PLATELET STUDIES IN CONGENITAL HEART DISEASE WITH CYANOSIS

Abstract

The etiology of thromhocytopenia in children with congenital heart disease with cyanosis (CHDWC) is unknown. Disseminated intravascular coagulation (DIC) as a possible cause of thrombocytopenia is controversial. We studied the hemostatic mechanism in 20 children with CHDWC (arterial O2 saturation, 50-907,). Tests included platelet count, Cr51 platelet survival times, prothrombin and partial thromboplastin times, and levels of fibrinogen, fibrin degradation products, factors V and VIII. Defects of the soluble coagulation system were found but no coherent pattern was seen. No evidence for DIC was found. Abnormal platelet half-lives(<80 hrs)were found in 12 of 20 patients (32-75 hrs); 9 of these 12 patients had normal platelet counts. Our patients may be divided into three groups: a) 8 patients with normal platelet count and normal survival, b) 9 with normal count and shortened survival, and c) 3 with thrombocytopenia and shortened survival. Our data suggest two new findings: 1) thrombocytopenia in CHDWC can be due to rapid platelet destruction without evidence of DIG, 2) some patients have a thrombocytolytic state where increased platelet production compensates for increased destruction resulting in a normal peripheral platelet count. We postulate that in CHDWC there is a spectrum of platelet survival from normal to a “compensated” thrombocytolytic phase, sometimes progressing to a “decompensated” stage where thrombocytopenia results from destruction too rapid to be met by increased production.