What is the management of pulmonary embolism based on risk?

Risk-Based Management of Pulmonary Embolism

Management of pulmonary embolism is determined by immediate hemodynamic status, followed by assessment of right ventricular dysfunction and myocardial injury markers in stable patients, with treatment escalating from anticoagulation alone in low-risk patients to primary reperfusion therapy in high-risk patients. 1

Risk Stratification Framework

Risk assessment occurs in three distinct categories that directly determine treatment intensity 1:

High-Risk PE (Massive PE)

High-risk PE is defined by shock or persistent arterial hypotension (systolic BP <90 mmHg or pressure drop ≥40 mmHg for >15 minutes not caused by arrhythmia, hypovolemia, or sepsis). 1, 2

• These patients face immediate life-threatening emergency with mortality rates potentially exceeding 30% 1
• Primary reperfusion treatment is the treatment of choice, typically systemic thrombolysis 1
• Surgical pulmonary embolectomy or percutaneous catheter-directed treatment are alternatives when thrombolysis is contraindicated 1
• Hemodynamic support with vasopressors (dobutamine and/or norepinephrine) should be considered 3
• Avoid aggressive fluid challenges as this worsens right ventricular failure 3

Intermediate-Risk PE (Submassive PE)

In hemodynamically stable patients, the presence of markers of right ventricular dysfunction (RVD) and/or myocardial injury (elevated troponin) identifies intermediate-risk PE. 1

• Patients with both RVD and positive myocardial injury markers (intermediate-high risk) have greater risk than those with discordant results (intermediate-low risk) 1
• These patients require hospital monitoring with anticoagulation as primary treatment 1
• Rescue thrombolytic therapy should be considered if hemodynamic deterioration occurs despite anticoagulation 3
• Catheter-directed therapies may be considered in intermediate-high risk patients, particularly when systemic thrombolysis is contraindicated 4

A critical caveat: RV dysfunction may be present and affect early outcomes even in patients classified as "low risk" by clinical scores alone. 1

Low-Risk PE

Hemodynamically stable patients without evidence of RVD or myocardial injury have low-risk PE, with mortality <1%. 1, 2

• Requires assessment of at least one myocardial dysfunction marker AND one myocardial injury marker to confirm low-risk status 1
• Anticoagulation alone is sufficient treatment 1
• The Pulmonary Embolism Severity Index (PESI) or simplified PESI (sPESI) should be used to identify patients suitable for outpatient management 2
• Early discharge (within 24-48 hours) is appropriate if RV dysfunction and right heart thrombi are excluded 1

Clinical Risk Scoring

The PESI score uses 11 clinical variables to stratify 30-day mortality risk into five classes, ranging from very low (<1%) to very high (24.4%). 1

Key predictors include 1:

• Age (1 point per year)
• Cancer (30 points)
• Systolic BP <100 mmHg (30 points)
• Altered mental status (60 points)
• Heart rate >110/min (20 points)
• SaO2 <90% (20 points)

Exclusion Criteria for Outpatient Management

Patients with the following should NOT be managed as outpatients: 2

• Hemodynamic instability
• Oxygen saturation <90% on room air
• Active bleeding
• Severe renal impairment

Supportive Care Considerations

Oxygen Management

Supplemental oxygen should be administered in all patients with SaO2 <90%. 3

• Escalate from conventional oxygen to high-flow nasal cannula, then non-invasive ventilation if needed 3
• Invasive mechanical ventilation should be reserved for extreme instability, as positive pressure may worsen RV failure 3
• If intubation is necessary, use tidal volumes of 6 mL/kg lean body weight and keep plateau pressure <30 cm H2O 3

Common Pitfalls to Avoid

• Do not rely on anatomical burden alone (CT obstruction index, Miller score) for risk stratification—functional hemodynamic assessment is superior 1
• Do not discharge patients early based on clinical scores alone without excluding RV dysfunction by echocardiography or CTPA 1
• Do not overlook patent foramen ovale as a cause of refractory hypoxemia 3
• Do not delay escalation of therapy in intermediate-risk patients showing hemodynamic deterioration 3

Anticoagulation Approach

NOACs (novel oral anticoagulants) are recommended as first-choice anticoagulation treatment in eligible patients, with vitamin K antagonists as an alternative. 1

• For cancer patients, edoxaban or rivaroxaban should be considered as alternatives to LMWH, though caution is warranted in gastrointestinal cancers due to increased bleeding risk 1
• Reduced-dose apixaban or rivaroxaban should be considered for extended anticoagulation after the first 6 months 1