RESUMEN
CONTEXT: Although adrenal vein sampling (AVS) is the standard method for subtype diagnosis in primary aldosteronism (PA), protocol details including the sampling position in the adrenal vein are not standardized. OBJECTIVE: To establish the optimum sampling position in the left adrenal vein based on postoperative outcome in PA patients. DESIGN AND SETTING: Retrospective study in nine referral centres. PARTICIPANTS: Of 496 consecutive PA patients who underwent AVS between 2006 and 2013, 217 with successful AVS under cosyntropin stimulation, and with concomitant data from two positions: proximal (common trunk) and distal (central vein) to the junction with the inferior phrenic vein, were included. MAIN OUTCOME MEASURES: Discordant rate of subtype diagnosis between common trunk and central vein, and postoperative outcomes in patients with discordant results. RESULTS: Subtype diagnosis using common trunk and central vein was discordant in 10 (4·6%) of the 217 patients (κ = 0·87, P < 0·05). Of these 10 patients, eight with left unilateral subtype and two with bilateral subtype using common trunk data showed bilateral subtype and unilateral subtype, respectively, using central vein data. Five patients with left unilateral subtype and one with bilateral subtype by common trunk data underwent unilateral adrenalectomy. All six patients were cured of PA after adrenalectomy, resulting in false-negative rates of 17% (1/6) by common trunk data, and 83% (5/6) by central vein data. CONCLUSION: In view of its better potential diagnostic accuracy, technical ease, lower cost and lower risk of vein rupture, blood sampling from the common trunk of the left adrenal vein may be preferable as the standard method of AVS in patients with PA, although additional studies in a larger number of cases are required.