Endocrine Abstracts

Background: Primary hyperaldosteronism (PA) is a prevalent, but underreported syndrome. Diagnostic procedures and treatment options have been relatively constant since the development of the latest guideline of the Endocrine Society in 2016.

Study objective: To clinically and biochemically describe subjects with PA who underwent a salt infusion test (SIT) or an adrenal venous sampling (AVS) in a tertiary hospital since 2009 and provide an overview of their treatment.

Results: A total of 59 subjects with a mean age of 53±13 were diagnosed with PA. 19% of patients only underwent a SIT and 46% underwent AVS after their SIT. In total 80% of patients underwent a AVS. Reasons for screening for PA were; therapy resistant hypertension (59%), hypertension with an incidental mass (7%) and hypertension with hypokalaemia (56%). One subject without hypertension had a positive screening for PA in the hormonal work-up of an adrenal incidentaloma. Echocardiogram showed left ventricular hypertrophy in 23 subjects (51%). Plasma aldosterone/ renin ratio (ARR) was above the threshold of 20 in 96% of subjects. With a mean plasma aldosterone (PA) of 349.4 pg/mL, 81% had a PA level above 150 pg/mL. A combination of both an elevated PA and ARR above the previous established threshold was seen in 77%. Of the patients who underwent a SIT, 15% had a PA between 100 - 150 μg/ml and 2 patients (5%) had a PA between 50 – 100 μg/mL. Of patients who received only a SIT, 75% had a positive SIT and except for 1 patient (11%), all were treated with medication. AVS was performed by the same experienced interventional radiologist. AVS showed unilateral aldosterone hypersecretion in 23 subjects and bilateral hypersecretion in 12 subjects. In 9 subjects the right adrenal vein was not reachable and in 3 subjects there were analytical problems. Of the 23 subjects with lateralization, 16 underwent a unilateral adrenalectomy of which 7 could stop all antihypertensive drugs. Of the 12 subjects with a non-diagnostic AVS, 6 underwent a unilateral adrenalectomy with the histological confirmation of an aldosterone producing adenoma and normal blood pressure was achieved in 3 of them.

Conclusion: Despite being a tertiary centre only 47 patients were referred since 2009 to undergo an AVS which suggests underdiagnosis of PA. Hypertension and hypokalaemia are not mandatory to screen for PA but were present in 63% and 56%, respectively. The number of patients with unilateral vs bilateral aldosterone hypersecretion was similar. The discrepancy between AVS and CT adrenals was 20%. Normal blood pressure was achieved in only 48% of patient who underwent a unilateral adrenalectomy after confirmation of lateralization, but the number of antihypertensive medication could be reduced in 92% subjects from an average of 5 to 1 or 2 pills.