What are the criteria for distinguishing between massive Pulmonary Embolism (PE) and submassive Pulmonary Embolism (PE)?

From the Guidelines

Pulmonary embolism (PE) severity is classified as massive, submassive, or low-risk based on hemodynamic stability and evidence of right heart dysfunction, with massive PE characterized by sustained hypotension (systolic blood pressure <90 mmHg for at least 15 minutes or requiring vasopressor support) and submassive PE presenting with normal blood pressure but evidence of right ventricular dysfunction (1).

Classification of PE

The classification of PE into massive, submassive, and low-risk categories is crucial for management decisions, as each category has distinct treatment approaches and outcomes.

• Massive PE is defined by the presence of sustained hypotension, pulselessness, or persistent profound bradycardia, indicating obstructive shock and requiring immediate aggressive intervention (1).
• Submassive PE, also known as intermediate-risk PE, presents with normal blood pressure but evidence of right ventricular dysfunction, such as RV dilation or hypokinesis on echocardiography, elevated BNP >100 pg/mL, elevated troponin, or CT evidence of RV enlargement with RV/LV ratio >0.9 (1).

Management of Massive and Submassive PE

The management of massive and submassive PE differs significantly, with massive PE requiring immediate reperfusion therapy, such as thrombolytic therapy with alteplase 100 mg IV over 2 hours or surgical thrombectomy, and submassive PE typically receiving anticoagulation with consideration of rescue thrombolytics if they deteriorate (1).

• The distinction between massive and submassive PE is critical, as massive PE carries a mortality rate of 25-65% and requires immediate reperfusion therapy, while submassive PE has a mortality rate of 3-15% and is generally managed with anticoagulation and close monitoring (1).

Importance of Early Diagnosis and Treatment

Early diagnosis and treatment of PE are essential to improve outcomes, as delayed treatment can lead to increased morbidity and mortality (1).

• The use of echocardiography, CT angiography, and other diagnostic tools can help identify patients with massive and submassive PE, allowing for prompt initiation of appropriate treatment (1).

From the Research

Massive PE vs Submassive PE Criteria

The distinction between massive and submassive pulmonary embolism (PE) is crucial for determining the appropriate treatment approach.

• Massive PE is typically characterized by the presence of hypotension, whereas submassive PE presents without hypotension but with evidence of right ventricular dysfunction or cardiac strain 2.
• Submassive PE can be identified through risk stratification using echocardiography, computed tomography, and serum biomarker assessment, which may reveal right ventricular dysfunction or elevations in serum troponin or brain-type natriuretic peptide 2.
• The management of submassive PE may involve consideration of therapies beyond systemic anticoagulation, such as systemic intravenous thrombolysis, catheter-directed thrombolysis, and percutaneous or surgical embolectomy, depending on the clinical presentation and risk of adverse outcomes 2, 3.

Diagnostic Criteria

• The diagnosis of massive or submassive PE is based on clinical presentation, imaging findings, and laboratory results 3.
• Imaging modalities such as computed tomography and echocardiography play a crucial role in assessing the severity of PE and guiding treatment decisions 3, 4.
• Laboratory tests, including serum troponin and brain-type natriuretic peptide, can help identify patients with cardiac strain and guide risk stratification 2, 5.

Treatment Approaches

• The treatment of submassive PE may involve catheter-directed thrombolysis, which has been shown to be safe and effective in improving pulmonary hemodynamics and cardiac function 4, 6.
• The use of low-dose thrombolysis, such as ultrasound-assisted, catheter-directed thrombolysis, may reduce the risk of bleeding complications while still providing effective treatment for intermediate-high risk PE patients 6.
• The management of massive PE typically requires more aggressive treatment, including systemic thrombolysis or surgical embolectomy, due to the high risk of mortality associated with this condition 3, 5.