Catheter-based Renal Denervation as a Treatment for Pulmonary Hypertension: Hope or Hype?

Autonomic nervous modulation: early treatment for pulmonary artery hypertension

Pulmonary artery hypertension (PAH) is a chronic vascular disease defined by the elevation of pulmonary vascular resistance and mean pulmonary artery pressure, which arises due to pulmonary vascular remodelling. Prior research has already established a link between the autonomic nervous system (ANS) and PAH. Therefore, the rebalancing of the ANS offers a promising approach for the treatment of PAH. The process of rebalancing involves two key aspects: inhibiting an overactive sympathetic nervous system and fortifying the impaired parasympathetic nervous system through pharmacological or interventional procedures. However, the understanding of the precise mechanisms involved in neuromodulation, whether achieved through medication or intervention, remains insufficient. This limited understanding hinders our ability to determine the appropriate timing and scope of such treatment. This review aims to integrate the findings from clinical and mechanistic studies on ANS rebalancing as a treatment approach for PAH, with the ultimate goal of identifying a path to enhance the safety and efficacy of neuromodulation therapy and improve the prognosis of PAH.

Neurohormonal Modulation as a Therapeutic Target in Pulmonary Hypertension

The autonomic nervous system (ANS) and renin-angiotensin-aldosterone system (RAAS) are involved in many cardiovascular disorders, including pulmonary hypertension (PH). The current review focuses on the role of the ANS and RAAS activation in PH and updated evidence of potential therapies targeting both systems in this condition, particularly in Groups 1 and 2. State of the art knowledge in preclinical and clinical use of pharmacologic drugs (beta-blockers, beta-three adrenoceptor agonists, or renin-angiotensin-aldosterone signaling drugs) and invasive procedures, such as pulmonary artery denervation, is provided.

Efficacy and safety of renal denervation for Chinese patients with resistant hypertension using a microirrigated catheter: study design and protocol for a prospective multicentre randomised controlled trial

INTRODUCTION

Available data show that approximately 8%-18% of patients with primary hypertension will develop resistant hypertension. In recent years, catheter-based renal denervation (RDN) has emerged as a potential treatment option for resistant hypertension. A number of observational studies and randomised controlled trials among non-Chinese patients have demonstrated its potential safety and efficacy.

METHODS AND ANALYSIS

This is a multicentre, randomised, open-label, parallel-group, active controlled trial that will investigate the efficacy and safety of a 5F saline-irrigated radiofrequency ablation (RFA) used for RDN in the treatment of Chinese patients with resistant hypertension. A total of 254 patients who have failed pharmacological therapy will be enrolled. Eligible subjects will be randomised in a 1:1 ratio to undergo RDN using the RFA plus antihypertensive medication or to receive treatment with antihypertensive medication alone. The primary outcome measure is the change in 24 hours average ambulatory systolic blood pressure from baseline to 3 months, comparing the RDN-plus-medication group with the medication-alone group. Important secondary endpoints include the change in office blood pressure from baseline to 6 months after randomisation. Safety endpoints such as changes in renal function will also be evaluated. The full analysis set, according to the intent-to-treat principle, will be established as the primary analysis population.

ETHICS AND DISSEMINATION

All participants will provide informed consent; the study protocol has been approved by the Independent Ethics Committee for each site. This study is designed to investigate the efficacy and safety of RDN using a 5F saline microirrigated RFA. Findings will be shared with participating hospitals, policymakers and the academic community to promote the clinical management of resistant hypertension in China.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02900729; pre-results.

Renal Denervation Reduces Pulmonary Vascular Remodeling and Right Ventricular Diastolic Stiffness in Experimental Pulmonary Hypertension

Neurohormonal overactivation plays an important role in pulmonary hypertension (PH). In this context, renal denervation, which aims to inhibit the neurohormonal systems, may be a promising adjunct therapy in PH. In this proof-of-concept study, we have demonstrated in 2 experimental models of PH that renal denervation delayed disease progression, reduced pulmonary vascular remodeling, lowered right ventricular afterload, and decreased right ventricular diastolic stiffness, most likely by suppression of the renin-angiotensin-aldosterone system.

Effect of High Thoracic Sympathetic Nerve Block on Serum Collagen Biomarkers in Patients with Chronic Heart Failure

OBJECTIVES

The impact of high thoracic sympathetic block (HTSB) on myocardial fibrosis in chronic heart failure (HF) is unclear. Myocardial collagen synthesis can be assessed by measuring circulating biomarkers. We observed the effect of HTSB on serum collagen biomarkers in HF.

METHODS

Forty-four patients were randomized to a control and a HTSB group. They received routine medications. Repeated epidural injections were given to the HTSB group for 4 weeks. Echocardiography and measurements of serum carboxy-terminal propeptide of procollagen type I (PICP) and amino-terminal propeptide of procollagen type III (PIIINP) were performed at baseline and 4 weeks later.

RESULTS

There were significant reductions in left atrial diameter, left ventricular (LV) diameter and volume, LV weight index (LVWI) and serum PICP and PIIINP levels in the HTSB group (p < 0.05). The changes in LV end-systolic volume and ejection fraction (LVEF) were greater in the HTSB group than in the control group (p < 0.05). In the HTSB group, the decreases in PICP and PIIINP were correlated with the decrease in LVWI (PICP: r = 0.695, p = 0.000; PIIINP: r = 0.642, p = 0.001), and the decrease in PICP was negatively associated with the rise in LVEF (r = -0.813, p = 0.000).

CONCLUSION

HTSB reduces myocardial fibrosis in HF, which may accompany the improvement of LV hypertrophy and dysfunction.