Coronary external diameter index for assessing coronary artery involvement in Kawasaki disease

Abstract

Aim: Transthoracic echocardiography is commonly used to assess coronary artery dilatation in Kawasaki disease (KD). However, existing criteria often miss early abnormalities. This study examines the utility of a new parameter, coronary external diameter index (CEDi), for early diagnosis and monitoring in KD. Methods: CEDi of left main (LM) and right coronary artery (RCA), calculated as the ratio of coronary artery external diameter (i.e., the distance between the outer coronary edges measured in the proximal segment of the artery) and the diameter of the aortic annulus, was evaluated in 34 patients (age 23 mouths ± 13 months) with KD at the hospital admission and after 2 weeks and 8 weeks of treatment. The control group consisted of 210 healthy children aged 20 months ± 13.4 months. Z-score charts for LM and RCA coronary external diameter (CED) were obtained. Results: Compared with controls, KD patients had a markedly higher mean value of LM CEDi (0.53 ± 0.06 vs. 0.33 ± 0.04; P < 0.0001) and RCA CEDi (0.48 ± 0.05 vs. 0.31 ± 0.04; P < 0.0001) at hospital admission. By ROC analysis, LM CEDi of 0.41, and RCA coronary artery thickness index (CATi) of 0.39 were the best cut-offs to confirm the clinical diagnosis of KD, both exhibiting 100% sensitivity and specificity. Mean LM CEDi and RCA CEDi values decreased significantly (P < 0.0001) after 2 weeks of follow-up and were similar to controls (P = 0.53 and P = 0.12, respectively) 8 weeks after admission. Conclusions: In patients with KD, CEDi of LM and RCA is an accurate parameter to evaluate coronary artery involvement in the early phase of the illness and during follow-up.