By Van Selby, MD

Assistant Professor of Medicine, University of California, San Francisco, Cardiology Division, Advanced Heart Failure Section

Dr. Selby reports no financial relationships relevant to this field of study.

SYNOPSIS: In a large retrospective cohort of patients hospitalized for new-onset heart failure, the majority did not receive testing for ischemic heart disease.

SOURCES: Doshi D, Ben-Yehuda O, Bonafede M, et al. Underutilization of coronary artery disease testing among patients hospitalized with new-onset heart failure. J Am Coll Cardiol 2016;68:450-458.

Coronary artery disease (CAD) is the most common cause of heart failure (HF). Current practice guidelines recommend screening for CAD in patients with newly diagnosed HF. However, few studies have evaluated how often clinicians perform diagnostic testing for CAD on patients hospitalized with newly diagnosed HF.

Doshi et al analyzed a large commercial administrative claims database, supplemented by Medicare data. They evaluated the frequency of diagnostic testing for CAD, both during the index hospitalization for new-onset HF and within 90 days of hospitalization. Between 2010 and 2013, the authors identified 67,691 patients.

Overall, 17.5% of patients underwent any testing for ischemic CAD during the index hospitalization, and 27% were evaluated for CAD within 90 days. The most common evaluation method was stress testing, followed by coronary angiography. In a multivariable analysis, predictors of undergoing noninvasive testing for CAD included baseline CAD (odds ratio [OR], 1.25; P < 0.001), hypertension, hyperlipidemia, and reduced ejection fraction. Patients who were > 70 years of age and those with prior stroke, peripheral arterial disease, prior arrhythmia, renal disease, or a prior workup for CAD were less likely to receive noninvasive testing for CAD.

Only 2% and 4.3% of patients underwent coronary revascularization during the index hospitalization and at 90 days, respectively. Baseline CAD (OR, 9.27; P < 0.001), male sex, diabetes, and smoking all were associated with greater odds of coronary revascularization, and percutaneous coronary intervention was used more commonly than coronary artery bypass grafting (CABG). The authors concluded that diagnostic testing for ischemic CAD is underutilized significantly among patients hospitalized for new-onset HF.

COMMENTARY

Not every patient hospitalized for new HF requires evaluation for CAD within 90 days, and the exact percentage of patients who should be evaluated is unknown. However, considering CAD is the most common cause of HF and present in more than half of patients with HF, the rate of CAD testing reported in this study (27% of all patients were evaluated within 90 days) is surprisingly low and suggests, as the authors concluded, that diagnostic testing for CAD is underutilized significantly in this population. Part of the explanation for low use of ischemic evaluation in new HF may be a perceived lack of evidence showing clear benefit of revascularization in patients with HF and CAD. Perhaps because of this lack of data, the most recent HF guidelines from the American College of Cardiology/American Heart Association only make a class IIa recommendation (meaning it is reasonable) to evaluate for CAD in the diagnostic evaluation of new HF. The recent publication of 10-year follow-up from STICHES, showing a mortality benefit associated with coronary artery bypass grafting in patients with CAD and systolic HF, may strengthen the argument for CAD testing. Regardless of the benefits associated with revascularization, identification of CAD also may guide medical therapy of a given patient.

When evaluating findings of large retrospective cohort studies, it is important to acknowledge limitations. Analyses of insurance claims databases depend on accurate coding, and it is possible that diagnostic testing for CAD was not always coded properly. Furthermore, complete clinical information is not available for these patients — some may have had a contraindication to diagnostic testing or other explanation for why testing was not performed. Despite these limitations, given the size of the cohort and the magnitude of the findings, it appears the majority of eligible HF patients are not screened for CAD.

Identifying which HF patients will have underlying CAD is difficult based on clinical history of risk factors alone. Many will not have angina or other clear ischemic symptoms. Once CAD is identified, it may be difficult to determine whether it is the cause of a given patient’s HF; however, this should not deter clinicians from testing. The authors suggested an increasingly cost-conscious medical environment, eager to minimize unnecessary diagnostic testing, is responsible for the low rates of CAD evaluation. By their estimate, clinicians miss 325,000 cases of CAD in patients with congestive HF every year due to underutilization of diagnostic testing. Whatever the reason, the rates of CAD testing reported in this study would strike most cardiologists as inappropriately low, and suggest those of us who evaluate and treat HF should consider screening for CAD more frequently in patients with newly diagnosed HF.