[CATHETER-BASED RENAL DENERVATION FOR THE TREATMENT OF HYPERTENSION]

Hypertension is a significant risk factor for cardiovascular morbidity and mortality. Despite a large variety of pharmacological treatment options, many patients remain uncontrolled. Medical inertia and patients' non-adherence to medications are the main reasons for lack of control. Experimental evidence shows that increased renal sympathetic nerve activity increases blood pressure and surgical denervation lowers blood pressure. In studies published between the years 2010-2013, radiofrequency endovascular ablation of renal sympathetic nerves (RDN) seemed to produce antihypertensive effects. However, a randomized sham-control study failed to prove active treatment-specific benefit. One of the main reasons for failure was the small number of ablations in each procedure. In recent years, technological progress has been made with the possibility to quadruple the number of ablation sites and extend them to the branches of the main renal arteries. Small sham-controlled studies were conducted in patients with grade 1-2 hypertension, either untreated or treated with up to three drugs. At three to six months follow-up, modest yet significant decrease of blood pressure was found, both in office and ambulatory measurements. Data from the Global SYMPLICITY Registry, which collects data from consecutive patients undergoing RDN with Medtronic radiofrequency ablation catheters, most of them with resistant hypertension, also showed significant improvement in blood pressure. However, in the absence of a control group, these real-life results should be interpreted with caution. Selection criteria of patients more likely to benefit from RDN have not been defined and will be discussed in the current review. In summary, RDN is a promising new treatment for hypertension. Randomized sham-controlled studies with a longer follow-up are still needed to confirm long-lasting treatment-specific effects and to show cardiovascular protection and safety.