Z-Score Based Classification of Aneurysms in Kawasaki Disease Requiring Anticoagulation

Classification and Anticoagulation Recommendations

The American Heart Association recommends anticoagulation therapy for patients with coronary artery aneurysms with a Z-score ≥10 or an absolute dimension ≥8 mm (large or giant aneurysms) 1, 2
The American Heart Association provides a Z-score based classification system for coronary artery abnormalities, including:
For large/giant aneurysms (Z-score ≥10 or ≥8 mm), anticoagulation is strongly recommended, with a regimen including low-dose aspirin (3-5 mg/kg/day) plus systemic anticoagulation with either warfarin (target INR 2.0-3.0) or low-molecular-weight heparin (LMWH) 1, 2, 5
For medium aneurysms (Z-score ≥5 to <10, absolute dimension <8 mm), dual antiplatelet therapy is often considered, with low-dose aspirin plus a second antiplatelet agent (typically clopidogrel), and anticoagulation is not routinely recommended unless there are additional risk factors 1, 5
For small aneurysms (Z-score ≥2.5 to <5), low-dose aspirin therapy alone is typically recommended, and no anticoagulation is indicated 1, 5
For dilation only or no involvement (Z-score <2.5), low-dose aspirin is recommended until 4-6 weeks after illness onset, and no anticoagulation is indicated 1

For patients at exceptionally high risk of thrombosis, such as those with Z-score ≥10 or absolute dimension ≥8 mm, "triple therapy" may be considered, including low-dose aspirin, a second antiplatelet agent, and anticoagulation with warfarin or LMWH 1, 2, 5, 6
Frequent echocardiography is recommended for patients with giant aneurysms, especially during the first 3 months when risk of thrombosis is highest, and sudden worsening in ventricular function or changes in ECG findings should raise suspicion for coronary thrombosis 5