Reviews

Do patients with submassive pulmonary embolism benefit from thrombolytic therapy?
The risk of hemorrhage is significant, and the benefit is unclear. A one-treatment-for-all approach cannot be applied.
Rama Hritani, MD
Department of Internal Medicine, Medstar Washington Hospital Center, Washington, DC
Abdulah Alrifai, MD
Cardiology Department, University of Miami School of Medicine/JFK Medical Center, Atlantis, FL
Mohamad Soud, MD
Department of Internal Medicine, Medstar Washington Hospital Center, Washington, DC
Homam Moussa Pacha, MD
Department of Internal Medicine, Medstar Washington Hospital Center, Washington, DC
M. Chadi Alraies, MD
Interventional Cardiology, Detroit Heart Hospital, Detroit Medical Center, Wayne State University, Detroit, MI
Address: M. Chadi Alraies, MD, Interventional Cardiology, DMC Heart Hospital, 311 Mack Avenue, Detroit, MI 48201; alraies@hotmail.com
Most patients admitted with pulmonary embolism (PE) do not need transthoracic echocardiography (TTE); it should be performed in hemodynamically unstable patients, as well as in hemodynamically stable patients with specific elevated cardiac biomarkers and imaging features.
The decision to perform TTE should be based on clinical presentation, PE burden, and imaging findings (eg, computed tomographic angiography). TTE helps to stratify risk, guide management, monitor response to therapy, and give prognostic information for a subset of patients at increased risk for PE-related adverse events.
PE has a spectrum of presentations ranging from no symptoms to shock. Based on the clinical presentation, PE can be categorized as high, intermediate, or low risk.
High-risk PE, often referred to as “massive” PE, is defined in current American Heart Association guidelines as acute PE with sustained hypotension (systolic blood pressure < 90 mm Hg for at least 15 minutes or requiring inotropic support), persistent profound bradycardia (heart rate < 40 beats per minute with signs or symptoms of shock), syncope, or cardiac arrest.1
Intermediate-risk or “submassive” PE is more challenging to identify because patients are more hemodynamically stable, yet have evidence on electrocardiography, TTE, computed tomography, or cardiac biomarker testing—ie, N-terminal pro-B-type natriuretic peptide (NT-proBNP) or troponin—that indicates myocardial injury or volume overload.1
Low-risk PE is acute PE in the absence of clinical markers of adverse prognosis that define massive or submassive PE.1
Scoring systems to evaluate PE severity include the PE severity index (PESI)2,3 and the Bova grading system.4 The PESI predicts adverse outcomes in acute PE independent of cardiac biomarkers, with risk categorized from lowest to highest as class I to class V (Table 1).4 The Bova score predicts the 30-day risk of PE-related complications in hemodynamically stable patients (Table 2). Points are assigned for each variable, for a maximum of 7. From 0 to 2 points is stage I, 3 to 4 points is stage II, and more than 4 points is stage III. The score is based on 4 variables: heart rate, systolic blood pressure, cardiac troponin level, and a marker of right ventricular dysfunction. The higher the stage, the higher the 30-day risk of PE-related complications.5Certain TTE findings suggest increased risk of a poor outcome and may warrant therapy that is more invasive and aggressive. High-risk features include the following:
These TTE findings often lead to treatment with thrombolysis, transfer to the intensive care unit, and activation of the interventional team for catheter-based therapies.1,8 Free-floating right heart thrombi or thrombus straddling the interatrial septum (“thrombus in transit”) through a patent foramen ovale may require surgical embolectomy.8
The risk of hemorrhage is significant, and the benefit is unclear. A one-treatment-for-all approach cannot be applied.
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