title: Determinants and time course of the postthrombotic syndrome after acute deep venous thrombosis.
abstract: BACKGROUND
  The reason some patients with deep venous thrombosis (DVT) develop the postthrombotic syndrome is not well understood.
  
  
  OBJECTIVE
  To determine the frequency, time course, and predictors of the postthrombotic syndrome after acute DVT.
  
  
  METHODS
  Prospective, multicenter cohort study.
  
  
  METHODS
  8 Canadian hospital centers.
  
  
  METHODS
  387 outpatients and inpatients who received an objective diagnosis of acute symptomatic DVT were recruited from 2001 to 2004.
  
  
  METHODS
  Standardized assessments for the postthrombotic syndrome using the Villalta scale at 1, 4, 8, 12, and 24 months after enrollment. Mean postthrombotic score and severity category at each interval was calculated. Predictors of postthrombotic score profiles over time since diagnosis of DVT were identified by using linear mixed modeling.
  
  
  RESULTS
  At all study intervals, about 30% of patients had mild (score, 5 to 9), 10% had moderate (score, 10 to 14), and 3% had severe (score >14 or ulcer) postthrombotic syndrome. Greater postthrombotic severity category at the 1-month visit strongly predicted higher mean postthrombotic scores throughout 24 months of follow-up (1.97, 5.03, and 7.00 increase in Villalta score for mild, moderate, and severe 1-month severity categories, respectively, vs. none; P < 0.001). Additional predictors of higher scores over time were venous thrombosis of the common femoral or iliac vein (2.23 increase in score vs. distal [calf] venous thrombosis; P < 0.001), higher body mass index (0.14 increase in score per kg/m(2); P < 0.001), previous ipsilateral venous thrombosis (1.78 increase in score; P = 0.001), older age (0.30 increase in score per 10-year age increase; P = 0.011), and female sex (0.79 increase in score; P = 0.020).
  
  
  CONCLUSIONS
  Decisions to prescribe compression stockings were left to treating physicians rather than by protocol. Because international normalized ratio data were unavailable, the relationship between anticoagulation quality and Villalta scores could not be assessed.
  
  
  CONCLUSIONS
  The postthrombotic syndrome occurs frequently after DVT. Patients with extensive DVT and those with more severe postthrombotic manifestations 1 month after DVT have poorer long-term outcomes.
authors.affiliation: Centre for Clinical Epidemiology and Community Studies, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada. susan.kahn@mcgill.ca
authors.forename: Susan R
authors.initials: SR
authors.lastname: Kahn
authors.forename: Ian
authors.initials: I
authors.lastname: Shrier
authors.forename: Jim A
authors.initials: JA
authors.lastname: Julian
authors.forename: Thierry
authors.initials: T
authors.lastname: Ducruet
authors.forename: Louise
authors.initials: L
authors.lastname: Arsenault
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Miron
authors.forename: Andre
authors.initials: A
authors.lastname: Roussin
authors.forename: Sylvie
authors.initials: S
authors.lastname: Desmarais
authors.forename: France
authors.initials: F
authors.lastname: Joyal
authors.forename: Jeannine
authors.initials: J
authors.lastname: Kassis
authors.forename: Susan
authors.initials: S
authors.lastname: Solymoss
authors.forename: Louis
authors.initials: L
authors.lastname: Desjardins
authors.forename: Donna L
authors.initials: DL
authors.lastname: Lamping
authors.forename: Mira
authors.initials: M
authors.lastname: Johri
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Ginsberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D054070:Postthrombotic Syndrome / Q000175:diagnosis / Q000209:etiology*; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D053828:Stockings, Compression; D013997:Time Factors; D020246:Venous Thrombosis / Q000150:complications* / Q000188:drug therapy / Q000517:prevention & control; D055815:Young Adult
chemical_list: D000925:Anticoagulants