Resistant hypertension: an overview.

Despite the availability of anti-hypertensive medications with proven efficacy and good tolerability, many hypertensive patients have blood pressure (BP) levels not at the goals set by international societies. Some of these patients are either non-adherent to the prescribed drugs or not optimally treated. However, a proportion has resistant hypertension (RH) defined as office BP above goal despite the use of ≥3 antihypertensive medications at maximally tolerated doses (one ideally being a diuretic). Diagnosis of RH based upon office measurements, however, needs confirmation through 24-h BP monitoring to exclude "white coat" RH since cardiovascular events and mortality rates follow mean ambulatory BPs. Standardized combination therapy based upon angiotensin converting enzyme inhibitors or angiotensin receptor blockers, amlodipine or other dihydropiridine calcium channel blockers and thiazide or thiazide-like diuretics has been advocated to treat RH with spironolactone as preferred fourth add-on drug. Interventional procedures such as renal denervation have been devised to treat RH and tested with insofar not positive results in series of patients not responding to medical treatment. It is unclear whether RH constitutes a specific phenotype of EH or should rather be considered a more serious form of uncontrolled hypertension. Whatever the case, its presence associates with an increased cardio- and cerebrovascular risk and deserves, therefore, particular care.