Device-based approaches for renal nerve ablation for hypertension and beyond

Abstract

Animal and human studies have demonstrated that chronic activation of renal sympathetic nerves is critical in the pathogenesis and perpetuation of treatment-resistant hypertension. Bilateral renal denervation has emerged as a safe and effective, non-pharmacological treatment for resistant hypertension that involves the selective ablation of efferent and afferent renal nerves to lower blood pressure. However, the most recent and largest randomized controlled trial failed to confirm the primacy of renal denervation over a sham procedure, prompting widespread re-evaluation of the therapy's efficacy. Disrupting renal afferent sympathetic signaling to the hypothalamus with renal denervation lowers central sympathetic tone, which has the potential to confer additional clinical benefits beyond blood pressure control. Specifically, there has been substantial interest in the use of renal denervation as either a primary or adjunct therapy in pathological conditions characterized by central sympathetic overactivity such as renal disease, heart failure and metabolic-associated disorders. Recent findings from pre-clinical and proof-of-concept studies appear promising with renal denervation shown to confer cardiovascular and metabolic benefits, largely independent of changes in blood pressure. This review explores the pathological rationale for targeting sympathetic renal nerves for blood pressure control. Latest developments in renal nerve ablation modalities designed to improve procedural success are discussed along with prospective findings on the efficacy of renal denervation to lower blood pressure in treatment-resistant hypertensive patients. Preliminary evidence in support of renal denervation as a possible therapeutic option in disease states characterized by central sympathetic overactivity is also presented.

Keywords: blood pressure; cardiovascular disease; renal denervation; renal nerve activity; resistant hypertension; sympathetic overactivity.

Figure 1

Schematic illustration of the role of increased renal efferent sympathetic outflow and increased renal afferent sensory signaling in the pathophysiology of hypertension and other cardiovascular, renal, and metabolic disease states. ERSNA, efferent renal sympathetic nerve activity; ARSNA, afferent renal sympathetic nerve activity; RAAS, renin–angiotensin–aldosterone system; LVH, left ventricular hypertrophy; LV, left ventricular; CNS, central nervous system.