Pulmonary embolism severity classes and risk-stratified treatment

What it is

PE is classified by severity, and the class decides the treatment. High risk PE, also called massive PE, is any of the signs of hemodynamic instability:

• Cardiac arrest, with the need for cardiopulmonary resuscitation.
• Obstructive shock: a systolic BP below 90 mmHg, or vasopressors required to achieve a BP of 90 mmHg or more despite adequate filling status, together with end-organ hypoperfusion (altered mental status; cold, clammy skin; oliguria or anuria; increased serum lactate).
• Persistent hypotension: a systolic BP below 90 mmHg, or a systolic BP drop of 40 mmHg or more lasting longer than 15 min and not caused by new-onset arrhythmia, hypovolaemia or sepsis.

When there is no hemodynamic instability the class is intermediate, also called submassive, or low risk. It is set by three things: the clinical sPESI, RV imaging by CTPA or ECHO, and troponin as the sign of myocardial injury. Intermediate high risk is an sPESI of 1 or more with both RV imaging and troponin positive. Intermediate low risk is an sPESI of 1 or more with one or none of the two positive. Low risk is an sPESI of 0 with both negative.