Outcomes of Implantable Cardioverter-Defibrillators for Secondary Prevention

A study published in the Journal of the American College of Cardiology investigated the morbidity and mortality risks in older patients with implantable cardioverter-defibrillators (ICDs) for secondary prevention of sudden cardiac death.¹

Indications for ICDs have expanded since the 1980s, from secondary prevention in survivors of cardiac arrest to primary prevention in high-risk patients who have not experienced such events. While outcomes in the latter group have been described — including mortality, re-hospitalization, and complications — such findings are lacking in regard to patients requiring secondary prevention, who account for an estimated one-quarter of procedures in the National Cardiovascular Data Registry (NCDR).²

Randomized controlled trials in this patient group were conducted almost 20 years ago and primarily included younger patients who are less likely to have co-occurring illnesses that could influence postimplantation outcomes.^3,4 Additionally, treatments for structural heart disease have improved significantly over time.

In the present study, researchers from multiple US universities examined demographic and clinical data from the NCDR ICD Registry, which includes patients of various payer types in a range of US hospitals. Their aim was to determine mortality, rehospitalization, and nursing home admission rates over a period of 2 years in Medicare patients aged ≥65 years receiving an ICD for secondary prevention.

“These data are intended to provide patients and clinicians with contemporary, representative estimates of the risks of adverse outcomes after ICD implantation to inform decision-making and understand the resource needs of this population to support health policy,” the investigators wrote.

The final cohort consisted of 12,420 patients with a mean age of 75 years at implantation. Multivariate analysis revealed the following observations.

• At 2 years, the overall risk of death was 21.8%, ranging from 14.7% to 28.9% among patients <70 years and ≥80 years, respectively (adjusted risk ratio [aRR]: 2.01; 95% CI, 1.85-2.33; P for trend <.001).
• The cumulative incidence of hospitalization was 65.4%, ranging from 60.5% in patients <70 years to 71.5% in patients ≥80 years (aRR: 1.27; 95% CI, 1.19-1.36; P for trend <.001).
• The cumulative incidence of admission to a skilled nursing facility ranged from 13.1% to 31.9% among patients <70 years vs patients ≥80 years, respectively (aRR: 2.67; 95% CI, 2.37-3.01; P for trend <.001).
• The risk of admission to a skilled nursing facility was highest in the first 30 days following ICD implantation.
• At 2 years, hospitalization had occurred in nearly two-thirds of the cohort (65.4%), and the cumulative overall incidence of hospitalization for heart failure was 18.8%.

The high rates admission to hospitals and skilled nursing facilities observed in the current study offer “perspective on the substantial health care needs of this population after receiving an ICD for a secondary prevention indication,” the researchers concluded.

Disclosures: Dr McManus reports receiving grant funding from Philips and Biotronik, and owns equity in ATRIA, Inc., and Mobile Sense, Inc. Dr McManus has also served as a consultant for Bristol-Myers Squibb.

References

1. Betz JK,  Katz DF,  Peterson PN, et al. Outcomes among older patients receiving implantable cardioverter-defibrillators for secondary prevention. From the NCDR ICD Registry. J Am Coll Cardiol. 2017;69(3):265-274. doi:10.1016/j.jacc.2016.10.062
2. Borne RT, Peterson PN, Greenlee R, et al. Temporal trends in patient characteristics and outcomes among Medicare beneficiaries undergoing primary prevention implantable cardioverter-defibrillator placement in the United States, 2006–2010. Results from the National Cardiovascular Data Registry’s Implantable Cardioverter-Defibrillator Registry. Circulation. 2014;130:845-853.
3. Antiarrhythmics vs Implantable Defibrillators (AVID) Investigators. A comparison of antiarrhythmic-drug therapy with implantable defibrillators in patients resuscitated from near fatal ventricular arrhythmias. N Engl J Med. 1997;337:1576-1583.
4. Connolly SJ, Hallstrom AP, Cappato R, et al. Meta-analysis of the implantable cardioverter defibrillator secondary prevention trials. Eur Heart J. 2000;21:2071-2078.