title: Elevation of FVIII: C in venous thromboembolism is persistent and independent of the acute phase response.
abstract: Recent literature has suggested a role for elevated FVIII:C in venous thromboembolic disease (VTED). However since FVIII:C is known to rise in response to an acute phase reaction, it is difficult to determine whether the increased FVIII:C precedes the thrombosis or represents a secondary reactive phenomenon. In an attempt to address this question, we followed 35 patients with confirmed VTED, raised FVIII:C level (>1.5 iu/ml) and no other thrombotic tendency. Serial measurements of FVIII:C, vWF:Ag, C-reactive protein and fibrinogen were performed. We hypothesized that a persistent increase in FVIII:C in the absence of any other measures of ongoing acute phase response, would support the idea that elevation of FVIII:C is a constitutional phenomenon. Of this initial group, 94% continued to have an elevated FVIII:C level throughout the period of follow up (median 8 months; range 3 to 39 months), with no significant difference between the FVIII:C levels determined at first estimation and those obtained during follow up (p = 0.58). Conversely, only 18% had evidence of an acute phase reaction when first assessed, and nonparametric ranking analysis demonstrated no correlation between FVIII:C and either C-reactive protein or fibrinogen (p = 0.315 and 0.425 respectively).We conclude that increased FVIII:C levels following VTED are persistent, independent of the acute phase reaction, and thus may represent a constitutional risk factor for VTED.
authors.affiliation: Department of Haematology, Imperial College School of Medicine/Hammersmith Hospital, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: O'Donnell
authors.forename: A D
authors.initials: AD
authors.lastname: Mumford
authors.forename: R A
authors.initials: RA
authors.lastname: Manning
authors.forename: M
authors.initials: M
authors.lastname: Laffan
mesh_terms: D000210:Acute-Phase Reaction; D002097:C-Reactive Protein / Q000378:metabolism*; D005169:Factor VIII / Q000378:metabolism*; D006801:Humans; D020246:Venous Thrombosis / Q000097:blood* / Q000503:physiopathology
chemical_list: D005169:Factor VIII; D002097:C-Reactive Protein