Anemia is a significant co-morbidity in patients with heart failure (HF) irrespective of EF (EF) and is routinely quantified by hemoglobin concentration. Hemodilution as a cause of anemia has been described in systolic HF. This study aims to further investigate the effects of plasma volume in HF patients by 1) assessing prevalence of dilutional anemia in patients with anemia and a preserved EF and 2) exploring the relation between hemoglobin and red cell volume in these patients. Forty-six anemic patients (as determined by standard hemoglobin measurement): 22 with HF and low EFs (HFLEF) and 24 with HF and a preserved EFs (HFPEF) all underwent plasma volume measurement with I-131 labeled albumin. Hemoglobin values did not differ between subjects with HFLEF and HFPEF (10.8±1.0 vs. 11.0±1.0 gm/dl, p=0.55) but a red cell deficit was found in 88% of patients with HFPEF as compared with 59% of HFLEF (p=0.04). This was the result of a higher prevalence of an expansion of plasma volume in HFLEF patients (100%) as compared with HFPEF patients (71%). Among all patients, no correlation was found between hemoglobin and red cell volume (r = 0.09, p=0.54), but a correlation did exist among patients with normal blood volumes (r=0.55, p = 0.02).
In conclusion, dilutional anemia resulting from an expansion in plasma volume without a red cell deficit occurs more commonly in HFLEF than HFPEF patients and hemoglobin does not correlated with red cell volume in anemic HF patients.
Introduction
The etiology of anemia in subjects with heart failure (HF) is multi-factorial1–3 and several therapies have been employed with varying success.2 While hemoglobin values are typically employed to diagnose anemia, low hemoglobin, on a physiologic basis, can be the result of either: (1) a true red cell deficit, or (2) hemodilution with plasma volume expansion.4 While hemoglobin or hematocrit provides a good estimate of red cell volume in healthy patients,5 discordance between hemoglobin and red cell volume has been described in patients with polycythemia vera6 , liver disease,7, 8 and in the presence of splenomegaly,9 due to the confounding effects of alterations in plasma volume.5, 9–11 Among patients with advanced HF and low ejection fraction (EF), almost half were reported to have anemia on the basis of hemodilution with a normal red cell volume.4 Whether a similar percentage of HF and a preserved EF (HFPEF) patients have such dilutional anemia is unclear. Given the mixed success in treatment of anemia,2, 12 issues surrounding measurement of anemia deserve clarification. Accordingly, the purpose of this study was 2-fold: (1) to explore the correlation between hemoglobin values and red cell volume in anemic HF patients and (2) to determine whether anemic patients with HFPEF have a similar prevalence of dilutional anemia as patients with HF with a low EF (HFLEF).