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.

BACKGROUND: 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.
METHODS: 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 to inferior vena cava/cortisol ratio of >3:1. Lateralization was defined as an aldosterone:cortisol ratio >3 times the unaffected side.
RESULTS: 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.
CONCLUSION: 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.