Modification of the protocol for selective adrenal venous sampling results in both a significant increase in the accuracy and necessity of the procedure in the management of patients with primary hyperaldosteronism

Abstract

Adrenal venous sampling (AVS) is used in the work-up of primary hyperaldosteronism (PA) to distinguish unilateral PA from bilateral adrenal hyperplasia. In 2006, we reported that only 44% of AVS had biochemical evidence of bilateral adrenal vein cannulation (BAVC). Critical appraisal of our practice resulted in a protocol change. This study examined the impact of this new protocol on both the technical success rate and its influence on management of PA. Since 2006, all patients with biochemically documented PA referred to either a single endocrine surgeon or endocrine specialist underwent AVS. Successful BAVC was defined as an adrenal vein toinferior vena cava/cortisol ratio of >3:1. Lateralization was defined as an aldosterone:cortisol ratio>3 times the unaffected side. Of the 86 AVS performed on 84 patients with PA, 82 had BAVC (95%). AVS altered the management in 26 of 84 (31%) patients. Despite clear unilateral findings on imaging in 45 patients, AVS demonstrated bilateral adrenal hyperplasia. in 10 and contralateral disease in 3. AVS confirmed unilateral PA in 5 patients with equivocal <1 cm nodules. In 4 of 25 patients with normal adrenal glands, AVS demonstrated lateralization. AVS demonstrated unilateral PA in 4 of 9 patients in whom imaging suggested bilateral adrenal hyperplasia. Our new AVS protocol resulted in a marked improvement in BAVC. AVS influenced management in a third of patients with PA. Surgical decision-making cannot be made solely on the basis of cross-sectional imaging.