Renal denervation. Current state and future perspectives

Hypertension is a well-known risk factor for major cardiovascular events. Despite advances in medical therapy, sufficient treatment of hypertension remains unsatisfying in a substantial number of patients and is therefore one of the main challenges in modern medicine. In Germany 5-15 % of patients with hypertension suffer from resistant hypertension with elevated blood pressure despite the use of at least three antihypertensive drugs. Additionally patients often suffer from side effects. In patients with resistant hypertension the important role of the sympathetic nervous system with increased sympathetic activity is well known. In the past surgical sympathectomy with extended removal of sympathetic ganglia was performed to reduce blood pressure in patients with malignant hypertension. The positive effect of this highly invasive procedure on blood pressure led to the development of new strategies for the treatment of uncontrolled hypertension. One of the novel procedures includes catheter-based renal sympathetic denervation. The most common system is the radiofrequency ablation catheter (SymplicityA (R), Medtronic, Minneapolis, USA) which ablates the nerve fibers in the adventitia of the renal arteries by using high-frequency energy. As the results of the Symplicity trials (HTN-1 and HTN-2) showed significant reduction of systolic and diastolic blood pressure after renal denervation there is growing interest in this novel procedure. Moreover, by reducing the sympathetic activity after renal denervation early results indicate a positive impact on glucose metabolism, sleep apnea syndrome, as well as heart and renal failure. These effects led to the development of many different devices for renal denervation; however, trials with a higher number of patients and longer follow-up need to confirm these initially promising results and the value of newer devices. Until then renal denervation should not be regarded as standard therapy for arterial hypertension or an alternative to medical antihypertensive treatment and should be reserved for selected patients with resistant hypertension and specialized medical centres.