Background

Lead failure is the major limitation in implantable cardioverter-defibrillator (ICD) therapy. Long-term follow-up data for Biotronik Linox ICD leads are limited. Therefore, we analyzed the performance of all these leads implanted at our institution.

Methods

All implanted Linox and Linox Smart ICD leads between 2006 and 2015 were identified. Lead failure was defined as electrical dysfunction (oversensing, abnormal impedance, exit block). Lead survival was described, according to Kaplan-Meier. Associations between lead failure and specific variables were examined. A p-value <0.05 was considered statistically significant.

Results

We identified 417 ICD leads. The median follow-up time for Linox (n=205) was 6.3 years and for Linox Smart (n=212) 3.1 years. During that follow-up time 20 Linox (9.8%) and 8 Linox Smart leads (3.8%) showed lead failure, respectively. The 5-year lead survival probability was 97.4% for Linox and 96.1% for Linox Smart (log-rank test, p=0.851).  The 6- and 8-year survival probability for Linox was 93.6% and 82.4%, respectively. The only factor significantly associated with lead failure was younger patient age at implantation (HR/year: 0.962, 95% KI: 0.93-0.99, p=0.01).

Conclusion

This relatively large study with a long follow-up period highlights a rather high failure rate of Biotronik Linox leads. The performance of Linox and Linox Smart ICD leads was comparable. Although we show an acceptable 5-year lead survival probability, we observed a marked drop after just one more year of follow-up. In an era of improving heart failure survival probability a prolonged follow-up of ICD leads is increasingly clinically relevant.