Diurnal variation of blood pressure in patients with catecholamine-producing tumors

To investigate the role of plasma catecholamines in diurnal blood pressure variation, invasive 24-h ambulatory blood pressure recordings (Oxford technique) were performed on 10 untreated patients; all had increased plasma concentrations of norepinephrine (mean 27.3; range 2.50 to 134.6 nmol/L) or epinephrine (mean 13.5; range 0.13 to 96.6 nmol/L) either attributable to a pheochromocytoma (n = 7) or a paraganglioma (n = 3). The nocturnal change in blood pressure was calculated as the percentage difference of blood pressure between night (midnight to 6 AM) and day (8 AM to 10 PM). The group average nocturnal change in blood pressure was 12.4%, ranging from a 32.0% decrease to a 2.8% increase, whereas the average nocturnal fall in heart rate was 18.6%, ranging from 2.2% to 33.4%. Although the nocturnal change in blood pressure was not significantly correlated with plasma values of norepinephrine (r = 0.60) or total catecholamines (r = 0.54), no nocturnal decrease in blood pressure occurred in the two patients with a plasma norepinephrine level of > 55 nmol/L. Recordings of three patients, all with a pheochromocytoma showed several paroxysms of blood pressure elevations, which lasted 18 to 47 min and had an amplitude of 32 to 94 mm Hg. In two cases these elevations had a true cyclic character. Our findings indicate that patients with a catecholamine-producing tumor may exhibit a normal diurnal blood pressure variation with a decrease in blood pressure during the night, suggesting that factors responsible for this diurnal variation remain operative in this condition.(ABSTRACT TRUNCATED AT 250 WORDS)