Relationship of resting hemoglobin concentration to peak oxygen uptake in heart failure patients

Anemia is frequent in chronic heart failure (HF). To calculate what change in peak oxygen uptake ((V) over dotO(2)) should be expected in the event of changes in hemoglobin concentration, we studied the correlation between peak (V) over dotO(2) and hemoglobin concentration in a large HF population. We carried out retrospective analysis of all cardiopulmonary exercise tests (CPET) performed in our HF Clinic between June 2001 and March 2009 in HF patients who had a resting hemoglobin concentration measurement taken within 7 days of the CPET. We collected 967 CPETs, 704 tests were considered maximal and analyzed. We identified 181 patients (26%) as anemic. Peak (V) over dotO(2) was lower (P < 0.001) in anemic patients (971 23 ml/min) compared with nonanemic (1243 +/- 18 ml/min). The slope of the (V) over dotO(2) vs. hemoglobin ratio was 109 ml/min/g/dl at peak exercise. This correlation remained significant also when several confounding variables were analyzed by multivariate. analysis. As an average, each gram of hemoglobin accounts, at peak exercise, for 109 ml/min change in (V) over dotO(2) which is equivalent to 0.97 ml/min/kg. Therefore, in HF patients anemia treatment should increase (V) over dotO(2) by 109 ml/min for each g/dl of hemoglobin increase. Am. J. Hematol. 85:414-417, 2010. (C) 2010 Wiley-Liss, Inc.