Point-of-care HEMOstasis in children with congenital heart disease, the POCHEMO study: Rotational thromboelastometry and impedance aggregometry in children with cyanotic and non-cyanotic congenital heart disease

Children with cyanotic congenital heart diseases have a higher risk of bleeding or thrombosis. Rotational thromboelastometry, using tissue factor (EXTEM), a contact activator (INTEM), or cytochalasin (FIBTEM), assesses coagulation by determining the time to initiation of clotting (CT) and clot firmness (MCF), including platelet-fibrin-interaction. This study aimed to evaluate rotational thromboelastometry and whole blood impedance aggregometry in cyanotic congenital heart diseases (CCHD) compared with a control group without chronic cyanosis (NCHD) in a pediatric cohort. We prospectively included 200 patients (60 CCHD, 140 NCHD). Oxygen saturation in CCHD was 76% [70-85], and 98% [97-100] in NCHD (p < 0.00001). Hemoglobin and hematocrit were significantly higher in CCHD; platelet count was significantly lower in the same group. Platelet aggregation was under normal range in 77% of CCHD after triggering with thrombin-receptor activating protein. Rotational thromboelastometry showed significantly longer clotting times and reduced clot firmness in both EXTEM and INTEM tests. FIBTEM clot firmness was also significantly reduced. In children with CCHD, a moderate inverse correlation was found between platelet count and hematocrit, with a stronger correlation after one year of age (r = -0.58, p < 0.00001). Significant correlations were found between hematocrit, rotational thromboelastometry parameters, and impedance aggregometry parameters, so as for platelet count-the strongest correlation in CCHD after one year of age. In conclusion, according to rotational thromboelastometry and impedance aggregometry, children with CCHD present relevant hypocoagulable disorders related to cyanosis duration, but no data demonstrate hypercoagulability.