Adrenal Vein Sampling for Primary Aldosteronism: A 2-Week Protocol for Withdrawal of Renin-Stimulating Antihypertensives.

OBJECTIVE: For evaluation of primary aldosteronism, international guidelines recommend a 4-6 week withdrawal of spironolactone, eplerenone, and amiloride prior to adrenal vein sampling (AVS). It is not always feasible to withdraw these drugs in patients with severe hypertension and hypokalemia. We present our experience evaluating the efficacy and clinical outcomes of a 2-week protocol for withdrawal of renin-stimulating antihypertensives prior to AVS.

DESIGN: A single-center retrospective review of all patients who underwent AVS for primary aldosteronism between January 2014 and December 2015.

PATIENTS: 32 patients (24 M:8F, mean age 54y) underwent AVS with the 2-week protocol, and 32 held their renin-stimulating antihypertensives for 2 weeks instead of the recommended 4-6 weeks.

MEASUREMENTS: Plasma renin activity (PRA) was measured immediately before venous sampling to assess for renin suppression (PRA < 0.5 ng/ml/hr). Demographics, antihypertensive medications, plasma aldosterone, plasma renin activity, and outcomes were reviewed.

RESULTS: 100% of procedures were diagnostic (selectivity index ≥ 3) and lateralization (lateralization index ≥ 4) was confirmed in 22/32 patients. 19/32 patients had contralateral suppression. PRA confirmed to be suppressed in 30/32 (94%) of patients. Of the 2 patients with unsuppressed renin, 1/2 lateralized diagnosing an aldosterone producing adenoma.

CONCLUSIONS: Renin was suppressed in nearly all patients following a 2-week withdrawal of renin-stimulating antihypertensives. Patients who cannot tolerate stopping these medications for 4-6 weeks as recommended by current guidelines may undergo a 2-week withdrawal without affecting the diagnostic outcome of AVS, provided renin suppression is confirmed.

LEVEL OF EVIDENCE: Level 4, Case Series.