title: Evaluation of hemostatic and coagulation factor abnormalities in patients undergoing the Fontan operation.
abstract: OBJECTIVE
  Low-velocity and nonlaminar flow patterns in the Fontan circulation, as well as abnormal liver function in some patients, may partly account for the coagulation abnormalities seen. We examined (1) coagulation factor abnormalities before and after the Fontan procedure and (2) regional coagulation factor abnormalities in the Fontan circulation.
  
  
  METHODS
  Levels of factors V, VII, VIII, X, antithrombin III, prothrombin fragment F1+2, protein C, and protein S were measured in 2 groups of patients: In 14 patients undergoing the Fontan procedure, blood was analyzed before the operation and 5 days after the operation (group 1). The median age in this group was 3.2 years. In 10 patients who had undergone the Fontan procedure, cardiac catheterization was performed and samples were taken from the femoral vein, inferior vena cava, right atrium, and pulmonary artery (group 2). The median age in this group was 6.2 years and the median follow-up from the Fontan procedure was 4.1 years.
  
  
  RESULTS
  In group 1 a significant increase was noted postoperatively in the concentration of factor VIII (P<.001), factor X (P<.001), and prothrombin fraction F1+2 (P <.001). A significant decrease in the levels of antithrombin III (P <.001), protein C (P<.004), and protein S (P<.02) was also found. The increase in factors VIII and X persisted at 4 years' follow-up in group 2 patients. In group 2, no significant regional differences were observed between the coagulation factors measured at different sites.
  
  
  CONCLUSIONS
  There is an increased tendency toward coagulation after the Fontan procedure. A prothrombotic state is supported by thrombin generation associated with reduced antithrombin III concentration. This increase in coagulation may contribute to the early and late risks of thromboembolism observed after the Fontan procedure. We did not find any regional differences in coagulation abnormalities in patients late after the Fontan procedure. Therefore, the mechanisms and causes of the coagulation abnormalities remain unclear.
authors.affiliation: Department of Cardiology and Cardiac Surgery, Children's Hospital, Boston, Mass. 02115, USA.
authors.forename: M
authors.initials: M
authors.lastname: Jahangiri
authors.forename: J
authors.initials: J
authors.lastname: Kreutzer
authors.forename: D
authors.initials: D
authors.lastname: Zurakowski
authors.forename: E
authors.initials: E
authors.lastname: Bacha
authors.forename: R A
authors.initials: RA
authors.lastname: Jonas
mesh_terms: D000990:Antithrombin III / Q000032:analysis; D001779:Blood Coagulation Factors / Q000032:analysis*; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects*; D006330:Heart Defects, Congenital / Q000097:blood / Q000601:surgery; D006801:Humans; D007223:Infant; D008297:Male; D011184:Postoperative Period; D011486:Protein C / Q000032:analysis; D017293:Protein S / Q000032:analysis
chemical_list: D001779:Blood Coagulation Factors; D011486:Protein C; D017293:Protein S; D000990:Antithrombin III