Coagulopathy and platelet activation in Kawasaki syndrome: identification of patients at high risk for development of coronary artery aneurysms.

Prospective evaluation of platelet activation and hypercoagulability was performed in 31 patients with Kawasaki syndrome. Most patients had elevated acute-phase reactants when studied during the first 3 weeks of their illness; 17 of 25 (68%) patients had factor VIII activity greater than 150%, 18 of 24 (75%) had fibrinogen greater than 400 mg/dl, and 17 of 31 (55%) had a platelet count greater than 450,000/mm3. Antithrombin III was depressed initially in 17 of 25 (68%) patients. Depleted fibrinolytic activity, as measured by a euglobulin lysis time greater than 300 minutes, was documented in nine of 20 (45%) patients. Plasma beta-thromboglobulin (BTG) measured at 0 to 3 weeks was elevated (greater than 43 ng/ml) in seven of 24 (29%) patients. All patients with coronary artery aneurysms had elevated BTG values. The mean BTG in the group with aneurysms was 72.3 ng/ml when measured during the first 3 weeks after onset of fever, and 87.7 ng/ml at 4 to 7 weeks. The group without aneurysms had mean BTG values of 29.4 and 28.3 ng/ml at 0 to 3 and 4 to 7 weeks, respectively. The difference between the two groups was significant (P less than 0.002) for both the initial and later values. An elevated BTG during the first 3 weeks after onset of fever was highly associated with aneurysm formation in our patients (P less than 0.007). No aneurysms occurred in patients with a normal BTG value.