Clinical and biochemical outcome after unilateral adrenalectomy in primary aldosteronism

Objective: Unilateral adrenalectomy is curative for primary aldosteronism (PA) due to an aldosterone producing adenoma and is routinely offered to patients with unilateral aldosterone excess, confirmed by adrenal vein sampling. Our aim was to evaluate the clinical and biochemical outcome after unilateral adrenalectomy in PA. Method: 103 patients were diagnosed with PA, enclosed in the German Conn Registry and underwent unilateral adrenalectomy between 2009 and 04/2014 in Munich. A standardized re-evaluation was recommended six months after surgery, including measurements of plasma potassium, the aldosterone to renin ratio (ARR) and a saline infusion test (SIT). Results: 93 patients presented for a clinical check-up six months after surgery. 27 (29%) were normotensive (< 140/90 mmHg) without medication, 49 (52.7%) required medication for blood pressure control and 17 (18.3%) suffered from resistant hypertension. 61 patients underwent SIT. 49 tests (80.2%) confirmed biochemical remission. In two cases (3.4%) the ARR at baseline was elevated, however aldosterone was suppressible beneath the cut-off of 50 ng/l. 10 patients (16.4%) showed an elevated ARR and insufficient suppression of aldosterone, confirming persistence or recurrence of PA. All of the latter required antihypertensive therapy. Conclusion: Normotension after unilateral adrenalectomy indicates therapeutic success, whereas hypertension combined with re-appearance of hypokalemia is suggestive of persisting or recurring PA. Most of our patients presented with normokalemia and hypertension six months after surgery. In this cohort biochemical re-evaluation is necessary to identify cases of continued autonomous aldosterone secretion. Our data indicate that persisting or recurring PA after adrenalectomy is more frequent than previously assumed. Since these patients can benefit from mineralocorticoid receptor inhibitors, screening for PA should be performed if arterial hypertension persists after surgery.