Renal Sympathetic Denervation: Hibernation or Resurrection?

Abstract

The most current versions of renal sympathetic denervation have been invented as minimally invasive approaches for the management of drug-resistant hypertension. The anatomy, physiology and pathophysiology of renal sympathetic innervation provide a strong background supporting an important role of the renal nerves in the regulation of blood pressure (BP) and volume. In addition, historical data with surgical sympathectomy and experimental data with surgical renal denervation indicate a beneficial effect on BP levels. Early clinical studies with transcatheter radiofrequency ablation demonstrated impressive BP reduction, accompanied by beneficial effects in target organ damage and other disease conditions characterized by sympathetic overactivity. However, the failure of the SYMPLICITY 3 trial to meet its primary efficacy end point raised a lot of concerns and put the field of renal denervation into hibernation. This review aims to translate basic research into clinical practice by presenting the anatomical and physiological basis for renal sympathetic denervation, critically discussing the past and present knowledge in this field, where we stand now, and also speculating about the future of the intervention and potential directions for research.

Renal sympathetic denervation: Ashes to ashes or rebirth from the ashes?

“…Regarding the latter, a post‐hoc analysis of the study revealed that the majority of patients received 4‐6 ablations per artery, and of major importance only 19 participants received a circumferential ablation of both renal arteries . Of note, blood pressure response was associated with the number of ablations, and patients receiving more than 14 ablations experienced a sufficient systolic blood pressure reduction (office: 14 mm Hg; ambulatory: 7 mm Hg), thus underlining the importance of adequate renal denervation . It is noteworthy that the study by Denegri and colleagues actually duplicates the findings of the post‐hoc analysis of Symplicity‐3, because for a similar number of ablations an identical blood pressure reduction is achieved.…”

Anatomic Conformation of Renal Sympathetic Nerve Fibers in Living Human Tissues

“…The results of SYMPLICITY HTN-3 became the focus of extensive debate and provoked efforts to identify and supplement the factors contributing to the failure 13–17 . As a result, there was a renewed interest in the renal nerve anatomy and physiology, and a substantial number of studies on the anatomy of the renal artery and peri-renal sympathetic nerve have since been published.…”