Relationship of Hemoglobin and Hematocrit to Systolic Function in Advanced Heart Failure

OBJECTIVES: The dataset from the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial provides a rare opportunity to evaluate the whole spectrum of associations of hemoglobin (HB) and hematocrit (HCT) in heart failure (HF). In that trial, subjective and objective data were recorded at multiple time points when HB and HCT were also measured. We investigated the relationship between anemia and ventricular systolic function. METHODS: A limited access dataset from the ESCAPE trial, provided by the National Heart, Lung and Blood Institute, was analyzed. Linear regression analysis, correlation coefficients and Student's t test were utilized. RESULTS: Besides the known association of anemia with poor prognosis, more severe symptoms, decreased functional capacity and impaired kidney function, we found a significant and very consistent inverse correlation between HB and HCT and ventricular contractility. Both left ventricular ejection fraction and right ventricular fractional area change improved with a decrease in HB and vice versa. We hypothesize that this effect can result from a change in viscosity, which decreases with a decrease in HCT, and may facilitate adaptation of the heart to a volume overload state accompanied by hemodilution. CONCLUSIONS: In HF, anemia is associated with poor prognosis and functional impairment, but also with mildly improved systolic function. It may represent an adaptive reaction to congestion.