[Ambulatory measurement of blood pressure and plasma catecholamines in the study of orthostatic hypotension].

The purpose of the study was to investigate the interest of ambulatory blood pressure (BP) monitoring (ABPM) and plasma catecholamines in the management of orthostatic hypotension (OH). Fifteen patients, 4 men, 11 females, 53.3 +/- 21.1 years old, with OH were included in the study: 7 with dysautonomia (G1) = multiple systemic atrophy, pure autonomic failure, OH in elderly people; 8 with OH from other origin (G2) = hypovolemia, neurodystonia, vaso-vagal syncope. ABPM and plasma catecholamines assays (HPLC) in lying then in standing position were carried out in all patients. BP was 131.2 +/- 31.9/78.1 +/- 12.0 mmHg in lying and 112.1 +/- 25.3/75.4 +/- 15.8 in standing position (n = 15). The systolic (S) standing-induced (delta) decrease in BP after 1 min and 10 min (delta SBP) correlated with standard-deviation and variation coefficient of mean SBP (r = 0.78, p < 0.01; r = 0.82, p < 0.01 for delta sBP 1 min and r = 0.80, p < 0.01; r = 0.81, p < 0.01 for delta sBP 10 min), but not with norepinephrine (NorE) or epinephrine levels. There was a significant correlation between diastolic nycthemeral BP variability expressed by mean night-time DBP/mean day-time DBP ratio/diastolic N/D) and standing-induced decrease in DBP after 1 min (r = 0.59, p < 0.05). delta SBP 1 min and 10 min, delta DBP 1 min (p = 0.02, p = 0.05, p = 0.01) and systolic and diastolic N/D (p = 0.02; p < 0.01) were significantly different in G1 and G2.(ABSTRACT TRUNCATED AT 250 WORDS)