title: The post-thrombotic syndrome: risk factors and impact on the course of thrombotic disease.
abstract: BACKGROUND
  The post-thrombotic syndrome (PTS) is a frequent complication of deep vein thrombosis (DVT). Patients with recurrent ipsilateral DVT have an increased risk of PTS; other risk factors are unknown.
  
  
  OBJECTIVE
  To establish risk factors of PTS and its impact on venous thrombotic disease.
  
  
  METHODS
  We prospectively followed 406 patients after a first symptomatic DVT for a median of 60 months. Patients with recurrent DVT, a natural inhibitor deficiency, the lupus anticoagulant, cancer, long-term anticoagulation, an observation time < 18 months and DVT-recurrence prior PTS-assessment were excluded. Study outcomes were occurrence of PTS and recurrent symptomatic DVT.
  
  
  RESULTS
  PTS was assessed after 44 +/- 23 months (mean +/- SD) using a clinical classification score. PTS developed in 176 of 406 patients (43.3%). Severe PTS was rare (1.4%). Proximal DVT was the strongest risk factor of PTS [odds ratio (OR) 2.1, 95% confidence interval (CI) 1.3-3.7]. Male gender (OR 1.6, 95% CI 1.0-2.8) and elevated D-dimer levels (OR 1.9, 95% CI 1.0-3.9) were weaker risk factors. Factor V Leiden, factor II G20210A or high factor VIII did not confer an increased risk of PTS. At 4 years, the cumulative probability of recurrence was 7.4% (95% CI 3.2-11.7) among patients with PTS when compared with 1.6% (95% CI 0-3.5; P < 0.02) among patients without PTS. The risk of recurrence was 2.6-fold (95% CI 1.2-5.9) increased when PTS was present.
  
  
  CONCLUSIONS
  Proximal DVT, male gender, and high D-dimer levels are independently associated with the development of PTS in patients with a first DVT. Patients with PTS have an increased risk of recurrent venous thromboembolism.
authors.affiliation: Division of Hematology and Hemostasis, Department of Internal Medicine I, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Stain
authors.forename: V
authors.initials: V
authors.lastname: Schönauer
authors.forename: E
authors.initials: E
authors.lastname: Minar
authors.forename: C
authors.initials: C
authors.lastname: Bialonczyk
authors.forename: M
authors.initials: M
authors.lastname: Hirschl
authors.forename: A
authors.initials: A
authors.lastname: Weltermann
authors.forename: P A
authors.initials: PA
authors.lastname: Kyrle
authors.forename: S
authors.initials: S
authors.lastname: Eichinger
mesh_terms: D000328:Adult; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011186:Postphlebitic Syndrome / Q000453:epidemiology* / Q000209:etiology; D011336:Probability; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012737:Sex Factors; D013923:Thromboembolism / Q000150:complications / Q000453:epidemiology / Q000473:pathology; D013927:Thrombosis / Q000150:complications / Q000453:epidemiology* / Q000473:pathology; D020246:Venous Thrombosis / Q000150:complications / Q000453:epidemiology / Q000473:pathology
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D