Sympathetic Renal Denervation Using the EnligHTN Multi-electrode Ablation System: The St Jude Experience

A reciprocal relationship between the brain and the kidneys has been long recognized. Efferent sympathetic nerves, originating from the brain, arrive to the kidneys and result in increased renin production, sodium and water reabsorption, and decreased renal blood flow. Afferent sympathetic nerves from the kidneys stimulate sympathetic centers in the central nervous system. Sympathetic overactivity plays a significant role in hypertension and several other disease conditions, such as chronic kidney disease, congestive heart failure, obstructive sleep apnea, polycystic ovary syndrome, and sympathetically driven tachyarrhythmias. Both efferent and afferent sympathetic fibers course within the renal vascular wall rendering transvascular disruption of sympathetic nerves feasible. Radiofrequency ablation is an established technique, used for several years in the management of atrial fibrillation, and has been found effective for renal nerve ablation. Accumulating data indicates that renal nerve ablation is effective and safe in resistant hypertension, while pilot data point towards beneficial effects of renal nerve ablation in conditions characterized by sympathetic overactivity. Many devices have been developed for renal nerve ablation, mainly using radiofrequency as the energy source, and six of them have been already approved in Europe. This chapter will present the experience with the St Jude device, will critically address the advantages and disadvantages of renal nerve ablation, and will provide future perspectives of this innovative interventional technique for the management of resistant hypertension and other conditions with sympathetic overdrive.