[Investigation of hyperaldosteronism in the hypertensive patient. Why? When? How?]

Primary aldosteronism (PA) has been regarded for a long time as being a rare cause of arterial hypertension, but its prevalence has recently been reassessed as about 10%. This etiology should obviously be sought in the following settings: hypertension associated with hypokaliemia < 3.6 mmol/L (or < 3.9 mmol/L on ACE inhibitors): refractory hypertension: severe hypertension occurring before 40 years of age, especially in women. It must be reminded that more than 20% of PA are normokaliemic. Most of the authors recommend to use the aldosterone/renin ratio (ARR) as a screening test within these selected patients. When ARR turns out to be equal to or higher than 23 (if aldosterone and renin are given in pg/mL or ng/L), a suppression testing should be performed, using salt loading and/or fludrocortisone. Computed tomography scanning yields a specificity of 58% and a positive predictive value of 72%, only. Adenoma and hyperplasia have to be distinguished, using either NP-59 scintigraphy or adrenal venous samplings. Such a strategy appears to be useful, for the following reasons: removal of an adenoma results in a significant blood pressure lowering and in a blood pressure normalization in 95% and in 32% of the patients, respectively; in patients with hyperplasia, spironolactone therapy is followed by a 20% mean reduction in blood pressure.