Background: Baroreflex sensitivity declines with age, creating a fall in systolic blood pressure and pulse pressure when standing. If, in addition, blood pressure is reduced as a result of antihypertensive medication, compensatory mechanisms may be inadequate and orthostatic problems may occur. This may be less true in patients on beta-blockers. beta-blockers cause pressor effects in standing patients with autonomic neuropathy, but their effects on standing pulse pressures in elderly subjects with mild hypertension have not been systematically studied.
Methods and results: We studied 3741 patients with mild hypertension for 6 months who were being treated with the beta-blocker nebivolol 5 mg daily. Blood pressures were measured after 10 minutes in the supine position and after 1 minute in the standing position. Overall, systolic and diastolic blood pressures rose slightly while standing, whereas pulse pressures remained unchanged. When previously untreated patients (n=2085) >60 and <60 years of age were assessed separately, supine pulse pressures were consistently higher in the elderly group compared with those of the younger subjects by 6 to 11 mm Hg (P<0.001 to 0.0001). However, while standing, pulse pressures rose in the younger subjects, whereas they tended to fall in the elderly group. After 6 months of beta-blockade, this pattern was unchanged in the younger subjects but reversed into significant rise of pulse pressures in the elderly group by 4 (SD 1) mm Hg (P<0.001). In the patients previously treated with other classes of antihypertensive drugs (n=712), the effects were essentially the same.
Conclusions: In elderly patients with mild hypertension, a depressor trend of pulse pressure while standing can be turned into a significant pressor response by treatment with a beta-blocker.