Coagulation factor abnormalities in patients with single-ventricle physiology immediately prior to the fontan procedure

Background. Coagulation abnormalities have been reported following the Fontan operation and have been attributed to various aspects of Fontan-associated physiology. Using age-matched controls, this study evaluated coagulation abnormalities in children who had undergone a bidirectional Glenn procedure to test the hypothesis that coagulation abnormalities are present before the Fontan operation. Methods. Coagulation factors were assayed in 38 children (mean age 34.4 ± 15 months) immediately before the Fontan operation; 37 healthy children (mean age 33 ± 17 months) were assayed as controls. Concentration of factors II, V, VII, VIII, IX, and X and of antithrombin III, plasminogen, proteins C and S, fibrinogen, serum albumin, and liver enzymes were measured. Normal reference intervals based on the control patients were determined using 95% confidence limits. Patient demographic data, hemodynamic variables, and elapsed time after the Glenn procedure were evaluated as possible predictors of coagulation abnormalities. Results. Concentrations of protein C; factors II, V, VII, and X; plasminogen; and antithrombin III were significantly lower before the Fontan operation compared with age-matched controls (p< 0.01); no specific hemodynamic variables were predictive of a pro- or anticoagulant deficiency. There were significant positive correlations between patients who had abnormally low factor VII, protein S, and protein C levels and a longer interval between the bidirectional Glenn procedure and the Fontan operation (p< 0.001). Conclusions. Coagulation abnormalities that could predispose patients to increased risk for clotting or bleeding are evident early in the course of staged single-ventricle repair.