Background: Long-term data on device-related untoward events in patients receiving defibrillators for resynchronization therapy (CRT-D) are lacking. We quantified the frequency of repeat invasive procedures and the nature of long-term complications in current clinical practice and examined possible predictors of device-related events and their association with long-term patient outcome.
Methods and results: We analyzed data from 3253 patients who underwent de novo successful implantation of CRT-D and were followed up for a median of 18 months (25th to 75th percentiles: 9 to 30) in 117 Italian centers. Device-related events were reported in 416 patients, and, specifically, surgical interventions for system revision were described in 390 patients. Four years after the implantation procedure, 50% of patients underwent surgical revision for battery depletion and 14% for unanticipated events. For comparison, at 4 years battery depletion occurred in 10% and 13% of patients who received single- and dual-chamber defibrillators at the study centers, and unanticipated events were reported as 4% and 9%, respectively. In CRT-D, infections occurred at a rate of 1.0%/y, and the risk of infections increased after device replacement procedures (hazard ratio, 2.04; 95% confidence interval, 1.01 to 4.09; P=0.045). Left ventricular lead dislodgements were reported at a rate of 2.3%/y and were predicted by longer fluoroscopy time and higher pacing threshold on implantation. Device-related events were not associated with a worse clinical outcome; indeed, the risk of death was similar in patients with and without surgical revision (hazard ratio, 0.90; 95% confidence interval, 0.56 to 1.47; P=0.682).
Conclusions: In current clinical practice device-related events are more frequent in CRT-D than in single- or dual-chamber defibrillators, and are frequently managed by surgical intervention for system revision. However, a worse clinical outcome is not associated with these events.
Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01007474.