Correlation Between Lateralization Index of Adrenal Venous Sampling and Standardized Outcome in Primary Aldosteronism

OBJECTIVES: The aim of this study was to investigate the impact of adrenal venous sampling (AVS) lateralization cutoffs on surgical outcomes. PATIENTS AND METHODS: Cosyntropin-stimulated AVS was used to guide surgical management of 377 patients with primary aldosteronism (PA) who were evaluated 6 months after surgery. MAIN OUTCOME MEASURES: The proportion of patients that achieved clinical benefit and complete biochemical success based on the AVS aldosterone lateralization index (LI) was determined. RESULTS: Clinical benefit was achieved in 29 of 47 patients with an LI between 2 and 4, in 66 of 101 with an LI between 4 and 10, and in 158 of 203 with an LI > 10 (P < 0.01 for trend). Complete biochemical success was achieved in 27 of 42 with an LI between 2 and 4, in 60 of 76 with an LI between 4 and 10, and in 127 of 155 with an LI > 10 (P = 0.024 for trend). After adjustment for confounders and using those patients with an LI between 2 and 4 as a reference, a clinical benefit was associated only with those with an LI > 10 (OR, 2.30; 95% CI, 1.03 to 5.16), whereas complete biochemical success was associated with those with an LI between 4 and 10 (OR, 2.83; 95% CI, 1.14 to 7.01) or LI > 10 (OR, 3.55; 95% CI, 1.47 to 8.55). CONCLUSIONS: Difference of clinical outcome was relatively small when strict LI diagnostic threshold was used; biochemical cure was sufficiently achieved when an LI > 4 was used. Our study by standardized outcome measures validated that an LI > 4 may be appropriate for determining unilateral disease in PA.