Do patients with a history of two pulmonary embolisms (PE) require lifelong anticoagulation?

Lifelong Anticoagulation for Patients with Two Pulmonary Embolisms

Patients with a history of two pulmonary embolisms (PE) should receive indefinite (lifelong) anticoagulation therapy as long as their bleeding risk is not prohibitively high. 1

Recommendation Based on Number of VTE Episodes

• For patients with a first episode of unprovoked PE, extended anticoagulation should be considered if bleeding risk is low or moderate 1
• For patients with a second unprovoked venous thromboembolism (VTE), extended anticoagulant therapy is recommended for those with low bleeding risk (strong recommendation) and suggested for those with moderate bleeding risk 1
• The American College of Chest Physicians specifically states that in patients with two or more episodes of documented PE, indefinite treatment with anticoagulation is suggested 2

Duration of Anticoagulation Decision Algorithm

1. Assess if PEs were provoked or unprovoked:

   • If both PEs were provoked by temporary risk factors (e.g., surgery), consider limited duration therapy 1
   • If either PE was unprovoked, proceed with consideration for indefinite therapy 1

2. Evaluate bleeding risk:

   • Low bleeding risk: Strongly recommend indefinite anticoagulation 1
   • Moderate bleeding risk: Suggest indefinite anticoagulation 1
   • High bleeding risk: Consider limited duration therapy (3 months) even with recurrent VTE 1

3. Monitor and reassess periodically:

   • The risk-benefit ratio should be reassessed at regular intervals (e.g., annually) for all patients on indefinite anticoagulation 1, 2

Rationale for Extended Anticoagulation

• Patients with unprovoked venous thrombosis have an annual risk of recurrence >5% 1
• The risk of recurrence continues even after extended periods of anticoagulation 3
• The benefit of anticoagulation continues only as long as therapy is continued 1
• Recurrent VTE events are often pulmonary embolisms, which can be fatal 3

Important Considerations and Caveats

• "Indefinite anticoagulation" refers to treatment with no defined stop date, which could be lifelong or until bleeding risk becomes prohibitive 1
• The term "long-term anticoagulation" refers to treatment beyond the initial 3-6 month period 1
• While direct oral anticoagulants (DOACs) have improved safety profiles compared to vitamin K antagonists, the risk of non-major clinically relevant bleeding is still not negligible 4
• Vena cava filters are not a substitute for anticoagulation in patients who can tolerate anticoagulant therapy 5
• Regular monitoring of patients on indefinite anticoagulation is essential to reassess the risk-benefit ratio as patient circumstances change 1

Special Situations

• If a patient has hormone-associated PE and discontinues hormonal therapy, extended anticoagulation may not be required 1
• For patients with PE associated with persistent risk factors (e.g., active cancer), extended anticoagulation is recommended regardless of the number of episodes 1

Remember that the decision for lifelong anticoagulation must balance the high risk of recurrent VTE (especially after two episodes) against the patient's individual bleeding risk, with the understanding that most patients with two unprovoked PEs will benefit from indefinite therapy 1, 2.