Renal denervation: Current opinions and practice

Renal nerves play a crucial role in regulation of kidney function and blood pressure (BP) control. Compelling evidence from both animal and human studies clearly demonstrate that activation of renal sympathetic nerves plays a critical role in the pathogenesis of hypertension. Sympathetic activation is also a hallmark of chronic and end-stage kidney disease and adversely affects cardiovascular prognosis. The concept of targeting the renal nerves therapeutically was first introduced by means of surgical splanchnicectomy for treatment of severe hypertension in the early twentieth century. Recent advances in biomedical engineering allowed a more specific and direct approach to target renal sympathetic nerves using trans-vascular catheter-based approaches. Initial proof-of-concept studies demonstrated the safety of the approach and revealed substantial reductions in office blood pressure in patients with resistant hypertension. These findings and additional evidence from other mainly uncontrolled clinical studies in various high CV risk cohorts sparked substantial interest in the scientific and medical community and led to expedited introduction of catheter-based renal denervation into clinical medicine in several countries. A subsequent larger and more rigorously designed randomized clinical trial while confirming the safety of the procedure failed to demonstrate efficacy compared to a sham procedure. Clinical trial design, endpoints and their evaluation, patient selection and management both before and after renal denervation and predictors of the BP response are just some of the aspects that have been scrutinized in the aftermath of this trial (Symplicity HTN-3) and remain to be addressed in ongoing clinical studies, which will ultimately determine the future role of renal denervation in clinical practice.