title: Anti-Xa-guided enoxaparin thromboprophylaxis reduces rate of deep venous thromboembolism in high-risk trauma patients.
abstract: Appropriate prophylaxis against venous thromboembolism (VTE) remains undefined. This study evaluated an anti-Xa-guided enoxaparin thromboprophylaxis (TPX) protocol on the incidence of VTE in high-risk trauma patients based on Greenfield's Risk Assessment Profile (RAP) score.
  
  
  
  This is a retrospective observational study of patients admitted to a trauma intensive care unit over a 12-month period. Patients were included if they received anti-Xa-guided enoxaparin TPX. Dosage was adjusted to a prophylactic peak anti-Xa level of 0.2 to 0.4 IU/mL. Subgroup analysis was performed on high-risk patients (RAP score ≥10) who received lower-extremity duplex ultrasound surveillance for deep vein thrombosis (DVT). Data are expressed as mean ± SD. Significance was assessed at p < 0.05.
  
  
  
  One hundred thirty-one patients received anti-Xa-guided enoxaparin TPX. Four patients were excluded for age or acute VTE on admission. Fifty-six patients with RAP score of ≥10 and surveillance duplex evaluations were included in the subgroup analysis with mean age 43 ± 20 years, Injury Severity Score of 25 ± 10, and RAP score of 16 ± 4. Prophylactic anti-Xa levels were initially achieved in 34.6% of patients. An additional 25.2% required 40 to 60 mg twice daily to reach prophylactic levels; 39.4% never reached prophylactic levels. Weight, body mass index, ISS, and RAP score were significantly higher with subprophylactic anti-Xa levels. One patient developed bleeding complications (0.8%). No patient developed intracerebral bleeding or heparin-induced thrombocytopenia.Nine VTE events occurred in the high-risk subgroup, including four DVT (7.1%), all asymptomatic, and five pulmonary emboli (8.9%). The historical rate of DVT in similar patients (ISS 31 ± 12 and RAP score 16 ± 5) was 20.5%, a significant decrease (p = 0.031). Mean chest Abbreviated Injury Scale scores were significantly higher for patients developing pulmonary emboli than DVT, 3.0 ± 1.1 vs. 0.0 (p < 0.001).
  
  
  
  Mean chest Abbreviated Injury Scale score was higher in patients developing pulmonary embolism. Increased weight, body mass index, ISS, and RAP score are associated with subprophylactic anti-Xa levels. Anti-Xa-guided enoxaparin dosing reduced the rate of DVT from 20.5% to 7.1% in high-risk trauma patients.
  
  
  
  Therapeutic study, level IV.
authors.affiliation: From the Dewitt-Daughtry Department of Surgery (G.A.S., C.A.K., T.M.V., H.M.L., E.G., N.M., E.B.L.), Divisions of Trauma and Surgical Critical Care, University of Miami Miller School of Medicine, Miami, Florida; and Department of Pharmacy (G.R.), Jackson Memorial Hospital, Miami, Florida.
authors.forename: George A
authors.initials: GA
authors.lastname: Singer
authors.forename: Gina
authors.initials: G
authors.lastname: Riggi
authors.forename: Charles A
authors.initials: CA
authors.lastname: Karcutskie
authors.forename: Tanaz M
authors.initials: TM
authors.lastname: Vaghaiwalla
authors.forename: Howard M
authors.initials: HM
authors.lastname: Lieberman
authors.forename: Enrique
authors.initials: E
authors.lastname: Ginzburg
authors.forename: Nicholas
authors.initials: N
authors.lastname: Namias
authors.forename: Edward B
authors.initials: EB
authors.lastname: Lineen
mesh_terms: D015998:Abbreviated Injury Scale; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D017984:Enoxaparin / Q000627:therapeutic use*; D015951:Factor Xa; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D054556:Venous Thromboembolism / Q000209:etiology / Q000517:prevention & control*; D020246:Venous Thrombosis / Q000209:etiology / Q000517:prevention & control*; D014947:Wounds and Injuries / Q000150:complications* / Q000628:therapy; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D015951:Factor Xa