Low-dose heparin and deep-vein thrombosis after total hip replacement

The effect of subcutaneous low-dose heparin on postoperative deep-vein thrombosis (D.V.T.) (diagnosed by the 125I-labelled fibrinogen test) has been investigated in a trial of 143 patients undergoing the operation of total hip replacement. Two randomized studies were carried out: in one the scanning for D.V.T. was carried out daily for 7 days postoperatively andin the other for 15 days. In both, the incidence of D.V.T. was significantly lower in the heparin-treated patients (P less than 0.005). Bilateral D.V.T. was also prevented (P less than 0.05), through the extension of D.V.T. to the distal veins of the thigh was not significantly reduced. Heparin treatment was, however, followed by a higher incidence of severe postoperative bleeding (P less than 0.02) and wound haematoma formation (P less than 0.005), and the postoperative haemoglobin was significantly lower than in the control group (P less than 0.005). A higher number of transfused blood units was also needed by the heparin treated patients (P less than 0.001).