Anaemia and coronary artery disease severity in patients with heart failure

BACKGROUND: Anaemia is common in heart failure (HF) and associated with higher mortality. Exacerbation of myocardial ischemia in patients with heart failure, coronary disease, and anaemia patients has been suggested as a potential mechanism underlying this association. AIMS: The aim of this study was to evaluate the hypothesis that greater CAD severity would exacerbate the adverse effects of anaemia in HF. METHODS: We examined data on patients with symptomatic heart failure (NYHA class > or = II) undergoing coronary angiography between 1995 and 2003 (n = 4951). Patients with primary valvular or congenital heart disease were excluded. Cox proportional hazards modeling was used to evaluate the relationship between coronary disease severity (as defined by no. of diseased vessels) and hemoglobin concentration. RESULTS AND CONCLUSIONS: In patients with symptomatic HF undergoing coronary angiography, we found an interaction between hemoglobin and CAD severity (p = 0.003 for interaction). Contrary to our hypothesis, the mortality hazard associated with anaemia was greatest in patients without CAD and progressively lower with increasing CAD severity. These data suggest that anaemia may exert its effect on HF outcomes through mechanisms beyond simply the exacerbation of myocardial ischemia.