A Multi-institutional Comparison of Adrenal Venous Sampling in Patients with Primary Aldosteronism: Caution Advised if Successful Bilateral Adrenal Vein Sampling is Not Achieved.

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.