Renal Sympathetic Denervation: A Viable Option for Treating Resistant Hypertension.

Accumulating evidence from mainly uncontrolled clinical studies with various types of ablation catheters have shown that renal denervation (RDN) can be applied safely and is effective in lowering blood pressure (BP) in patients with treatment-resistant hypertension. Sustained BP lowering has been documented up to 3 years. Furthermore, RDN has been associated with regression of target organ damage, such as left ventricular hypertrophy, arterial stiffness, and others. Several studies indicate potential benefit in other common clinical conditions associated with increased sympathetic tone including chronic kidney disease and heart failure. However, the recently published Symplicity HTN-3 study, the largest and most rigorously designed sham-controlled clinical trial, while confirming the safety of the procedure, failed to demonstrate a BP lowering effect beyond that of a sham procedure in patients with resistant hypertension. Efforts to unravel the reasons for the discrepant results from Symplicity HTN-3 have focused on a range of potential confounders including anatomical and procedural aspects. Indeed, data from post-hoc analyses indicate that sufficient RDN may not have been achieved in the majority of patients in Symplicity HTN-3. Furthermore, recent evidence from human postmortem and functional animal studies revealed new insights into the anatomical distribution of renal nerves and their accessibility by intravascular approaches. Initial results from recent clinical trials integrating these important findings indeed seem to confirm that RDN remains a viable option for the treatment of hypertension. Thorough further investigations will be key to determine the true potential of RDN in clinical conditions characterized by increased sympathetic drive.