Very low dose warfarin as prophylaxis against ultrasound detected deep vein thrombosis following primary hip replacement

Abstract

One mg daily warfarin was compared to variable dose warfarin (PT 1.3-1.5 times the normal PT), as prophylaxis against deep vein thrombosis (DVT) following unilateral hip replacement for degenerative joint disease (DJD). Ninety-eight patients entered onto study after having had negative color Doppler ultrasounds of the legs. Patients receiving 1 mg began therapy 7 days preoperatively and continued daily until discharge. Patients receiving the variable dose took 5 mg the night preoperatively, and thereafter daily based upon the daily PT. Seventy-eight patients completed the study protocol. No patient completing the protocol had DVT or pulmonary embolus (PE). Based upon intent to treat for all registered patients, one from each group had DVT after withdrawal from study. For patients receiving 1 mg warfarin daily, PTs extended none or slightly. Therefore, 1 mg warfarin can be used to prevent postoperative DVT following elective hip surgery.