Conclusion
To date, the majority of clinical studies have evaluated the efficacy of RF (and non-RF) RSD in predominantly severe RHTN. However, given that the pathophysiological basis for RSD therapy is based not on BP level but on the recognition that RHTN is associated with elevated central SNS tone, RSD may be an effective treatment for other conditions that exhibit similar elevated central SNS tone, whether renally mediated or not. As such, RF RSD has been evaluated in other systemic conditions and pleiotropic effects of RF RSD have been reported in both systolic83 and diastolic84 heart failure, obstructive sleep apnoea,85 glycaemic control in RHTN patients85,86 and both supra-ventricular74 and ventricular arrhythmias.87
With the proliferation of different technologies and devices for RSD, much more rigorous research is required so that clinicians can confidently and fully inform patients with RHTN which is the most efficacious and safe intervention for them, taking into account the individual pathophysiological basis for RHTN and matching that to available technologies or not as is appropriate. The principles that should guide development of and selection of appropriate RSD technologies should include: minimally/entirely non-invasive device; predictability of injury pattern; selectivity for renal nerves; permanent nerve destruction; minimal injury to renal artery and collateral structures; minimal procedural pain; short procedure time; durable modulation of central SNS tone; and BP lowering. The publication of the Simplicity HTN-3 dataset is now critical so that the full implications of this disappointing result can further inform the most appropriate use of this technology and treatment for RHTN and potentially other disorders as well. The hypertension specialist, and patients, should welcome this paradigm shift in the landscape for treatment of RHTN but a cautious approach should be maintained with newer, novel technologies until evidence emerges to support their use.