Increased Red Cell Volume is a Relevant Contributing Factor to an Expanded Blood Volume in Compensated Systolic Chronic Heart Failure

Abstract Background In patients with chronic heart failure (CHF), volume overload is usually described as an expansion of plasma volume (PV). Additional red cell volume (RCV) expansion is less recognized. So far, little is known about quantitative differences in blood volume (BV) status and its different components in stable CHF patients compared to healthy controls. Methods This study aimed at quantification of BV and its constituents RCV and PV using an abbreviated carbon monoxide (CO) rebreathing method (aCORM) with particular focus on its primary measure total hemoglobin mass (Hbmass) in 47 patients (10 women) with systolic CHF and a left ventricular ejection fraction (EF) of 29.0 ± 9.4%. These were compared to an age-matched control group (CON) of 84 healthy subjects (44 women) using the same method. Results In both absolute and body-surface-area-corrected analysis, Hbmass (446 ± 81 vs. 353 ± 64 g/m2) as well as RCV (1293 ± 231 vs. 1033 ± 176 ml/m2) were significantly increased in CHF. In addition, significant PV expansion was observed in CHF (2069 ± 400 vs. 1750 ± 231 ml/m2) and, in conjunction with RCV, constituted a significantly increased BV (3361 ± 574 vs. 2783 ± 369 ml/m2). In 66% of compensated CHF patients RCV was excessive compared to 14% in CON. Conclusions An increased RCV is a relevant contributing factor to hypervolemia in stable CHF. As this is associated with an increased oxygen carrying capacity it may be regarded as a possible compensatory mechanism for a reduced EF.