Coronary Artery Dilation in Acute Kawasaki Disease and Acute Illnesses Associated With Fever

Background: In the absence of a specific test, the diagnosis of clinically incomplete Kawasaki disease (KD) can be challenging. The 2004 American Heart Association guidelines state that the diagnosis of KD is supported by the presence of coronary artery dilation documented by echocardiography. However, the specificity of coronary artery dilation and its prevalence in children with other acute illnesses associated with fever has not been studied. Methods: A 2-center, prospective study compared the internal diameters and Z-scores (standard deviation [SD] units from the mean internal diameter normalized for body surface area) of the proximal left anterior descending and right coronary arteries measured by echocardiography in febrile children (FC) and children with KD. Results: The median Z-score (interquartile range) of the left anterior descending coronary artery was -0.05 (-0.86, 0.62) and 1.06 (0.36, 2.06) SD units for the 45 FC and the 145 KD patients, respectively (P < 0.0001). For the right coronary artery, the median Z-score was 0.21 (-0.20, 0.87) and 1.04 (0.31, 1.85) SD units for the FC and KD patients, respectively (P < 0.0001). There was no correlation between body temperature at the time of echocardiography and coronary artery Z-score. No febrile child had a coronary artery Z-score >= 2.5 SD units. Conclusions: Z-scores >= 2.5 SD units were not observed in our cohort of FC. Therefore, echocardiographic evidence of coronary artery dilation can be used to support the diagnosis of KD.