[Screening tests and diagnostic examinations of hypertensives for primary aldosteronism].

Primary aldosteronism (PA) is a form of surgically curable secondary hypertension. The prevalence of PA among hypertensive patients is reportedly between 5 and 15% and hypokalemia is rare in patients with PA. Therefore, hypertensives should be screened for PA. The aldosterone (PAC)-renin activity (PRA) ratio (ARR) has widely been used as the initial screening for PA; however, it is reported that the diagnosis of PA should not be based on the finding of a raised ARR. We compared the sensitivity and specificity of ARR for PA screening with those of PAC and PRA in 236 hypertensives, and ROC analysis revealed that PAC and PRA are more sensitive and specific than ARR for PA screening. The sensitivity and specificity of the captopril suppression test, furosemide plus upright test and ACTH stimulation test for secondary screening for PA were retrospectively examined in 94 patients with PA and 44 patients without PA. ROC analysis demonstrated that the ACTH stimulation test was the most sensitive and specific among these three tests. Therefore, we propose that hypertensives should initially be screened for PA using the criteria of PAC > or = 12.0 ng/dl and PRA < or = 1.0 ng/ml/h and should be secondarily screened using the ACTH stimulation test. Then ACTH-stimulated adrenal venous sampling should be performed in patients with the ratio of maximal PAC to cortisol after ACTH stimulation 0.85. Patients with unilateral secretion of aldosterone2 1400 ng/dl should undergo unilateral adrenalectomy and patients with bilateral secretion of aldosterone2 1400 ng/dl should be treated with antihypertensive agents.