Utility of whole‐blood aggregometry for evaluating anti‐platelet therapy for K awasaki disease

Background Anti‐platelet therapy for Kawasaki disease ( KD ) is often done without monitoring drug efficacy. The aim of this study was to investigate the utility of whole‐blood aggregometry to evaluate the efficacy of anti‐platelet therapy for KD . Methods Of 37 late‐phase KD patients included in the present study, 20 were prescribed anti‐platelet drugs. Platelet‐rich plasma ( PRP ) aggregation with collagen as the stimulus was measured using an optical aggregometer. The area under the curve of small and large size aggregations was calculated, and categorized into five classes: –2, –1, 0, 1, and 2. Whole‐blood aggregation with collagen or adenosine 5′‐diphosphate ( ADP ) as stimulus was evaluated using the platelet aggregation threshold index ( PATI ), which is the concentration of stimulus that induces a whole‐blood aggregation rate of 50%. Results In both collagen‐ and ADP ‐induced aggregation, there was a negative correlation between PATI and class determination using the PRP technique (collagen, rs = −0.870, P < 0.0001; ADP , rs = −0.620, P < 0.0001). Moreover, the PATI in collagen‐ and ADP ‐induced aggregation was significantly higher in the anti‐platelet drug therapy group than in the untreated group (collagen, P < 0.0001; ADP , P = 0.0002). The serum thromboxane B 2 level in the anti‐platelet drug therapy group was also significantly lower than that in the untreated group ( P < 0.0001). PATI was significantly higher in those treated with thienopyridine drug combinations than those without drug therapy ( P = 0.0036). Conclusions Whole‐blood aggregometry is useful for monitoring the efficacy of anti‐platelet therapy for KD .