title: Risk factors for clinically relevant pulmonary embolism and deep venous thrombosis in patients undergoing primary hip or knee arthroplasty.
abstract: BACKGROUND
  Prevention of thromboembolic complications after elective lower extremity arthroplasty has increasingly relied on routine thromboprophylaxis in all patients. Not all patients are at equal risk, however, and prophylaxis is not devoid of complications. The aim of this study was to examine the risk factors for clinically relevant pulmonary embolism and deep venous thrombosis after elective primary hip or knee arthroplasty in a large patient population.
  
  
  METHODS
  During the 10-yr study period, 116 of 9,791 patients undergoing primary hip or knee arthroplasty at the authors' institution who experienced pulmonary embolism or deep venous thrombosis within 30 days of surgery were matched at a 1:1 ratio with patients undergoing the same surgery with the same surgeon who did not experience an adverse event. Medical records were reviewed, with data abstracted using a standardized data collection form.
  
  
  RESULTS
  Increased body mass index (P = 0.031; odds ratio = 1.5 for each 5-kg/m2 increase) and American Society of Anesthesiologists physical status classification of 3 or greater (P = 0.005; odds ratio = 2.6) were found to independently increase the likelihood of pulmonary embolism or deep venous thrombosis. In addition, use of antithrombotic prophylaxis was found to decrease the likelihood of these thromboembolic events (P = 0.050; odds ratio = 0.2 for aspirin or subcutaneous heparin, and odds ratio = 0.4 for warfarin or low-molecular-weight heparin).
  
  
  CONCLUSIONS
  In patients undergoing primary elective lower extremity arthroplasty, obesity, poor American Society of Anesthesiologists physical status classification, and lack of thromboprophylaxis are independent risk factors for clinically relevant thromboembolic events.
authors.affiliation: Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA. mantilla.carlos@mayo.edu
authors.forename: Carlos B
authors.initials: CB
authors.lastname: Mantilla
authors.forename: Terese T
authors.initials: TT
authors.lastname: Horlocker
authors.forename: Darrell R
authors.initials: DR
authors.lastname: Schroeder
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Berry
authors.forename: David L
authors.initials: DL
authors.lastname: Brown
mesh_terms: D000368:Aged; D000758:Anesthesia; D000925:Anticoagulants / Q000627:therapeutic use; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D001241:Aspirin / Q000627:therapeutic use; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011655:Pulmonary Embolism / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D012307:Risk Factors; D020246:Venous Thrombosis / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control
chemical_list: D000925:Anticoagulants; D005343:Fibrinolytic Agents; D006493:Heparin; D001241:Aspirin