Prevention of deep vein thrombosis with low molecular-weight heparin in patients undergoing total hip replacement. A randomized trial. The German Hip Arthroplasty Trial (GHAT) Group.

In a double-blind, randomized multicentre trial, the efficacy and safety of two regimens for the prevention of postoperative venous thrombo-embolism, low-molecular-weight heparin (LMWH) CY 216 and unfractionated heparin (UH), were compared in 341 patients undergoing elective total hip replacement. A group of 169 patients received one subcutaneous injection of 48 mg (approximately 10,000 anti-Xa IC units) LMWH and two placebo injections per day and 172 patients received a fixed dose of 5000 IU UH t.i.d. Deep vein thrombosis was assessed by bilateral phlebography on day 14 +/- 1 after surgery. Phlebography was successfully performed in 136 patients in the LMWH group and 137 patients in the UH group. Deep vein thrombosis occurred in 45 of 137 patients (33.1%) treated with LMWH CY 216 and in 47 of 136 patients (34.3%) who received UH. Pulmonary embolism occurred in 2 of 167 evaluable patients (1.2%) in the LMWH group and in 6 of 168 patients (3.6%) in the UH group. In addition, the incidence of proximal deep vein thrombosis was evaluated and was found to be 10.3% (14/137 patients) in the LMWH group and 19% (26/136 patients) in the UH group (P = 0.044, two-sided). The safety of the treatments, as assessed by the incidence of major haemorrhage, intra- and postoperative blood loss, transfusion requirements, haemoglobin drop and frequency of wound haematomata, was similar in the two groups. It is concluded that prophylaxis of postoperative thrombo-embolism in hip surgery with one subcutaneous injection (48 mg) of LMWH CY 216 is as effective and as safe as prevention with fixed low-dose heparin (5000 IU t.i.d.). A tendency to reduced rates of pulmonary embolism (3.6% vs. 1.2%) and proximal deep vein thrombosis (19% vs. 10.3%) was observed in favour of LMWH CY 216.