Background

Resistant or refractory hypertension is a condition characterised by blood pressure (BP) levels persistently over target, despite the contemporary use of three different classes of antihypertensive agents at optimal doses, including a diuretic.1 Epidemiology data indicate that this form of hypertension is not as rare as supposed. Analyses from the US National Health and Nutrition Examination Survey data and from a large Spanish database estimate that among treated adults with hypertension, about 12%–13% have resistant hypertension,2 while in trials of individuals aggressively titrated to reach BP target, the prevalence of this condition peaks up to 20%–30%.1

This burden of poorly manageable patients with hypertension poses a major health problem because individuals with resistant hypertension are 50% more likely to experience adverse cardiovascular events and poor outcomes than those with controlled hypertension.

The search for new, useful approaches for treating this condition remains an unmet issue. In fact, combined interventions including multipharmacological therapy, lifestyle and dietary modifications failed to achieve concrete results in the mid-long term.

For decades, sympathetic hyperactivity has been considered a key protagonist in the pathogenesis of refractory hypertension. In the 1980s, surgical sympathectomy was extensively studied as an effective way for lowering BP and symptoms associated with severe hypertension. After the advent of the pharmacological era, however, this procedure was no longer performed due to a variety of considerable side effects that made it poorly tolerated.

Unlike surgical sympathectomy, renal denervation is a minimally invasive, endovascular catheter-based procedure performed via femoral access. A low-dose radiofrequency energy produces a thermal increase that ablates large portions of nervous fibres in the adventitia of the renal artery, reducing sympathetic afferent and efferent activity to the kidney and, eventually, BP.

In addition, this manoeuvre may improve other systemic conditions that are …