Usefulness of the Red Blood Cell Distribution Width to Predict Heart Failure in Patients With a Fontan Circulation

The red blood cell distribution width (RDW) is a quantitative measure of the variability in the size of circulating erythrocytes. We aimed to study whether higher levels of the RDW were associated with heart failure in a Fontan circulation and to analyze its clinical value compared to brain natriuretic peptide. This retrospective study included 38 consecutive pediatric patients with a Fontan circulation who underwent routine cardiac catheterization at the International Medical Center, Saitama Medical University from October 2010 to July 2014. We assessed the relation between the RDW and catheterization data such as the central venous pressure (CVP), mixed venous oxygen saturation (SvO₂), and cardiac index (CI). The RDW was positively correlated with the CVP (p = 0.0002). The elevated RDW group had a significantly greater CVP than the normal RDW group (p = 0.0003). Also, the RDW was negatively correlated with the SvO₂ (p = 0.0004). The elevated RDW group had a significantly less SvO₂ than the normal RDW group (p <0.0001). The CI in the elevated RDW group was lower than that in the normal RDW group (p = 0.0421). In the multivariate regression analysis, the RDW was a significant independent predictor of the CVP and SvO₂. The BNP level did not have any significant relation with the CVP, SvO_2, or CI. The RDW is a convenient and powerful marker for detecting heart failure in a Fontan circulation.