Rationale: Primary hyperaldosteronism (PA) is the most frequent form of secondary hypertension. In PA autonomous hypersecretion of aldosterone by one or both adrenal glands causes hypertension that is often refractory to treatment. PA is usually caused by either a unilateral aldosterone-producing (micro)adenoma (APA) or by bilateral adrenal hyperplasia(BAH). Distinction between APA and BAH is critical since the former is treated with the aim of cure by adrenalectomy, and the latter by mineralocorticoid receptor antagonists. This Distinction can be made by adrenal vein sampling (AVS), as recommended by The Endocrine Society 2008 guideline or by CT-scanning, as is common practice in the Netherlands. AVS is invasive, demands great skill, and is expensive, while CT-scanning is non-invasive, easy and cheap, but might be less accurate. However, the advantage of AVS has never been demonstrated in prospective randomized studies. Here we propose to perform a prospective, randomized,multicenter study that compares effectiveness of AVS with effectiveness of CT-scanning for the diagnosis of PA subtype.Objective: To assess the quantity of antihypertensive medication needed in order to normalize blood pressure in patients who have been managed for PA according to either AVS or CT-scan.Secondary objectives: to assess potassium, costs of management and quality of life.Study design: Prospective, randomized trial in a multi-centre setting. Two hundred patients will be recruited within two years. Follow-up will be one year after (start of) treatment.Study population: Adult patients with therapy-resistant hypertension, with or without hypokalemia, caused by PA.Intervention: Patients will be randomized to undergo either adrenal CT-scanning or AVS (with pre-AVS adrenal CT-scanning for phlebography). The result of either of these tests will determine the course of action: adrenalectomy for adenoma or MRAs for bilateral hyperplasia.Main study parameters/endpoints: The quantity of antihypertensive drugs patients are using to obtain target blood pressure, expressed in Daily Defined Dosages, is used as the main study parameter. There is no criterion standard for accuracy of the diagnosis of PA-subtype, but we assume that if treatment is based on a more accurate diagnosis, treatment is more effective.The most important secondary endpoints are the costs of the diagnostic course and long-term medical treatment and the quality of life as assessed by a validated questionnaire.
