A comparison of low-dose heparin with low-molecular-weight heparin as prophylaxis against venous thromboembolism after major trauma

N Engl J Med. 1996 Sep 5;335(10):701-7. doi: 10.1056/NEJM199609053351003.


Background: Patients who have had major trauma are at very high risk for venous thromboembolism if they do not receive thromboprophylaxis. We compared low-dose heparin and a low-molecular-weight heparin with regard to efficacy and safety in a randomized clinical trial in patients with trauma.

Methods: Consecutive adult patients admitted to a trauma center who had Injury Severity Scores of at least 9 and no intracranial bleeding were randomly assigned to heparin (5000 units) or enoxaprin (30 mg), each given subcutaneously every 12 hours in a double-blind manner, beginning within 36 hours after the injury. The primary outcome was deep-vein thrombosis as assessed by contrast venography performed on or before day 14 after randomization.

Results: Among 344 randomized patients, 136 who received low-dose heparin and 129 who received enoxaparin had venograms adequate for analysis. Sixty patients given heparin (44 percent) and 40 patients given enoxaparin (31 percent) had deep-vein thrombosis (P=0.014). The rates of proximal-vein thrombosis were 15 percent and 6 percent, respectively (P=0.012). The reductions in risk with enoxaparin as compared with heparin were 30 percent (95 percent confidence interval, 4 to 50 percent) for all deep-vein thrombosis and 58 percent (95 percent confidence interval, 12 to 87 percent) for proximal-vein thrombosis. Only six patients (1.7 percent) had major bleeding (one in the heparin group and five in the enoxaparin group, P=0.12).

Conclusions: Low-molecular-weight heparin was more effective than low-dose heparin in preventing venous thromboembolism after major trauma. Both interventions were safe.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anticoagulants / administration & dosage
  • Anticoagulants / therapeutic use*
  • Double-Blind Method
  • Female
  • Hemorrhage / chemically induced
  • Heparin / administration & dosage*
  • Heparin, Low-Molecular-Weight / therapeutic use*
  • Humans
  • Male
  • Phlebography
  • Pulmonary Embolism / etiology
  • Pulmonary Embolism / prevention & control
  • Risk
  • Thromboembolism / prevention & control*
  • Thrombophlebitis / diagnostic imaging
  • Thrombophlebitis / etiology
  • Thrombophlebitis / prevention & control
  • Treatment Outcome
  • Wounds and Injuries / complications


  • Anticoagulants
  • Heparin, Low-Molecular-Weight
  • Heparin