Best Clinical Practice: Current Controversies in Pulmonary Embolism Imaging and Treatment of Subsegmental Thromboembolic Disease

Background: Pulmonary embolism (PE) affects >600,000 patients per year in the United States. Evaluation includes clinical decision rules, laboratory tests, and several imaging modalities. The diagnosis of PE has risen in recent years, particularly subsegmental PE (SSPE). Controversy exists concerning the diagnosis and treatment of these lesions. Objective: We sought to provide emergency physicians with a review of the controversies surrounding PE testing and the diagnosis and treatment of SSPE. Discussion: With the rise of computed tomography (CT) testing for PE, diagnosis has increased. Providers often omit risk stratification in favor of D-dimer or imaging, which does not have literature support. The detection of PE has risen by 80%, and this increased testing is associated with several risks, including contrast reaction, nephropathy, and increased radiation. SSPE diagnosis has risen with improved imaging technology, but the literature shows low interobserver agreement with diagnosis of true SSPE. Studies disagree on the clinical significance and dangers of this PE subset. The American College of Chest Physicians 2016 guidelines recommend withholding anticoagulation for SSPE with low risk for recurrent thrombus and no concurrent deep vein thrombosis. Patients at high risk for recurrent venous thromboembolism or with deep vein thrombosis warrant anticoagulation. The provider is ultimately responsible for appropriate evaluation with risk stratification and selective testing. Conclusions: SSPE presents a quandary, because the literature differs in showing harm despite increased diagnosis. American College of Chest Physicians guidelines for the treatment of SSPE take into account the patient, the imaging, and other imaging modalities. Providers should use risk stratification with shared decision-making in the evaluation and treatment of SSPE.