Effects of Auricular Vagal Neuromodulation Therapy (AVNT) on Microcirculation in Endothelial Cells in Heart Failure with Reduced Ejection Fraction

Abstract

The study evaluated the effectiveness of Nurosym Auricular Vagal Neuromodulation Therapy (AVNT) in improving vascular function in patients with heart failure with reduced ejection fraction (HFrEF). The prospective, single-blind, placebo-controlled, randomised clinical trial involved participants undergoing active neuromodulation or a placebo equivalent in a crossover design. Microvascular function was assessed using laser speckle contrast imaging (LSCI). Results showed that Nurosym significantly improved hand perfusion and hyperemia, indicating enhanced microcirculatory function and oxygen delivery. The findings suggest that Nurosym could reduce cardiac workload and improve tissue perfusion, offering a promising non-pharmacological treatment option for heart failure patients, particularly those with comorbidities. Further research is necessary to confirm these benefits and understand the long-term implications of Nurosym therapy in cardiovascular care.

Background and aims

The aim of the study was to determine the effectiveness of Nurosym compared with a placebo intervention in improving vascular function. The vagus nerve plays a crucial role in maintaining physiological homeostasis, including the regulation of cardiac function through reflex pathways. Because of the vagus nerve's innervation of the heart, Nurosym has been identified as a potential therapy for cardiovascular disorders. Recent studies have also highlighted its effects on the circulatory system, particularly microcirculation. Microcirculation is essential for tissue perfusion and oxygen delivery. In patients with heart failure, microcirculatory disorders are common and can exacerbate the condition, contributing to symptoms such as fatigue and shortness of breath, which significantly deteriorate quality of life.

Methods

The study employed a prospective, single-blind, placebo-controlled, randomised clinical trial design. The study included patients diagnosed with heart failure with reduced ejection fraction (HFrEF). Participants were randomly assigned in a 1:1 ratio to receive active tragus stimulation or a placebo equivalent. The study was a crossover design, with participants switching groups on day two to ensure everyone received both treatments. Microvascular function was assessed using laser speckle contrast imaging (LSCI). Stimulation was adjusted to remain below pain thresholds and lasted for 60 minutes, after which further vascular assessment was performed. Statistical analysis of the data included paired t tests or Wilcoxon signed rank tests based on the distribution of the data, assessing changes in vascular function before and after the intervention. Results are presented in box plots and assessed for statistical significance.

Results

Nurosym has shown effectiveness in improving blood flow and has the potential to enhance oxygen delivery and nutrient exchange at the microvascular level. This device could prove beneficial in reducing cardiac workload and ensuring adequate blood flow to tissues without imposing additional strain on the heart.

Nurosym increased hand perfusion, a marker of microcirculatory function. Significantly higher perfusion rates in the neuromodulation group were observed after Nurosym compared to placebo. Nurosym was associated with a significant increase in hyperemia above baseline values (from 85.57% to 140.5%, p = 0.03) and a X-fold change in perfusion (from 1.86 to 2.41, p = 0.03).

Conclusion

The Nurosym device study provided important insights into potential non-pharmacological treatments for heart failure, particularly emphasising the improvement of microvascular endothelial function. The study focused on a population with heart failure with reduced ejection fraction (HFrEF), which included patients with significant comorbidities such as hypertension (75%), diabetes (46%), and coronary artery disease (60%). These findings suggest that the Nurosym device could help control symptoms and potentially slow the progression of heart failure and associated comorbidities that contribute to vascular damage. Furthermore, by demonstrating significant improvements in endothelial function using a non-invasive approach, Nurosym represents a potential safe adjunctive therapy option that can be used concurrently with conventional drug-based therapies.