Long-Term Lead Performance for Vagus Nerve Stimulation: Low Rate of Complications and Failures

Background: Vagus nerve stimulation (VNS) has been shown to improve cardiac function and heart failure symptoms. The VITARIA System provides chronic stimulation through a self-sizing, atraumatic lead placed around the cervical vagus nerve. The lead is identical to the predecessor M304 lead, which has been implanted in patients since 2009 for treatment of epilepsy and depression. Its long-term performance has not been previously reported. Methods: All leads implanted in the United States for any indication were included in this analysis. All available data on lead explants, replacements, and customer complaints were used to identify failures. Lead survival was defined as likelihood of the implanted lead remaining implanted and performing as intended. Results: The M304 lead has been part of 31,000 implantations, with 72,100 device-years of patient exposure. In 11,000 patients, 99.4% of leads remained implanted and performing as intended after 1 year. At 7 years, 95.7% of leads performed as intended. Lead failure is rare, with common causes being infection (0.87%) and vocal cord dysfunction (0.68%). Conclusions: The M304 VNS lead has been used for neuromodulation in over 30,000 patients for over 70,000 device-years. Cumulative lead survival has exceeded design requirements and has low rates of complications and failures.