Management of Patients in the Subacute Phase of Kawasaki Disease
The management of patients in the subacute phase of Kawasaki disease should be tailored based on the presence and severity of coronary artery abnormalities, with low-dose aspirin (3-5 mg/kg/day) as the cornerstone therapy for all patients until 6-8 weeks after disease onset if no coronary abnormalities develop. 1
Antiplatelet and Anticoagulation Therapy Based on Coronary Involvement
For Patients Without Coronary Abnormalities
- Continue low-dose aspirin (3-5 mg/kg/day) until 4-6 weeks after disease onset
- Discontinue aspirin if echocardiograms show no coronary abnormalities at 6-8 weeks
- Monitor for any late-developing coronary changes
For Patients With Small Coronary Aneurysms
- Continue low-dose aspirin (3-5 mg/kg/day) indefinitely 1
- Regular cardiac follow-up with appropriate imaging studies
For Patients With Moderate-Sized Aneurysms (4-6 mm)
- Low-dose aspirin plus consideration of a second antiplatelet agent
- Consider adding clopidogrel (1 mg/kg/day up to 75 mg) to antagonize adenosine diphosphate-mediated activation 1
- More frequent cardiac imaging to monitor aneurysm progression
For Patients With Large or Giant Aneurysms (≥8 mm or Z score ≥10)
- Combination therapy is required due to high thrombosis risk:
- For patients with extraordinarily high risk (giant aneurysms with recent thrombosis history), consider "triple therapy":
- Aspirin + second antiplatelet agent + anticoagulation (warfarin or LMWH) 1
Special Considerations in the Subacute Phase
Rapidly Expanding Aneurysms
- For patients with rapidly expanding coronary artery aneurysms, consider adding systemic anticoagulation with LMWH or warfarin to low-dose aspirin 1
- Consider abciximab (platelet glycoprotein IIb/IIIa receptor inhibitor) for patients with large aneurysms in the subacute phase to promote vascular remodeling 1
Medication Interactions and Precautions
- Avoid ibuprofen and other NSAIDs in patients taking aspirin for antiplatelet effects as they may antagonize aspirin-induced platelet inhibition 1
- During influenza or varicella infection, discontinue aspirin temporarily due to risk of Reye syndrome 1
- Consider substituting clopidogrel or LMWH during these periods
- Administer annual influenza vaccine to children on long-term aspirin therapy 1
Monitoring Requirements
- Regular echocardiographic assessment to monitor coronary artery dimensions
- For patients with large aneurysms, more advanced imaging may be needed:
Management of Complications in Subacute Phase
For Coronary Thrombosis
- Immediate thrombolytic therapy or mechanical restoration of coronary blood flow through catheterization (in patients of sufficient size) 1
- Options include streptokinase, urokinase, or tissue plasminogen activator (tPA) 1
- Treatment should target multiple steps in the coagulation process
For Myocardial Dysfunction
- Monitor for signs of myocardial dysfunction, valvular regurgitation, and other cardiac complications that may persist into the subacute phase 1, 2
- Appropriate cardiac support as needed
Important Pitfalls to Avoid
- Premature discontinuation of antiplatelet/anticoagulant therapy before adequate follow-up imaging
- Failure to recognize that myocardial abnormalities can persist even without coronary artery abnormalities
- Overlooking the need for long-term cardiac follow-up, especially in patients who had coronary involvement
- Using ibuprofen for fever or pain in patients on aspirin therapy
The management approach during the subacute phase is critical for preventing long-term cardiac complications and requires careful monitoring and appropriate antithrombotic therapy based on the degree of coronary involvement.