July 1, 2003Hypertension235 citationsOpen Access
View Full PaperAssociation Between Supine Hypertension and Orthostatic Hypotension in Autonomic Failure
Structured PICO
Is supine hypertension associated with orthostatic hypotension and altered baroreflex-cardiovagal gain in patients with chronic autonomic failure?
P
Population
Patients with pure autonomic failure (PAF), multiple-system atrophy (MSA) with or without orthostatic hypotension (OH), and Parkinson's disease (PD) with or without OH. Controls included age-matched healthy volunteers, patients with essential hypertension, and patients referred for dysautonomia.
C
Comparator
Patients without orthostatic hypotension, healthy volunteers, and patients with essential hypertension
O
Outcome
Association between supine hypertension and orthostatic hypotension, measured by supine and upright blood pressures, hemodynamic responses to the Valsalva maneuver, baroreflex-cardiovagal gain, and plasma norepinephrine (NE) levelssurrogate
In chronic autonomic failure, supine hypertension is strongly linked to orthostatic hypotension and low baroreflex-cardiovagal gain, suggesting pressor mechanisms independent of the sympathetic nervous system.
Abstract
Supine hypertension occurs commonly in primary chronic autonomic failure. This study explored whether supine hypertension in this setting is associated with orthostatic hypotension (OH), and if so, what mechanisms might underlie this association. Supine and upright blood pressures, hemodynamic responses to the Valsalva maneuver, baroreflex-cardiovagal gain, and plasma norepinephrine (NE) levels were measured in pure autonomic failure (PAF), multiple-system atrophy (MSA) with or without OH, and Parkinson's disease (PD) with or without OH. Controls included age-matched, healthy volunteers and patients with essential hypertension or those referred for dysautonomia. Baroreflex-cardiovagal gain was calculated from the relation between the interbeat interval and systolic pressure during the Valsalva maneuver. PAF, MSA with OH, and PD with OH all featured supine hypertension, which was equivalent in severity to that in essential hypertension, regardless of fludrocortisone treatment. Among patients with PD or MSA, those with OH had higher mean arterial pressure during supine rest (109+/-3 mm Hg) than did those lacking OH (96+/-3 mm Hg, P=0.002). Baroreflex-cardiovagal gain and orthostatic increments in plasma NE levels were markedly decreased in all 3 groups with OH. Among patients with PD or MSA, those with OH had much lower mean baroreflex-cardiovagal gain (0.74+/-0.10 ms/mm Hg) than did those lacking OH (3.13+/-0.72 ms/mm Hg, P=0.0002). In chronic autonomic failure, supine hypertension is linked to both OH and low baroreflex-cardiovagal gain corrected. The finding of lower plasma NE levels in patients with than without supine hypertension suggests involvement of pressor mechanisms independent of the sympathetic nervous system.