What are the criteria for thrombectomy in a patient with pulmonary embolism (PE), considering factors such as shock, hypotension, right ventricular dysfunction, age, comorbidities, and prior history of bleeding or thrombotic events?

Criteria for Thrombectomy in Pulmonary Embolism

Thrombectomy (surgical or catheter-based) should be performed in patients with high-risk PE presenting with shock or persistent hypotension who have absolute contraindications to thrombolysis, have failed systemic thrombolysis, or are in such profound shock that death is imminent before thrombolysis can take effect (within hours). 1

Primary Indication: High-Risk PE with Contraindications or Failed Thrombolysis

The clearest indication for thrombectomy is in high-risk PE (defined as shock or persistent hypotension) when systemic thrombolysis cannot be used or has failed. 1

Specific Clinical Scenarios for Thrombectomy:

• Absolute contraindications to thrombolysis exist: Active internal bleeding, hemorrhagic stroke or stroke of unknown origin at any time, ischemic stroke within 6 months, CNS neoplasms, recent major trauma/surgery/head injury within 3 weeks, or gastrointestinal bleeding within the last month. 2

• Systemic thrombolysis has failed: Patient remains hemodynamically unstable despite receiving thrombolytic therapy. 1

• Imminent death from shock: Patient is in such profound cardiogenic shock that death is likely within hours, before systemic thrombolysis could take effect. 1

• Presence of right heart thrombi in transit or patent foramen ovale with intracardiac thrombi: These anatomic findings favor surgical embolectomy over thrombolysis. 1

Risk Stratification Framework

Risk stratification must precede any decision about thrombectomy. 3, 4

High-Risk PE (Primary Thrombectomy Candidates):

• Shock (systolic BP <90 mmHg) or persistent hypotension requiring vasopressors. 1, 3
• These patients have the highest mortality and warrant aggressive reperfusion therapy. 1, 3

Intermediate-Risk PE (Selective Consideration):

• Hemodynamically stable but with right ventricular dysfunction on echocardiography or CT AND elevated cardiac biomarkers (troponin, BNP). 3, 5
• Thrombectomy is not routinely recommended for intermediate-risk PE. 1
• However, if intermediate-risk patients develop hemodynamic deterioration despite anticoagulation, they should be reclassified as high-risk and thrombectomy considered. 1, 6

Low-Risk PE:

• Hemodynamically stable without RV dysfunction. 3
• Thrombectomy is contraindicated—anticoagulation alone is appropriate. 1

Choice Between Surgical vs. Catheter-Based Thrombectomy

Surgical Pulmonary Embolectomy:

• Preferred when absolute contraindications to thrombolysis exist in high-risk PE. 2, 3
• Performed via median sternotomy with normothermic cardiopulmonary bypass. 1
• Should be terminated as soon as hemodynamics improve, regardless of angiographic appearance. 1
• In centers with established cardiac surgery programs, this is a straightforward operation with dramatic hemodynamic improvement. 1

Catheter-Based Thrombectomy:

• Alternative when surgical embolectomy is not immediately available or when surgery carries prohibitive risk. 1, 3
• Includes percutaneous mechanical thrombectomy, aspiration thrombectomy, and catheter-directed thrombolysis (though the latter involves local thrombolytics). 4, 6
• Recent evidence shows aspiration thrombectomy in intermediate-high risk PE improves RV function and oxygenation with low complication rates. 7
• For patients with contraindications to thrombolysis, percutaneous thrombectomy shows 4-5% mortality at 30 days with only 4% major bleeding. 8

Critical Caveats and Pitfalls

When NOT to Perform Thrombectomy:

• Intermediate-risk PE that remains hemodynamically stable: These patients should receive anticoagulation alone, not thrombectomy. 1
• Low-risk PE: Thrombectomy is never indicated. 1

Systemic Thrombolysis Remains First-Line for High-Risk PE:

• If no contraindications exist, systemic thrombolysis via peripheral vein is preferred over catheter-directed approaches in high-risk PE. 1
• Thrombectomy is reserved for when thrombolysis cannot be used or has failed. 1

Relative vs. Absolute Contraindications in Life-Threatening PE:

• In high-risk PE with imminent death, some contraindications that would be absolute in other contexts become relative. 2
• However, active hemorrhage and recent hemorrhagic stroke remain absolute even in life-threatening PE. 2
• Recent surgery (within 3 weeks) is traditionally an absolute contraindication to thrombolysis, but in cardiac arrest from massive PE, thrombolysis may still be considered. 9

Multidisciplinary Decision-Making:

• Complex cases benefit from a Pulmonary Embolism Response Team (PERT) combining interventional cardiology, cardiac surgery, interventional radiology, and critical care expertise. 4, 6
• This team determines which specific intervention—surgical embolectomy, catheter thrombectomy, or thrombolysis—best suits the individual patient. 4, 6

Anticoagulation Must Continue:

• Thrombectomy does not replace anticoagulation. 1
• Unfractionated heparin should be initiated immediately in high-risk PE, even before thrombectomy. 3
• After thrombectomy, transition to therapeutic anticoagulation for minimum 3 months. 9, 3