Risk of coronary artery lesions in young infants with Kawasaki disease: need for a new diagnostic method

AimTo examine clinical characteristics of Kawasaki disease (KD) in infants younger than 3 months of age and to develop a method for detecting KD in febrile infants. MethodIn a case-control study, we retrospectively collected clinical and laboratory data from 24 KD infants younger than 3 months of age out of 410 KD patients. We then compared younger infants with both older patients and febrile infants with respiratory syncytial virus (RSV) infection and urinary tract infections (UTI). ResultsThe frequency of incomplete KD was higher in the younger group than in the control group (79% vs. 36%, P < 0.0001). Furthermore, before treatment, the incidence of coronary artery lesions (CAL) was significantly higher in the younger group (29% vs. 3.9%, P = 0.0001), resulting in a higher incidence of coronary artery sequelae (21% vs. 3.4%, P = 0.0023). Our results revealed that the serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP) level of KD patients was higher than that of RSV and UTI patients (3110 2076 vs. 698 +/- 436, P = 0.0001; and 971 +/- 589 pg/mL, P = 0.0002, respectively). Thus, NT-proBNP might be suitable as a diagnostic marker of KD in young infants (P = 0.0005, criterion values: 1555 pg/mL [sensitivity: 80%, specificity: 85%]). ConclusionKawasaki disease infants younger than 3 months of age appear to be at higher risk for incomplete KD and early-onset CAL prior to the appearance of coronary artery sequelae. We suggest performing an echocardiogram and evaluating NT-proBNP in young infants with fever that has lasted longer than 2 days, regardless of the presence or absence of manifestations associated with KD.