Subcutaneous ancrod in prevention of deep-vein thrombosis after operation for fractured neck of femur.

In a randomised double-blind controlled trial 53 patients received 5 daily subcutaneous injections of ancrod ('Arvin') after operation for fractured neck of femur, and 52 patients received saline fractured neck of femur, and 52 patients received saline injections. Deep-vein thrombosis (D.V.T.) was detected by bilateral ascending venography or necropsy 6--16 days after surgery. The frequency of D.V.T. and bilateral D.V.T. was significantly lower in the ancrod group (P less than 0.01). The frequency of major D.V.T. (thrombi in veins proximal to the calf, or calf-vein thrombi more than 3 cm long) was also significantly lower in the ancrod group (P less than 0.001). No complications of ancrod prophylaxis occurred. Ancrod reduced plasma-fibrinogen, and hence plasma and blood viscosity, during the first week after surgery; preoperative levels of fibrinogen and viscosity were not associated with post-operative D.V.T. Subcutaneous ancrod is a simple and effective alternative to oral anticoagulants for the reduction of the frequency of D.V.T. after operation for hip fracture, and merits assessment in other high-risk groups of patients.