The Evaluation of Fibrin-Related Markers for Diagnosing or Predicting Acute or Subclinical Venous Thromboembolism in Patients Undergoing Major Orthopedic Surgery

Objective: The cutoff values of fibrin-related markers (FRMs) diagnosing or predicting the occurrence of a venous thromboembolism (VTE) were evaluated. Materials and Methods: Fibrin-related markers such as fibrin monomer complex (FMC), D-dimer, and fibrinogen and fibrin degradation products (FDPs) before surgery were measured in 326 patients undergoing orthopedic surgery to diagnose subclinical VTE or predict postoperative VTE. Results: Although the FMC, D-dimer, and FDP levels were all useful for the diagnosis of acute VTE, the FDP level was not useful for diagnosing subclinical VTE or predicting postoperative VTE. The results of several D-dimer assays closely correlated with other D-dimer assays. There were various cutoff ranges for diagnosing or predicting VTE. Some D-dimer assays were useful for diagnosing low levels of D-dimer and others were useful for diagnosing moderate to high D-dimer levels. Increased D-dimer levels were useful for diagnosing acute (cutoff values: 2.0-5.9 μg/mL) or about 10% of subclinical VTE (cutoff values: 3.4-5.3 μg/mL), for predicting about 10% of postoperative VTE (cutoff values: 3.4-5.3 μg/mL), and for excluding VTE. Conclusion: Although increased D-dimer levels were useful for diagnosing subclinical VTE and predicting the risk of VTE, there were various cutoff values for the diagnosis or prediction of VTE.