Acute and Chronic Pulmonary Emboli.

Under most circumstances, the goal of treatment of pulmonary embolism is the prevention of recurrent embolic events, achieved through conventional anticoagulant therapy with unfractionated heparin or a low molecular weight heparin, followed by warfarin therapy for a minimum of 6 months. When acute pulmonary embolism is associated with significant right ventricular dysfunction or systemic hypotension, more aggressive intervention may be warranted. Under these circumstances, potential interventions include thrombolytic therapy (either systemic or catheter-directed), placement of an inferior vena caval filter, catheter-based embolectomy, or surgical embolectomy. Chronic thromboembolic pulmonary hypertension may develop in a small minority of patients who survive an acute, massive embolic event or who have suffered recurrent thromboembolic events. Due to the fixed nature of the pulmonary vascular obstruction, vasodilator therapy has proven far less effective in chronic thromboembolic disease than it has in primary pulmonary hypertension and other secondary forms of pulmonary hypertension. Correction of hypoxemia and volume overload and the prevention of recurrent embolic events are essential. Definitive therapy, however, requires surgical intervention to remove the chronic thromboembolic obstruction and to restore patency of the pulmonary vascular bed.