Dextran and postoperative thromboembolism

Two preparations of dextran have been tried for prevention of venous thromboembolic disease, dextran-40 (average m. w. 40,000) and dextran-70 (average m.w. 70,000). Dextrans reduce platelet aggregation and lower blood viscosity.1 Dextran may also reduce the peri-operative rise in the coagulation factors V and VIII.2 However, in some tests dextrans increase platelet aggregation3 and accelerate fibrin formation,4 so that only clinical trial can show whether dextran reduces the incidence of either deep-vein thrombosis or of pulmonary embolism.