title: Extended oral anticoagulant therapy after a first episode of pulmonary embolism.
abstract: BACKGROUND
  The optimal duration of oral anticoagulant treatment after a first episode of pulmonary embolism remains uncertain.
  
  
  OBJECTIVE
  To evaluate the long-term clinical benefit of extending a 3-month course of oral anticoagulant therapy to 6 months (pulmonary embolism associated with temporary risk factors) or to 1 year (idiopathic pulmonary embolism) in patients with a first episode of pulmonary embolism.
  
  
  METHODS
  Multicenter randomized study with independent, blinded assessment of the outcome events.
  
  
  METHODS
  19 Italian hospitals.
  
  
  METHODS
  326 patients who had had 3 months of oral anticoagulant therapy without experiencing recurrence or bleeding.
  
  
  METHODS
  The primary study outcome was recurrence of symptomatic, objectively confirmed venous thromboembolism.
  
  
  RESULTS
  Among 165 patients assigned to extended anticoagulant therapy, 15 patients (9.1%) had a recurrence of venous thromboembolism (3.1% per patient-year; average follow-up, 34.9 months), as compared with 18 of 161 patients (11.2%) assigned to discontinue treatment (4.1% per patient-year; average follow-up, 32.7 months); the rate ratio was 0.81 (95% CI, 0.42 to 1.56). All but one of the recurrences occurred after anticoagulant treatment was discontinued. Nineteen recurrences (57.6%) were episodes of pulmonary embolism, two of which were fatal. Three major bleeding episodes were observed during extended anticoagulation (1.8%). Among patients with idiopathic venous thromboembolism, 11 of 90 patients assigned to extended anticoagulation and 11 of 91 patients assigned to discontinue treatment experienced a recurrence (relative risk, 0.99 [CI, 0.45 to 2.16]).
  
  
  CONCLUSIONS
  Patients with pulmonary embolism have a substantial risk for recurrence after discontinuation of oral anticoagulation, regardless of treatment duration. Physicians should try to identify patients who are at high risk for recurrent venous thromboembolism and are therefore potential candidates for indefinite oral anticoagulant therapy.
authors.affiliation: Sezione di Medicina Interna e Cardiovascolare, Dipartimento di Medicina Interna, Università di Perugia, Via Enrico Dal Pozzo, 06123 Perugia, Italy. agnellig@unipg.it
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Agnelli
authors.forename: Paolo
authors.initials: P
authors.lastname: Prandoni
authors.forename: Cecilia
authors.initials: C
authors.lastname: Becattini
authors.forename: Mauro
authors.initials: M
authors.lastname: Silingardi
authors.forename: Maria Rita
authors.initials: MR
authors.lastname: Taliani
authors.forename: Maddalena
authors.initials: M
authors.lastname: Miccio
authors.forename: Davide
authors.initials: D
authors.lastname: Imberti
authors.forename: Renzo
authors.initials: R
authors.lastname: Poggio
authors.forename: Walter
authors.initials: W
authors.lastname: Ageno
authors.forename: Enrico
authors.initials: E
authors.lastname: Pogliani
authors.forename: Fernando
authors.initials: F
authors.lastname: Porro
authors.forename: Pietro
authors.initials: P
authors.lastname: Zonzin
mesh_terms: D000074:Acenocoumarol / Q000008:administration & dosage / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D004334:Drug Administration Schedule; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000188:drug therapy* / Q000517:prevention & control; D012307:Risk Factors; D055502:Secondary Prevention; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects; D028761:Withholding Treatment
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D000074:Acenocoumarol