title: Extended outpatient therapy with low molecular weight heparin for the treatment of recurrent venous thromboembolism despite warfarin therapy.
abstract: OBJECTIVE
  The optimal management of patients who have recurrent thromboembolism while being treated with oral anticoagulation therapy is unknown. This study reports managing such patients with extended duration low molecular weight heparin therapy.
  
  
  METHODS
  This study was a retrospective review of the prospective databases of three tertiary care teaching hospitals over a 27-month period. All patients who had recurrent symptomatic thromboembolism while being treated with warfarin were identified. All patients were treated with low molecular weight heparin (dalteparin), 200 U/kg daily. Data were collected for recurrent venous thromboembolism, bleeding, and survival.
  
  
  RESULTS
  Eight hundred eighty-seven patients were managed for acute thromboembolism. In 32 patients, symptomatic, objectively documented thromboembolism recurred while they were taking warfarin; 63% of the patients with recurrence had cancer, compared with 30% of patients without recurrence. All recurrences were treated with dalteparin. In 3 patients (9% [95% confidence interval: 2% to 25%]), symptomatic recurrence developed while they were being treated with low molecular weight heparin. Nineteen patients (59%) died while receiving anticoagulation therapy; all deaths but 1 were due to malignancy, and none was due to pulmonary embolism or bleeding.
  
  
  CONCLUSIONS
  These results suggest that recurrent venous thromboembolism is more likely to develop in cancer patients while being treated with warfarin and that long-term therapy with low molecular weight heparin may be effective in managing warfarin-failure thromboembolic disease.
authors.affiliation: University of Western Ontario, London, Ontario, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Luk
authors.forename: P S
authors.initials: PS
authors.lastname: Wells
authors.forename: D
authors.initials: D
authors.lastname: Anderson
authors.forename: M J
authors.initials: MJ
authors.lastname: Kovacs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D010045:Outpatients; D012008:Recurrence; D012189:Retrospective Studies; D013923:Thromboembolism / Q000188:drug therapy* / Q000209:etiology; D016896:Treatment Outcome; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D014859:Warfarin