Chronic persistent pulmonary embolism. Report of three cases

Nonresolution of acute pulmonary embolism and resultant chronic persistent pulmonary occlusion is uncommon; documentation of its occurrence in patients receiving anticoagulants is sparse. We report three cases with hemodynamic data and follow-up of up to seven years. All patients had mild to moderate dyspnea on exertion. All patients had normal resting pulmonary artery pressures; two patients demonstrated pulmonary hypertension with exercise. One patient underwent successful thromboendarterectomy but had subsequent reocclusion secondary to in situ thrombosis. With all patients receiving long-term anticoagulant therapy, there was no clinical recurrence of embolization or progression of symptoms. Patients with chronic persistent pulmonary embolism should be identified and should receive long-term follow-up. Therapy aimed at prevention of recurrent embolization is required. Pulmonary thromboendarterectomy is indicated for selected patients.