title: Decreased plasma levels of activated factor VII in patients with deep vein thrombosis.
abstract: BACKGROUND
  The initiating trigger in the development of deep vein thrombosis (DVT) remains unidentified. It has been suggested that tissue factor (TF)-bearing microparticles play a key role, which indicates a role for the TF pathway in the initiation of DVT.
  
  
  OBJECTIVE
  To assess the role of the TF pathway in the initiation of venous thrombosis, we measured plasma levels of factor VII and VIIa in patients with acute DVT and in controls.
  
  
  METHODS
  We included 148 patients diagnosed with acute DVT and 179 controls in this study. Antigen levels of FVII and FVIIa were measured by using assays recently developed in our laboratory.
  
  
  RESULTS
  Median FVII levels in patients were 109.8% (interquartile range [IQR] 86.0-153.2) compared with 102.2% (IQR 76.1-141.7) in controls. Individuals with FVII levels in the upper quartile had a 1.6-fold increased risk for the presence of a DVT (odds ratio 1.6, 95% confidence interval 0.8-3.1). Median FVIIa levels in patients were 50.2 ng mL(-1) (IQR 25.2-86.1) compared with 96.6 ng mL(-1) (69.9-168.9) in controls. Individuals with FVIIa levels in the lowest quartile had a > 5-fold increased risk for the presence of a DVT (odds ratio 5.5, 95% confidence interval 2.8-10.6). Both risks did not change substantially after adjustment for potential confounders.
  
  
  CONCLUSIONS
  Decreased plasma levels of FVIIa in patients with deep vein thrombosis may indicate ongoing consumption of FVIIa and suggest a contributory role for TF in venous thrombus formation.
authors.affiliation: Surgical Research Laboratory, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Schut
authors.affiliation: Department of Experimental Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.|Department of Plasma Proteins, Sanquin Research, Amsterdam, the Netherlands.
authors.forename: J C M
authors.initials: JC
authors.lastname: Meijers
authors.affiliation: Department of General Practice, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors.forename: Y
authors.initials: Y
authors.lastname: Lisman-van Leeuwen
authors.affiliation: Department of Experimental Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: M L
authors.initials: ML
authors.lastname: van Montfoort
authors.affiliation: Department of Clinical Chemistry and Haematology, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Roest
authors.affiliation: Department of Clinical Chemistry and Haematology, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: P G
authors.initials: PG
authors.lastname: de Groot
authors.affiliation: Department of Clinical Chemistry and Haematology, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: R T
authors.initials: RT
authors.lastname: Urbanus
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Coppens
authors.affiliation: Surgical Research Laboratory, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Lisman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D015536:Down-Regulation; D015942:Factor VIIa / Q000032:analysis*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012307:Risk Factors; D020246:Venous Thrombosis / Q000097:blood* / Q000175:diagnosis; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015942:Factor VIIa
keywords: blood coagulation; factor VII; factor VIIa; tissue factor; venous thrombosis