Adrenal vein sampling may not be a gold-standard diagnostic test in primary aldosteronism: final diagnosis depends upon which interpretation rule is used. Variable interpretation of adrenal vein sampling.

BACKGROUND: Adrenal vein sampling (AVS) is considered the gold-standard test to demonstrate unilateral aldosterone excess in primary aldosteronism, yet no single approach to interpretation of AVS has been externally validated. HYPOTHESIS: There may be significant inter-observer variability in the final diagnosis of unilateral vs. bilateral aldosterone excess depending on which AVS interpretation rule is used.
METHODS: Retrospective chart review of 63 subjects with primary aldosteronism undergoing AVS and 40 subsequent adrenalectomies for presumed unilateral aldosteronism. The data from the AVS were retrospectively re-analyzed according to a variety of interpretation criteria published in the literature. Using 40 subjects undergoing surgery, pathology and clinical outcomes defined the final diagnosis of aldosteronism subtype, and these subjects' AVS results were used to estimate the true sensitivity and specificity of the various approaches to AVS interpretation.
RESULTS: Diagnostic discrepancies exist between the different AVS interpretation rules. Successful adrenal vein catheterization was confirmed in between 13% and 77% of AVS attempts. Sensitivity of AVS ranged from 47% to 100% and specificity 55-100%. Only 17% of all cases would be categorized uniformly by all interpretation criteria. Use of biochemical catheter placement criteria and ACTH infusion improved the proportions of AVS results defined as successful and showing lateralization.
CONCLUSIONS: We found substantial variabilty in final diagnosis by using different systems of interpreting AVS results as suggested in the literature This suggests AVS may not always be considered a gold-standard diagnostic test.