Hemostatic changes following the modified Fontan operation (total cavopulmonary connection)

Area of Science:

• Cardiovascular Surgery
• Hematology
• Pediatric Cardiology

Background:

• Thromboembolism is a significant risk following the Fontan operation.
• Alterations in the coagulation system are suspected contributors to post-Fontan thromboembolism.
• Understanding these coagulation changes is crucial for managing patient outcomes.

Purpose of the Study:

• To investigate pro- and anticoagulant factors in patients after Fontan operation.
• To compare markers of thrombin activation and fibrinolysis between Fontan patients and healthy controls.
• To assess in vitro clotting and clot-lysis in this patient cohort.

Main Methods:

• Studied 20 patients (aged 4-21 years) 4-63 months post-total cavopulmonary connection.
• Measured levels of protein C, protein S, and Factor VIII (FVIII).
• Assessed markers of thrombin-antithrombin III (TAT), plasmin-antiplasmin (PAP), and prothrombin fragments F1+2.

Main Results:

• Fontan patients exhibited significantly lower protein C and protein S levels compared to controls.
• Approximately 50% of patients had elevated FVIII levels, indicating increased thrombotic risk.
• Increased TAT and PAP levels, with a trend in prothrombin fragments, suggested enhanced thrombin and plasmin generation.

Conclusions:

• Fontan operation is associated with a prothrombotic state due to decreased anticoagulant factors and increased procoagulant factors.
• Elevated thrombin and plasmin generation markers indicate a hypercoagulable state post-Fontan.
• These coagulation alterations may underlie the increased risk of thromboembolism in Fontan survivors.