Cosyntropin stimulation in adrenal vein sampling improves the judgment of successful adrenal vein catheterization and outcome prediction for primary aldosteronism.

The importance of cosyntropin stimulation during adrenal vein sampling (AVS) is not fully established, partly due to insufficient AVS data relating the presence and absence of cosyntropin stimulation with postoperative outcome. Therefore, we investigated differences in AVS indices before and after cosyntropin stimulation, and determined whether unstimulated or stimulated AVS indices better correlated with treatment outcome. A retrospective study was conducted in two parts: one with 185 patients who underwent AVS and the other with 81 patients who underwent unilateral adrenalectomy for unilateral aldosterone oversecretion. The selectivity index (SI), lateralized ratio (LR), and contralateral ratio (CR) before and after cosyntropin stimulations were determined, along with blood pressure outcome 1 year after surgery. Primary aldosteronism was diagnosed according to the Japanese Endocrine Society 2009 guidelines. The percentage of AVS patients with successful catheterization, defined as unstimulated SI > 2 before and stimulated SI > 5, increased after cosyntropin stimulation from 52% to 93% and from 74% to 98% for the right and left adrenal veins, respectively. LR decreased after cosyntropin stimulation (P < 0.001). In the postoperative patients, complete and partial clinical success was achieved in 49 and 27%, respectively. Low CR (<1) and high LR (≥2.6) after cosyntropin stimulation better correlated with postoperative blood pressure outcome than those before stimulation (CR < 1 and LR ≥ 2). These data suggest that cosyntropin stimulation facilitated the judgment of catheter insertion and postcosyntropin AVS indices may be more useful for predicting treatment outcome after unilateral adrenalectomy. Further study should examine the usefulness of cosyntropin stimulation in AVS performed in other settings.