Optimal Medical Therapy Use Among Patients Receiving Implantable Cardioverter/Defibrillators: Insights From the National Cardiovascular Data Registry

Study Questions:

What are the national patterns of optimal medical therapy (OMT) use among first-time implantable cardioverter-defibrillator (ICD) recipients in a contemporary, real-world practice?

Methods:

Among 1,201 centers reporting data on consecutive ICD procedures from January 1, 2007, to June 30, 2009, the authors examined 175,757 patients undergoing first-time ICD implantation and excluded those younger than 18 years, who had a left ventricular ejection fraction (LVEF) higher than 35%, or who had in-hospital death or unknown OMT status. Patients’ clinical and procedural characteristics and implanting physician and hospital characteristics were compared among patients stratified by OMT use. Multivariable hierarchical logistic regression modeling using backward variable selection (p < 0.01) examined factors associated with OMT, beta-blocker, and angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker (ACEI/ARB) use.

Results:

Among 175,757 initial ICD recipients with an LVEF of 35% or lower, 45,240 (25.7%) were eligible for, but did not receive OMT. Similar rates were observed when ICD placement was the primary purpose of hospitalization (24.6%), and among primary prevention ICD recipients (25.6%). The rate of OMT prescription by site ranged from 0-100%, with a median of 73.5% (interquartile range, 64%-82%). Patients receiving OMT were more likely to be younger, have commercial insurance, and have a diagnosis of hypertension, and were less likely to have a history of ischemic heart disease, recent heart failure hospitalization, atrioventricular node conduction abnormalities, or renal dysfunction. In multivariate analysis, factors associated with higher OMT use included treatment at a teaching hospital (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.06-1.27), PCI during the admission (OR, 1.11; 95% CI, 1.04-1.19), history of hypertension (OR, 1.32; 95% CI, 1.28-1.36), and a cardiovascular indication for admission (OR, 1.11; 95% CI, 1.04-1.19). Factors associated with the lowest odds of OMT use were coronary artery bypass graft during the admission (OR, 0.66; 95% CI, 0.61-0.72) and an implanting care provider who was board certified in surgery (OR, 0.73; 95% CI, 0.66-0.80).

Conclusions:

The authors concluded that despite well-proven benefits and guideline recommendations, gaps in medical therapy optimization of ICD recipients persist.

Perspective:

The study suggests that although medical therapy optimization reduces mortality, the risks of heart failure decompensation, and ventricular arrhythmias requiring shocks, one in four ICD recipients with an LVEF of 35% or lower are not prescribed beta-blockers and ACEI/ARBs. These results highlight the need for dedicated strategies, optimized quality of care, and improved cost-effectiveness of care for patients with heart failure. The study also raises an important question as to why device implant occurred in some patients during a hospitalization for a revascularization procedure, which can lead to improvements in both ventricular function and the arrhythmia substrate.

Keywords: Odds Ratio, Defibrillators, Multivariate Analysis, Primary Prevention, Tachycardia, Registries, Death, Heart Failure, Stroke Volume, Ventricular Function, Confidence Intervals, Coronary Artery Bypass, Hypertension, Logistic Models, Atrioventricular Node


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