Treatment Approach for Pulmonary Embolism Based on PESI Score
Patients with confirmed pulmonary embolism and low PESI scores (Class I/II or sPESI=0) should be managed as outpatients with direct oral anticoagulants (apixaban or rivaroxaban), provided they meet exclusion criteria, while intermediate and high-risk patients require inpatient management with escalating intensity of monitoring and consideration of reperfusion therapy. 1, 2
Risk Stratification Framework
The PESI score stratifies patients into five classes (I-V) with 30-day mortality rates of ≤1.6% for Class I and 3.6% for Class II, demonstrating excellent discriminatory power. 2, 3 The simplified PESI (sPESI) uses six binary variables, with a score of 0 identifying low-risk patients with 30-day mortality of 1.0-1.1%. 1, 4
Key distinction: While the original PESI classifies more patients as low-risk (40.9% vs 36.8%), both versions have similar sensitivity (90% vs 89%) and negative predictive values (98% vs 97%) for mortality prediction. 3 The sPESI is easier to use clinically and equally powerful for identifying low-risk patients suitable for outpatient management. 1
Treatment Algorithm by Risk Category
Low-Risk PE (PESI Class I/II or sPESI=0)
Outpatient management is appropriate when exclusion criteria are absent. 1, 2, 5
Mandatory exclusion criteria that require inpatient admission: 1, 5
- Physiologic instability: heart rate >110 bpm, systolic BP <100 mmHg, oxygen saturation <90% on room air, or severe pain requiring opiates
- Active bleeding or recent major bleeding risk, already on full-dose anticoagulation at time of PE diagnosis
- Severe renal impairment (eGFR <30 mL/min) or severe liver disease
- Social factors: inability to return home, inadequate home care, lack of telephone communication, compliance concerns, or patient preference for admission
Anticoagulation for outpatients: 2, 5
- First-line: Apixaban or rivaroxaban (single-drug regimens without bridging)
- Alternative: Dabigatran or edoxaban (require initial LMWH bridging)
Critical implementation requirements: 2, 5
- Same-day anticoagulation initiation before discharge
- Consultant or senior clinician review before discharge
- Robust follow-up pathway with access to prompt care if symptoms worsen
Intermediate-Risk PE (PESI Class III or Higher with sPESI ≥1)
These patients require inpatient management with further stratification based on right ventricular dysfunction and cardiac biomarkers. 1, 6
Intermediate-high risk (RV dysfunction on imaging PLUS elevated troponin or NT-proBNP ≥600 ng/L): 1
- Inpatient monitoring in setting with capability for escalation
- Standard anticoagulation
- Close monitoring for clinical deterioration
- Consider reperfusion therapy if hemodynamic decompensation occurs
Intermediate-low risk (RV dysfunction OR elevated biomarkers, but not both): 1
- Inpatient management with standard anticoagulation
- Less intensive monitoring than intermediate-high risk
High-Risk PE (Hemodynamically Unstable)
Defined by sustained hypotension (systolic BP <90 mmHg for >15 minutes), obstructive shock, or cardiac arrest. 1, 6
- Emergency systemic thrombolysis is indicated
- Intensive care unit admission
- Hemodynamic support as needed
Important Clinical Nuances
Right heart thrombi represent a critical exception where anatomic location significantly impacts prognosis, with mortality of 21% versus 11% without right heart thrombi, and thrombolytic therapy is the only treatment independently associated with decreased mortality in this subset. 6
Concomitant DVT is an adverse prognostic factor independently associated with 30-day all-cause mortality (OR 1.9,95% CI 1.5-2.4), indicating significant comorbidity. 1
Common Pitfalls to Avoid
Do not rely solely on RV dilation on imaging to exclude patients from outpatient management; if RV dilation is present, measure cardiac biomarkers (BNP/troponin) for additional risk stratification, as normal biomarkers identify low-risk patients even with RV dysfunction. 1, 5
Do not use routine bleeding risk scores beyond the exclusion criteria already outlined for patients deemed low-risk by PESI/sPESI. 5
Do not discharge without same-day anticoagulation - patients must have immediate access to anticoagulation medications before leaving the emergency department. 5
Incidental troponin elevation in low-risk PE patients requires senior review and consideration of alternative causes for troponin release beyond the PE itself. 1