Postural stimulation test in patients with aldosterone producing adenomas.

Abstract

The purpose of this study was to evaluate the postural stimulation test before and after surgical treatment in patients with aldosterone-producing adenomas. The retrospective study was made on patients with aldosterone producing adenomas. The postural stimulation test was analysed in 60 patients with surgically proven aldosterone producing adenoma and in 15 healthy volunteers. The postural stimulation test was based on measurements of plasma aldosterone, cortisol and renin activity (PRA) at 0800 h and at noon after 4 hours ambulation. The patients were divided into two groups according to the individual pattern of plasma aldosterone concentration following the postural test. Plasma aldosterone concentration decreased or did not change after 4 hours of standing in 42 patients (group 1, 70% of total) and increased in 18 patients (group 2, 30% of total). Mean plasma aldosterone was significantly higher in group 1 than in group 2 (1325 +/- 164 pmol/l (mean +/- SE) and 538 +/- 53 pmol/l, respectively). Mean plasma cortisol concentration after 4 hours of upright posture in both groups remained low (242 +/- 35 vs 401 +/- 63 nmol/l (group 1) and 317 +/- 46 vs 367 +/- 43 nmol/l (group 2)). Mean PRA in both groups was suppressed after 4 hours of upright posture (0.2 +/- 0.04 vs 0.2 +/- 0.04 pmol/l/s and 0.3 +/- 0.06 vs 0.1 +/- 0.02 pmol/l/s, respectively). Diverse changes in plasma aldosterone and cortisol found in response to the postural test may indicate pathogenetic heterogeneity amongst patients with aldosterone producing adenomas and should be considered during diagnosis of primary aldosteronism.