ICD Use and Mortality Among Elderly After Acute MI

Jul 08, 2015
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Authors:
Pokorney SD, Miller AL, Chen AY, et al.
Citation:
Implantable Cardioverter-Defibrillator Use Among Medicare Patients With Low Ejection Fraction After Acute Myocardial Infarction. JAMA 2015;313:2433-2440.
Summary By:
Debabrata Mukherjee, MD, FACC

Study Questions:

What are the implantable cardioverter-defibrillator (ICD) implantation rates and associated mortality among older myocardial infarction (MI) patients with low ejection fraction (EF)?

Methods:

This was a retrospective observational study of Medicare beneficiaries with an EF of ≤35% after MI, treated at 441 US hospitals between 2007 and 2010, excluding patients with prior ICD implantation. Follow-up data were available through December 2010. The main outcome measures were patient characteristics associated with receiving an ICD within 1 year after discharge and 2-year mortality associated with ICD implantation.

Results:

Among 10,318 MI patients with EF of ≤35%, the cumulative 1-year ICD implantation rate was 8.1% (95% confidence interval [CI], 7.6%-8.7%). Patients with ICD implantation were more likely to have prior coronary artery bypass grafting procedures, higher peak troponin levels, in-hospital cardiogenic shock, and cardiology follow-up within 2 weeks after discharge relative to patients who did not receive an ICD within 1 year. Implantation of an ICD was associated with lower 2-year mortality (15.3 events per 100 patient-years [128 deaths in 838 patient-years vs. 26.4 events per 100 patient-years [3,033 deaths in 11,479 patient-years]; adjusted hazard ratio, 0.64; 95% CI, 0.53-0.78).

Conclusions:

The authors concluded that among older patients who experience MI, fewer than 1 in 10 eligible patients with low EF received an ICD within 1 year after MI.

Perspective:

This large registry study of older patients who experienced MI reports that fewer than 1 in 10 eligible patients with low EF received an ICD within 1 year after MI, although ICD implantation was associated with lower risk-adjusted mortality at 2 years. Additional research is needed to understand reasons for nonimplantation, which may be very legitimate and include improvement in EF, patient refusal, etc. Meanwhile, we need to work on optimal strategies to increase ICD implantation among eligible patients.

Keywords: Arrhythmias, Cardiac, Coronary Artery Bypass, Defibrillators, Implantable, Geriatrics, Heart Failure, Myocardial Infarction, Outcome Assessment, Health Care, Shock, Cardiogenic, Stroke Volume, Troponin


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