The significance of evaluating conventional inflammatory markers in Von Willebrand factor measurement

Background: The appropriate clinical interpretation of Von Willebrand factor (VWF) measurements is crucial since inherited or acquired deficiencies are responsible for a potentially life threatening bleeding disorder, whereas increased plasma concentrations may be associated with an increased thrombotic risk. Besides age and blood group, the variability introduced by the presence of an acute phase response might contribute to decrease the clinical usefulness of this measurement. Methods: To investigate the relationship between conventional inflammatory markers and VWF, 387 consecutive unselected patients undergoing surgical procedures at our University Hospital were systematically investigated for routine laboratory testing, including also VWF Antigen (VWT:Ag), C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) as parts of a routine preoperative screening program. Results: After stratifying the study population according to the upper limit of the reference range of the two inflammatory markers, a significantly increased median VWF:Ag plasma concentration was observed for subjects with increased value of both CRP (CRP > 5 mg/L = VWF:Ag > 120 UI/dL; CRP < 5 mg/L = VWF:Ag 98 UI/dL,p = 0.003) and ESR (ESR > 30 mm/hg = VWF:Ag > 120 UI/dL; ESR < 30 mm/hg = VWF:Ag 96 UI/dL,p < 0.001). A significantly different frequency distribution of VWF:Ag concentrations was also observed in subjects with values of inflammatory markers above the upper limits of the reference ranges when compared to those with normal values. In particular, the prevalence of subjects with VWF:Ag levels > 120 UI/dL was six- and nearly three-times higher in subjects with abnormal values of CRP (55.8% versus 9.3%, p < 0.001) and ESR (54.5% versus 18.7%, P < 0.001), respectively. Conclusions: Results of this investigation demonstrate that the evaluation of conventional inflammatory markers would represent a valuable tool to enhance the clinical usefulness of VWF measurements, especially in patients with transitory and subclinical inflammation. Since VWF,and factor VIII are likely to increase in parallel, we suggest that their measurements should be repeated at least after 6 months to one year in the presence of concomitantly increased values of inflammatory markers, such as ESR and/or CRP. (c) 2007 Elsevier B.V. All rights reserved.