Renal Denervation for Chronic Heart Failure: Background and Pathophysiological Rationale

The Potential Role of Renal Denervation in the Management of Heart Failure

Sympathetic nervous system activation in patients with heart failure is one of the main pathophysiologic mechanisms associated with the worse outcomes. Pharmacotherapies targeting neurohormonal activation have been at the center of heart failure management. Despite the advancement of therapies and the available treatments, heart failure continues to have an overall poor prognosis. Renal denervation was originally developed to lower systemic blood pressure in patients with poorly controlled hypertension, by modulating sympathetic outflow. However, more recently, multiple studies have investigated the effect of renal denervation in heart failure patients with both preserved (HFpEF) and reduced ejection fractions (HFrEF). This paper provides an overview of the potential effect of renal denervation in altering the various pathophysiologic, sympathetically mediated pathways that contribute to heart failure, and reviews the literature that supports its future use in those patients.

Valsartan Dosage on Ventriculo-Vascular Coupling Index Dose-Dependency in Heart Failure Patients

PURPOSE

Heart failure (HF) poses significant morbidity and mortality. Recently, the ventriculo-vascular coupling index (VVI) was introduced as an independent prognostic factor reflective of the overall cardiovascular performance index in HF. We aimed to determine the effectiveness of force-titration of valsartan on VVI values in HF patients.

MATERIALS AND METHODS

In this multicenter and prospective observational trial, the effect of valsartan was stratified according to dosages [non-ceiling dose (NCD) vs. ceiling dose (CD)] in HF patients with left ventricular ejection fraction (LVEF) <55%. Biochemical studies, including N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiography with VVI, the treadmill test, and the activity scale index were assessed at baseline and after 24 weeks of treatment.

RESULTS

One-hundred thirty-eight patients were force-titrated to either a CD group (n=81) or a NCD group (n=57). The mean age of the study participants was 59 years and 66% were male. After 6 months of follow up, left ventricular mass index (LVMI) values had significantly improved in the CD group but not in the NCD group. Intriguingly, in HF patients with a reduced ejection fraction (HFrEF) (n=52, LVEF <40%), a significant improvement in VVI was only observed in the CD group (from 2.4±0.6 to 1.8±0.5, p<0.001).

CONCLUSION

CDs of valsartan for 6 months showed better improvement in VVI, as well as LVMI, in patients with HFrEF, compared with NCDs.

An Open-label, Single-arm, Multicenter Feasibility Study Evaluating the Safety of Catheter-based Renal Denervation with DENEX™ in Patients with Uncontrolled Hypertension on Standard Medical Therapy

Background and Objectives

DENEX™ is a novel renal sympathetic denervation (RDN) system that is equipped with 3 electrodes that deliver radiofrequency energy to the renal nerves along renal arteries. The purpose of this study was to evaluate the safety and efficacy of RDN with DENEX™ in resistant hypertension.

Methods

This was an open-label, single-arm, multicenter, first-in-man pilot study. Between November 2016 and May 2018, a total of 16 patients were enrolled at 4 centers in South Korea. The inclusion criteria were systolic blood pressure (SBP) ≥150 mmHg and use of 3 or more antihypertensive medications, including diuretics. The primary objective was the safety outcome of RDN with the DENEX™ system. The secondary objective was efficacy outcome based on changes of office, and 24-hour ambulatory SBP from baseline to 3 months. The patients underwent abdominal computed tomography (CT) or duplex ultrasonogram before and 6 months after RDN.

Results

No major adverse events occurred after RDN for 6 month of follow-up period. There was no vascular complication either by CT or duplex ultrasonogram. The office SBP was significantly reduced from 164.6±11.6 mmHg at baseline to 142.0±20.4 mmHg (−24.4±24.4 mmHg, p=0.003) at 3 months. The ambulatory SBP was reduced from 151.44±12.85 mmHg at baseline to 140.0±16.5 mmHg (−13.1±18.9 mmHg, p=0.056) at 3 months.

Conclusion

RDN with the DENEX™ system showed a favorable safety profile in resistant hypertension. A significant reduction in office SBP and a borderline reduction in ambulatory SBP were observed.

