What are the treatment options for pulmonary embolism (PE), including indications for thrombectomy?

Treatment of Pulmonary Embolism

Risk Stratification Determines Treatment Intensity

Treatment of PE must be immediately stratified by hemodynamic status, as this determines whether aggressive reperfusion therapy is warranted or anticoagulation alone suffices. 1

Risk Categories

• High-risk PE: Shock or persistent hypotension (systolic BP <90 mmHg for ≥15 minutes or requiring vasopressor support) 1
• Intermediate-risk PE: Hemodynamically stable but with evidence of right ventricular dysfunction (RVD) and/or myocardial injury 1
• Low-risk PE: Hemodynamically stable without RVD 1

---

High-Risk PE: Immediate Reperfusion Required

Initial Management

Systemic thrombolysis is the first-line treatment for high-risk PE and should be administered immediately unless absolute contraindications exist. 1

• Initiate unfractionated heparin (UFH) with weight-adjusted bolus (80 U/kg or 5,000-10,000 units) followed by continuous infusion (18 U/kg/h) without delay 1, 2
• Administer oxygen to correct hypoxemia 1
• Use vasopressors (norepinephrine and/or dobutamine) to maintain adequate perfusion pressure 1
• Avoid aggressive fluid resuscitation as it can worsen RV failure 1

Thrombolytic Therapy

• Systemic thrombolysis carries Class I, Level A recommendation for high-risk PE 1
• Absolute contraindications include active bleeding, recent intracranial surgery/trauma, or hemorrhagic stroke 1
• Relative contraindications (which become less relevant in life-threatening PE) include recent surgery, pregnancy, or uncontrolled hypertension 1

When Thrombolysis Fails or Is Contraindicated

Surgical pulmonary embolectomy is the recommended alternative when thrombolysis is contraindicated or has failed (Class I, Level C). 1

• Performed via median sternotomy with normothermic cardiopulmonary bypass 1
• Does not require cardiac arrest unless intracardiac thrombi or patent foramen ovale present 1
• Previous thrombolysis is not a contraindication to surgery, though bleeding risk increases 1

Percutaneous catheter-directed treatment should be considered as an alternative to surgery when thrombolysis is contraindicated or has failed (Class IIa, Level C). 1

• FDA-approved devices include the Indigo Aspiration System, FlowTriever embolectomy device, and EKOSonic endovascular system 3, 4
• Complications include vessel perforation, cardiac tamponade, and local vascular injury 1
• ECMO may be considered in combination with surgical or catheter-directed treatment for refractory circulatory collapse or cardiac arrest 1, 5

---

Intermediate-Risk and Low-Risk PE: Anticoagulation First

Initial Anticoagulation

For hemodynamically stable patients, initiate anticoagulation immediately while diagnostic workup proceeds. 1

• Low molecular weight heparin (LMWH) or fondaparinux is preferred over UFH for most non-high-risk patients (Class I, Level A) 1
• UFH is reserved for patients with severe renal impairment (CrCl <30 mL/min) or high bleeding risk, targeting aPTT 1.5-2.5 times control 1
• Continue parenteral anticoagulation for at least 5 days 1

Transition to Oral Anticoagulation

Direct oral anticoagulants (DOACs/NOACs) are preferred over vitamin K antagonists (VKAs) when oral anticoagulation is initiated (Class I, Level A). 1

• Approved agents include rivaroxaban, apixaban, edoxaban, and dabigatran 1, 6, 7
• Rivaroxaban: 15 mg twice daily for 21 days, then 20 mg once daily (with food) 6
• Apixaban: 10 mg twice daily for 7 days, then 5 mg twice daily 7
• If using VKAs, overlap with parenteral anticoagulation until INR reaches 2.0-3.0 (target 2.5) for at least 2 consecutive days 1

NOAC Contraindications

NOACs are contraindicated in severe renal impairment (CrCl <15-30 mL/min depending on agent), pregnancy/lactation, and antiphospholipid antibody syndrome (Class III, Level C). 1

---

Thrombolysis in Intermediate-Risk PE: Selective Use Only

Routine systemic thrombolysis is NOT recommended for intermediate-risk PE (Class III, Level B), but may be considered in highly selected patients after careful bleeding risk assessment. 1

• One trial showed reduced clinical deterioration requiring escalation of treatment, but no mortality benefit and increased bleeding risk 1
• Rescue thrombolytic therapy IS recommended if hemodynamic deterioration occurs on anticoagulation (Class I, Level B) 1
• Surgical embolectomy or catheter-directed treatment should be considered as alternatives to rescue thrombolysis 1

---

Indications for Thrombectomy (Surgical or Catheter-Based)

Surgical Pulmonary Embolectomy

Primary indications:

• High-risk PE with absolute contraindications to thrombolysis (Class I, Level C) 1
• High-risk PE with failed thrombolysis (Class I, Level C) 1
• Presence of intracardiac thrombi or patent foramen ovale with risk of paradoxical embolism 1

Catheter-Directed Thrombectomy

Primary indications:

• High-risk PE when thrombolysis contraindicated or failed, and surgical expertise unavailable (Class IIa, Level C) 1
• Intermediate-risk PE with hemodynamic deterioration as alternative to rescue thrombolysis (Class IIa, Level C) 1

Critical caveat: Current evidence for catheter-based devices consists primarily of single-arm studies with surrogate endpoints; no adequately powered mortality trials exist 3. Treatment decisions should factor in bleeding risk, thrombus location, and local expertise 3.

---

Inferior Vena Cava (IVC) Filters

IVC filters should be considered only in patients with absolute contraindications to anticoagulation or recurrent PE despite therapeutic anticoagulation. 1

• Filters increase risk of recurrent DVT (21% vs 12% at 2 years) and venous insufficiency (59% at 6 years) 1
• Not indicated for free-floating thrombi when adequate anticoagulation is possible (recurrence rate 3.3% vs 3.7% for occlusive thrombi) 1
• If filter placed, resume anticoagulation when bleeding risk resolves to prevent filter thrombosis 1

---

Duration of Anticoagulation

• Minimum 3 months for all PE patients 8
• Provoked PE (major transient risk factor): Discontinue after 3 months 8
• Unprovoked PE or recurrent VTE: Consider indefinite anticoagulation 8
• Cancer-associated PE: LMWH preferred for at least 6 months, then continue as long as cancer active 1

---

Follow-Up and Monitoring

• Routinely reassess patients at 3-6 months post-PE 8
• Evaluate for persistent dyspnea or functional limitation 8
• If symptoms persist, perform diagnostic workup to exclude chronic thromboembolic pulmonary hypertension (CTEPH) 8

---

Common Pitfalls

• Do not delay anticoagulation while awaiting diagnostic confirmation in high-probability cases 1
• Do not use aggressive fluid boluses in high-risk PE; this worsens RV failure 1
• Do not routinely thrombolyse intermediate-risk PE; reserve for hemodynamic deterioration 1
• Do not place IVC filters prophylactically for free-floating thrombi when anticoagulation is feasible 1
• Do not use NOACs in severe renal impairment, pregnancy, or antiphospholipid syndrome 1