Is pulmonary embolism (PE) preventable in patients of any age with risk factors such as recent surgery, prolonged immobility, active cancer, obesity, hormonal therapy, pregnancy, prior DVT (deep‑vein thrombosis) or PE (pulmonary embolism), inherited or acquired thrombophilia, or chronic inflammatory disease?

Is Pulmonary Embolism Preventable?

Yes, pulmonary embolism is often preventable through risk stratification and appropriate thromboprophylaxis, as venous thromboembolism is explicitly described as "often preventable" despite being a major cause of mortality and morbidity. 1

Evidence for Preventability

The European Society of Cardiology explicitly states that VTE (which encompasses PE) "may be lethal in the acute phase or lead to chronic disease and disability, but it is also often preventable." 1 This preventability is demonstrated through multiple mechanisms:

Proven Efficacy of Thromboprophylaxis

• Antithrombotic prophylaxis significantly reduces the risk of perioperative VTE, with the highest risk occurring during the first two post-operative weeks but remaining elevated for two to three months. 1
• Pharmacological and physical measures to reduce postoperative DVT risk in high-risk patients have achieved substantial reduction in fatal PE incidence. 2
• The incidence of VTE is reduced with increasing duration of thromboprophylaxis after major orthopaedic surgery and cancer surgery. 1

Risk Stratification Enables Targeted Prevention

The 2019 ESC/ERS guidelines categorize risk factors by strength, allowing clinicians to identify patients requiring prophylaxis: 1

Strong risk factors (OR >10) requiring aggressive prophylaxis:

• Lower limb fractures 1, 3
• Hip or knee replacement 1, 3
• Major trauma 1, 3
• Myocardial infarction within 3 months 1, 3
• Previous VTE 1, 3
• Spinal cord injury 1, 3

Moderate risk factors (OR 2-9) requiring prophylaxis in appropriate clinical contexts:

• Active cancer (especially pancreatic, hematologic, lung, gastric, brain) 1, 4
• Chemotherapy 1
• Infection (pneumonia, UTI, HIV) 1, 3
• Central venous catheters 1
• Oral contraceptives and hormone replacement therapy 1, 4
• Postpartum period 1

Weak risk factors (OR <2) that contribute to cumulative risk:

• Bed rest >3 days 1, 3
• Obesity 1, 4
• Prolonged immobility (e.g., air travel) 1
• Age >40 years (risk doubles each decade) 1, 4

Practical Prevention Strategies

Pharmacological Prophylaxis

• Low-molecular-weight heparin (LMWH) or fondaparinux are recommended as well-tolerated and effective thromboprophylactic agents in medical patients, with LMWH having lower bleeding rates than unfractionated heparin. 5
• For surgical patients undergoing hip or knee replacement, apixaban 2.5 mg orally twice daily is FDA-approved for DVT prophylaxis, which prevents PE. 6
• Duration of prophylaxis should extend beyond hospitalization in high-risk surgical patients, particularly after major orthopedic surgery. 1, 2

Mechanical Prophylaxis

• Immobilized pneumonia patients require DVT prophylaxis with subcutaneous anticoagulants or intermittent pneumatic compression. 3
• Early mobilization when medically feasible reduces PE risk. 3

High-Risk Surgical Patients

• Prophylactic inferior vena cava filter placement in very high-risk patients undergoing complex spine surgery reduced symptomatic PE from 4.2% to 1.5% (p<0.05) with no insertion complications. 7
• Mandatory implementation of evidence-based care pathways is helpful in lowering PE-related mortality. 8

Clinical Implementation Algorithm

1. Identify all risk factors using the ESC/ERS stratification (strong, moderate, weak) 1
2. Calculate cumulative risk recognizing that multiple weak factors compound (e.g., obesity + age >40 + immobility) 4
3. Initiate prophylaxis based on risk level:
   • Strong risk factors: pharmacological prophylaxis mandatory unless contraindicated 2
   • Moderate risk factors: prophylaxis recommended, especially with multiple factors 4
   • Weak risk factors: consider prophylaxis if ≥3 factors present 4
4. Perform dynamic reassessment during hospitalization as clinical events may change risk level 8
5. Determine discharge prophylaxis duration based on procedure type and persistent risk factors 2

Critical Caveats

• PE remains a leading preventable cause of death in surgical patients, with fatal PE rates actually increasing despite available prophylaxis, indicating underutilization of prevention strategies. 8
• Approximately 50% of PE episodes occur without classical predisposing factors, requiring high clinical suspicion even when known risk factors are absent. 3
• After a first VTE episode, recurrence risk is 21.5%, rising to 27.9% after a second event, meaning VTE should be considered a chronic illness requiring long-term management. 9
• The risk of recurrence never resolves to zero, with highest risk in the first 6-12 months after an event. 9
• Premature discontinuation of anticoagulation increases thrombotic event risk; consider coverage with another anticoagulant if stopping for reasons other than bleeding or completion of therapy. 6

Common Pitfalls to Avoid

• Not recognizing that PE risk increases exponentially with age (doubles each decade after age 40). 4
• Underestimating the significance of immobility as a risk factor. 4
• Overlooking the synergistic effect of multiple risk factors (e.g., oral contraceptives increase risk 2-6 fold, but combined with Factor V Leiden mutation, risk increases 35-fold). 4
• Failing to extend prophylaxis beyond hospitalization in high-risk surgical patients. 2
• Not performing dynamic risk reassessment during hospitalization when clinical status changes. 8