Resistant hypertension and hyperaldosteronism.

Resistant hypertension is defined as blood pressure that remains uncontrolled in spite of >or= 3 antihypertensive medications at effective doses, ideally including a diuretic. Although exact prevalence is unknown, clinical trials suggest that 20% to 30% of study participants are resistant. Hyperaldosteronism, obesity, refractory volume expansion, and obstructive sleep apnea are common findings in resistant hypertension patients. Multiple studies indicate that primary aldosteronism (PA) is common (approximately 20%) in patients with resistant hypertension. Screening for PA is recommended for most patients with resistant hypertension, ideally by measurement of 24-hour urinary aldosterone excretion, or by the plasma aldosterone/plasma renin activity ratio. Successful treatment of resistant hypertension is predicated on improvement of lifestyle factors; accurate diagnosis and treatment of secondary causes of hypertension; and use of effective multidrug regimens. A long-acting diuretic, specifically chlorthalidone, is recommended as part of the treatment regimen. Recent studies demonstrate that mineralocorticoid receptor antagonists provide substantial antihypertensive benefit when added to multidrug regimens, even in patients without demonstrable aldosterone excess.