Time course of thrombosis and fibrinolysis during total hip surgery

Venous thrombosis is common in elective hip surgery, and prophylactic treatment is used up to 12 hours before or after surgery. Recent clinical trials suggested that the timing of initiating prophylaxis significantly influenced the antithrombotic effectiveness. Furthermore, the timing of initiating antifibrinolytic treatment to reduce blood loss has been a question of debate. We studied the time course of coagulation and fibrinolysis at all phases during total hip arthroplasty. Specific markers of thrombosis (prothrombin fragment F1.2) and of fibrinolysis (plasminantiplasmin (PAP) and D-dimer) were examined in eight female and two male patients aged 16–62 years. There was a progressive increase in plasma concentrations of F1.2 during the operation. From the end of operation to 4 hours afterwards, there was no further increase in F1.2. Levels of D-dimer did not change until wound closure, when they began to increase up to 4 hours postoperatively, but there were no changes in PAP during the operation or during the 4-h postoperative period. Therefore, surgery for total hip arthroplasty activates thrombin generation during operation with fibrin degradation at a later stage. These observations harmonize with the notion that the interval between surgery and first administration of antithrombotic treatment is a critical variable.