Acute Intensification May Reduce Persistent Coronary Artery Damage from Kawasaki Disease in Infants Younger Than 6 Months

OBJECTIVE: To characterize outcomes in patients <6 months old with Kawasaki disease who did or did not receive intensification of initial therapy.

STUDY DESIGN: A retrospective cohort study of infants <6 months admitted to Rady Children's Hospital San Diego (n = 48) and Children's Hospital Colorado (n = 23) between January 1, 2014, and January 12, 2023, with Kawasaki disease diagnosed by American Heart Association criteria within 10 days of fever onset. Data included demographics, laboratory values, treatment, and echocardiogram results. Intensified therapy was defined as at least 1 therapy in addition to intravenous immunoglobulin.

RESULTS: Of 71 patients, 33 (46.5%) had an initial echocardiogram obtained within 24 hours of intravenous immunoglobulin that demonstrated coronary artery aneurysms (CAA) (z score of the left anterior descending or right coronary artery ≥+2.5). CAA subsequently developed in an additional 6 patients. In total, 79% of patients received intensified therapy, most commonly infliximab (98%). Ten patients who received intensified therapy developed medium or giant aneurysms of whom 6 remodeled completely during the study period. Of the 15 patients with initially normal findings on echocardiogram who did not receive intensification, 13 remained normal and 2 developed transient, mild CA dilatation (z score ≥+2 and <+2.5). Echocardiograms closest to 1-year follow-up demonstrated 5 (7%) patients with residual CAA, none with z score >+3.

CONCLUSIONS: In this observational series, no infants <6 months treated within 10 days of fever onset with intensification of initial therapy had more than mild CAA by 1 year after illness onset. Larger, multicenter studies are needed to support causal inference.