Deep venous thrombosis and postsplenectomy thrombocytosis.

Eighty-six patients undergoing elective splenectomy have been investigated preoperatively and postoperatively by serial platelet counts and leg scanning using iodine 125-labeled fibrinogen. The presence of deep leg vein thromboses detected by labeled fibrinogen was confirmed by dye phlebography. In only five patients (6%) did deep venous thrombosis develop. In none of these five patients did an elevation in platelet count to 600,000/cu mm develop before or at the time of development of the thrombosis. None of 21 other patients who did have a rise in platelet count greater than 1,000,000/cu mm had evidenced of venous thrombosis. These data do not substantiate the need for routine prophylactic antithrombotic therapy in patients in whom postsplenectomy thrombocytosis develops.