Sub-segmental pulmonary embolism in three academic teaching hospitals: a review of management and outcomes

The availability of computed tomography pulmonary angiography (CTPA) has led to an increase in the diagnosis of sub-segmental pulmonary embolism (SSPE). Current clinical practice guidelines do not make any treatment distinctions for SSPE, though the benefits of anticoagulation for SSPE have not been established.

To review the frequency of pulmonary embolism and sub-segmental pulmonary embolism identified through CTPA as well as their management.

Cross-sectional review of the charts of 2213 patients who underwent CTPA in three Hamilton teaching hospitals from 2009 to 2011. In-depth review of the charts of patients with SSPE was undertaken to determine the frequency with which patients received anticoagulation therapy for SSPE, as well as bleeding complications and recurrent thrombosis.

A total of 2216 CTPAs were reviewed. The frequency of PE was 24.8% (n = 550). The most frequent filling defect was SSPE in 82 patients (3.9% of total scans and 15.0% of identified PEs). In 55 of these 82 SSPEs, an alternative diagnosis to PE was identified on CT to explain the patients' symptoms. Approximately 52.4% (n = 43) received anticoagulation for SSPE. Major life-threatening bleeding complications occurred in two of the 43 who received anticoagulation for SSPE. There was no documented recurrent thrombosis in any patients with SSPE, with or without anticoagulation.

A substantial proportion of patients received anticoagulation for SSPE (52%) and two developed life-threatening bleeding complications. Randomized controlled trial data are needed to further investigate the risks and benefits of anticoagulation in patients with SSPE.