Management of Patients in a Pulmonary Embolism Clinic
Patients in a pulmonary embolism clinic should receive immediate anticoagulation with low molecular weight heparin (LMWH) as initial treatment, followed by transition to direct oral anticoagulants (DOACs) such as rivaroxaban or apixaban for most patients, with specific duration based on risk factors. 1
Initial Assessment and Treatment
Immediate Management
- Start anticoagulation immediately upon suspicion of PE, even before diagnostic confirmation in patients with intermediate/high clinical probability 1
- LMWH is preferred over unfractionated heparin (UFH) for most patients:
- Enoxaparin: 1 mg/kg twice daily or 1.5 mg/kg once daily
- Dalteparin: 200 U/kg once daily 1
Special Considerations for Initial Treatment
- Consider UFH instead of LMWH in patients with:
- Massive PE with hemodynamic instability
- Need for potential rapid reversal
- Severe renal impairment (CrCl <30 mL/min) 1
- UFH dosing: 80 U/kg initial bolus followed by 18 U/kg/hour continuous infusion, targeting aPTT 1.5-2.5 times control 1
- For massive PE with hemodynamic instability, consider thrombolysis with rtPA, streptokinase, or urokinase 1
Transition to Oral Anticoagulation
DOAC Options (Preferred for Most Patients)
- Rivaroxaban: 15 mg twice daily for 21 days, then 20 mg daily 1, 2
- Apixaban: 10 mg twice daily for 7 days, then 5 mg twice daily 1, 3
Vitamin K Antagonist Option
- Target INR: 2.0-3.0
- Overlap with heparin for at least 4-5 days
- Discontinue heparin after 5 days of warfarin therapy if INR is at least 2.0 1
Duration of Anticoagulation
Duration should be tailored based on risk factors:
| Patient Population | Recommended Duration |
|---|---|
| Secondary PE due to transient/reversible risk factors | 3 months |
| Unprovoked PE or persistent risk factors | Extended (>3 months) |
| Recurrent PE | Indefinite |
Special Populations
Cancer-Associated PE
- Continue anticoagulation as long as cancer is active
- LMWH preferred: Consider dose reduction to 75-80% of initial dose after 6 months (e.g., dalteparin 150 U/kg once daily)
- DOACs (apixaban, edoxaban, rivaroxaban) are effective alternatives to LMWH 1
Antiphospholipid Syndrome
- DOACs should not be used
- Vitamin K antagonists are preferred 1
Pregnancy
- Use therapeutic doses of LMWH based on early pregnancy weight
- DOACs are contraindicated 1
Follow-Up Assessment
Short-term Follow-up
- Monitor patients on UFH with aPTT 4-6 hours after initial bolus and daily once therapeutic
- Monitor patients on VKAs with regular INR checks, targeting 2.0-3.0 1
Long-term Follow-up
- Assess at 3-6 months for:
- Chronic thromboembolic pulmonary hypertension
- Underlying causes of PE
- Need for continued anticoagulation 1
Common Pitfalls to Avoid
- Delaying anticoagulation while awaiting diagnostic confirmation in patients with intermediate/high clinical probability of PE 1
- Inadequate duration of anticoagulation, especially in unprovoked PE or cancer-associated PE 1
- Insufficient overlap between heparin and oral anticoagulants (minimum 4-5 days overlap required) 1
- Failure to achieve adequate anticoagulant response (APTT >1.5 times control for UFH) 1
- Premature discontinuation of rivaroxaban which increases risk of thrombotic events 2
Discharge Criteria
- For patients on VKAs: INR between 2.0-3.0
- Patient education on anticoagulant side effects and interactions completed
- Anticoagulant supervision appointments arranged 1