Table 1:

Classification of pulmonary embolism according to European Society of Cardiology and American Heart Association guidelines

Classification	Definition
High-risk PE	Acute PE with signs of hemodynamic instability, presenting 1 of the following clinical manifestations: Cardiac arrest (need for CPR) Obstructive shock (SBP < 90 mm Hg or vasopressors required to achieve SBP ≥ 90 mm Hg, despite adequate filling status) and end-organ hypoperfusion (i.e., altered mental status; cold, clammy skin; oliguria or anuria; increased serum lactate) Persistent hypotension (SBP < 90 mm Hg or SBP drop ≥ 40 mm Hg, lasting longer than 15 min and not caused by new onset arrhythmia, hypovolemia or sepsis)
Intermediate-risk (submassive) PE	Acute PE without signs of hemodynamic instability, but with a PESI class III–IV or simplified PESI ≥ 1 Signs of RV dysfunction on TTE (or CTPA) or elevated cardiac biomarker levels may be present
	Intermediate-high risk is defined if both of the following criteria are also present: Signs of RV dysfunction on an imaging test (echo or CT) Positive cardiac laboratory biomarkers of cardiac damage Intermediate-low risk is defined if 1 or none of these criteria are present
Low-risk PE*	Acute PE with no hemodynamic instability, no RV dysfunction and no comorbidity, with a PESI class I or simplified PESI score < 1

Note: CDT = catheter-directed thrombolysis, CPR = cardiopulmonary resuscitation, CT = computed tomography, CTPA = computed tomography pulmonary angiogram, PE = pulmonary embolism, PESI = Pulmonary Embolism Severity Index, RV = right ventricle, SBP = systolic blood pressure, TTE = transthoracic echocardiogram.

^*Patients with low-risk PE are not candidates for systemic or catheter-directed thrombolysis and were not included in our study.