When is mechanical thrombectomy indicated in pulmonary embolism?

Mechanical Thrombectomy in Pulmonary Embolism

Mechanical thrombectomy is indicated in pulmonary embolism when patients have high-risk (massive) PE with contraindications to thrombolysis or when thrombolytic therapy has failed. 1

Primary Indications

High-Risk (Massive) PE

• Patients with hemodynamic instability (shock and/or persistent hypotension) 1
• When thrombolysis is contraindicated or has failed 1
• When shock is likely to cause death before systemic thrombolysis can take effect (within hours) 1

Contraindications to Thrombolysis

Common contraindications that may necessitate mechanical thrombectomy include:

• Recent hemorrhagic stroke 1
• Ischemic stroke within preceding 6 months 1
• Central nervous system damage or neoplasms 2
• Recent major trauma/surgery/head injury (within preceding 3 weeks) 2
• Active gastrointestinal bleeding 1
• Advanced liver disease 1

Patient Selection Criteria

Anatomical Considerations

• Optimal candidates have thrombus in the main pulmonary artery or major branches 1
• Patients without fixed pulmonary hypertension (which suggests chronic thromboembolic disease) 1
• Central thrombus propagation despite anticoagulation 1
• Risk of limb loss (e.g., phlegmasia cerulea dolens) 1

Clinical Considerations

• Patients deemed high risk for surgical thrombectomy 3
• Moderate to severely symptomatic proximal DVT 1
• Patients with right ventricular dysfunction and elevated cardiac biomarkers who show clinical deterioration on anticoagulation 1

Procedural Approaches

Catheter-Directed Techniques

• Aspiration mechanical thrombectomy using large-bore catheters 2, 4
• Pharmacomechanical thrombectomy (combining mechanical disruption with local thrombolytic agents) 1
• Conservative approach (early termination once hemodynamic parameters improve) may reduce complication rates 3

Surgical Embolectomy Considerations

• Surgical embolectomy should be considered when catheter-based interventions are not available or feasible 1
• Requires median sternotomy with cardiopulmonary bypass 1
• Higher mortality rates (20-50%) but may be life-saving in appropriate candidates 1

Expected Outcomes

Hemodynamic Improvements

• Increase in systemic arterial pressure 3
• Decrease in heart rate 3
• Reduction in pulmonary artery systolic pressure 4
• Improvement in right ventricular size and function 3, 4

Clinical Benefits

• Reduced right ventricular/left ventricular ratio 4
• Improved pulmonary oxygen saturation 2
• Decreased Miller index (measure of pulmonary vascular obstruction) 2, 4

Cautions and Considerations

Procedural Risks

• Bleeding complications (estimated blood loss 200-450cc) 5
• Need for blood transfusions in some patients 5
• Local damage to venous access site 1
• Potential for cardiac perforation or tamponade 1

Institutional Factors

• Should only be performed at centers with appropriate expertise and resources 1
• Requires collaboration between interventional radiology or vascular surgery colleagues 1
• Decision should be made on a case-by-case basis 1

Follow-up Considerations

• Monitor for recurrent PE 2
• Assess for development of pulmonary hypertension 2
• Continue appropriate anticoagulation therapy post-procedure 1
• Consider IVC filter placement in select patients with contraindications to anticoagulation 1

Mechanical thrombectomy represents an important treatment option for patients with high-risk PE who cannot receive thrombolysis or who have failed thrombolytic therapy, with evidence showing improvements in hemodynamic parameters and right ventricular function when performed at experienced centers.