The association of ICD device complications and risk factors in patients with cardiac sarcoidosis
With sudden cardiac death accounting for up to 80% of all fatalities in cardiac sarcoidosis, ICD implantation should always be considered in those selected groups in whom it is appropriate(28), however implantation of an ICD is a high-cost procedure with its own risk profile. A Danish study in 2014 of nearly 6000 patients with cardiac implantable electronic devices (CIED) for a variety of indications (not necessarily CS) estimated approximately 10% of their patients experienced device complications(29).
The first publication to analyse the association between ICD complications in CS patients was Kron et al. in 2012, showing adverse events in 17.4% of their 235 patients at a median follow-up of 4.2 ± 4.0 years. Over half of these complications were related to lead dislodgement or fracture(14). A later retrospective study of 105 patients showed device-related complications at a comparable rate of ~18% at a shorter median follow-up time of 2.8 years(10). Again, complications were most commonly caused by lead malfunction in nearly 1/3 of patients. Both of these papers link this specific complication to the young age and increased level of activity of CS patients when compared to the average ICD patient – a difference of 10 years at point of implantation(30,5). As commented on by the authors, combining this variable with the high failure rates of the ‘Medtronic Sprint Fidelis’ leads (particularly in the younger population), which were prominent at the time of the study, may account for these particularly high rates of adverse effects(31).
Many patients are also treated with immunosuppressive drugs such as prednisolone and methotrexate. We expected this to have an impact on infection rates in the CS cohort. In both the Kron et al. and Mathijssen et al. papers, infection was the second commonest adverse event after lead-related complications at rates of 2.6% and 4.8% respectively. CIED analysis from the previously referenced Danish study showed infection rates of 0.83% in a their population(29).