Adrenal vein sampling with and without cosyntropin stimulation for detection of surgically remediable aldosteronism

Bilateral adrenal vein sampling (AVS), the diagnostic standard for identifying surgically remediable aldosteronism (SRA), is commonly performed after cosyntropin stimulation (post-ACTHstim). The role of AVS without cosyntropin stimulation (pre-ACTHstim) has not been established. The selectivity index (SI), the adrenal vein (av) serum cortisol concentration divided by that in a peripheral vein, confirms av sampling. The minimally acceptable SI is controversial. The objectives of this study were to determine the role of pre-ACTHstim AVS and a predetermined SI.

Using biochemical cure as the endpoint, we performed a retrospective head-to-head comparison of pre-ACTHstim AVS to post-ACTHstim AVS. The specificity of a predetermined minimum SI of 1.5 in pre-ACTHstim AVS was determined.

At a regional AVS referral centre, we analysed 32 patients who had undergone simultaneous bilateral AVS both pre- and post-ACTHstim and had returned for postadrenalectomy evaluation.

Simultaneous bilateral AVS was performed with measurements of venous concentrations of aldosterone and cortisol. End points were postadrenalectomy plasma renin activity, serum aldosterone concentration, and number of antihypertensive medications.

All 32 patients achieved a biochemical cure following adrenalectomy. The two AVS protocols were complementary. Notably, seven patients (22%; CI = 11-38) were found to have SRA by a lateralization index (LI) > 4 on the pre-ACTHstim AVS, but not on the post-ACTHstim AVS. SI pre-ACTHstim was divided into tertiles. Specificity was 100% in all.

Simultaneous bilateral AVS performed both pre-ACTHstim and post-ACTHstim maximizes SRA identification. A SI of 1.5 pre-ACTHstim does not reduce specificity.