Red blood cell distribution width in addition to N-terminal prohormone of B-type natriuretic peptide concentration improves assessment of risk of cardiovascular events in adult patients with congenital heart disease

Abstract

Red blood cell distribution width (RDW) is a predictor of adverse outcomes in patients with heart disease. To establish predictors of high RDW values in patients with congenital heart disease (CHD), and their relationship with cardiovascular events. Overall, 561 patients with stable CHD who attended a single outpatient clinic and a matched control population of 2128 patients were studied. Exclusion criteria were renal failure, anaemia, receiving iron therapy and cyanosis. Blood tests included glucose, creatinine, iron, apoferritin, liver enzymes and a complete blood count. C-reactive protein and N-terminal prohormone of B-type natriuretic peptide (NT-pro-BNP) concentrations were also measured in patients with CHD. Major adverse cardiac events (MACE) were defined as cardiovascular/total mortality, arterial thrombotic events, arrhythmias, major bleedings, pulmonary embolism or heart failure needing hospital admission. The median age in patients with CHD was 23 (17-36) years and the median follow-up time was 5.8 (3.2-8.7) years; 103 (4.8%) controls and 40 (7.1%) patients with CHD had an RDW>15% (P=0.032). During follow-up, MACE were reported in 48 patients. CHD of great complexity, cardiovascular risk factors, low haemoglobin concentration and high NT-pro-BNP concentration were risk factors for an RDW>15%. Kaplan-Meier analysis showed a significantly worse cardiovascular outcome in patients with CHD with an RDW>15% (P<0.001). The multivariable survival analysis determined that age, CHD of great complexity, high NT-pro-BNP concentration and an RDW>15% were independent predictive factors for MACE. RDW and NT-pro-BNP concentration are independent analytical predictors of MACE in patients with CHD.