Clinical outcomes in patients with isolated subsegmental pulmonary emboli diagnosed by multidetector CT pulmonary angiography

Abstract

Introduction: CT Pulmonary Angiography has been shown to be equivalent to Ventilation/ Perfusion scanning in 3-month outcome studies, but it detects more pulmonary emboli. Isolated subsegmental pulmonary emboli are thought to account for some of the increase in diagnosis, but it is not known whether these emboli represent a harbinger for future thromboembolic events. The objective of this study was to determine the 3-month clinical outcomes of a cohort of patients diagnosed with isolated subsegmental pulmonary emboli.

Materials and methods: Review of 10,453 consecutive CTPA radiology reports over 74-month period since the implementation of Multidetector CT Pulmonary Angiography identified a cohort of 93 patients found to have acute pulmonary embolism isolated to subsegmental pulmonary arteries without other evidence of deep venous thrombosis at one institution. The study measured 3-month clinical outcomes (anticoagulation use, recurrence, death, hemorrhage) determined by review of records and telephone interviews with physicians.

Results: Seventy-one patients (76%) were treated with anticoagulation and/or IVC filter, while 22 (24%) were observed without therapy. One patient (1/93, 1.05%; 95% CI: 0-6.6%) who was treated with anticoagulants and a vena caval filter had a recurrent subsegmental pulmonary embolus. No patients died of pulmonary embolism. There were 8 hemorrhages, including 5 (5.3%) major hemorrhages without any hemorrhage-related mortality.

Conclusions: Patients diagnosed with isolated subsegmental pulmonary emboli have favorable 3-month outcomes. Short-term prognosis for recurrent thromboembolism may be lower than the risk of adverse events with anticoagulation in patients at high risk of hemorrhage.