In Kawasaki disease, the aneurysm predictors are mostly about timing

Design

longitudinal single-centre observational cohort with annual echocardiographic follow-up, 1982–2025

Population

533 children with Kawasaki disease at an Italian tertiary referral centre, median age 26 months

Primary outcome

acute and persistent coronary involvement

Effect

22% acute coronary involvement; aneurysm predictors age <6 months OR 7.64, IVIG resistance 9.89, IVIG after day 10 5.27

Kawasaki disease is the leading cause of acquired heart disease in children in high-income settings, and everything about long-term prognosis turns on whether a coronary aneurysm forms. This Italian tertiary centre followed 533 consecutive children diagnosed between 1982 and 2025 — median age 26 months, 59.8% male — with echocardiography in the acute phase and annual follow-up thereafter.

Acute coronary involvement occurred in 117 children (22%): 90 dilatations and 27 aneurysms. The important negative is that persistent coronary abnormality was confined to children with medium or giant aneurysms — dilatation did not leave a lasting mark. Independent predictors of aneurysm were age under six months (odds ratio 7.64), immunoglobulin resistance (9.89), immunoglobulin given after day 10 (5.27) and pericardial effusion (3.16). Immunoglobulin use rose from 53.3% in the 1980s to 99% after 2020, and the worst decade for both resistance and coronary lesions was 2011 to 2020, improving since. No child treated with an interleukin-1 inhibitor for high-risk disease had persistent sequelae.

Three of the four predictors are things a service can act on, and two are simply about speed. Late immunoglobulin is a diagnostic delay problem, which in practice means a febrile infant seen more than once before the diagnosis is made. The very young infant is the same problem in harder form, because incomplete presentations are commonest under six months. Pericardial effusion is a free warning sign on the echo you are already doing.

• Treat fever of five days or more in an infant under six months as possible incomplete Kawasaki disease until excluded
• Aim to give immunoglobulin before day 10 — after that the aneurysm odds rise fivefold
• Record pericardial effusion explicitly on the acute echo report; it independently predicted aneurysm
• Escalate promptly in immunoglobulin resistance rather than waiting for a second dose to fail
• Reassure families about isolated dilatation — persistent abnormality occurred only with medium or giant aneurysms

Why it matters

It locates most of the residual coronary damage in delay and escalation, not in the limits of the treatment itself.

Don't overread it

This is a single-centre observational cohort — the interleukin-1 inhibitor finding is from small numbers of selected high-risk children, not a trial.

The statistics, in plain English

An odds ratio of 9.89 for immunoglobulin resistance is large, but note what it is measuring: resistance is identified after treatment has already failed, so it marks a sicker disease rather than being something you can prevent. The two timing predictors are different in kind — treatment after day 10 is a decision, and its odds ratio of 5.27 is therefore actionable in a way the others are not. With 27 aneurysms in total, the intervals around all of these estimates will be wide.

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