Cardiac function on 3-D speckle tracking imaging and cytokines in Kawasaki disease

BACKGROUND Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) tends to rise in acute phase Kawasaki disease (KD), but the cause of NT-proBNP elevation has not been clarified. In a previous study, cardiac function evaluated on 2-D echocardiography (2D-E) such as ejection fraction was normal, but this does not reflect subtle changes in cardiac dysfunction, and hence the association between cardiac function and NT-proBNP elevation is still controversial. The aim of this study was therefore to elucidate the influence of cardiac function on NT-proBNP elevation, by evaluating cardiac function via strain on 3-D speckle tracking imaging (3D-STI), in acute and subacute KD patients. Given that cytokines are also thought to induce NT-proBNP in acute phase KD, serum cytokines and cytokine receptors were measured at the same time. METHODS Laboratory data and echocardiography in 52 KD patients in the acute and subacute phases were reviewed. RESULTS Median NT-proBNP was significantly elevated in the acute phase compared with the subacute phase (356.5 pg/mL; IQR, 145-904 pg/mL vs 103.5 pg/mL; IQR, 59-150 pg/mL, P < 0.01). All cytokines were also significantly elevated in the acute phase compared with the subacute phase. Tumor necrosis factor (TNF)-α, soluble TNF receptor (sTNFR)1, and sTNFR2 concentration were all significantly higher in the acute phase. Indices of cardiac function were not significant different between phases. NT-proBNP in the acute and subacute phases correlated with sTNFR1 (r = 0.63/0.43, P < 0.01), sTNFR2 (r = 0.50/0.31, P < 0.05), and interleukin-6 (r = 0.58/0.43, P < 0.01). NT-proBNP did not correlate with global longitudinal strain (GLS) on 3D-STI. CONCLUSION Although no correlation was seen between NT-proBNP and GLS on 3D-STI, correlations between NT-proBNP and cytokines were clear. NT-proBNP might be a marker of inflammation in KD, but is not a marker of cardiac function.