Medical therapy often not tried before ICDs in heart failure patients

Guidelines that recommend medical therapy before placement of an implantable cardioverter defibrillator (ICD) in patients with heart failure and reduced ejection fraction are often not followed, according to a recent study.

Researchers merged data from the National Cardiovascular Data Registry ICD Registry with a 40% random sample of administrative data from Medicare to look at the use of guideline-directed medical therapy 90 days before placement of an ICD for primary prevention in patients with heart failure and reduced ejection fraction. Guideline-directed medical therapy was defined as at least 1 prescription filled for a renin-angiotensin inhibitor (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker) and a beta-blocker approved for heart failure (carvedilol, metoprolol, or bisoprolol). The researchers analyzed use of therapy overall and for U.S. hospital referral regions. Characteristics of therapy use and association with mortality at 1 year were also analyzed. The study results appear in the March 8 Journal of the American College of Cardiology.

A total of 19,773 patients with heart failure and reduced ejection fraction who received an ICD for primary prevention from 2007 to 2011 were included in the study. Ischemic heart disease was present in 74.4%, and nonischemic dilated cardiomyopathy was present in 62.0%, with some patients having both conditions. The mean patient age was 74.9 years, and 35.4% of patients were women. Overall, 12,073 patients (61.1%) filled any prescription for guideline-directed medical therapy in the 90 days before receiving an ICD, with 5,590 (28.3%) receiving an adequate supply (defined as ≥80% coverage for the 90 days before ICD implantation) of both a beta-blocker approved for heart failure and a renin-angiotensin inhibitor.

Absence of chronic renal disease or nonsustained ventricular tachycardia, low-income prescription benefits subsidy, and less recent evaluation of left ventricular ejection fraction were the strongest predictors of guideline-directed medical therapy. Mortality rates at 1 year were lower in patients who received any guideline-directed medical therapy before implantation versus those who didn't (11.1% vs. 16.2%). This association held true after adjustment for comorbid conditions, left ventricular ejection fraction, and functional heart failure class. The proportion of patients who filled any prescription for guideline-directed medical therapy was 51% to 71% across hospital referral regions.

The authors noted that their study was a retrospective data analysis, that a causal association between therapy and 1-year survival should not be assumed, and that other definitions of guideline-directed medical therapy could have yielded different results. In addition, they said, low medical therapy rates could be due to inadequate prescribing or barriers to patients filling prescriptions, and data were lacking on contraindications to such therapy. However, they concluded that rates of guideline-directed medical therapy were low in this population before implantation of ICDs for primary prevention, with significant regional variation, and that lack of medical therapy was associated with decreased survival time in the first year.

“An adequate trial of [guideline-directed medical therapy] before ICD implantation should be part of routine clinical practice,” the authors wrote. “Better delivery of [guideline-directed medical therapy] may improve clinical outcomes and decrease the need for ICD therapy among those patients whose heart failure responds to medical therapy.”

The authors of an accompanying editorial comment also acknowledged the study's limitations but said the results suggest that at least some patients with heart failure are receiving ICDs needlessly and highlight the treatment gap between real-world management of heart failure with reduced ejection fraction and opportunities to improve care. They called for additional research on barriers to optimal care in this population.

“A new diagnosis of [heart failure] in an opportunity to reverse myocardial dysfunction, improve quality of life, and reduce the need for implanted device therapies such as ICDs through the optimal use of [guideline-directed medical therapy],” the editorialists wrote. “Establishing systems of care that streamline guideline-based treatments and improve patients' medication adherence are critical to maximizing patient health, improving survival, and preventing unnecessary health care utilization.”