Is there a relationship between supine systemic blood pressure and orthostatic hypotension in the elderly?

Abstract

The relationship between blood pressure and orthostatic hypotension was studied in 48 elderly patients with orthostatic hypotension and 29 healthy age-matched controls. Individuals were designated as hypertensive (systolic > 160 and or diastolic > 90 mmHg) or normotensive on the basis of supine blood pressure levels. Systolic, diastolic and mean blood pressures, heart rate, stroke volume, cardiac output, cardiac index and total peripheral resistance were measured every 5 min before, during and after 10 min head-up tilt to 70 degrees. Eighteen orthostatic hypotension subjects and six controls were hypertensive, while 30 orthostatic hypotension subjects and 23 controls were normotensive. There were no differences between hypertensive and normotensive patients in mean age, weight, height or body surface area. Mean systolic blood pressure in orthostatic hypotension subjects was higher than in controls (148.8 +/- 3.6 vs. 137.5 +/- 3.34 mmHg). Mean diastolic pressure was not different (79.1 +/- 2.0 vs. 79.0 +/- 2.0 mmHg). There were no differences between patients with or without hypertension in the haemodynamic changes produced by head-up tilt. Heart rates in orthostatic hypotension subjects with hypertension were significantly lower throughout the study when compared with normotensive orthostatic hypotension patients. Further, the increases in heart rate on tilting were significantly smaller (8.4 +/- 1.9 vs. 14.5 +/- 1.8 beats/min). Control hypertensive subjects had significantly higher mean cardiac output and cardiac index compared with non-hypertensives from before and during tilt. We conclude that hypertension is not related to the development or the degree of orthostatic hypotension in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)