Resistant hypertension: Definition, prevalence, and therapeutic approaches
Resistant hypertension (RH) is defined as blood pressure (BP) above goal despite adherence to at least three optimally dosed antihypertensive medications of different classes, one of which is a diuretic. Not all patients with BP that is difficult to control have RH. Evaluation of possible RH begins with assessment of adherence to medications. White-coat effect should be ruled out by out-of-office BP monitoring. Obesity, heavy alcohol intake, and interfering substances all contribute to RH. Lifestyle modifications including exercise and dietary sodium restriction are important to emphasize. RH may be due to secondary causes such as renal disease, obstructive sleep apnea, and/or aldosteronism. Adequate diuretic treatment is a key part of therapy. Chlorthalidone is more potent and longer-lasting than hydrochlorothiazide and may reduce cardiovascular events to a greater extent. For patients with a glomerular filtration rate <30 ml/min, a loop diuretic is usually needed. In addition to a diuretic, patients with RH should usually be on a dihydropyridine calcium channel blocker and either an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II AT1 receptor blocker (ARB). Spironolactone is an evidence-based fourth-line agent for treatment of RH. Other add-on medication options include a beta-blocker, a long-acting nondihydropyridine calcium channel blocker, or clonidine. When BP is not coming under control despite the prescription of four or five agents, referral to a hypertension specialist should be considered.
