Sympathetic renal denervation: hypertension beyond SYMPLICITY. 
Despite a wide range of drug treatment for hypertension, resistant hypertension rates remain high.  The Symplicity™ Renal Denervation System (Medtronic, Santa Rosa, CA), which creates renal nerve denervation, has shown initial success in lowering blood pressure among patients with resistant hypertension.  Given the enormous market for this treatment approach, an estimated two dozen other companies are pursuing technologies with alternative approaches.  Despite this fact, very little has been published on preclinical and clinical experience with these new devices.  The current review summarizes the most prominent technologies in the pipeline and provides insight into the mechanism of action, preclinical, and clinical experience with these new devices.