Preoperative diagnosis and localization of aldosterone-producing adenoma by adrenal venous sampling after administration of metoclopramide.
OBJECTIVE
Adrenal venous sampling is the most reliable test to distinguish aldosterone-producing adenoma (APA) from idiopathic hyperaldosteronism (IHA). The diagnostic accuracy can be improved by administration of adrenocorticotropin to minimize pulsatile secretion of aldosterone. Metoclopramide (MCP), a dopamine antagonist, can increase aldosterone secretion promptly without affecting cortisol secretion. This study investigated the diagnostic accuracy of adrenal venous sampling after MCP injection for the preoperative diagnosis and localization of APA.


METHODS
Prospective diagnosis and adrenalectomy was based on adrenal venous sampling in 23 patients with a diagnosis of primary aldosteronism. Plasma aldosterone concentrations from adrenal veins and the inferior vena cava were measured before and 30 minutes after intravenous administration of 10 mg MCP. The ratio of bilateral adrenal venous aldosterone concentrations after MCP was used for diagnosis as follows: a ratio greater than 5 indicated APA, less than 3 indicated IHA, and 3-5 indicated an intermediate diagnosis.


RESULTS
Catheterization of the right adrenal vein was unsuccessful in three patients. Twelve of 13 patients with an aldosterone ratio greater than 5 after MCP underwent unilateral adrenalectomy, and APA was confirmed in 11 of these patients. One patient with an intermediate diagnosis also had surgically confirmed APA. Six patients had a ratio less than 3. Before MCP administration, 10 of 13 patients with APA had a ratio greater than 5, and three patients had a ratio between 3 and 5; one patient with IHA had a ratio greater than 5. MCP improved the diagnosis of APA to an accuracy of 92% (12/13). Correct diagnosis of APA based on computerized tomography (CT) was 85% (11/13). There was discordance between the findings of adrenal venous sampling and CT in four of 20 patients.


CONCLUSIONS
Administration of MCP to stimulate aldosterone secretion during adrenal venous sampling can improve the accuracy of differential diagnosis between APA and IHA.
Wu
K D
KD
Department of Medicine, Urology, National Taiwan University Hospital, Taipei, Taiwan.
Liao
T S
TS
Chen
Y M
YM
Lai
M K
MK
Chen
S J
SJ
Su
C T
CT
Chu
T S
TS
Chang
C C
CC
Hsieh
B S
BS
D000236:Adenoma / Q000175:diagnosis*; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D000311:Adrenal Glands / Q000098:blood supply*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000097:blood / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000175:diagnosis*; D008297:Male; D008787:Metoclopramide; D008875:Middle Aged
D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D008787:Metoclopramide