Altered viscosity and yield stress in patients with abdominal malignancy: relationship to deep vein thrombosis.

Twenty-eight patients undergoing laparotomy were studied. Blood viscosity at both high and low rates of shear and a yield stress index were measured preoperatively and correlated with the incidence of post-operative deep vein thrombosis (DVT). There was a correlation between a raised index of yield stress and the incidence of DVT. Patients with cancer had a very high incidence of postoperative DVT and a high index of yield stress.