Severe cardiovascular involvement is associated with mortality in multisystem inflammatory syndrome in children (MIS-C). This study aimed to test a previously published cardiogenic shock risk score at diagnosis of MIS-C and build a new screening tool in a larger pediatric cohort. The first score published in a single-center cohort (age > 8 years, time to diagnosis ≥ 6 days, and NT-proBNP at diagnosis ≥ 11.103 ng/L) was tested in a multicenter cohort of pediatric patients diagnosed with MIS-C from 2020 to 2023. In the multicenter cohort, the factors associated with the occurrence of cardiogenic shock were determined and a new score was built using a multivariate regression model. In 127 children with MIS-C, (median age [interquartile range] 8.6 [5.2; 11.5] years, 67 (53%) patients with cardiogenic shock), age > 8 years, time to treatment ≥ 6 days, dyspnea, altered mental status, general deterioration, gastrointestinal symptoms, ≤ 1 Kawasaki sign, absence of rhinopharyngitis signs, NT-proBNP ≥ 11.103 ng/L, high C-Reactive Protein (CRP), and high leucocytes at diagnosis of MIS-C were associated with a high risk of cardiogenic shock. The new score was 0.128*Age(year) + 1.195*(1 if dyspnea, 0 otherwise) + 0.007*CRP(mg/L) − 2.6732. The sensitivity was 0.88 and negative likelihood ratio 0.23 (cutoff − 0.4761). The score correlated with the minimal left ventricular ejection fraction (ρ = 0.51, p < 0.001). In a multicenter cohort, each item of the previous score was associated with the occurrence of cardiogenic shock. The new score, combining age, dyspnea, and CRP at diagnosis of MIS-C, had a high sensitivity.
