertension group, th e reduction of capacitive compliance in isolated systolic hypertension pers isted even when comparison was made with a more nearly age-matched group of essential hypertension. In contrast, oscillatory compliance was reduced si milarly in isolated systolic hypertension and essential hypertension compar ed to normotensive control subjects (P < .0001). Although pulse pressure wa s greater in isolated systolic hypertension than in essential hypertension, only a weak correlation (r = -0.34) existed between pulse pressure and cap acitive compliance. These data indicate that both essential hypertension an d isolated systolic hypertension patients exhibit comparably abnormal struc ture or tone of the small vessels that are the site of oscillations or refl ections in the arterial vasculature. In isolated systolic hypertension ther e is a profound reduction in large artery or capacitive compliance that acc ounts for the increase in systolic BP and decrease in diastolic BP. This ab normality cannot be accurately assessed by pulse pressure alone. Am J Hyper tens 2001;14: 1007-1011 (C) 2001 American Journal of Hypertension, Ltd.