Prevention of recurrent pulmonary embolism.

Fifty patients have been studied by bilateral phlebography following their first, or sometimes recurrent, pulmonary embolus. Nineteen were found to have fresh loose peripheral thrombus, and in eight of them the thrombus looked big enough to cause a major pulmonary artery obstruction and death. These 19 patients were treated by vein ligation in addition to anticoagulants.The incidence of recurrent embolism in the trial group is significantly lower than that found in a retrospective study of 50 patients treated with anticoagulants only. It is suggested that anticoagulants will not prevent all recurrent pulmonary emboli, and that phlebography, and if necessary surgery, should be part of the routine investigation and treatment of all patients after their first pulmonary embolus.