Resolution of pulmonary embolism.

To assess restoration of pulmonary perfusion after pulmonary embolism serial lung scans were carried out on 74 patients. Of these, one-third showed almost complete recovery, one-third improved, and the remainder either failed to improve or became worse. Perfusion was most rapidly restored in the first few days after the embolus and more slowly during the next two to three weeks.Untreated patients improved less often and had more new defects in perfusion than patients treated with anticoagulant therapy, no difference occurring in either the amount of improvement or in the rate of recovery of perfusion between patients treated with different anticoagulant regimens. There was evidence of further pulmonary emboli in 35% of treated patients, 82% of these occurring within two weeks of the initial embolus. Patients with defects in perfusion greater than 30% showed considerable improvement but recovered less well than those with smaller defects.