Predictive value of preoperative tests in discriminating bilateral adrenalhyperplasia from an aldosterone-producing adrenal adenoma

In primary hyperaldosteronism, discriminating bilateral adrenal hyperplasia (BAH) from an aldosterone-producing adenoma (APA) is important because adr enalectomy, which is usually curative in APA, is seldom effective in BAH. W e analyzed the results from our most recent 7-yr series to evaluate the pre dictive value of preoperative noninvasive tests compared with adrenal vein sampling (AVS). Forty-eight patients with hypertensive hyperaldosteronism u nderwent bed side testing, computed tomography (CT) imaging, and AVS. Those in whom the results of AVS indicated APA underwent adrenalectomy. Twelve ( 30%) and 14 (34%) of 41 patients with APA had paradoxical falls with ambula tion in plasma aldosterone concentration (PAC) and 18-hydroxycorticosterone (18-OH-B), respectively. Twenty-nine (70%) and 26 (65%) APA patients had a rise in PAC and 18-OH-B, respectively, as did all 8 BAH patients. Signific ant identifiers of BAH were supine PAC values less than 15 ng/dL (P = 0.04) , an increase greater than 60% (P = 0.02) in PAC with ambulation, and supin e 18-OH-B values less than 60 ng/dL (P = 0.04). CT imaging alone was not pr edictive for BAH or APA. In our population, patients with a positive bedsid e test result (e.g. a fall in PAC and/or 18-OH-B) and a unilateral adrenal nodule on CT (10 of 41 patients) could have proceeded directly to adrenalec tomy for ATA. However, a positive bedside test result with a negative CT or a negative bedside test result regardless of CT findings required AVS to c onfirm the diagnosis and site of disease.