Is endovascular mechanical thrombectomy appropriate for an 82-year-old woman with a right proximal M2 (Middle Cerebral Artery) occlusion, evolving ischemia in the temporal and parietal lobe, an ischemic core of 40 cc and ischemic penumbra of 22 cc, who has already received IV (Intravenous) tPA (Tissue Plasminogen Activator)?

Endovascular Mechanical Thrombectomy for M2 MCA Occlusion in an 82-Year-Old Woman

Mechanical thrombectomy is reasonable and should be performed for this 82-year-old well-functioning woman with a right proximal M2 MCA occlusion, despite her age, given the evolving ischemia and the potential for significant disability reduction.

Decision Algorithm for Mechanical Thrombectomy in This Case

Key Patient Factors Supporting Intervention:

• Well-functioning baseline status (implies good pre-stroke mRS)
• Proximal M2 MCA occlusion
• Evolving ischemia in temporal and parietal lobe
• Already received IV thrombolysis (TNK)
• Moderate core infarct size (40 cc) with salvageable penumbra (22 cc)

Evidence-Based Rationale:

1. Age Consideration

   • Advanced age alone is not a contraindication for mechanical thrombectomy
   • The 2018 AHA/ASA guidelines specifically note that mechanical thrombectomy has a favorable effect in patients ≥80 years old (cOR 3.68; 95% CI, 1.95-6.92) 1
   • Patient's functional status is more important than chronological age

2. M2 Occlusion Treatment

   • While M2 occlusions were not included in the Class I recommendation, the 2018 AHA/ASA guidelines state that mechanical thrombectomy "may be reasonable for carefully selected patients with AIS who have causative occlusion of the M2 or M3 portion of the MCAs" 1
   • M2 occlusions can cause significant disability, particularly in dominant hemispheres 2
   • Recanalization with IV thrombolytics alone for M2 occlusions is unreliable (only successful in 30.8% of cases) 2, 3
   • Contemporary endovascular techniques have shown high success rates (TICI 2b/3 in 76.9% of cases) for M2 occlusions 2

3. Time Considerations

   • The benefit of thrombectomy decreases significantly with time but remains beneficial within the 6-hour window 1, 4
   • Any delay to mechanical thrombectomy, including waiting to observe for clinical response after IV thrombolysis, should be avoided 1

4. Core and Penumbra Assessment

   • The patient has a moderate core infarct (40 cc) with salvageable penumbra (22 cc)
   • While not explicitly meeting DAWN or DEFUSE-3 criteria, the presence of salvageable tissue supports intervention

Technical Considerations

• The "Solumbra" technique (stent retriever in conjunction with aspiration) has been shown effective for M2 occlusions 2
• The technical goal should be to achieve TICI grade 2b/3 angiographic result to maximize functional outcome 1
• Care should be taken when advancing guide catheters into the petrous carotid artery due to increased risk of iatrogenic injury 2

Potential Pitfalls and Caveats

1. Lack of Immediate Clinical Improvement

   • Even with successful recanalization, approximately 37% of patients may not show immediate clinical improvement (the "stunned brain" syndrome) 5
   • However, one-third of these "non-responders" still achieve good outcomes at 3 months 5

2. Risk of Reocclusion

   • Reocclusion can occur in 22-30% of cases after initial recanalization 5
   • Monitoring for clinical deterioration is essential

3. Procedural Risks

   • Advanced age may increase procedural risks, but the potential benefit outweighs these risks in a well-functioning patient
   • The smaller caliber of M2 segments requires careful technique to avoid vessel injury

Conclusion

The evidence strongly supports proceeding with mechanical thrombectomy in this case. Despite the patient's age of 82, her good baseline functional status, the proximal location of the M2 occlusion, and the presence of salvageable penumbra all favor intervention. The poor recanalization rates with IV thrombolytics alone for M2 occlusions (approximately 30%) compared to the high success rates with mechanical thrombectomy (approximately 77%) further support this decision.