Background: The clinical relevance of emboli limited to the segmental or sub-segmental pulmonary arteries and the role of anticoagulation in patients with these conditions remains to be clarified. Objectives: To determine the clinical characteristics and treatment outcomes of peripheral pulmonary embolism (PE), and in particular, isolated sub-segmental PE (ISSPE). Methods: We reviewed the data for 334 patients who were diagnosed with a PE by computed tomographic (CT) pulmonary angiography and indirect CT venography. Results: All patients were classified into one of three groups: central (245 patients, 73.4%); segmental (67 patients, 20.1%), and sub-segmental (22 patients, 6.6%). An incidental CT finding (63.6%) was the most common presentation in the segmental and sub-segmental groups. Compared with the central group, the sub-segmental group had less frequent proximal deep venous thrombosis (14 vs. 47%, Bonferroni’s corrected p = 0.002), and greater preservation of oxygenation levels (p < 0.05) without hemodynamic instability. The recurrence of PE and deaths related to PE did not occur in the sub-segmental group, although approximately 30% of the patients did not receive anticoagulation therapy. Conclusions: Patients with ISSPE may have a more benign clinical presentation, as compared to the central type, and may follow a good clinical course without mortality or recurrence.

Keywords:
Computed tomography, Pulmonary arteries, Pulmonary embolism, Treatment
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2010
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