title: Characteristics and outcomes of patients receiving new and replacement implantable cardioverter-defibrillators: results from the NCDR.
abstract: BACKGROUND
  Little is known about the clinical features, procedural risks, or survival of patients receiving replacement versus new implantable cardioverter-defibrillators (ICDs).
  
  
  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.
authors.affiliation: Beth Israel Deaconess Medical Center, Boston, MA, USA. danielkramer@hsl.harvard.edu
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Kramer
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Kennedy
authors.forename: Peter A
authors.initials: PA
authors.lastname: Noseworthy
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Buxton
authors.forename: Mark E
authors.initials: ME
authors.lastname: Josephson
authors.forename: Sharon-Lise
authors.initials: SL
authors.lastname: Normand
authors.forename: John A
authors.initials: JA
authors.lastname: Spertus
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Zimetbaum
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Reynolds
authors.forename: Susan L
authors.initials: SL
authors.lastname: Mitchell
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D020878:Device Removal; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D011475:Prosthesis Failure; D012042:Registries; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States
keywords: death, sudden; defibrillation; implantable cardioverter-defibrillators