Marked changes in platelet count and function following pediatric congenital heart surgery.

BACKGROUND: Reduced hemostatic capacity is common following congenital heart surgery using cardiopulmonary bypass (CPB). The etiology is multifactorial with dilutional coagulopathy, as well as platelet adhesion and activation in the CPB circuit and oxygenator. The purpose of the present study was to evaluate platelet count and function in children following CPB.

METHODS: In a prospective, observational study comprising 40 children, platelet count and function (Multiplate Analyzer(®)) were measured before surgery, immediately after bypass, and on the first postoperative day. Furthermore, conventional coagulation analysis and thromboelastometry (ROTEM(®)) were carried out.

RESULTS: A significant decrease in platelet count was observed immediately after coming of bypass (P < 0.001) and persisted to the first postoperative day (P = 0.002). Platelet function was reduced immediately after bypass after induction with ADP (P < 0.001) or TRAP (P = 0.03). The duration of CPB correlated significantly with the decrease in platelet count (r = -0.62, P = 0.0001) and reduction in platelet function (r = -0.42-0.63; P < 0.01). Moderate to deep hypothermia during CPB was associated with a decreased platelet function (P = 0.01-0.12), whereas cyanosis or previous heart surgery caused no further changes in platelet function following CPB.

CONCLUSION: Both platelet count and platelet function were significantly reduced after CPB in children undertaken correctional heart surgery. Duration of CPB and hypothermia was associated with significant changes in platelet function.