Trial Registration

ClinicalTrials.gov Identifier: NCT04248530

Renal denervation restrains the inflammatory response in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury leads to intensive sympathetic nervous system (SNS) activation and inflammatory reactions. Whether renal sympathetic denervation (RDN) could be a new therapeutic strategy to modulate I/R inflammation and reduce infarct size after myocardial I/R injury needs to be explored. First, we investigated the correlation between plasma norepinephrine concentrations and circulating myeloid cell numbers in patients with acute myocardial infarction. And then, C57BL/6 mice underwent a "two-hit" operation, with 10% phenol applied to bilateral renal nerves to abrogate sympathoexcitation, and a 45-min ligation of the left coronary artery to induce myocardial I/R injury. The effects of RDN on the mobilization of immune cells in mice following myocardial I/R injury were explored. We observed a strong association between SNS overactivation and myeloid cell excessive accumulation in patients. In animal experiments, there was a significant reduction in infarct size per area at risk in the denervated-I/R group when compared to that of the innervated-I/R group (39.2% versus 49.8%; p < 0.005), and RDN also improved the left ventricular ejection fraction by 20% after 1 week. Furthermore, the denervated-I/R group showed a decrease in the number of neutrophils and macrophages in the blood and the myocardium as reflected by immunohistochemical staining and flow cytometry analysis (p < 0.05); the decrease was associated with a significant reduction in the circulating production of IL-1, IL-6 and TNF-α (p < 0.05). In summary, our study reveals a novel link between the SNS activity and inflammatory response undergoing myocardium I/R injury and identifies RDN as a potential therapeutic strategy against myocardium I/R injury via preserving the spleen immune cells mobilization.

Renal denervation attenuates pressure overload-induced cardiac remodelling in rats with biphasic regulation of autophagy

AIM

This study aimed to investigate effects of renal denervation (RDN) on pressure overload-induced cardiac remodelling in rats and the related mechanisms.

METHODS

Adult male Sprague-Dawley rats underwent transverse aortic constriction (TAC) to generate cardiac remodelling. RDN was performed 1 week after TAC. The animals were divided into four groups: control group, TAC group, TAC+RDN group and control+RDN group. Rats in all groups were studied at 3 and 10 weeks after TAC respectively. Echocardiography and histology were used to evaluate cardiac function and pathological changes. TUNEL staining and western blotting were used to assess apoptosis. Western blotting and transmission electron microscopy (TEM) were used to evaluate autophagy.

RESULTS

Three weeks after TAC, the TAC rats exhibited cardiac hypertrophy with normal cardiac function and no myocardial interstitial fibrosis or apoptosis, accompanied by a lower LC3 II level and fewer autophagic vacuoles in the left ventricles, both in the presence and absence of chloroquine (CQ), indicating suppressed autophagy at this stage. RDN ameliorated these pathological changes and attenuated the decrease in autophagy. Ten weeks after TAC, the TAC rats had decreased cardiac function, obvious cardiac interstitial fibrosis and apoptosis, with increased autophagy. RDN prevented these pathological changes, coincident with attenuation of increased autophagy.

CONCLUSION

Autophagy was suppressed at the early stage but activated at the late stage of TAC-induced cardiac remodelling. RDN attenuated the pathological changes of TAC rats, accompanied by attenuation of the changes in autophagy. Thus, RDN ameliorated TAC-induced cardiac remodelling partially associated with biphasic modulation of autophagy.

Renal Denervation: Is It Ready for Prime Time?

PURPOSE OF REVIEW

Interventional cardiology and in particular the field of renal denervation is subject to constant change. This review provides an up to date overview of renal denervation trials and an outlook on what to expect in the future.

RECENT FINDINGS

After the sham-controlled SYMPLICITY HTN-3 trial dampened the euphoria following early renal denervation trials, the recently published results of the sham-controlled SPYRAL HTN and RADIANCE HTN trials provided proof-of-principle for the blood pressure-lowering efficacy of renal denervation. However, these studies underline the major issue of patients' non-adherence to antihypertensive medication as well as the need for reliable patient- and procedure-related predictors of response. The second generation of sham-controlled renal denervation trials provided proof of principle for the blood pressure-lowering efficacy of RDN. However, larger trials have to assess long-term safety and efficacy.

Update on heart failure management and future directions

Heart failure (HF) is an important cardiovascular disease because of its increasing prevalence, significant morbidity, high mortality, and rapidly expanding health care cost. The number of HF patients is increasing worldwide, and Korea is no exception. There have been marked advances in definition, diagnostic modalities, and treatment of HF over the past four decades. There is continuing effort to improve risk stratification of HF using biomarkers, imaging and genetic testing. Newly developed medications and devices for HF have been widely adopted in clinical practice. Furthermore, definitive treatment for end-stage heart failure including left ventricular assist device and heart transplantation are rapidly evolving as well. This review summarizes the current state-of-the-art management for HF and the emerging diagnostic and therapeutic modalities to improve the outcome of HF patients.