Biochemical Evaluation by Confirmatory Tests after Unilateral Adrenalectomy for Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. Unilateral PA can be cured using unilateral adrenalectomy (Adx). PA surgery outcome (PASO) criteria, which include clinical and biochemical outcomes, have been proposed to evaluate PA cure after Adx. However, clinical outcomes are often inconsistent with biochemical outcomes. In addition, although confirmatory tests are included as endpoints of biochemical outcomes in the PASO criteria, their clinical usefulness has not yet been established. We evaluated clinical parameters and confirmatory test results before and after Adx in 16 patients with PA and assessed the usefulness of the confirmatory tests. The following were the clinical outcomes after Adx: 37.5% complete success, 62.5% partial success, and 0% absent success. The ratio of biochemical complete success was as follows: 69% aldosterone/renin ratio and basal plasma aldosterone concentration, 19% as assessed by the captopril challenge test, 47% as assessed by the saline infusion test, 30% as assessed by the furosemide upright test, and 100% urine aldosterone. Of these, biochemical complete success was judged in four cases by aldosterone/renin ratio and basal plasma aldosterone concentration, one case by captopril challenge test, five cases by saline infusion test, and one case by furosemide upright test. Although clinical outcomes and urine aldosterone levels improved after Adx, confirmatory tests failed to improve in some cases. The current criteria are not considered useful for biochemical evaluation after Adx. To determine whether additional treatment with mineralocorticoid receptor antagonists is required, more accurate biochemical criteria should be established after Adx.