Intracranial Hemorrhage After Mechanical Thrombectomy: Proximal Versus Distal MCA M1 Occlusions
Dogan Hasan, Aytac Emrah, Balgetir Ferhat, Akpinar Cetin KursadABSTRACT
Background and Purpose
Intracranial hemorrhage (ICH) is a recognized complication of mechanical thrombectomy that may affect outcomes. Whether the occlusion site within the MCA M1 segment (proximal vs. distal) influences the risk and subtype distribution of post‐procedural ICH remains uncertain. We compared the frequency and subtypes of ICH between proximal and distal MCA M1 occlusions and evaluated their impact on 90‐day clinical outcomes.
Methods
We retrospectively analyzed consecutive patients from two stroke centers who underwent mechanical thrombectomy for isolated MCA M1 occlusion. Patients were classified as proximal or distal. Post‐procedural ICH was assessed on 24‐h non‐contrast CT (or earlier if NIHSS worsened by ≥ 4 points) and categorized as hemorrhagic infarction (HI, Types 1–2) or parenchymal hematoma (PH, Types 1–2). Ninety‐day outcomes were evaluated using the modified Rankin scale (mRS).
Results
Among 178 patients (107 proximal, 71 distal), successful reperfusion (mTICI 2b–3) was achieved in 89.1%. HI was more frequent in proximal than distal occlusions (27.1% vs. 12.6%, p = 0.037), mainly due to HI1 (12.1% vs. 1.4%, p = 0.009). PH and symptomatic ICH rates were similar between groups. In logistic regression analysis, occlusion site was not an independent determinant of post‐thrombectomy hemorrhage (OR 1.52, 95% CI 0.80–2.91, p = 0.20). At 90 days, functional outcomes did not differ significantly between groups (mRS 0–2: 39.2% proximal vs. 47.9% distal, p = 0.271).
Conclusion
Hemorrhagic infarction is more frequently observed in proximal MCA M1 occlusions, likely due to involvement of lenticulostriate arteries. However, this does not translate into a worse functional outcome.