This study evaluates the safety of defibrotide with IVIG in children with high risk Kawasaki disease.

Inclusion Criteria:

• Kawasaki disease presumptive diagnosis defined according AHA criteria;
• Signed informed consent and patient assent (if applicable)
• Diagnosis of KD and initiation of defibrotide within 96 hours from the conclusion of IVIG treatment
• Age: 0 - 11 years old
• High risk category defined as patient meeting ≥2 of the following criteria: male, age <6 months or >8yrs, IVIG-resistance, Fever lasting greater than 10 days, prior to diagnosis, Coronary artery aneurysms, and/or Laboratory tests indicating worse systemic inflammation
• PT and PTT within institutional normal limits
• Platelet count ≥100,000/mm3

Exclusion Criteria:

• History of Grade III or IV hemorrhage or active bleeding;
• Previous Grade II-IV hypersensitivity to defibrotide
• Current systemic anti-coagulant therapy and/or fibrinolytic therapy, excluding aspirin (5 mg/kg/dose maximum).
• Patients on an active experimental trial for Kawasaki disease