Effect of Nonobstructive Coronary Artery Disease on Heart Failure Outcomes

The presence of nonobstructive coronary artery disease (CAD) among patients with heart failure with reduced left ventricular ejection fraction was associated with an increased risk for cardiovascular death (CV) or CV hospitalization, as well as an increased risk for all-cause mortality, compared with similar patients with no apparent CAD, according to study results published in JACC: Heart Failure.

Patients with heart failure are often classified as either ischemic or nonischemic, in a dichotomy that creates a heterogenous nonischemic group that combines patients with nonobstructive CAD and patients with normal coronaries. This cohort study was designed to evaluate the prognostic significance of nonobstructive CAD in patients with heart failure as a distinct category.

The CorHealth Cardiac Registry was used to identify a cohort of patients with heart failure with reduced ejection fraction undergoing invasive coronary angiogram. Participants were divided into a normal coronary group, a nonobstructive disease group, and an obstructive disease group. The primary study outcome was the composite of CV death, nonfatal stroke, nonfatal acute myocardial infarction, or heart failure hospitalization. Secondary outcomes included the individual components of the primary composite outcome and all-cause mortality.

Among the 12,814 study participants, 20.7% (n=2656) had normal coronaries, 17.6% (n=2254) had nonobstructive CAD, and 61.7% (n=7904) had obstructive CAD. Relative to the group with normal coronaries, an increased risk for the primary outcome was found in the nonobstructive group (hazard ratio [HR] 1.17; 95% CI, 1.04-1.32; P =.01).

Nonobstructive CAD was associated with an increased risk for CV death (HR 1.82; 95% CI, 1.27-2.62; P =.001) and all-cause mortality (HR 1.18; 95% CI, 1.05-1.33; P =.005). No significant differences in rates of stroke, acute myocardial infarction, or heart failure hospitalization were found.

Study investigators concluded, “Our study underscores the prognostic importance of non-obstructive CAD, suggesting that a binary classification, which dichotomizes the risk of adverse clinical events by assigning non-obstructive disease under the nonischemic label, may be an inadequate estimator of prognosis in the [heart failure] population.”

Reference

Braga JR, Austin PC, Ross HJ, Tu JV, Lee DS. Importance of nonobstructive coronary artery disease in the prognosis of patients with heart failure [published online May 8, 2019]. JACC: Heart Fail. doi: 10.1016/j.jchf.2019.02.014