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 during maximum of 14 years.

Materials & Methods

All Linox and Linox Smart ICD leads implanted 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. P-value <0.05 was considered significant.

Results

We included 417 ICD leads. The median follow-up time for Linox (n=205) was 81 months and for Linox Smart (n=212) 75 months. During that follow-up time 30 Linox (14.6%) and 17 Linox Smart leads (8%) showed a malfunction, respectively. The 5-year lead survival probability was 97.4% for Linox and 95.2% for Linox Smart (log-rank test, p=0.26).  The 6- and 8-year lead survival probability for Linox was 93.6% and 84.6%, and for Linox Smart 93% and 90.8%, respectively. The only factor significantly associated with lead failure was younger patient age at implantation (HR/year: 0.97, 95% KI: 0.95-0.99, p=0.005).

Conclusion

This relatively large study with a long follow-up period highlights a relevant failure rate of Biotronik Linox leads. The performance of Linox vs. 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.