Endocrine Abstracts

Background: Primary hyperaldosteronism (PA) is a prevalent, but underdiagnosed syndrome. Diagnosis and treatment have been relatively constant since the development of the latest Endocrine Society guidelines in 2016.

Study objective: Baseline characteristics, treatment and follow-up of subjects with PA referred for adrenal venous sampling (AVS) in a tertiary hospital since 2009 are presented.

Results: Thirty five subjects (M/F: 17/18, mean age 49±10 years) underwent AVS. Reasons for screening were; therapy-resistant hypertension (46%), sustained blood pressure > 150/100 mmHg (20%), hypertension and an incidental mass (3%), hypertension with hypokalaemia (28%). One subject without hypertension had a positive screening for PA in the work-up of an adrenal incidentaloma. Echocardiogram showed left ventricular hypertrophy in 19 subjects (54%). Plasma aldosterone/renin ratio (ARR) was above the threshold of 24 (pg/ml)/(μu/ml) in most (94%) subjects. With a mean plasma aldosterone (PAC) of 306 pg/ml, 88% had a PAC > 150 pg/ml. A combination of an elevated PAC and ARR was seen in 81%. Saline infusion test was still performed in 60% of subjects of which 81% had a PAC above 100 μg/ml and 19% between 50 and 100 μg/ml. AVS showed unilateral aldosterone hypersecretion in 12 and bilateral hypersecretion in 11 subjects. In 9 subjects the right adrenal vein was not reachable and in 3 subjects there were analytical problems. Discrepancy in lateralization between CT adrenals and AVS was seen in 57%; normal CT vs AVS with lateralization (2 subjects), normal CT vs AVS with bilateral hypersecretion (4 subjects), adrenal adenoma on CT with lateralization on the contrary adrenal (2 subjects), adrenal adenoma on CT without lateralization on AVS (5 subjects). Of the 12 subjects with lateralization, 9 underwent unilateral adrenalectomy of which 3 could stop all antihypertensive drugs, but all could reduce medication from 5 to 2, average. Of the 12 subjects with a non-diagnostic AVS, 6 underwent unilateral adrenalectomy with the histological confirmation of an aldosterone producing adenoma and antihypertensive drugs could be stopped postoperatively in 3 subjects.

Conclusion: Since 2009 only 35 subjects were referred to undergo AVS which suggests the underdiagnosis of PA. Hypertension and hypokaliëmie are not mandatory characteristics of PA but were present in 97% and 57%, respectively. The number of patients with unilateral vs bilateral aldosterone hypersecretion was similar. 57% had a discrepancy in lateralization between AVS and CT adrenals. Antihypertensive drugs could be stopped in 40% of subjects who underwent unilateral adrenalectomy.