Resistant hypertension: what the cardiologist needs to know.

Treatment-resistant hypertension (TRH) affects between 3 and 30% of hypertensive patients, and its presence is associated with increased cardiovascular morbidity and mortality. Until recently, the interest on these patients has been limited, because providing care for them is difficult and often frustrating. However, the arrival of new treatment options [i.e. catheter-based renal denervation (RDN) and baroreceptor stimulation] has revitalized the interest in this topic. The very promising results of the initial uncontrolled studies on the blood pressure (BP)-lowering effect of RDN in TRH seemed to suggest that this intervention might represent an easy solution for a complex problem. However, subsequently, data from controlled studies have tempered the enthusiasm of the medical community (and the industry). Conversely, these new studies emphasized some seminal aspects on this topic: (i) the key role of 24 h ambulatory BP and arterial stiffness measurement to identify 'true' resistant patients; (ii) the high prevalence of secondary hypertension among this population; and (iii) the difficulty to identify those patients who may profit from device-based interventions. Accordingly, for those patients with documented TRH, the guidelines suggest to refer them to a hypertension specialist/centre in order to perform adequate work-up and treatment strategies. The aim of this review is to provide guidance for the cardiologist on how to identify patients with TRH and elucidate the prevailing underlying pathophysiological mechanism(s), to define a strategy for the identification of patients with TRH who may benefit from device-based interventions and discuss results and limitations of these interventions, and finally to briefly summarize the different drug-based treatment strategies.