Procoagulant and anticoagulant factor abnormalities following the Fontan procedure: increased factor VIII may predispose to thrombosis.
OBJECTIVE
Using age-matched controls, this study prospectively evaluated coagulation factor abnormalities and hemodynamic variables in children who had undergone the Fontan operation.


METHODS
Coagulation factors were assayed in 20 children (mean age 6.4 +/- 2.9 years), at a mean 3.7 +/- 2.3 years after the Fontan procedure; 24 healthy children (mean age 6.8 +/- 2.8 years) were assayed as controls. Concentration of factors II, V, VII, VIII, IX, X; ATIII; 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, hemodynamic variables, and elapsed time after the Fontan procedure were evaluated as possible predictors of coagulation abnormalities.


RESULTS
Concentrations of protein C; factors II, V, VII, X; plasminogen; and ATIII were significantly lower in Fontan patients compared with age-matched controls (P <.01); factor VIII was significantly elevated in 6 patients (35%), 2 of whom had a thromboembolic event. A higher superior vena cava pressure was predictive of an elevated factor VIII level (P =.003). No other specific hemodynamic variables were predictive of a procoagulant or anticoagulant abnormality.


CONCLUSIONS
Procoagulant and anticoagulant factor levels were significantly lower in patients after the Fontan operation independent of hemodynamic variables peculiar to the Fontan circulation. Increased factor VIII level requires further evaluation as a cause of thrombosis in patients with Fontan physiology and may also indicate a subset of these patients in whom anticoagulation is indicated.
Odegard
Kirsten C
KC
Department of Anesthesia, Children's Hospital, Boston, MA 02115, USA. kirsten.odegard@tch.harvard.edu
McGowan
Francis X
FX
Zurakowski
David
D
Dinardo
James A
JA
Castro
Robert A
RA
del Nido
Pedro J
PJ
Laussen
Peter C
PC
D000293:Adolescent; D000990:Antithrombin III / Q000032:analysis; D001779:Blood Coagulation Factors / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005165:Factor V / Q000032:analysis; D005167:Factor VII / Q000032:analysis; D005170:Factor X / Q000032:analysis; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D010958:Plasminogen / Q000032:analysis; D011446:Prospective Studies; D011486:Protein C / Q000032:analysis; D011516:Prothrombin / Q000032:analysis; D013927:Thrombosis / Q000209:etiology*
D001779:Blood Coagulation Factors; D011486:Protein C; D000990:Antithrombin III; D005165:Factor V; D005167:Factor VII; D011516:Prothrombin; D005170:Factor X; D010958:Plasminogen