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

Abstract

Background Autonomic Regulation Therapy (ART) is a novel therapy for heart failure (HF) that has been shown in a pilot study to be associated with improvement in left ventricular function, 6-minute walk distance, NYHA class, and quality of life. ART is provided using chronic stimulation through a self-sizing lead that is placed on the cervical vagus nerve without any need for response-mapping. The lead is functionally identical in its design and manufacture to a commercially available lead that has been implanted since February 2009 for the treatment of refractory epilepsy and treatment-resistant depression. Purpose A survival analysis was performed to evaluate long-term lead performance. Methods Lead survival was calculated for those patients whose survival status was obtainable from public records. All devices registered as implanted in the United States for any indication were included for the analysis. All available data on device explants, device replacements, returned product analyses, and customer complaints were collected and used to identify failures and out-of-specification conditions. Device survival probability was defined as the likelihood of the implanted device remaining implanted and performing as intended. Results As of the time of this analysis, there have been 26,467 registered system implantations and a total of 53,200 device-years of lead use. Survival status was obtainable for 9,700 patients from public records. After 1 year, 99.5% of implanted leads have remained implanted and performing as intended. At 7 years, 95.8% of leads have remained implanted and performing as intended. The most common causes of lead failure have been infection (0.87%), vocal cord dysfunction (0.68%), lead protrusion (0.36%), and lead extrusion (0.27%). Conclusions Lead performance during chronic vagus nerve stimulation has included over 50,000 device-years of use in over 25,000 patients. A low rate of long term complications and failures have been reported, and the cumulative survival probability of the lead appears to be high.