Impairment in Platelet Aggregation in Congenital

Platelet function and coagulation studies were performed on 65 children with congenital heart disease (CHD) and five wtih acquired heart disease, varying in age from 2 wk to 17 yr. Approximately l10/a of the children with CHD had mild bleeding symptoms, and 9#{176}/a had prolonged bleeding times, despite normal platelet counts. In 14 of 37 children (37.8#{176}/a)with cyanotic CHD and four of 28 (l4.3#{176}/o) with the acyanotic variety, platelet aggregation by adenosine diphosphate (ADP), noradrenalin, and connective tissue suspension was impaired. The possibility of a platelet inhibitory factor in plasma was unlikely. Platelet content of ADP was normal, and high concentrations of exogenous ADP produced an improvement in aggregation, suggesting that the disturbance may be due to defective release of intrinsic ADP from the platelets. Impairment in aggregation was correlated with the severity of hypoxemia and polycythemia in cyanotic patients. Coagulation data did not support the concept that disseminated intravascular coagulation is a frequently associated finding in cyanotic CHD. Our findings reveal a disturbance in platelet function, until now, not commonly associated with CHD.