What are the risks and considerations for thrombectomy (blood clot removal)?

Risks of Thrombectomy

Endovascular thrombectomy carries significant risks including intracranial hemorrhage, vessel perforation/dissection, embolization to new territories, and access-site complications, with approximately 15% of patients experiencing complications with clinical sequelae. 1, 2

Major Complications

Neurological Complications

• Intracranial hemorrhage (ICH)

  • Occurs in 6-8% of patients undergoing thrombectomy 1
  • Higher risk in patients receiving concurrent thrombolytic therapy
  • Requires immediate management with blood pressure control (target systolic 130-150 mmHg) 1
  • Mortality rate of 20-50% following ICH 1

• Embolization to new territories

  • Clot fragmentation during retrieval can cause distal emboli 2
  • Can lead to new infarcts in previously unaffected areas
  • Risk is higher with certain retrieval techniques

• Vessel injury

  • Arterial perforation (potentially catastrophic)
  • Vessel dissection
  • Vasospasm during catheter manipulation 2

Procedural/Access Complications

• Access-site problems 2

  • Groin hematoma
  • Vessel injury
  • Nerve injury
  • Infection
  • Pseudoaneurysm formation

• Device-related complications

  • Device detachment/misplacement
  • Stent retriever failure to deploy or retrieve

Risk Factors for Complications

• Patient-related factors

  • Advanced age
  • Severe neurological deficits (NIH Stroke Scale ≥6)
  • Extensive infarction prior to procedure
  • Concurrent anticoagulation or antiplatelet therapy

• Procedural factors

  • Time from symptom onset (>6 hours increases risk) 1
  • Vessel occlusion location (distal vessels have higher complication rates) 1
  • Operator experience
  • Device selection

Special Considerations for Different Patient Populations

Patients with Contraindications to IV Thrombolysis

• Primary mechanical thrombectomy appears safe in patients with contraindications to IV thrombolysis 3
• Recanalization rates are similar to those receiving combined IV thrombolysis plus thrombectomy
• However, functional independence rates may be lower (43% vs 68%) 3

Patients with Infective Endocarditis

• Thrombectomy is as effective and safe in patients with infective endocarditis as in those without 4
• Prior IV thrombolysis may decrease procedural safety in these patients
• Successful recanalization rates are comparable (76% vs 83%) 4

Cancer Patients with Venous Thromboembolism

• For hemodynamically unstable pulmonary embolism (PE) in cancer patients with lower bleeding risk, thrombectomy should be considered 1
• Rescue thrombectomy can be considered in patients with hemodynamically stable PE who deteriorate despite anticoagulation 1

Emerging Technologies and Risk Mitigation

Recent innovations like the milli-spinner thrombectomy device aim to reduce complications by:

• Modifying clot microstructure rather than rupturing or cutting
• Reducing clot volume by up to 95% for easier removal
• Potentially reducing distal embolization rates 5

Risk-Benefit Assessment

The decision to perform thrombectomy should balance:

1. Benefits:

   • High recanalization rates (75-85%)
   • Improved functional outcomes in appropriate patients
   • Reduced mortality in large vessel occlusions

2. Risks:

   • ~15% risk of complications with clinical sequelae 2
   • 6-8% risk of symptomatic intracranial hemorrhage
   • Procedural complications

Clinical Decision Algorithm

1. For acute ischemic stroke with large vessel occlusion:

   • If NIH Stroke Scale ≥6 and within 6 hours of symptom onset → thrombectomy indicated 1
   • If 6-24 hours from symptom onset → use advanced neuroimaging to identify salvageable tissue 1

2. For basilar artery occlusion:

   • Consider thrombectomy up to 24 hours after symptom onset 1, 6
   • Administer IV thrombolysis to eligible patients even if thrombectomy is planned 6

3. For pulmonary embolism:

   • If hemodynamically unstable with lower bleeding risk → consider thrombectomy 1
   • If contraindication to anticoagulation → consider IVC filter (retrievable preferred) with or without thrombectomy 1

4. Post-procedure monitoring:

   • Close blood pressure monitoring (target systolic 130-150 mmHg)
   • Neurological assessments
   • Early imaging to detect hemorrhagic complications

Remember that thrombectomy requires an integrated, multidisciplinary approach including stroke physicians, interventional specialists, and neurologists to optimize outcomes and manage potential complications 1.