Renal Denervation: Past, Present, and Future

Over the past decade, percutaneous renal denervation has been vigorously investigated as a treatment for resistant hypertension. The SYMPLICITY radiofrequency catheter system (Medtronic CardioVascular Inc., Santa Rosa, CA, USA) is the most tested device in clinical trials. After the positive results of small phase I and II clinical trials, SYMPLICITY HTN-3 (a phase III, multi-center, blinded, sham-controlled randomized clinical trial) was completed in 2014, but did not show significant blood pressure lowering effect with renal denervation compared to medical therapy and caused the investigators and industry to revisit both the basic science elements of renal denervation as well as the design of related clinical trials. This review summarizes the SYMPLICITY trials, analyzes the SYMPLICITY HTN-3 data, and provides insights gained from this trial in the design of the most recent clinical trial, the SPYRAL HTN Global clinical trial. Other than hypertension, the role of renal denervation in the management of other disease processes such as systolic and diastolic heart failure, metabolic syndrome, arrhythmia, and obstructive sleep apnea with the common pathophysiologic pathway of sympathetic overactivity is also discussed.