Outcomes After Unilateral Adrenalectomy in Asymmetrical Bilateral Primary Aldosteronism

Lateralization by adrenal vein sampling (AVS) is the gold standard for diagnosis of unilateral primary aldosteronism. Aldosterone production from the contralateral gland suggests bilateral disease; however, little is known regarding outcomes from patients with grossly elevated (but asymmetrical) contralateral aldosterone production after unilateral adrenalectomy.

A retrospective chart review was performed of cases from the Calgary AVS database with (1) successful AVS (selectivity index ≥3 bilaterally after cosyntropin stimulation); (2) lateralization by AVS (lateralization index ≥3), stimulated or unstimulated; (3) absence of contralateral suppression (contralateral suppression index ≥2 on the nondominant side) stimulated or unstimulated; and (4) underwent unilateral adrenalectomy guided by AVS lateralization. Postsurgical outcomes were classified per PASO criteria.

A total of 29 cases met inclusion criteria and underwent unilateral adrenalectomy with postsurgical outcomes available. Of patients with biochemical follow-up data, 20 of 27 had a complete biochemical response and 3 of 27 a partial response (median follow-up time of 10.3 weeks, interquartile range, 4.0-18.3). Four of 29 patients had a complete clinical response, while 18 of 29 patients had a partial clinical response (median follow-up time of 27.3 weeks, interquartile range, 10.7-35.6), such that 75% of patients had either complete or partial clinical response to unilateral adrenalectomy.

In patients with bilateral (elevated contralateral suppression index) but asymmetrical primary aldosteronism, unilateral adrenalectomy can achieve positive biochemical and clinical outcomes in the short to mid-term. Elevated contralateral suppression index should not necessarily preclude recommendation of unilateral adrenalectomy in patients with lateralized primary aldosteronism, though longer-term studies are needed to clarify the rates of disease recurrence and benefits of a debulking procedure.