What is the recommended treatment for a patient with pulmonary embolism?

Treatment of Pulmonary Embolism

For hemodynamically stable PE patients, initiate anticoagulation immediately with a direct oral anticoagulant (NOAC) such as apixaban, rivaroxaban, edoxaban, or dabigatran, which is preferred over warfarin. 1, 2, 3

Immediate Risk Stratification

Before initiating treatment, classify PE severity based on hemodynamic status:

• High-risk PE: Systolic blood pressure <90 mmHg, cardiogenic shock, or requiring vasopressors 1, 2
• Intermediate-risk PE: Hemodynamically stable (SBP ≥90 mmHg) but with right ventricular dysfunction on imaging or elevated cardiac biomarkers (troponin, BNP) 4, 2
• Low-risk PE: Hemodynamically stable without RV dysfunction or myocardial injury 2

Acute Management by Risk Category

High-Risk PE (Hemodynamically Unstable)

Administer systemic thrombolytic therapy immediately—this is a Class I recommendation. 1, 2, 3

• Start unfractionated heparin (UFH) without waiting for diagnostic confirmation: 80 U/kg IV bolus followed by 18 U/kg/h continuous infusion 1, 4, 3
• Adjust UFH dosing to maintain aPTT at 1.5-2.3 times control (46-70 seconds) 1
• If thrombolysis is contraindicated or fails, proceed immediately to surgical pulmonary embolectomy 1, 2, 3
• Catheter-directed therapy may be considered as an alternative to surgery if appropriate expertise is available 1

Intermediate-Risk and Low-Risk PE (Hemodynamically Stable)

Do NOT routinely administer thrombolysis—this is a Class III recommendation (contraindicated). 1, 4, 2, 3

Initiate anticoagulation immediately, even before diagnostic confirmation if clinical probability is high or intermediate. 1, 4

Parenteral Anticoagulation Options (if used):

• Preferred: Low-molecular-weight heparin (LMWH) or fondaparinux over UFH 1, 3
• LMWH dosing for treatment: 1 mg/kg subcutaneously every 12 hours OR 1.5 mg/kg once daily 5
• UFH: Reserve for patients with severe renal impairment (CrCl <30 mL/min) as it does not accumulate and can be rapidly reversed 4

Oral Anticoagulation Selection

NOACs are the preferred first-line oral anticoagulants over vitamin K antagonists (VKAs). 1, 2, 3

NOAC Options (choose one):

• Apixaban, rivaroxaban, edoxaban, or dabigatran 1, 2, 3
• Some NOACs (apixaban, rivaroxaban) can be started immediately without parenteral bridging 1

When VKAs Must Be Used:

• Overlap with parenteral anticoagulation until INR reaches 2.5 (range 2.0-3.0) for 2 consecutive days 1, 3
• Continue parenteral anticoagulation for minimum 5 days 5

Absolute Contraindications to NOACs:

• Severe renal impairment (CrCl <30 mL/min) 1, 3
• Antiphospholipid antibody syndrome 1, 3
• Pregnancy or lactation 1, 3

For these patients, use VKA with parenteral bridging, or LMWH monotherapy for cancer/pregnancy. 3

Duration of Anticoagulation

All PE patients require therapeutic anticoagulation for at least 3 months. 1, 2, 3

After 3 Months, Decide Based on Risk Factors:

• Discontinue anticoagulation: First PE provoked by major transient/reversible risk factor (surgery, trauma, immobilization) 1, 2, 3
• Continue indefinitely:
  • Recurrent VTE (≥1 prior episode) 1, 2, 3
  • Unprovoked PE 3
  • Active cancer 4, 3
  • Antiphospholipid antibody syndrome (must use VKA, not NOAC) 1, 2, 3

Reassess bleeding risk, drug tolerance, adherence, and renal/hepatic function at regular intervals during extended anticoagulation. 1, 3

Special Populations

Cancer-Associated PE:

LMWH is the preferred initial and long-term treatment, continued indefinitely or until cancer is cured. 4, 2

• Therapeutic dosing: 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg once daily 5
• Transition from UFH to LMWH once CrCl >30 mL/min 4

Pregnancy:

Use therapeutic fixed-dose LMWH based on early pregnancy weight throughout pregnancy. 1, 3

• Do not use NOACs or VKAs 1, 3

Rescue Therapy for Clinical Deterioration

If a patient on anticoagulation develops hemodynamic deterioration (SBP <90 mmHg, shock, need for vasopressors), immediately administer rescue thrombolytic therapy. 1, 2, 3

• Alternatively, consider surgical embolectomy or catheter-directed treatment if thrombolysis is contraindicated 1

Interventions NOT Recommended

• Do NOT routinely use inferior vena cava filters (only consider if absolute contraindication to anticoagulation or recurrent PE despite therapeutic anticoagulation) 1, 2, 3
• Do NOT perform CT venography as adjunct to CTPA 1
• Do NOT measure D-dimers in high clinical probability patients 1

Common Pitfalls

• Avoid delaying anticoagulation while awaiting diagnostic confirmation in high/intermediate probability patients—mortality increases with delay 4
• Do not use thrombolysis in intermediate-risk PE unless hemodynamic deterioration occurs—bleeding risk outweighs benefit 1, 4, 2
• Monitor closely for hemodynamic deterioration in intermediate-risk PE during first 24-48 hours, as these patients may decompensate 4
• Remember NOAC contraindications: severe renal impairment, antiphospholipid syndrome, pregnancy require alternative anticoagulation 1, 3