Aspirin is acceptable thromboprophylaxis agent in trauma patients

TAMPA, Fla. — Aspirin as a thromboprophylaxis agent was noninferior to low-molecular-weight heparin for all-cause mortality in patients with extremity, pelvic or acetabular fractures.

“Venous thromboembolism (VTE) is a well-recognized, potentially fatal complication after orthopedic trauma. Current guidelines recommend low-molecular-weight heparin (LMWH) for VTE prophylaxis,” Robert V. O’Toole, MD, FAAOS, said. “However, arthroplasty literature suggests aspirin may be equally effective as LMWH for VTE prevention. Patients strongly prefer aspirin because of its pill form and because of its cost — if it has acceptable performance regarding the prevention of death.”

From 2017 to 2021, O’Toole and colleagues in the Major Extremity Trauma Research Consortium randomly assigned 6,110 patients (mean age of 44.7 years) to receive twice-daily administration of LMWH (30 mg enoxaparin) and 6,101 patients (mean age of 44.5 years) to receive twice-daily administration of 81 mg aspirin.

Patients were recruited from 21 U.S. and Canadian academic trauma centers. Inclusion criteria were patients needed a plan for prophylaxis after operative metatarsal and carpal fractures or after operative or nonoperative treatment of pelvis and acetabulum fractures.

Outcome measures included 90-day all-cause mortality and infection rates, pulmonary embolism (PE) and deep vein thrombosis (DVT) rates. Outcomes were assessed with treatment-specific Kaplan-Meier analysis and cumulative incidence function estimators with an intention-to-treat approach. Final follow-up was in January 2022.

At 90 days, all-cause mortality was 0.78% (n = 47) in the aspirin cohort and 0.73% (n = 45) in the LMWH cohort. Death from PE was 0.07% (n = 4) in the aspirin cohort and 0.08% (n= 5) in the LMWH cohort. Overall PE rates were 1.49% (n = 90) in both cohorts.

DVT rates were 2.51% (n = 151) in the aspirin cohort and 1.71% (n = 103) in the LMWH cohort. O’Toole said the disparity in DVT rates was due to a slight difference in distal DVT in the LMWH cohort (1.5%) vs. the aspirin cohort (0.9%). No differences were seen in bleeding complications, wound complications or infection.

“This randomized controlled trial of over 12,000 patients demonstrated that aspirin was noninferior to LMWH for the outcome that is most important to patients: all-cause mortality,” O’Toole told Healio/Orthopedics Today. “There was no significant difference for all other outcomes except DVT, which was driven by a difference in distal blood clots that are of questionable clinical importance.”

“This study was designed from a hospital policy perspective, so we believe providers should consider these data when enacting guidelines for VTE prophylaxis for orthopedic trauma patients,” O’Toole said. – by Max R. Wursta

• Reference:
• O’Toole RV, et al. Paper 83. Presented at: Orthopaedic Trauma Association Annual Meeting; Oct. 12-15, 2022; Tampa, Fla.

• For more information:
• Robert V. O’Toole, MD, FAAOS, can be reached at University of Maryland Medical System, 22 S. Greene St., R. Adams Cowley Shock Trauma Center, Baltimore, MD 21201; email: [email protected].