title: Early anticoagulation is associated with reduced mortality for acute pulmonary embolism.
abstract: BACKGROUND
  Acute pulmonary embolism (PE) may be rapidly fatal if not diagnosed and treated. IV heparin reduces mortality and recurrence of PE, but the relationship between survival and timing of anticoagulation has not been extensively studied.
  
  
  METHODS
  We studied 400 consecutive patients in the ED diagnosed with acute PE by CT scan angiography and treated in the hospital with IV unfractionated heparin from 2002 to 2005. Patients received heparin either in the ED or after admission. Time from ED arrival to therapeutic activated partial thromboplastin time (aPTT) was calculated. Outcomes included in-hospital and 30-day mortality, hospital and ICU lengths of stay, hemorrhagic events on heparin, and recurrent venous thromboembolism within 90 days.
  
  
  RESULTS
  In-hospital and 30-day mortality rates were 3.0% and 7.7%, respectively. Patients who received heparin in the ED had lower in-hospital (1.4% vs 6.7%; P = .009) and 30-day (4.4% vs 15.3%; P < .001) mortality rates as compared with patients given heparin after admission. Patients who achieved a therapeutic aPTT within 24 h had lower in-hospital (1.5% vs 5.6%; P = .093) and 30-day (5.6% vs 14.8%; P = .037) mortality rates as compared with patients who achieved a therapeutic aPTT after 24 h. In multiple logistic regression models, receiving heparin in the ED remained predictive of reduced mortality, and ICU admission remained predictive of increased mortality.
  
  
  CONCLUSIONS
  We report an association between early anticoagulation and reduced mortality for patients with acute PE. We advocate further study with regard to comorbidities to assess the usefulness of modifications to hospital protocols.
authors.affiliation: Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA. tmorgenthaler@mayo.edu
authors.forename: Sean B
authors.initials: SB
authors.lastname: Smith
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Geske
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Maguire
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Zane
authors.forename: Rickey E
authors.initials: RE
authors.lastname: Carter
authors.forename: Timothy I
authors.initials: TI
authors.lastname: Morgenthaler
mesh_terms: D000208:Acute Disease; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D016009:Chi-Square Distribution; D004636:Emergency Service, Hospital; D005260:Female; D006493:Heparin / Q000008:administration & dosage*; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D010314:Partial Thromboplastin Time; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000401:mortality*; D012008:Recurrence; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D006493:Heparin