Audit of adrenal vein sampling for primary aldosteronism
L Sibal1, A Raza1, B Leen2 & W Kelly1
INTRODUCTION: Hypertension with hypokalaemia suggests primaryaldosteronism, which is confirmed by high plasma aldosterone with low renin concentrations. CT and MRI scans frequently fail to detect small primary aldosteronomas, and may incorrectly identify ' incidentalomas', so adrenal vein sampling is needed.AIM: To review the clincal and biochemical results on 12 patients who had catheter sampling of adrenal and ivc aldosterone(A) and Cortisol (C)with calculation of Aldosterone/Cortisol (A/C) ratios.METHODS: Femoral veins were catheterised and samples taken fromadrenal veins, inferior vena cava, before and after Synacthen stimulation. Ratios were calculated for Cside/Civc and A/C to assess whether adrenal cannulation had been successful, and to identify the likely aetiology, eg primary adenoma, or bilateral hyperplasia. Histology of adrenal glands and subsequent BP, plasma K and hypotensive medication were determined.RESULTS: Twelve patients,six male were studied.Successful sampling was done in all the patients on the left side and bilaterally in nine(75%) patients.Aetiology was unilateral adenoma in five patients, bilateral hyperplasia in six and inconclusive in one patient. Treatment was adrenalectomy in three patients(excluding one patient who refused surgery and one patient who developed adrenal infarction during sampling), spironolactone in five patients and amiloride in three patients. Two of the three patients who underwent adrenalectomy had normal K levels without supplements and one patient became normotensive. Four patients had a reduction in number of hypotensive medicines.CONCLUSIONS: Because scanning may fail to establish the aetiology of aldosteronism, catheter sampling is necessary. The adrenal venous anatomy makes catheterisation technically difficult. However using A/C and Cside/Civc ratios, accuracy of diagnosis can be improved and inappropriate surgical treatment can be prevented.