Introduction: In patients with primary aldosteronism (PA), adrenal venous sampling (AVS) is recommended to differentiate between unilateral (UNI) or bilateral (BIL) adrenal disease. A recent study suggested that lateralization could be predicted, based on the ratio of aldosterone/cortisol levels (A/C) between the left adrenal vein (LAV) and inferior vena cava (IVC), with a 100% positive predictive value (PPV). This study aimed to validate those findings utilizing a larger, multi-institutional cohort.
Methods: A retrospective review was performed of patients with PA who underwent AVS from 2 tertiary-care institutions. Laterality was predicted by an A/C ratio of >3:1 between the dominant and non-dominant adrenal. AVS results were compared to LAV/IVC ratios utilizing the published criteria (Lt ≥ 5.5; Rt ≤ 0.5).
Results: Of 222 patients, 124 (57%) had UNI and 98 (43%) had BIL disease based on AVS. AVS and LAV/IVC findings were concordant for laterality in 141 (64%) patients (69 UNI, 72 BIL). Using only the LAV/IVC ratio, 54 (24%) patients with UNI disease on AVS who underwent successful surgery would have been assumed to have BAH unless AVS was repeated, and 24 (11%) patients with BIL disease on AVS may have been incorrectly offered surgery (PPV 70%). Based on median LAV/IVC ratios (left 5.26; right 0.31; BIL 2.84), no LAV/IVC ratio accurately predicted laterality.
Discussion: This multi-institutional study of patients with both UNI and BIL PA failed to validate the previously reported PPV of LAV/IVC ratio for lateralization. Caution should be used in interpreting incomplete AVS data to differentiate between UNI versus BIL disease and strong consideration given to repeat AVS prior to adrenalectomy.