The PREVENT CLOT trial is a pragmatic, multicenter RCT of 12,211 patients testing whether aspirin is noninferior to enoxaparin for thromboprophylaxis after orthopedic trauma. It enrolled patients with operatively managed extremity fractures or any pelvic/acetabular fracture at 21 North American trauma centers. The primary outcome was all-cause mortality at 90 days.
For decades, enoxaparin was the default thromboprophylaxis after fracture surgery, backed by guidelines despite limited head-to-head RCT data against aspirin in trauma patients. The PREVENT CLOT trial closes that evidence gap with 12,211 patients: aspirin is noninferior to enoxaparin for preventing death, and PE rates were identical at 1.49% in both groups.
When counseling a patient with an operatively fixed tibia fracture or acetabular fracture, you can now offer aspirin 81 mg twice daily as a supported alternative to enoxaparin injections. Reserve enoxaparin for patients with elevated VTE risk (prior VTE, malignancy, hypercoagulable state) — those patients were excluded from this trial and its conclusions do not apply to them.
The one nuance worth knowing: enoxaparin still prevents more DVTs, but the difference is less than 1 percentage point in absolute terms and is largely confined to distal calf clots. That small DVT benefit does not translate to a mortality or PE advantage, which is what patients actually care about.
The PREVENT CLOT trial is a pragmatic, multicenter RCT of 12,211 patients testing whether aspirin is noninferior to enoxaparin for thromboprophylaxis after orthopedic trauma. It enrolled patients with operatively managed extremity fractures or any pelvic/acetabular fracture at 21 North American trauma centers. The primary outcome was all-cause mortality at 90 days.
For decades, enoxaparin was the default thromboprophylaxis after fracture surgery, backed by guidelines despite limited head-to-head RCT data against aspirin in trauma patients. The PREVENT CLOT trial closes that evidence gap with 12,211 patients: aspirin is noninferior to enoxaparin for preventing death, and PE rates were identical at 1.49% in both groups.
When counseling a patient with an operatively fixed tibia fracture or acetabular fracture, you can now offer aspirin 81 mg twice daily as a supported alternative to enoxaparin injections. Reserve enoxaparin for patients with elevated VTE risk (prior VTE, malignancy, hypercoagulable state) — those patients were excluded from this trial and its conclusions do not apply to them.
The one nuance worth knowing: enoxaparin still prevents more DVTs, but the difference is less than 1 percentage point in absolute terms and is largely confined to distal calf clots. That small DVT benefit does not translate to a mortality or PE advantage, which is what patients actually care about.