Performance of Primary Aldosteronism Screening Tests Before Washout of Dihydropyridine Calcium Channel Blockers: An Exploratory Retrospective Study.

This retrospective cohort study preliminarily investigated the feasibility of implementing primary aldosteronism (PA) screening without discontinuing dihydropyridine calcium channel blockers (DHP-CCBs). We screened all patients undergoing diagnostic testing for secondary hypertension from January 2017 to May 2022 at authors' center. For inclusion, patients must be on DHP-CCBs monotherapy for hypertension. Aldosterone and renin concentration were measured pre- and post-washout. Confirmatory tests were conducted in patients with positive screen [combination of ARR >2.5 (ng/dL)/(μIU/mL), aldosterone ≥10 ng/dL, and renin ≤8.2 μIU/mL] after washout. The final analysis included a total of 198 patients (median age: 49.5 years and 117 men). Confirmatory tests identified PA in 31 (15.7%) patients. Aldosterone-to-renin ratio (ARR) increased in 158 (79.8%) patients after washout. In 168 patients with a negative pre-washout screen, 22 turned positive after washout, and 14 were diagnosed PA. Consequently, the missed diagnosis rate of PA was 45.2% (14/31) when using standard positive screen criteria before washout of DHP-CCBs monotherapy. Exploratory analysis indicated that a pre-washout ARR cutoff of >1.2 (ng/dL)/(μIU/mL) demonstrated 0.97 sensitivity and 0.75 specificity. In conclusions, caution is warranted when interpretating screening results from patients on DHP-CCBs monotherapy due to the potential risk of missed diagnosis. Preliminary data suggest that ARR ≤1.2 (ng/dL)/(μIU/mL) before washout may serve as a candidate threshold for excluding PA in these patients, though this observation remains a hypothesis-generating finding that requires further investigation.