Treatment and prognosis of patients with Kawasaki disease and giant coronary artery aneurysm: a retrospective observational study.

Background: There is no established regimen for antithrombotic therapy in patients with Kawasaki disease (KD) who develop giant coronary artery aneurysm (GA). This single-center retrospective study evaluated the outcome of a unified antithrombotic regimen in these patients. Methods: Sixteen KD patients with GA onset between 1999 and 2013 were included. The patients were started on intravenous heparin and then switched to warfarin in addition to low-dose aspirin when blood tests indicated that the inflammatory response had subsided and the aneurysm had ceased dilating. The target prothrombin time-international normalized ratio (PT-INR) was 2.0-2.5. Patients with no cardiac events or thrombus formation within 2-3 years of onset were considered for discontinuation of anticoagulation and continuation on antiplatelet treatment alone. Results: The median follow-up duration was 5.8 years (range, 0.25-9.9 years). There were 7 cases of myocardial infarction, including 1 that was fatal and 1 that were asymptomatic. There was no significant difference in the day of KD treatment initiation, onset of GA, or follow-up duration between patients with cardiovascular events (CEs; n=7) and those without CEs (n=9). CEs were significantly more common in patients with larger maximum Z-score (P=0.044) and multiple GAs than in those with a single GA (P=0.007). The prothrombin time at the time of events was below the management target in 3 of the 7 patients with CEs. Conclusions: The prognosis of KD patients with GA was unsatisfactory in this study, especially in those with large and multiple GAs. In addition to antiplatelet therapy, we recommend continuation of strict anticoagulation therapy in these patients.