Diagnosis of Coronary Artery Aneurysm in a Caucasian Population Cohort: Evaluating the Agreement Between Japanese Criteria and Different Z Score Formulas

<b>Background/Objectives</b>: Evaluating coronary artery abnormalities (CAAs) in Kawasaki disease (KD) is essential for treatment decisions and long-term management and prognosis. Accurate diagnosis is challenging due to differing criteria across guidelines. This study aimed to assess the variability in CAA prevalence using Japanese Ministry of Health (JMH) criteria and Z score formulas and identify the formula pair with the highest CAA diagnostic agreement. <b>Methods</b>: Echocardiographic data from 309 patients with acute KD were collected. CAA prevalence was evaluated using JMH criteria and Z score formulas of Kobayashi, de Zorzi, Kurotobi, McCrindle, Olivieri and Dallaire. Prevalence differences were analyzed using McNemar's t-tests, Z score values with paired samples t-test, and agreement between Z score formula pairs with Cohen's Kappa (κ) coefficients and Bland-Altman plots. <b>Results</b>: The CAA prevalence varied significantly across definitions. For the right CA, prevalence was lower by JMH criteria than by Z scores (32.7% vs. 37.2-39.8%). For the left main CA, JMH (47.6%) and Kobayashi (44.8%) showed higher prevalence compared to other formulas (25.8-42.9%). Variability was greater at higher Z score values (>5 mm, medium/large aneurysm). Overall, the Kobayashi-Dallaire and McCrindle-Dallaire pairs showed the highest agreement (κ = 0.745-0.831 and 0.569-0.870, respectively); however, the McCrindle-Dallaire reached only moderate agreement for the left main CA (κ = 0.569). <b>Conclusions</b>: The Kobayashi and Dallaire formulas appear most suitable for evaluating CAA in predominantly Caucasian populations. Larger validation studies are warranted to refine diagnostic criteria and optimize global KD care.