*Prophylaxis for Deep Vein Thrombosis in Trauma: A Prospective RandomizedComparison of Mechanical and Pharmacologic Prophylaxis

Session V - Polytrauma

Fri., 10/10/03 Polytrauma, Paper #25, 10:21 AM

*Prophylaxis for Deep Vein Thrombosis in Trauma: A Prospective Randomized Comparison of Mechanical and Pharmacologic Prophylaxis

James P. Stannard, MD; Robert R. Ben-Lopez, MD; Edward R. Anderson, MD; Matt Busbee, BS; Donna K. Karr, RN; Gerald McGwin, Jr., DO; David A. Volgas, MD; Jorge E. Alonso, MD; University of Alabama at Birmingham, Birmingham, Alabama, USA (a-Aventis)

Purpose: We report on the incidence of deep vein thrombosis (DVT) and pulmonary embolus in patients who sustained blunt trauma and were enrolled in a prospective, randomized, blinded study. A second purpose was to evaluate the occurrence of DVT after discharge in trauma patients who were not ambulatory and were randomly treated with either acetylsalicylic acid or Enoxaparin.

Methods: Of the 224 patients who were initially enrolled, 200 completed the inpatient study, which randomly compared the use of two different regimens of prophylaxis. Group A patients received Enoxaparin (30 mg sq BID) starting 24 to 48 hours after sustaining blunt trauma. Group B patients received foot pumps at admission combined with Enoxaparin on a delayed basis. All patients were screened with Magnetic Resonance Venography (MRV) and ultrasound prior to discharge. The radiologists were blinded regarding the patient prophylaxis group. All patients who did not develop DVT or pulmonary embolism were rerandomized into an outpatient portion of the study if they were not able to bear at least 50% of their body weight on both lower extremities. Patients in group 1 received Enoxaparin (40 mg sq QD) and in group 2 received acetylsalicylic acid (325 mg QD). When they were permitted to begin weight-bearing of 50% or more on both lower extremities, they were reevaluated with ultrasound.

Results: A total of 200 patients completed the inpatient study, with 97 in group A and 103 in group B. Of these, 22 patients developed DVT, with 2 also developing a pulmonary embolism. There were 13 DVTs and 2 pulmonary emboli in group A, compared with nine DVTs and no pulmonary emboli in group B. The incidence of DVT for the whole group was 11.5%, with 14.4% in group A and 8.7% in group B. There was no significant difference in the overall incidence of DVT. There were 11 large or occlusive clots in group A, compared with only 3 in group B. This difference was significant with a P value of 0.025 with analysis by use of Fisher's Exact Test. The incidence of occlusive DVTs was 11.3% in group A compared with only 2.9% in group B. The incidence of pulmonary embolism was 2.1% in group A and 0% in group B. Thirteen patients in group A and 10 patients in group B developed prolonged drainage, with two patients (both in group A) requiring surgical incision and drainage and one developing an infection. Patients who developed DVT during the inpatient portion of this study required a mean of 7.4 units of blood during their hospitalization, compared with 3.9 units of blood for those who did not develop DVT. This difference was significant with a P value of less than 0.05, according to analysis of variance. A total of 128 patients completed the outpatient study, with 65 in group 1 and 63 in group 2. Only one patient developed a DVT and a pulmonary embolus; she was in group 1. The incidence of DVT was 0.8% for the outpatients, with a 1.5% incidence in group 1 and 0% incidence in group 2.

Conclusion/Significance: Deep vein thrombosis remains an important issue in the care of skeletal trauma patients. Anticoagulation may be contraindicated or have to be delayed due to internal bleeding. Dual treatment strategies have been developed that utilize mechanical prophylaxis early and add anticoagulation on a delayed basis. There have been no prospective randomized studies comparing a dual-treatment strategy with standard anticoagulation. Our results indicate that early mechanical prophylaxis with foot pumps and the addition of Enoxaparin on a delayed basis is a very successful strategy. The incidence of large or occlusive clots was only 2.9%, which was significantly better than that for the patients treated with Enoxaparin alone. Outpatient prophylaxis for patients who are not ambulatory is a wise strategy. On the basis of our results, subcutaneous injections with Enoxaparin are not necessary to successfully protect against DVT in the outpatient setting. Aspirin was effective at a much lower cost and with no need for injections.

* If noted, the author indicates something of value received. The codes are identified as a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options and e-consultant or employee.