title: Management and outcomes of axial isolated distal deep vein thrombosis at North Shore Hospital, New Zealand: a retrospective audit.
abstract: BACKGROUND
  It is standard of care to treat proximal vein deep vein thrombosis (DVT) for a minimum of 3 months. Conversely, management of isolated distal DVT (IDDVT) is controversial, with options including observation and repeat ultrasound scan within 1 week to detect and anticoagulate those with proximal propagation, or anticoagulation for periods of up to 3 months.
  
  
  OBJECTIVE
  The aim was to assess the rates of proximal propagation and venous thromboembolism (VTE) recurrence within 3 months of diagnosis of IDDVT, and to examine how the duration of treatment might influence this.
  
  
  METHODS
  Study patients were identified by retrospective audit of data from the North Shore Hospital VTE database. All patients presenting with established axial vein distal DVT from July 2007 to June 2012 were included. A 6-week treatment duration cut-off was used to separate the treatment arms (<6 weeks vs 6 weeks vs >6 weeks), and Fisher's exact or Pearson's Chi-squared tests were used to assess between-group comparisons.
  
  
  RESULTS
  Five hundred and seven patients were included in the study, mean age 59.7 years; 53% female. There were three cases of proximal propagation, all occurring in those receiving <6 weeks treatment. There were six VTE recurrences, three in the <6 week and three in the ≥6 week treatment groups respectively. Malignancy was the only significant predictor of VTE recurrence (P = 0.001).
  
  
  CONCLUSIONS
  A 6-week duration of anticoagulation appears to be an effective and safe treatment for isolated axial distal DVT, with low rates of VTE recurrence and proximal propagation.
authors.affiliation: Haematology Department, North Shore Hospital, Auckland, New Zealand.
authors.forename: A Y
authors.initials: AY
authors.lastname: Li
authors.forename: T
authors.initials: T
authors.lastname: Woulfe
authors.forename: V
authors.initials: V
authors.lastname: Rolfe-Vyson
authors.forename: V
authors.initials: V
authors.lastname: Rowland
authors.forename: D
authors.initials: D
authors.lastname: Simpson
authors.forename: E
authors.initials: E
authors.lastname: Merriman
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D002423:Cause of Death; D016009:Chi-Square Distribution; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D017052:Hospital Mortality; D006779:Hospitals, Public; D006801:Humans; D008297:Male; D008485:Medical Audit; D008875:Middle Aged; D015999:Multivariate Analysis; D009520:New Zealand; D011237:Predictive Value of Tests; D012008:Recurrence; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D016896:Treatment Outcome; D014463:Ultrasonography; D054556:Venous Thromboembolism / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000401:mortality; D020246:Venous Thrombosis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000401:mortality*
chemical_list: D000925:Anticoagulants
keywords: DVT; anticoagulation; calf vein thrombosis; distal deep vein thrombosis; management