Reassessment of Cardiac Function and Implantable Cardioverter-Defibrillator Use Among Medicare Patients With Low Ejection Fraction After Myocardial InfarctionClinical Perspective
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Background: Guidelines recommend that patients with low ejection fraction (EF) after myocardial infarction (MI) have their EF reassessed 40 days after MI for implantable cardioverter-defibrillator (ICD) candidacy. This study examines rates of EF reassessment and their association with 1-year ICD implantation in post-MI patients with low EF.
Methods: We examined rates of postdischarge EF reassessment and ICD implantation among 10 289 Medicare-insured patients ≥65 years of age with an EF≤35% during the index MI admission from January 2007 through September 2010 in ACTION Registry–GWTG (Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines). Multivariable Cox models tested the association between time-dependent EF reassessment and 1-year ICD implantation, stratified by revascularization status during the index MI admission.
Results: Among patients with EF ≤35% during the index MI admission, 66.8% (95% confidence interval [CI], 65.9–67.8) had EF reassessment within the next year. Revascularized patients were more likely to have EF reassessment (76.9% [95% CI, 75.8–78.0)] versus 53.7% [95% CI, 52.2–55.2]; P<0.001) and had shorter times to EF reassessment (median, 67 versus 84 days; P<0.001) than nonrevascularized patients. Among patients with EF reassessment, only 11% received an ICD within 1 year. Reassessment of EF was associated with a higher likelihood of ICD implantation for both revascularized (unadjusted, 12.1% versus 2.4%, P<0.001; adjusted hazard ratio, 10.6, 95% CI, 7.7–14.8) and nonrevascularized (unadjusted, 10.0% versus 1.7%, P<0.001; adjusted hazard ratio, 6.1, 95% CI, 4.1–9.2) patients.
Conclusions: In US practice, EF reassessments are commonly performed among patients with MI with an initially reduced EF. Although 1-year EF reassessment is associated with increased likelihood of ICD implantation, 1-year ICD implantation rates remain very low even among patients with EF reassessment, regardless of revascularization status.
- Received March 3, 2016.
- Accepted October 21, 2016.
- © 2016 American Heart Association, Inc.