Arterial stiffness and orthostatic blood pressure changes in untreated and treated hypertensive subjects.

Carotid-femoral pulse wave velocity (PWV), an integrated marker of segmental aortic stiffness, was recently proposed as one of the underlying mechanisms inducing orthostatic hypotension in the elderly with marked arterial rigidity. We examined the relationship between PWV (Complior; Colson, Paris, France) and orthostatic blood pressure (BP) changes, measured repeatedly, over a wide range of age and arterial stiffness. Sixty-nine hypertensive subjects (age, 37 to 76 years; 39 untreated and 30 treated) were studied. BP, in both sitting and erect position, was measured at two occasions a few weeks apart, and in between PWV was assessed by means of pulse wave analysis. In untreated hypertensive subjects, the orthostatic alterations in systolic, but not in diastolic blood pressure (DBP), were inversely related to PWV, independently from age, gender, mean BP, and diabetes mellitus. The greater the aortic stiffness the larger was the systolic blood pressure (SBP) decrease during upraises. On the contrary, no such association was found between PWV and orthostatic changes of BP in treated hypertensive subjects. These results suggest the presence of a pathophysiological association between arterial stiffening and BP postural changes. Antihypertensive drug treatment, as well as other factors that have not been evaluated in the present study, might have modulated this association. However, it might be argued that a causal association between arterial stiffness - disturbed baroreflex sensitivity - postural BP changes, even in subjects without pronounced vascular aging or orthostatic hypotension, is implied.