Guidelines recommend withdrawing mineralocorticoid-receptor antagonists (MRAs) for 4 weeks prior to adrenal vein sampling (AVS), but this is not always feasible because of hypertension and hypokalemia. This retrospective study of primary aldosteronism (PA) patients who underwent AVS between 2008 and 2018 assessed the effect of continuing MRA on the AVS procedure.

Clinical data including antihypertensive regimen defined by the World Health Organization Daily Defined Dose (DDD) system were collected for 19 patients with adequate cannulation and lateralization during AVS. Results were compared between 5 patients who continued and 14 patients who discontinued MRA therapy (MRA and non-MRA groups).

At diagnosis, plasma renin activity, plasma aldosterone concentration (PAC), potassium (K) doses, and DDD were not significantly different between groups. Aldosterone-renin ratio was significantly higher in the MRA group (median, 375.0; interquartile range [IQR], 224.8 to 544.3 vs. 148.7, 118.4 to 192.1; P = .034). No difference was found in lateralization index (median 48.3; IQR, 23.6 to 52.1 vs. 8.7; 4.9 to 20.2; P = .10). Contralateral suppression, defined as aldosterone-cortisol ratio of unaffected adrenal to periphery, trended lower in the MRA group (median, 0.17; IQR, 0.03 to 0.39 vs. 0.51; 0.27 to 1.1; P = .056). All five MRA patients underwent successful adrenalectomy with at least 50% reduction in DDD and PAC and normal K postoperatively. One MRA patient did not lateralize, which was confirmed on repeat AVS, after MRA withdrawal.

Continuation of MRA may not interfere with AVS lateralization or affect contralateral adrenal suppression. Continuation of MRA in preparation for AVS may be considered, especially in patients with severe PA, to avoid uncontrolled hypertension and severe hypokalemia.