Long-Term Performance of the Riata/ST Implantable Cardioverter-Defibrillator Lead

Abstract

Riata and Riata ST implantable cardioverter-defibrillator leads are prone to structural and electrical failure (EF). Our objective was to evaluate Riata/ST lead performance over a long-term follow-up. Of 184 patients having undergone Riata/ST and Riata ST Optim lead implantation from September 2003 to June 2008, 154 patients were evaluated for EF and radiographic conductor externalization (CE). Survival analysis for EF was performed for Riata/ST leads, both for failure-free lead survival and cumulative hazard. Subanalysis on 7Fr leads was performed to evaluate EF and CE rates both for different Riata ST lead management (monitoring vs proactive) and between Riata ST and Riata ST Optim leads. During a mean follow-up of 7 years, Riata/ST lead EF rate was 13% overall. Similar failure-free survival rate was noted for 7Fr as for 8Fr leads (log-rank, p = 0.63). Of all failed leads, 64% failed only after 5 years of follow-up. Compared with the absolute failure rate of 1.84% per device year, cumulative hazard analysis for leads surviving past 5 years revealed an estimated failure rate of 7% per year. No clinical or procedural predictors for EF were found. The subanalysis on 7Fr leads showed an excellent outcome both for a proactive lead management approach as for Optim leads. In conclusion, long-term survival of the Riata/ST lead is impaired with an accelerating EF risk over time. An initial exponential trend was followed by a linear lead failure pattern for leads surviving past 5 years, corresponding to an estimated 7% annual EF rate. These findings may have repercussions on the lead management strategy in patients currently surviving with a Riata/ST lead to prevent significant clinical events like inappropriate shocks or failed device interventions.