Factors influencing the restoration of blood flow following pulmonary embolization as determined by angiography and scanning.

Twenty-five patients with proven pulmonary emboli were followed for at least 20 weeks with serial scans and, in select cases, angiograms to determine the factors influencing the rate of resolution. Fifteen patients showed complete resolution at some time during the observation period. Five of these 15 patients experienced recurrent embolic episodes either before or after complete resolution. The remaining 10 patients included two who died of recurrent massive emboli, three who had recurrent episodes resulting in incomplete resolution, two who showed incomplete resolution at 20 weeks without recurrent emboli, and three who were lost to follow-up. Twenty-one patients exhibited prompt resolution in single or multiple embolic episodes, and four experienced slow resolution. Recurrent embolization is the most significant event in preventing restoration of blood flow. This is most likely to occur in the patient who presents with (1) an initial field defect in excess of 35%, (2) associated heart disease, and (3) peripheral thrombophlebitis and pulmonary embol without other disease. These factors identified the patients susceptible to recurrent embolization in this study.