International journal of cardiology
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Abnormal platelet function has been hypothesised to play a role in the haemostatic abnormalities in cyanotic congenital heart disease (CCHD) patients. Using whole blood flow cytometry we found that platelets from cyanotic patients were hyperreactive and we related such hyperreactivity directly to young age, unoperated state, high haematocrit, reduced saturation with oxygen and low platelet count. Circulating platelets from CCHD children showed significantly enhanced P-selectin expression (P<0.004) and remained more reactive to 0.2 IU/ml thrombin, 1-8 microM TRAP and 2-4 microM ADP (P<0.04), especially in younger (0-3-year-olds) patients. ⋯ Overall, our data encourage the reasoning that circulating platelets are remarkably hyperreactive in non-MBTS cyanotic children, which are at higher risk to often encounter platelets activation in circulation. It seems unlikely that the apparently unchanged platelet reactivity in MBTS-operated children is due to the advantageous effects of the shunt, since these patients showed neither altered haematological parameters nor improved oxygen carrying capacity. Otherwise, it may rather result from more frequent episodes of platelet degranulation and preactivation in the past, and/or post-operative enhanced platelet consumption.