Mechanical Thrombectomy of M2-Occlusion

Area of Science:

• Neurology
• Interventional Radiology
• Stroke Medicine

Background:

• Mechanical thrombectomy is established for anterior circulation large-vessel occlusions in acute stroke.
• Distal middle cerebral artery (MCA) occlusions (M2-segment) often cause severe symptoms but are not typically first-line for endovascular therapy.
• This study investigates the efficacy and safety of mechanical thrombectomy for M2-segment occlusions.

Purpose of the Study:

• To evaluate the efficacy and safety of stent-retriever thrombectomy for acute M2-segment middle cerebral artery occlusions.
• To compare outcomes between M2-segment occlusions and more proximal M1-segment occlusions.

Main Methods:

• A retrospective analysis of 119 patients undergoing stent-retriever thrombectomy for acute MCA occlusions (October 2011 - April 2013).
• Patients were categorized into M1 (n=104) and M2 (n=15) occlusion groups.
• Outcomes assessed included recanalization success, periprocedural complications, hemorrhage, and modified Rankin Scale (mRS) at 90 days.

Main Results:

• Higher reperfusion rates (TICI 2b/3) were observed in the M2 group (93.3%) compared to the M1 group (76.0%).
• A good clinical outcome (mRS 0-2) at 3 months was more frequent in the M2 group (60%) versus the M1 group (43.3%).
• No periprocedural complications occurred in the M2 group, while 3 occurred in the M1 group; mortality was higher in the M1 group (21.2% vs 6.7%).

Conclusions:

• Endovascular treatment for M2-segment occlusions is safe, with no increased procedural risk or hemorrhage.
• Mechanical thrombectomy for M2 occlusions demonstrated a greater likelihood of favorable angiographic and clinical results compared to M1 occlusions.
• Stent-retriever thrombectomy should be considered for patients with severe symptoms due to acute M2-segment occlusions.