Endocrine Abstracts

Aim: To identify usefulness of adrenal vein sampling (AVS) in clinical management of primary hyperaldosteronism (PHA).

Method: Biochemical and radiological review (by two independent radiologists) of 48 AVS in 45 patients with PHA who underwent CT adrenals/AVS.

Results: CT adrenal findings were: 31/45 (68.9%) unilateral nodule (one had two nodules unilaterally), 5/45 (11.1%) bilateral nodules, 7/45 no nodules, 1/45 bilateral bulky adrenals, and 1/45 left adrenal limb thickening. Selectivity index (adrenal vein cortisol/infra adrenal IVC cortisol) >5 and lateralisation index (ratio of higher over lower aldosterone/cortisol ratio) >4 for aldosterone producing adenoma (APA) and <3 for bilateral adrenal hyperplasia (BAH) were used for AVS. Based on radiological review, 29% (14/48) of cases were cannulated bilaterally. Between radiologists, there was discordance in opinion regarding successful cannulation; 48% (23/48) right side vs 8.3% (4/48) left side. There was better agreement between radiological review and biochemical criteria on the left side (37/48 vs 18/48). Based on biochemical criteria, 59% (29/48) of cases were cannulated bilaterally; 14/29 APA, 12/29 BAH, and 3/29 inconclusive. Clinical conclusion in the remaining 19 unsuccessful cases were; 4/19 APA on secondary criteria (non-suppression of aldosterone on contralateral side) and 3/19 BAH and 12/19 inconclusive. AVS finding in patients with unilateral nodule on CT; 13/31 (42%) APA on same side as CT (four using secondary criteria), 10/31 (32.2%) BAH, and 8/31 inconclusive. On the contrary, AVS lateralised to one side in four patients with bilateral nodules and one with normal CT. Nodules >1.5 cm predicted lateralisation to the same side in AVS, with a positive predictive value of 70% compared to nodules ≤1.5 cm on CT.

Conclusion: AVS provided additional information over CT in the management of PHA; AVS helped to save 11 patients from unnecessary surgery and directed five patients who would otherwise have been treated medically, for curative surgery.