Should I be on anticoagulants, such as warfarin or direct oral anticoagulants (DOACs) like rivaroxaban (Xarelto) or apixaban (Eliquis), in addition to or instead of baby aspirin (acetylsalicylic acid) for long-term management after a previous pulmonary embolism (PE)?

Management of Previous Pulmonary Embolism: Beyond Baby Aspirin

For a patient with a history of pulmonary embolism, baby aspirin alone is not sufficient therapy - a reduced-dose direct oral anticoagulant (DOAC) is strongly recommended over aspirin for long-term prevention of recurrent venous thromboembolism. 1

Assessment of Risk Factors and Classification

The appropriate management depends on whether the original PE was:

1. Provoked by major transient risk factor (surgery with general anesthesia >30 min, hospitalization with bed rest ≥3 days, cesarean section, major trauma)

   • Standard recommendation: 3 months of anticoagulation, then stop 1

2. Provoked by minor transient risk factor (surgery with general anesthesia <30 min, hospitalization <3 days, estrogen therapy, pregnancy, prolonged travel)

   • Standard recommendation: 3 months of anticoagulation, then consider stopping 1

3. Unprovoked or provoked by persistent risk factor (active cancer, antiphospholipid syndrome)

   • Standard recommendation: Extended-phase anticoagulation 1

Recommended Management

For Unprovoked PE or PE with Persistent Risk Factors:

1. First-line therapy: Extended-phase anticoagulation with a reduced-dose DOAC

   • Apixaban 2.5 mg twice daily OR
   • Rivaroxaban 10 mg once daily 1

2. If DOAC not suitable: Vitamin K antagonist (warfarin) with target INR 2.0-3.0 1, 2

3. Not recommended: Baby aspirin alone is insufficient for secondary prevention

   • Aspirin is much less effective than anticoagulants for preventing recurrent VTE 1, 3
   • Anticoagulants reduce recurrent VTE by 46 fewer events per 1,000 cases compared to aspirin 3

For PE Provoked by Transient Risk Factors:

• If the PE occurred many years ago and was provoked by a major transient risk factor that has resolved, extended anticoagulation is not recommended 1
• If the patient has already completed the standard 3-month course of anticoagulation, aspirin may provide modest protection against recurrence 1

Additional Investigations Needed

1. Risk assessment for recurrent VTE:

   • Determine if any persistent risk factors are present
   • Evaluate for underlying thrombophilia if unprovoked PE and considering discontinuation of therapy

2. Bleeding risk assessment:

   • History of prior bleeding
   • Concomitant medications (NSAIDs, antiplatelet agents)
   • Renal function
   • Age (>80 years increases bleeding risk) 1

3. Annual reevaluation:

   • All patients on extended anticoagulation should have their therapy reassessed at least annually 1
   • Reassess at times of significant health status changes 1

Important Considerations and Caveats

• Duration of therapy: Extended-phase anticoagulation does not have a predefined stop date, but most studies followed patients for 2-4 years 1

• Bleeding risk: Reduced-dose DOACs have a better safety profile than full-dose therapy

  • Major bleeding with reduced-dose DOACs: 10 fewer events per 1,000 cases compared to full-dose 1

• Pitfall to avoid: Do not consider aspirin equivalent to anticoagulation

  • The CHEST guidelines explicitly state that aspirin is not a reasonable alternative to anticoagulant therapy for extended treatment 1

• Patient preference matters: The decision to continue extended anticoagulation should incorporate patient values and preferences regarding the trade-off between recurrence risk and bleeding risk 1

If the patient cannot take anticoagulants due to bleeding risk or other contraindications, only then should aspirin be considered as a second-line option, recognizing its significantly lower efficacy compared to anticoagulation 1.