What are the indications for interventional thrombectomy in patients with Pulmonary Embolism (PE)?

Indications for Interventional Thrombectomy in Pulmonary Embolism

Interventional thrombectomy is primarily indicated for patients with high-risk (massive) pulmonary embolism who have contraindications to fibrinolysis or who remain unstable after fibrinolysis therapy. 1

Risk Stratification for PE Treatment Decision-Making

High-Risk (Massive) PE

• Hypotension (systolic BP <90 mmHg or drop >40 mmHg for ≥15 minutes)
• Need for vasopressor support
• Cardiogenic shock
• Mortality rate: approximately 30% within 1 month 1

Intermediate-Risk (Submassive) PE

• Hemodynamically stable but with RV dysfunction on imaging
• Elevated cardiac biomarkers (troponin, BNP)
• Mortality rate: higher than low-risk but lower than high-risk PE 1

Low-Risk PE

• No RV dysfunction or elevated cardiac biomarkers
• Hemodynamically stable
• Mortality rate: approximately 1% within 1 month 1

Primary Indications for Interventional Thrombectomy

1. High-risk PE with contraindications to fibrinolysis (Class IIa; Level of Evidence C) 1

   • Hemorrhagic stroke or stroke of unknown origin
   • Ischemic stroke in preceding 6 months
   • Central nervous system damage or neoplasms
   • Recent major trauma/surgery/head injury
   • Active bleeding
   • Gastrointestinal bleeding within the last month 2

2. High-risk PE with failed fibrinolysis (Class IIa; Level of Evidence C) 1

   • Persistent hemodynamic instability
   • Worsening respiratory failure
   • Refractory shock

3. Selected intermediate-risk PE patients with clinical deterioration (Class IIb; Level of Evidence C) 1

   • Worsening hemodynamic parameters
   • Worsening respiratory failure
   • Severe RV dysfunction
   • Major myocardial necrosis

4. Thrombus in transit (particularly with high risk of decompensation) 1

   • Especially with right atrial or ventricular thrombus
   • 5-fold increased risk of death

Additional Factors Favoring Interventional Thrombectomy

• Clot characteristics:

  • Proximal clot location (more amenable to catheter-based removal)
  • Large thrombus burden
  • Clot in transit with risk of "second hit" 1

• Patient characteristics:

  • Severe respiratory distress despite anticoagulation
  • Deteriorating respiratory status
  • Poor cardiopulmonary reserve
  • Impaired functional status before PE 1

Contraindications to Interventional Thrombectomy

• Absolute:

  • Inability to access the venous system
  • Inability to anticoagulate the patient

• Relative:

  • Very poor preexisting functional status (futility)
  • Short life expectancy
  • Metastatic cancer with poor prognosis 1

Procedural Considerations

• Only operators experienced with these techniques should perform catheter-based intervention 1
• Interventionalists must be comfortable managing:
  • Cardiogenic shock
  • Bradyarrhythmias
  • Anticoagulation
  • Cardiac tamponade 1
• Invasive arterial access is recommended for patients with shock/hypotension 1

Cautions and Pitfalls

• Rheolytic thrombectomy has been associated with pulmonary hemorrhage and hemodynamic/respiratory collapse (FDA black-box warning) 1
• Procedural hemodynamic or respiratory decompensation is a concern, particularly in already unstable patients
• Institutions without expertise in advanced intervention for PE should establish transfer protocols to centers with these capabilities 1
• Catheter embolectomy and surgical thrombectomy are not recommended for patients with low-risk PE or submassive PE with minor RV dysfunction and no clinical worsening 1

Algorithm for Decision-Making

1. Assess PE severity (high-risk, intermediate-risk, low-risk)
2. For high-risk PE:
   • First-line: Systemic thrombolysis if no contraindications
   • If contraindicated or failed: Interventional thrombectomy or surgical embolectomy
3. For intermediate-risk PE:
   • First-line: Anticoagulation with close monitoring
   • If clinical deterioration: Consider interventional thrombectomy
4. For low-risk PE:
   • Anticoagulation alone (interventional thrombectomy not indicated)

By following this evidence-based approach, clinicians can appropriately select patients who will benefit most from interventional thrombectomy while avoiding unnecessary procedures in those who can be managed with anticoagulation alone.