Endocrine Abstracts

Background: PA is a frequent cause (5–13%) of secondary hypertension (HT), yet diagnostic work-up of PA remains challenging.

Aim: To describe the characteristics of a series of hypertensive patients diagnosed with PA compared to those with negative biochemical screening (aldosterone-to-renin ratio/ARR)

Methods: Clinical, hormonal and imaging evaluation.

Results: We have screened for PA 34 patients diagnosed with HT, using as screening criteria: 1. HT+hypokaliemia,2. early-onset HT, 3. drug-resistant HT, 4. HT+sleep apnea, 5. HT+adrenal incidentaloma. 15 patients (7M/8F), aged 39.5 yo (17–58, median/range) at HT onset had a diagnosis of PA confirmed by biochemical testing. Twelve patients (80%) with PA and 14 patients (73.7%) with primary HT had stage 3 HT. Systolic and diastolic BP were significantly higher in PA confirmed group (median SBP 140 mmHg vs 125 mmHg and median DBP 90 mmHg vs 80 mmHg). There was a higher prevalence of drug-resistant HT in PA patients (60% vs 10%). Hypokaliemia history was documented in 6 patients (40%) with PA and in 2 patients (10.5%) with primary HT. ARR on RAAS-interfering drugs (ARRon) was 87 (1.04–426.6) in PA group and 17.28 (0.47–63.44) in primary HT group. Repeated ARR after RAAS-interfering drugs discontinuation in 10 patients (ARRoff) was 59.85 (1.21–926). We performed 20 confirmatory tests in 14 patients (17 tests for PA pts and 3 for primary HT pts): 14 saline infusion tests (SIT), 5 captopril challenge tests (CCT) and one oral salt loading. 13 patients were SIT-positive (aldosterone>5 ng/dl), 2 patients were CCT-positive (aldosterone suppression <30%), one CCT-negative patient (2 h suppression = 25.6%) was SIT-positive. Adrenal CT identified unilateral adenomas in 8 patients (53.3%), 5 of whom associated a diffusely enlarged contralateral adrenal. One patient underwent unilateral adrenalectomy and he was biochemically cured, the 14 remaining received mineralocorticoid receptor antagonists. Target organ complications were present in 6 pts with PA (40%) patients: 5 presented cardiomiopathy, 4 had CKD and 3 patients had retinopathy.

Conclusions: PA was a frequent cause of severe secondary HT in our cohort. Systolic and diastolic BP were significantly higher in PA patients compared with those with primary HT and drug-resistant HT prevalence was higher in hypertensive patients with confirmed PA. ARR in patients taking RAAS-interfering medication decreased after drug discontinuation. There were no significantly differences in target organ complications between PA and primary HT patients.

Keywords: primary aldosteronism, aldosterone renin ratio, SIT, CCT