title: Acenocoumarol and heparin compared with acenocoumarol alone in the initial treatment of proximal-vein thrombosis.
abstract: BACKGROUND
  In most countries, heparin is used in the initial treatment of patients with deep-vein thrombosis. Well-designed studies establishing the efficacy of heparin therapy are lacking, however. Treatment with acenocoumarol alone, according to the hypothesis that high dosages of oral anticoagulants obviate the need for heparin, is considered an effective alternative in some countries.
  
  
  METHODS
  In a randomized, double-blind study we compared the efficacy and safety of continuous intravenous heparin plus acenocoumarol with the efficacy and safety of acenocoumarol alone in the initial treatment of outpatients with proximal-vein thrombosis. The principal study end point was a confirmed symptomatic extension or recurrence of venous thromboembolism during six months of follow-up. In addition, we assessed asymptomatic extension or pulmonary embolism by repeating venography and lung scanning after the first week of treatment. The incidence of major bleeding was determined during three months of follow-up.
  
  
  RESULTS
  The study was terminated early by the Data Safety and Monitoring Committee because of an excess of symptomatic events in the group that received acenocoumarol alone (in 12 of 60 patients [20 percent], as compared with 4 of 60 patients [6.7 percent] in the combined-therapy group by intention-to-treat analysis; P = 0.058). Asymptomatic extension of venous thrombosis was observed in 39.6 percent of the patients in the acenocoumarol group and in 8.2 percent of patients treated with heparin plus acenocoumarol (P < 0.001). Major bleeding complications were infrequent and comparable in the two groups.
  
  
  CONCLUSIONS
  Patients with proximal-vein thrombosis require initial treatment with full-dose heparin, which can safely be combined with acenocoumarol therapy.
authors.affiliation: Center for Haemostasis, Thrombosis, Atherosclerosis and Inflammation Research, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: D P
authors.initials: DP
authors.lastname: Brandjes
authors.forename: H
authors.initials: H
authors.lastname: Heijboer
authors.forename: H R
authors.initials: HR
authors.lastname: Büller
authors.forename: M
authors.initials: M
authors.lastname: de Rijk
authors.forename: H
authors.initials: H
authors.lastname: Jagt
authors.forename: J W
authors.initials: JW
authors.lastname: ten Cate
mesh_terms: D000074:Acenocoumarol / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced; D006493:Heparin / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000517:prevention & control; D012008:Recurrence; D013924:Thrombophlebitis / Q000188:drug therapy*
chemical_list: D006493:Heparin; D000074:Acenocoumarol