SAT-065 Adrenal Vein Sampling Without Discontinuation Of Mineralocorticoid-Receptor Antagonist Therapy

In primary hyperaldosteronism (PA), adrenal vein sampling (AVS) is a critical step in determining if the source of aldosterone is unilateral or bilateral. Guidelines recommend withdrawing mineralocorticoid-receptor antagonists (MRA) for 4 weeks prior to testing as unsuppressed renin levels may stimulate the contralateral normal adrenal gland and mask the lateralization of aldosterone secretion. However, it is not always feasible to withdraw these drugs in patients with severe hypertension and hypokalemia. We conducted a retrospective study of PA patients who underwent AVS at our institution between 2008-2018 to assess the effect of MRA on the AVS procedure. We analyzed demographics, laboratory results, pathology and follow-up data. Antihypertensive regimen between groups was compared using the WHO Defined Daily Dose (DDD) system. Nineteen patients with adequate adrenal vein cannulation during AVS using cortisol corrected selectivity index, as well as lateralization were studied. Five continued MRA therapy and in 14 MRA therapy was discontinued. At diagnosis, plasma renin activity, plasma aldosterone concentration and potassium (K) doses, and DDD were not significantly different between MRA and non-MRA groups. Aldosterone renin ratio was significantly higher in the MRA group compared to the non-MRA group (375.0, IQR 224.8-544.3 vs 148.7, IQR 118.4-192.1; p 0.034). The dose of MRA when continued ranged from 25-100mg of spironolactone. The results of the AVS showed that there was no difference in lateralization index (LI) between both groups (48.3, IQR 23.6-52.1 vs 8.7, IQR 4.9-20.2; p 0.10). Contralateral suppression index of the unaffected adrenal was not different between the groups (0.17, IQR 0.03-0.39 vs 0.51, IQR 0.27-1.1; p 0.056). Seventeen out of 19 patients with AVS lateralization had unilateral adrenalectomy (5 patients on MRA and 12 patients off MRA). Two patients were not deemed surgical candidates. All 5 patients in the MRA group and 7/12 patients in the non-MRA group had at least 50% reduction in DDD postoperatively. All 17 patients had normal K postoperatively off supplements. All 5 patients on MRA and 11/12 patients off MRA had at least 50% reduction in postoperative PAC. One patient on MRA did not lateralize on AVS, which was confirmed on repeat AVS after withdrawal of MRA for four weeks. Conclusion: The current study shows that continuation of MRA therapy does not interfere with AVS lateralization, nor does it affect the contralateral unaffected adrenal suppression index. Continuation of MRA in preparation for AVS may be considered especially in patients with high ARR to avoid uncontrolled BP and significant hypokalemia.