Abstract：
BACKGROUND: The M1 middle cerebral artery (MCA) commonly bifurcates into M2 superior and M2 inferior segments. However, MCA anatomy is highly variable rendering classification for mechanical thrombectomy trials difficult. This study explored safety and effectiveness of M2 MCA stroke thrombectomy stratified by M2 MCA anatomy.
METHODS: Cases of large vessel occlusion strokes treated by mechanical thrombectomy between February 2016 and August 2022 were reviewed (N = 784). M1 (n = 431) and M2 (n = 118) MCA occlusions were assessed. Among M2 MCA occlusions, only prototypical MCA bifurcation anatomy cases were included (n = 99). Dominance was assessed based on angiography. Procedural and outcome data were compared between M1, M2 superior, and M2 inferior MCA occlusions.
RESULTS: Baseline demographics and periprocedural criteria of M2 superior (n = 56) and M2 inferior (n = 43) occlusion mechanical thrombectomies were comparable. The occluded branch was dominant in 41/43 (95.3%) M2 inferior cases, but in only 37/56 (66.1%) M2 superior cases (P < 0.001). The 90-day favorable functional outcome (modified Rankin Scale score 0-2) and mortality (modified Rankin Scale score 6) rates were 60.0% and 8.9% in M2 superior, 42.9% and 32.6% in M2 inferior, and 44.1% and 26.0% in M1 (n = 431) cases. Compared with M2 superior cases, in M2 inferior cases, favorable outcome rates were lower (P = 0.094) and mortality rates were higher (P = 0.003) and resembled M1 rates (P = 0.750 and P = 0.355, respectively).
CONCLUSIONS: In the setting of prototypical MCA bifurcation anatomy, thrombectomy of dominant M2 inferior occlusions had outcome rates similar to M1 occlusions. In contrast, M2 superior occlusions had significantly lower mortality rates and a trend toward better favorable functional outcome rates.
METHODS: Cases of large vessel occlusion strokes treated by mechanical thrombectomy between February 2016 and August 2022 were reviewed (N = 784). M1 (n = 431) and M2 (n = 118) MCA occlusions were assessed. Among M2 MCA occlusions, only prototypical MCA bifurcation anatomy cases were included (n = 99). Dominance was assessed based on angiography. Procedural and outcome data were compared between M1, M2 superior, and M2 inferior MCA occlusions.
RESULTS: Baseline demographics and periprocedural criteria of M2 superior (n = 56) and M2 inferior (n = 43) occlusion mechanical thrombectomies were comparable. The occluded branch was dominant in 41/43 (95.3%) M2 inferior cases, but in only 37/56 (66.1%) M2 superior cases (P < 0.001). The 90-day favorable functional outcome (modified Rankin Scale score 0-2) and mortality (modified Rankin Scale score 6) rates were 60.0% and 8.9% in M2 superior, 42.9% and 32.6% in M2 inferior, and 44.1% and 26.0% in M1 (n = 431) cases. Compared with M2 superior cases, in M2 inferior cases, favorable outcome rates were lower (P = 0.094) and mortality rates were higher (P = 0.003) and resembled M1 rates (P = 0.750 and P = 0.355, respectively).
CONCLUSIONS: In the setting of prototypical MCA bifurcation anatomy, thrombectomy of dominant M2 inferior occlusions had outcome rates similar to M1 occlusions. In contrast, M2 superior occlusions had significantly lower mortality rates and a trend toward better favorable functional outcome rates.
摘要：
背景：M1大脑中动脉（MCA）通常分为M2上段和M2下段。然而,MCA解剖结构高度可变，机械血栓切除术（MT）试验的分类困难。根据M2MCA解剖分层的M2MCA卒中血栓切除术的安全性和有效性仍有待探索。
方法：回顾了2016年2月至2022年8月2日接受MT的大血管闭塞卒中（n=784）。评估M1（n=431）和M2MCA（n=118）闭塞。在M2MCA闭塞中，仅包括典型的MCA分叉解剖病例（n=99）。根据血管造影评估优势。比较M1，M2上和M2下MCA闭塞之间的程序和结果数据。
结果：M2上（n=56）和M2下（n=43）闭塞MT的基线人口统计学和围手术期标准具有可比性。在M2次品病例中，在M2优势病例中，闭塞分支占41/43（95.3％），但仅占37/56（66.1％）（p<0.001）。在M2中，90天有利功能结局（mRS0-2）和死亡率（mRS6）分别为60.0％和8.9％。M2中的42.9%和32.6%，M1组分别为44.1%和26.0%(n=431)。相比M2优越,M2不良结局率较低（p=0.094），死亡率较高（p=0.003），与M1结局率相似（分别为p=0.750和p=0.355）。
结论：在建立典型的MCA分叉解剖结构时，显性M2下壁闭塞的血栓切除术的结局率与M1闭塞相似.相比之下,M2上闭塞具有显著较低的死亡率和更有利的功能结局率的趋势。
方法：回顾了2016年2月至2022年8月2日接受MT的大血管闭塞卒中（n=784）。评估M1（n=431）和M2MCA（n=118）闭塞。在M2MCA闭塞中，仅包括典型的MCA分叉解剖病例（n=99）。根据血管造影评估优势。比较M1，M2上和M2下MCA闭塞之间的程序和结果数据。
结果：M2上（n=56）和M2下（n=43）闭塞MT的基线人口统计学和围手术期标准具有可比性。在M2次品病例中，在M2优势病例中，闭塞分支占41/43（95.3％），但仅占37/56（66.1％）（p<0.001）。在M2中，90天有利功能结局（mRS0-2）和死亡率（mRS6）分别为60.0％和8.9％。M2中的42.9%和32.6%，M1组分别为44.1%和26.0%(n=431)。相比M2优越,M2不良结局率较低（p=0.094），死亡率较高（p=0.003），与M1结局率相似（分别为p=0.750和p=0.355）。
结论：在建立典型的MCA分叉解剖结构时，显性M2下壁闭塞的血栓切除术的结局率与M1闭塞相似.相比之下,M2上闭塞具有显著较低的死亡率和更有利的功能结局率的趋势。
