Subsegmental Pulmonary Embolism and Anticoagulant Therapy: The Impact of Clinical Context.

Abstract

Anticoagulation for subsegmental pulmonary embolism (SSPE) is controversial. We aimed to assess the impact of clinical context on anticoagulation and outcomes of SSPE. We electronically searched computed tomographic pulmonary angiogram reports to identify SSPE. We extracted demographic, risk factor, investigations and outcome data from the electronic medical record. We stratified patients according to anticoagulation/no-anticoagulation. From January 1st 2017 to December 31st 2019, we identified 166 patients with SSPE in 5827 pulmonary angiogram reports. Of these, 123 (74%) received anticoagulation. Compared with non-anticoagulated patients such patients had a different clinical context: higher rates of previous venous thromboembolism (11% vs 0%, p = 0.019), more recent surgery (26% vs 9%, p = 0.015), more elevated serum D-dimer (22% vs 5%, p = 0.004), more lung parenchymal abnormalities (76% vs 61%, p = 0.037) and were almost twice as likely to require inpatient care (76% vs 42%, p < 0.001). Such patients also had twice the all-cause mortality at one year (32% vs 16%). SSPE is diagnosed in almost 3% of pulmonary angiograms and is associated with high mortality, regardless of anticoagulation, due to coexistent disease processes rather than SSPE. Anticoagulation appears dominant but markedly affected by the clinical context of risk factors, alternative indications, and illness severity. Thus, the controversy is partly artificial because anticoagulation after SSPE is clinically contextual with SSPE as only one of several factors. This article is protected by copyright. All rights reserved.