[11C]Metomidate PET-CT vs Usual Care for People With Primary Aldosteronism: a Proof-of-concept Study

[11C]Metomidate PET-CT vs Usual Care for People With Primary Aldosteronism: a Proof-of-concept Study

The goal of this randomised open-label controlled study is to compare the biochemical and clinical responses following [11C]Metomidate-PET CT(MTO-PET) versus usual care with adrenal venous sampling as first lateralisation strategy in people with biochemically confirmed primary aldosteronism(PA). The main question it aims to answer is: what is the proportion of people who achieved complete or partial clinical success among those who underwent PA treatment?

Inclusion Criteria:

• Diagnosis of PA made based on Endocrine Society guidelines:

• Participants should demonstrate a positive screening test for primary aldosteronism, defined as:

  • Paired measurement of renin and aldosterone demonstrating a raised aldosterone-to-renin ratio >550 pmol/L/ng/mL/h AND
  • Suppressed renin <=1ng/ml/h

• AND participants should demonstrate autonomous aldosterone secretion following salt-loading confirmatory tests, defined as:

  • 1) Non-suppressed aldosterone >162pmol/L following seated saline infusion OR
  • 2) raised 24-hour urine aldosterone >38 nmol/d following oral salt loading test (17)

• For participants with spontaneous hypokalemia with renin below detection level and plasma aldosterone > 416 pmol/L(by LC-MS) at screening, the above confirmatory tests can be omitted due to high pre-test probability as proposed by latest guidelines (10).

• Adrenal nodule on CT

Exclusion Criteria:

• Unable to give informed consent
• Participants who neither agree to AVS nor MTO-PET
• Patients who indicate they will not proceed to adrenalectomy
• Patients contraindicated for mineralocorticoid receptor antagonists
• Patients who are unable/unwilling or contraindicated for dexamethasone required for MTO-PET
• Estimated GFR < 30 ml/min/1.73m2
• Any illness or condition that is considered unfit for study by the investigators