The Role of Adrenal Venous Sampling in the Surgical Management of Primary Aldosteronism

OBJECTIVE: Primary aldosteronism is the most common endocrine form of secondary hypertension, but no single test or imaging method always identifies it. Identification of a unilateral overproduction of aldosterone due to Conn's adenoma or unilateral hyperplasia is of utmost importance to the surgeon. MATERIALS AND METHODS: We reviewed our experience with primary aldosteronism in 46 consecutive patients who had undergone adrenalectomy at the Surgical Pathology Institute, University of Padua since 1993. All the patients underwent a CT scan. Adrenal venous sampling was performed in those patients with negative or equivocal findings on imaging studies. RESULTS: Computed tomography was non-contributory in 12 patients and frankly misleading in 2 patients, demonstrating a probable mass lesion in the contralateral but not in the ipsilateral adrenal. Eighteen patients had selective venous sampling that was successful in altering the management of 14 cases. Eleven patients who biochemically had an adrenal adenoma, had normal/equivocal CT, while the remaining 3 had bilateral or contralateral adrenal masses. Venous sampling localized aldosterone secretion and an adenoma, less than 1 cm in diameter, was removed, curing their hypertension. Eleven patients were treated by open adrenalectomy and 35 by the lateral transperitoneal laparoscopic approach. Histological examination revealed 45 Conn's adenomas, of which 13 had a diameter of less than 1 cm (range 0.3-0.8), and 1 case of nodular hyperplasia. CONCLUSIONS: Patients who have equivocal or unexpected CT findings should proceed to hormonal localization. Adrenal venous sampling is essential in patients with equivocal CT scans to avoid unnecessary and inappropriate adrenalectomy.