Brain natriuretic peptide (BNP) has been considered a biochemical marker for myocarditis in Kawasaki disease. We performed this study to determine its quantitative significance.

We attempted to correlate log-transformed BNP concentrations (log-BNP) and clinical, laboratory, and echocardiographic variables in 81 children with Kawasaki disease. Stepwise multiple linear regression analysis was used to determine the variables independently associated with log-BNP concentration.

Serum C-reactive protein level ( P <0.0001), serum alanine aminotransferase concentration ( P =0.0032), white blood cell count ( P =0.0030), and left ventricular mass index ( P =0.0024) were positively related with log-BNP, and hemoglobin level ( P <0.0001), serum albumin level ( P <0.0001), Na⁺ concentrations ( P <0.0001), left ventricular fractional shortening ( P =0.0080), and peak early diastolic tissue velocity of the left ventricular basal lateral segment ( P =0.0045) were negatively related to the log-BNP concentration. Multiple regression analysis showed that serum albumin concentration (R₂=0.31, P =0.0098) and left ventricular mass index (R₂=0.09, P =0.0004) were significantly associated with the log-BNP concentration.

Elevated BNP levels during the acute phase of Kawasaki disease may be attributable to cardiac dysfunction associated with the increase in left ventricular mass, and log-BNP concentration may be a quantitative biochemical marker of myocarditis in Kawasaki disease.