Resistant hypertension: concepts and approach to management.

Resistant hypertension (RH), defined simply, is blood pressure (BP) requiring the use of four or more antihypertensive agents, whether controlled or uncontrolled. RH is an increasingly common problem in elderly patients and may affect as many as 20% of the hypertensive population. Unfortunately, at least 30% of patients evaluated for RH are actually adequately controlled when more carefully assessed by home BP monitoring or ambulatory BP monitoring, thus representing a white coat effect. It is also essential to exclude pseudoresistance resulting from improper BP recording techniques or failure of the patient to adhere to the prescribed treatment regimen. Concurrent use of drugs that may interfere with prescribed antihypertensive agents, including many over the counter herbal preparations, must also be excluded. The underlying mechanisms principally driving true RH include pathophysiologic abnormalities of aldosterone signaling, sodium and water retention, excessive sympathetic nervous system activity, and obstructive sleep apnea. Appropriate treatment regimens will usually include an inhibitor of the renin-angiotensin-aldosterone system, a calcium channel blocker, and a diuretic. An aldosterone receptor blocker can be instituted at any step, and is very effective as a fourth drug. Beta-blockers can also be integrated into these treatment plans and may be especially helpful when excessive sympathetic nervous system activity is suspected. Novel device therapies that interrupt sympathetic nerve stimulation at the carotid sinus and kidney are under investigation, and may add entirely new directions in the management of RH. What is most important is that treatment regimens should be targeted to specific patient profiles.