Does Renal Denervation a Reasonable Treatment Option in Hemodialysis-Dependent Patient with Resistant Hypertension? A Narrative Review

The effect of renal denervation in microcirculation: focusing on coronary microvascular dysfunction

Arterial hypertension is one of the most prevalent cardiovascular pathologies worldwide. Considering the increased rates of uncontrolled hypertension and treatment non-adherence, catheter-based methods, with the most prominent being renal denervation, have been recently included in international guidelines for the management of the pathology, naming the method the third pillar in hypertension management. However, sympathetic overactivation is not only a major pathophysiologic driver in hypertension, but in other cardiovascular pathologies as well. Considering the effect of renal denervation in hypertension-mediated target organ damage, as well as the pleotropic effects of this modality, recent evidence have evaluated the modality in coronary microvascular dysfunction (CMD). Interestingly, despite preclinical data showcase a benefit of renal denervation in microcirculatory homeostasis, with enhancement of endothelial-mediated vasodilation and reduction of inflammation, these effects have failed to be translated into clinical benefit, with the limited, to date, non-interventional studies in coronary microcirculation reporting neutral effects. Therefore, this review aims to delineate the pathophysiological processes which relate microvascular dysfunction with hypertension, discuss the effect of the procedure in hypertension-mediated target organ damage, analyze preclinical and clinical data on the safety and efficacy of renal denervation in improving microcirculatory indices, as well as provide future directions for this novel field.

Opportunities and Limitations of Renal Denervation: Where Do We Stand?

Hypertension is a primary contributor to cardiovascular disease, and the leading risk factor for loss of quality adjusted life years. Up to 50% of the cases of hypertension in the United States remain uncontrolled. Additionally, 8%-18% of the hypertensive population have resistant hypertension; uncontrolled pressure despite 3 different antihypertensive agents. Recently, catheter-based percutaneous renal denervation emerged as a method for ablating renal sympathetic nerves for difficult-to-control hypertension. Initial randomized (non-sham) trials and registry analyses showed impressive benefit, but the first sham-controlled randomized controlled trial using monopolar radiofrequency ablation showed limited benefit. With refinement of techniques to include multipolar radiofrequency, ultrasound denervation, and direct ethanol injection, randomized controlled trials demonstrated significant blood pressure improvement, leading to US Food and Drug Administration approval of radiofrequency- and ultrasound-based denervation technologies. In this review article, we summarize the major randomized sham-controlled trials and societal guidelines regarding the efficacy and safety of renal artery denervation for the treatment of uncontrolled hypertension.

Renal Denervation in End-Stage Renal Disease: Current Evidence and Perspectives

In patients with end-stage renal disease (ESRD) undergoing haemodialysis, hypertension is of common detection and frequently inadequately controlled. Multiple pathophysiological mechanisms are involved in the development and progression of the ESRD-related high blood pressure state, which has been implicated in the increased cardiovascular risk reported in this hypertensive clinical phenotype. Renal sympathetic efferent and afferent nerves play a relevant role in the development and progression of elevated blood pressure values in patients with ESRD, often leading to resistant hypertension. Catheter-based bilateral renal nerves ablation has been shown to exert blood pressure lowering effects in resistant hypertensive patients with normal kidney function. Promising data on the procedure in ESRD patients with resistant hypertension have been reported in small scale pilot studies. Denervation of the native non-functioning kidney's neural excitatory influences on central sympathetic drive could reduce the elevated cardiovascular morbidity and mortality seen in ESRD patients. The present review article will focus on the promising results obtained with renal denervation in patients with ESRD, its mechanisms of action and future perspectives in these high risk patients.