Lungpacer Medical Announces STIMULUS Trial Results

Lungpacer Medical, a neurostimulation company, shared the results of the STIMULUS trial, a phase 1 clinical study. This clinical study was done in collaboration with Toronto General Hospital and investigated diaphragm neurostimulation to optimize hemodynamic performance during invasive mechanical ventilation. 

The results showing improvement in hemodynamic performance were presented at the 2025 Transcatheter Heart Therapies (THT) conference.

The STIMULUS trial (NCT05465083) marks a significant milestone in the advancement of medical technologies designed to optimize patient care in intensive care units (ICUs). This trial aimed to evaluate the safety and efficacy of diaphragm neurostimulation, delivered via the investigational AeroNova System, in patients with acute hypoxemic respiratory failure or post-thoracic surgery respiratory failure.

Lungpacer Medical’s investigational AeroNova System comprises a cardiovascular catheter embedded with stimulating electrodes and a software-controlled system that contracts the diaphragm via transvenous phrenic nerve neurostimulation. The system is designed to achieve ventilation using lower positive pressures from the ventilator to mitigate ventilator-induced injury to the lung, diaphragm, heart, and brain of patients on mechanical ventilation.

The study specifically focused on measuring how diaphragm activation, when synchronized with mechanical ventilation, could improve cardiovascular function and mitigate the negative hemodynamic effects commonly seen with invasive mechanical ventilation.

The STIMULUS trial showed that diaphragm neurostimulation using a minimally invasive catheter-based system can serve as an adjunct to ventilation strategies, helping to maintain hemodynamic stability in critically ill patients.

The study enrolled 19 patients, of which 16 underwent a stimulation titration procedure, with most patients (75%) having pre-existing cardiac dysfunction and exhibiting a high incidence of right ventricular dysfunction and/or pulmonary hypertension. 

Using the AeroPace Catheter, transvenous bilateral neurostimulation was delivered safely using stimulation levels titrated to achieve diaphragm activation, resulting in increasing levels of expiratory occlusion pressure. 

The study results indicate that diaphragm neurostimulation merits further exploration as a novel therapy to counteract the harmful cardiovascular effects associated with positive pressure ventilation by improving cardiac function and pulmonary hemodynamics.

Key Results

• Cardiac Function Improvement: Increasing levels of diaphragm neurostimulation led to a significant increase in cardiac index (p=0.003) and stroke volume index (p=0.016), indicating better heart performance and enhanced blood flow. 
• Enhanced Mean Arterial Pressure: The study demonstrated that mean arterial pressure rose significantly (p=0.002), supporting overall hemodynamic stability. 
• Decreased Pulmonary Artery Pressure: The results also showed a decrease in pulmonary artery pressure (p<0.001), likely driven by reduced pulmonary vascular resistance. This reduction is crucial for patients with cardiovascular compromise and pulmonary hypertension, where the heart struggles to pump blood through the lungs.

The study also suggests a dose-response relationship, where increasing stimulation correlates with further improvements in cardiac and pulmonary parameters, providing a strong foundation for future trials and clinical applications.