Resistant hypertension: an overview

Despite the availability of anti-hypertensive medications with proven efficacy and good tolerability, many hypertensive patients have blood pressure levels(BP) 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, despite adequate treatment, 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. Although several studies have approached the issue of the prevalence of RH in the hypertensive population, its prevalence is by and large based upon reasonable but approximate estimates for reasons detailed in the text. Standardized combination therapy based upon angiotensin converting enzyme inhibitors or angiotensin receptor blockers, amlodipine or other dihydropiridine calcium channel blockers and a diuretic (thiazide and thiazide-like compounds as cholrthalidone or indapamide) has been advocated to treat RH with spironolactone as fourth add-on drug. Interventional procedures such as renal denervation have been devised to treat RH and implemented in some patients with RH not responding to medical treatment. However, the results of this interventional procedure have insofar not been positive. 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 and increased cardio- and cerebrovascular risk and deserves, therefore, particular care.