Implantable Cardioverter-Defibrillators for Primary Prevention in Patients With Ischemic or Nonischemic Cardiomyopathy: A Systematic Review and Meta-analysis.

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) have a role in preventing cardiac arrest in patients at risk for life-threatening ventricular arrhythmias.

PURPOSE

To compare ICD therapy with conventional care for the primary prevention of death of various causes in adults with ischemic or nonischemic cardiomyopathy.

DATA SOURCES

MEDLINE, Cochrane Central Register of Controlled Trials, Google Scholar, and EMBASE databases, as well as several Web sites, from 1 April 1976 through 31 March 2017.

STUDY SELECTION

Randomized controlled trials, published in any language, comparing ICD therapy with conventional care and reporting mortality outcomes (all-cause, sudden, any cardiac, or noncardiac) in the primary prevention setting.

DATA EXTRACTION

2 independent investigators extracted study data and assessed risk of bias.

DATA SYNTHESIS

Included were 11 trials involving 8716 patients: 4 (1781 patients) addressed nonischemic cardiomyopathy, 6 (4414 patients) ischemic cardiomyopathy, and 1 (2521 patients) both types of cardiomyopathy. Mean follow-up was 3.2 years. An overall reduction in all-cause mortality, from 28.26% with conventional care to 21.37% with ICD therapy (hazard ratio [HR], 0.81 [95% CI, 0.70 to 0.94]; P = 0.043), was found. The magnitude of reduction was similar in the cohorts with nonischemic (HR, 0.81 [CI, 0.72 to 0.91]) and ischemic (HR, 0.82 [CI, 0.63 to 1.06]) disease, although the latter estimate did not reach statistical significance. The rate of sudden death fell from 12.15% with conventional care to 4.39% with ICD therapy (HR, 0.41 [CI, 0.30 to 0.56]), with a similar magnitude of reduction in patients with ischemic (HR, 0.39 [CI, 0.23 to 0.68]) and those with nonischemic disease (HR, 0.44 [CI, 0.17 to 1.12]). Noncardiac and any cardiac deaths did not differ significantly by treatment.

LIMITATION

Heterogeneous timing of ICD placement; heterogeneous pharmacologic and resynchronization co-interventions; trials conducted in different eras; adverse events and complications not reviewed.

CONCLUSION

Overall, primary prevention with ICD therapy versus conventional care reduced the incidence of sudden and all-cause death.

PRIMARY FUNDING SOURCE

None.