title: Clot structure and fibrinolytic potential in patients with post thrombotic syndrome.
abstract: BACKGROUND
  Post-thrombotic syndrome (PTS) is a chronic sequel of deep vein thrombosis (DVT). The clot structure and fibrinolytic potential in PTS is currently unknown.
  
  
  OBJECTIVE
  To assess the fibrinolytic potential and clot structure in patients with PTS.
  
  
  METHODS
  Patients with a history of DVT were included in a case-control study: patients with PTS (cases n=30) and without PTS (controls n=30), and 30 apparently healthy individuals (HI) without venous thromboembolism (VTE) or venous insufficiency were enrolled. Fibrinolysis and clot structure were assessed by turbidimetric assays, permeation, and confocal microscopy. Fibrinogen was measured by Clauss and fibrinogen γ' by ELISA.
  
  
  RESULTS
  We observed a significant trend of decreasing maximum turbidity from HI (median 0.52 [IQR 0.46-0.62]), to controls (0.49 [IQR 0.41-0.55]), to cases (0.46 [IQR 0.39-0.49]) p=0.020. Fibrinogen was lower in patients (cases and controls) (3.69g/L [IQR 3.31-4.26]) compared to HI (4.17 [IQR 3.69-4.65]) p=0.041. Patients with recurrent VTE had lower maximum turbidity and lower permeation than patients with one episode of VTE; (0.31 [IQR 0.25-0.39] versus 0.38 [IQR 0.34-0.44] p=0.008) and (6.0×10(-9)/cm(2) [IQR 5.1-7.9] versus 7.7×10(-9)/cm(2) [IQR 6.0-10.0] p=0.047) respectively, at equal fibrinogen levels. There were no differences in lysis time, confocal microscopy, or fibrinogen γ'.
  
  
  CONCLUSIONS
  Lower maximum turbidity, indicating a tendency towards thinner fibres and denser clots, was found in patients with PTS as well as in patients with recurrent VTE. Fibrinogen levels did not explain these differences in clot structure. The abnormal clot structure may contribute to the increased thrombotic risk profile in patients with PTS.
authors.affiliation: Laboratory for Thrombosis and Hemostasis, Maastricht University Medical Centre, Maastricht, The Netherlands. Electronic address: annemieke.bouman@maastrichtuniversity.nl.
authors.forename: A C
authors.initials: AC
authors.lastname: Bouman
authors.affiliation: Division of Cardiovascular and Diabetes Research, Leeds Institute for Genetics, Health and Therapeutics, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, UK.
authors.forename: H
authors.initials: H
authors.lastname: McPherson
authors.affiliation: Department of Internal Medicine, Flevohospital, Almere, The Netherlands.
authors.forename: Y W
authors.initials: YW
authors.lastname: Cheung
authors.affiliation: Department of Internal Medicine, Flevohospital, Almere, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Ten Wolde
authors.affiliation: Laboratory for Thrombosis and Hemostasis, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Ten Cate
authors.affiliation: Division of Cardiovascular and Diabetes Research, Leeds Institute for Genetics, Health and Therapeutics, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, UK.
authors.forename: R A S
authors.initials: RAS
authors.lastname: Ariëns
authors.affiliation: Laboratory for Thrombosis and Hemostasis, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Ten Cate-Hoek
mesh_terms: D000368:Aged; D001777:Blood Coagulation; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D005340:Fibrinogen / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D054070:Postthrombotic Syndrome / Q000097:blood* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020246:Venous Thrombosis / Q000097:blood* / Q000473:pathology*
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; D005340:Fibrinogen
keywords: Clot structure; Deep vein thrombosis; Fibrinolysis; Post thrombotic syndrome