ADP-dependent platelet function prior to and in the early course of pediatric liver transplantation and persisting thrombocytopenia are positively correlated with ischemia/reperfusion injury.

Little is known about the role of platelets in relation to ischemia/reperfusion injury (IRI) of the liver graft especially in children. Thrombocyte function was prospectively analysed in 21 consecutive pediatric liver transplantation (pLT) patients by platelet aggregometry secondary to adenosine diphosphate (ADP), collagen, and the von Willebrand factor activator ristocetin (VWF:rco). Post-OP serum levels of ALT were used to divide patients into groups with high (highHD, n = 8) and low (lowHD, n = 13) hepatocellular damage. Clinically, highHD-patients showed impaired plasmatic coagulation and elevated serum bilirubin levels early after pLT when compared with lowHD-patients. Further, platelet counts markedly decreased between pre-OP and postreperfusion (postrep.) in the highHD group (P = 0.003) and did not recuperate by POD6. In lowHD individuals thrombocytopenia improved from both pre-OP (P < 0.05) and postrep. (P < 0.001) respectively towards POD6. Experimental thrombocyte testing revealed that before graft reperfusion only ADP-dependent platelet aggregation correlated with reperfusion injury, thrombocytopenia and early graft function. During the first 48 h after graft reperfusion, all inducers tested demonstrated elevated platelet aggregation levels in the highHD group. Our data suggest a possible role of platelets and their aggregative status in liver IRI subsequent to clinical pLT. Reperfusion-independent ADP-triggered platelet function may be a determinant for IRI in the pediatric hepatic graft recipient.