BACKGROUND: The complex between activated protein C (APC) and the protein C inhibitor (PCI) is a sensitive indicator of the degree of activation of blood coagulation and higher concentrations have been measured in carriers of the FV Leiden mutation who were in the recovery phase after treatment for venous thromboembolism (VTE). OBJECTIVES: The main purpose of this study was to correlate the APC-PCI complex concentration to thrombomodulin activity and antigen concentration in the same group of patients. We also add a prospective clinical follow-up of the VTE recurrence after 1 year to investigate if the markers can predict the risk for a new VTE. PATIENTS/ METHODS: Blood samples were collected from 50 patients with the FV Leiden mutation and 132 without any known risk factor for thrombophilia after finished treatment. RESULTS: The APC-PCI complex, s-TM activity and the quotient (s-TM activity)/(s-TM antigen) were higher in VTE patients with FV Leiden. In total, there were 19 VTE recurrences (10%) after 1 year. The OR for recurrence was 1.9 (95% CI 0.68-5.0) in all VTE patients with elevated APC-PCI complex (above 75th percentile) and 3.6 (95% CI 1.1-12) in VTE patients without any known risk factor for thrombophilia and with elevated s-TM activity. CONCLUSION: The APC-PCI complex concentration, s-TM activity and the quotient (s-TM activity)/(s-TM antigen) were higher in VTE patients with FV Leiden. The s-TM activity showed higher OR for recurrence of VTE in patients without known thrombophilic risk factor. Both methods could be sensitive markers of increased risk for venous thrombosis.
BACKGROUND: The complex between activated protein C (APC) and the protein C inhibitor (PCI) is a sensitive indicator of the degree of activation of blood coagulation and higher concentrations have been measured in carriers of the FV Leiden mutation who were in the recovery phase after treatment for venous thromboembolism (VTE). OBJECTIVES: The main purpose of this study was to correlate the APC-PCI complex concentration to thrombomodulin activity and antigen concentration in the same group of patients. We also add a prospective clinical follow-up of the VTE recurrence after 1 year to investigate if the markers can predict the risk for a new VTE. PATIENTS/ METHODS: Blood samples were collected from 50 patients with the FV Leiden mutation and 132 without any known risk factor for thrombophilia after finished treatment. RESULTS: The APC-PCI complex, s-TM activity and the quotient (s-TM activity)/(s-TM antigen) were higher in VTEpatients with FV Leiden. In total, there were 19 VTE recurrences (10%) after 1 year. The OR for recurrence was 1.9 (95% CI 0.68-5.0) in all VTEpatients with elevated APC-PCI complex (above 75th percentile) and 3.6 (95% CI 1.1-12) in VTEpatients without any known risk factor for thrombophilia and with elevated s-TM activity. CONCLUSION: The APC-PCI complex concentration, s-TM activity and the quotient (s-TM activity)/(s-TM antigen) were higher in VTEpatients with FV Leiden. The s-TM activity showed higher OR for recurrence of VTE in patients without known thrombophilic risk factor. Both methods could be sensitive markers of increased risk for venous thrombosis.