Approach to the surgical management of primary aldosteronism
Primary aldosteronism (PA) is the most common cause of endocrine hypertension; it has been reported in more than 11% of referred hypertensive patients. PA may be caused by unilateral adrenal involvement [aldosterone producing adenoma (APA) or unilateral adrenal hyperplasia (UAH)], and bilateral disease (idiopathic adrenal hyperplasia). Only patients with unilateral adrenal hypersecretion may be cured by unilateral adrenalectomy, while patients with bilateral and non-surgically correctable PA are usually treated by mineralocorticoid receptor antagonists; thus the distinction between unilateral and bilateral aldosterone hypersecretion is crucial. Most experts agree that the referral diagnostic test for lateralization of aldosterone hypersecretion should be adrenal venous sampling (AVS) because the interpretation of other imaging techniques [computed tomography (CT), magnetic resonance imaging (MRI) and scintigraphy] may lead to inappropriate treatment. Adrenalectomy represents the elective treatment in unilateral PA variants. Laparoscopic surgery, using transperitoneal or retroperitoneal approaches, is the preferred strategy. Otherwise, the indications to laparoscopic unilateral total or partial adrenalectomy in patients with unilateral PA remain controversial. Adrenalectomy is highly successful in curing the PA, with correction of hypokalemia in virtually all patients, cure of hypertension in about 30-60% of cases, and a marked improvement of blood pressure values in the remaining patients. Interestingly, in several papers the outcomes of surgery focus only on blood pressure changes and the normalization of serum potassium levels is often used as a surrogate of PA recovery. However, the goal of surgery is the normalization of aldosterone, because chronically elevated levels of this hormone can lead to cardiovascular complications, independently from blood pressure levels. Thus, we strongly advocate the need of considering the postoperative normalization of aldosterone-renin ratio (ARR) as the main endpoint for determining outcomes of PA.