Isolated systolic hypertension from a vascular point of view

Due to the results of antihypertensive intervention studies, isolated systo lic hypertension (ISH) has gained new interest lately. Yet, apart from incr eased aortic stiffness, the specific pathophysiological features of ISH hav e remained largely undetermined. Therefore, we investigated the elastic pro perties of the vascular bed of an upper arm segment in uncomplicated ISH pa tients and matched normotensive controls using an electrical bioimpedance t echnique. Compared with the controls, the compliance of the arterial bed as a whole at normotensive blood pressure level was on the average 108.0% hig her (p < 0.005) in the hypertensive patients. The blood volume of the arter ial bed as a whole at operating blood pressure level and that of the larger arteries were significantly higher (40.5%, p < 0.05, and 40.5%, p < 0.01, respectively). The same held true for the venous blood volume (64.4%, p < 0 .05), a nd for the width of the arterial compliance-pressure relation (34.6 %, p < 0.01). We concluded that ISH is a separate pathophysiological entity in which all parts of a peripheral vascular bed are changed and the decrea sed buffering function of the aorta and large arteries is partly compensate d for by an increase in small artery compliance. Copyright (C) 2000 S. Karg er AG, Basel.