Pulmonary Embolism - Emergency Management

Definition: Pulmonary embolism (PE) is a type of venous thromboembolic event which occludes the pulmonary vasculature to varying degrees depending on the amount of clot burden. As a result of the varying degrees of occlusion, PE is divided into three major categories based on hemodynamic stability and right heart strain. Categorization helps to stratify prognosis and guide treatment.

Treatment options:

Systemic thrombolysis:

• tPA (most commonly used; dose 100 mg over 2 hrs IV), urokinase or streptokinase
•  Indicated for massive pulmonary embolism; can be used in submissive (potentially at half dose) if clinical evidence of adverse prognosis (i.e. new hemodynamic instability, worsening respiratory insufficiency, severe RV dysfunction or major myocardial necrosis) and low risk of bleeding complications
• Adverse effect - risk of hemorrhage

Catheter-based intra-arterial thrombolytic infusion/mechanical clot disruption:

• Commonly called “EKOS” (trade name)
• Indicated for submissive PE and massive PE (if systemic thrombolysis contraindicated)
• Performed in cath lab; thrombolytic agent is introduced through the catheter directly into the clot

Surgical embolectomy:

• Indicated (if thrombolytics are contraindicated) for massive PE or submassive PE with severe RV dysfunction
• Typically considered second line to thrombolytics and catheter directed therapy due to invasiveness of procedure and mortality rate (review paper by Stein et al (2007) discussed a 20-30% mortality, although more recent study by Leacche et al (2005) with 47 patients had a 96% survival rate)

Anti-coagulation:

• All patients with strongly suspected or confirmed PE regardless of severity should be immediately started on anticoagulation (typically heparin infusion with bolus)
• Patients with non-massive PE and no contraindications should be started on anticoagulation as definitive treatment and are typically admitted or observed for monitoring and to transition to subcutaneous or oral anticoagulants (Coumadin or a DOAC)

Sources:

Handal-Orefice, RC and Moroz, LA. Pulmonary embolism management in the critical care setting. Semin Perinatol. 2019; 43(4):205-212.

Jaff, MR et al. Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association. Circulation: Journal of the American Heart Association. 2011; 123(16):1788-1830

Leacche M et al. Modern surgical treatment of massive pulmonary embolism: results in 47 consecutive patients after rapid diagnosis and aggressive surgical approach. J Thorac Cardiovasc Surg . 2005;129:1018–1023.

Stein PD et al. Outcome of pulmonary embolectomy. Am J Cardiol . 2007;99:421–423.