Objective: After unilateral adrenalectomy (uADX) in patients with a unilateral aldosterone-producing adenoma (APA), the remaining contralateral adrenal gland is generally considered sufficient to support life. However, few studies have compared adrenal reserve function before and after uADX. Therefore, we closely evaluated adrenal cortisol secretory function before and after uADX in patients with unilateral APA.
Methods: Patients who were diagnosed with APA and underwent uADX for unilateral APA were initially included in this study. Patients with subclinical Cushing's syndrome (SCS) or Cushing's syndrome were excluded on suspicion of autonomous cortisol secretion. Fourteen patients were finally evaluated. Morning basal serum cortisol and plasma adrenocorticotropin hormone (ACTH) levels were measured, and ACTH stimulation tests under 1-mg dexamethasone suppression (dex-ACTH test) were performed before and after uADX.
Results: No patient developed clinical adrenal insufficiency. Basal cortisol levels were not significantly different before and after uADX. However, basal ACTH levels were significantly elevated after uADX. In addition, peak cortisol levels on the dex-ACTH test decreased in all patients after uADX. The peak cortisol level after uADX was 86.6 (81.4–92.4)% of the level before uADX.
Conclusion: The adrenal cortisol secretory response to ACTH stimulation is mildly reduced after uADX in patients with unilateral APA without SCS or Cushing's syndrome, although their basal cortisol level is sustained by elevated ACTH. These data will be important as a point of discussion when patients with unilateral APA consider either uADX or specific pharmacotherapy as treatment options.
aDepartment of Medicine and Clinical Science, Kyoto University Graduate School of Medicine
bDepartment of Clinical Trial Design & Management, Translational Research Center, Kyoto University Hospital
cEBM Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
Correspondence to Masakatsu Sone, MD, PhD, Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606–8507, Japan. Tel: +81 75 751 3170; fax: +81 75 771 9452; e-mail: firstname.lastname@example.org
Abbreviations: A/C, aldosterone-to-cortisol ratio; ACTH, adrenocorticotropin hormone; APA, aldosterone-producing adenoma; ARR, aldosterone-to-renin ratio; AUC, area under the curve; AVS, adrenal venous sampling; dex-ACTH test, ACTH stimulation test under 1-mg dexamethasone suppression; HPA, hypothalamic-pituitary-adrenal; PAC, plasma aldosterone concentration; PRA, plasma renin activity; SCS, subclinical Cushing's syndrome; uADX, unilateral adrenalectomy
Received 21 January, 2013
Revised 2 April, 2013
Accepted 16 May, 2013
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