Low molecular weight heparin (Alfa LHWH) compared with unfractionated heparin in prevention of deep-vein thrombosis after hip fractures.

Efficacy and safety of a low molecular weight heparin (Alfa LMWH) was compared with unfractionated heparin (UFH) in the prevention of post-operative venous thromboembolism after hip fractures. Forty-nine patients were randomized to treatment with Alfa LMWH 7500 anti-Xa coagulometric units twice daily or with UFH 5000 IU t.i.d. Screening for thrombosis was performed with 125-I-fibrinogen leg scanning and strain-gauge plethysmography. Positive results were confirmed by venography. Five patients in the Alfa LMWH group (20 per cent) developed venographycally proven deep vein thrombosis (DVT) versus seven (29 per cent) in the UFH group. One pulmonary embolism and two deaths occurred in the UFH group and none in the LMWH group. No differences in haemorrhagic complications and blood loss indices were observed. Alfa LMWH appears to be a promising drug for prevention of venous thromboembolism after orthopaedic surgery. A "flexible" schedule of administration is proposed on the basis of the results of plasma anti-Xa assays.