Characteristics and outcomes of patients receiving new and replacement implantable cardioverter-defibrillators: results from the NCDR.

BACKGROUND: Little is known about the clinical features, procedural risks, or survival of patients receiving replacement versus new implantable cardioverter-defibrillators (ICDs). METHODS AND
RESULTS: Entries in the National Cardiovascular Data Registry (NCDR) ICD Registry from 2005 through 2010 were eligible for inclusion (n=463,978). Baseline demographic data, clinical information, and procedural variables were compared between patients receiving new (n=359,993; 77.6%) and replacement (n=103,985; 22.4%) ICDs and entered into a propensity match model to determine adjusted survival rates. Patients receiving replacement ICDs were older (70.7 versus 67.5 years of age) and more likely to have atrial fibrillation (41.8% versus 31.4%; P<0.001) and ventricular tachycardia (60.5% versus 33.9%; P<0.001) compared with patients receiving new ICDs. Median battery life was only 4.6 years (25%-75% interquartile range, 3.7-5.8) for all replaced devices, 5.8 (25%-75% interquartile range, 4.2-7.5) for single-chamber, 5.1 (25%-75% interquartile range, 4.1-6.1) for dual-chamber, and 3.9 (25%-75% interquartile range, 3.2-4.6) years for biventricular devices. Patients receiving replacement ICDs had lower rates of index admission complications (0.9% versus 3.2%; P<0.001) but greater risk for death compared receiving patients receiving new ICDs in unadjusted analysis (hazard ratio, 1.18; 95% confidence interval, 1.16-1.20; P<0.0001) and after propensity-score matching (hazard ratio, 1.28; 95% confidence interval, 1.25-1.30; P<0.0001).
CONCLUSIONS: Patients receiving replacement ICDs are older and at greater risk for death compared with those receiving initial ICD implants. The battery life of initial ICDs is shorter than previously reported.