Non-coronary cardiac events, younger age, and IVIG unresponsiveness increase the risk for coronary aneurysms in Italian children with Kawasaki disease.

Objectives: Kawasaki disease (KD) is the most frequent cause of acquired heart disease in children in high-income countries because of coronary artery involvement. Risk factors for coronary lesions can vary in consideration of different genetic background and environmental factors.

Methods: Multicenter retrospective and prospective study including 372 consecutive children (58% boys; mean age 34.3 ± 30.3 months, Caucasian 85%) was diagnosed with KD. We divided the cohort into 2 groups according to the presence of coronary anomalies (CAA) and aneurysms. We compared the groups and studied the risk factors for CAA and for aneurysms, the most severe lesions.

Results: Children with CAA were 91/372 (24.46%, aneurysms 20/372, 5.37%). Children with CAA were more likely to have a longer duration of fever (p < 0.001), later day of treatment (p < 0.001), to be IVIG non-responders and late treated (p < 0.001), while age, clinical presentation, and seasonality were not different. They also had significantly higher WBC and neutrophils, lower lymphocytes, Hb and Na during the acute stage, and slower resolution of inflammation. Age, IVIG unresponsiveness, and presence of non-coronary cardiac findings were independent risk factors for CAA and for aneurysms, while neutrophils just for CAA. Age under 6 months was a risk factor for the aneurysm. Aneurysms occurred more frequently in the first quartile of the age of KD onset (under 14 months).

Conclusion: Very young children with non-coronary cardiac findings are at increased risk for a more severe form of KD with aneurysms. These children could benefit from adjunctive therapy beside IVIG, especially if they have higher markers of inflammation, particularly neutrophils. Key points • Risk factors for coronary lesions can vary in consideration of different genetic background and environmental factors. • Risk factors for coronary involvement have been extensively studied in the Asian population, and others have been validated in cohorts with mixed ethnicities. • In our predominantly Caucasian population, non-coronary cardiac findings, age younger than 6 months, and IVIG unresponsiveness are independent risk factors for a more severe form of KD with aneurysms.