Natural History and Acute-phase Predictors of Medium Coronary Artery Aneurysm Outcomes in Kawasaki Disease: A 3-year Prospective Cohort Study

Background: Kawasaki disease (KD), the leading cause of pediatric acquired coronary artery aneurysms (CAAs), exhibits heterogeneous outcomes in medium CAAs (4–8 mm), which lack standardized risk stratification. This study aimed to identify acute-phase predictors of prognostic outcomes in medium CAAs to optimize monitoring strategies. Methods: A single-center retrospective cohort analyzed 78 KD patients with acute-phase medium CAAs (2013-2021). Serial echocardiography assessed CAA evolution, defining persistence (medium/giant CAAs) and progression (≥8% diameter increase). Multivariate logistic regression, ROC analysis, and Kaplan-Meier survival curves evaluated associations between clinical/laboratory parameters and outcomes. Results: The persistent group (n=23) exhibited significantly prolonged prothrombin time (PT: 15.69 ± 5.53 vs. 12.68 ± 2.18 s, P = 0.014) and larger maximum CAA diameters (maximal CAA: 6.69 ± 1.35 vs. 5.04 ± 0.97mm, P<0.001). Multivariate analysis identified PT (OR=1.47, 95% CI:1.04-2.08, P = 0.031) and maximal CAA (OR=3.29, 95% CI:1.16-9.35, P = 0.025) as independent predictors of persistence. ROC-derived thresholds for risk stratification included PT >13.6s (AUC=0.712) and maximal CAA ≥5.65mm (AUC=0.857). Kaplan-Meier analysis confirmed significant divergence in persistence between threshold-stratified groups (log-rank P<0.001 for maximal CAA). Conclusion Acute-phase PT elevation and maximal CAA diameter ≥5.65mm are robust predictors of medium CAA persistence. These findings advocate for intensified surveillance in high-risk subgroups, integrating coagulation profiles and serial echocardiography to mitigate long-term coronary complications.