RESUMO
PURPOSE: Aspirin(acetylsalicylic acid) has been used to treat unstable angina and acute myocardial infarction in adults and Kawasaki disease in children. The antithrombotic effect of aspirin was attributed to its ability to inhibit platelet aggregation by inhibiting platelet cyclooxygenase, which leads to decreased thromboxane synthesis. The purpose of this study was to evaluate the effect on the platelet aggregation by low dose aspirin in Kawasaki patients and to learn the side effects of low-dose aspirin. METHODS: Fifty patients with Kawasaki disease who were treated with low-dose aspirin, and 22 normal children were studied from Jan. 1996 to Dec. 1997. The platelet count, bleeding time, clotting time, platelet aggregation test(induced by ADP, epinephrine, collagen and ristocetin) and blood aspirin level by colorimetric method were checked. RESULTS: The platelet count, bleeding time, and clotting time in the patient group were not significantly different from the control group. The mean maximum platelet aggregation was 54.4+/-12.8% induced by ADP, 15.9+/-11.7% by epinephrine, 55.5+/-23.8% by collagen, 52.6+/-32.2% by ristocetin in the patient group. It was significantly lower than the control group(P<0.05). The mean blood aspirin level in the patient group was 5.4+/-3.7mg/dl. Side effects of low-dose aspirin were bruise, epistaxis and hematuria. CONCLUSION: Low-dose aspirin therapy in patients with Kawasaki disease inhibited platelet aggregation, but attention would be needed because of the tendency to bleed in these patients. Further investigations should be focused on the subject such as the onset of the maximal antiplatelet effect and time needed for the recovery of platelet function.