Supplementary Material for: Infarct Pattern and Clinical Outcome in Acute Ischemic Stroke Following Middle Cerebral Artery Occlusion

<b><i>Background:</i></b> Cerebral arterial occlusion develops via two distinct mechanisms: thrombosis and embolism. Discrimination between thrombosis and embolism is an important aspect needed for further determining the etiology of stroke in a patient. This study evaluated infarct patterns and outcomes in acute stroke patients with relevant artery occlusions, focusing on features specific to each occlusion mechanism. <b><i>Methods:</i></b> Acute ischemic stroke patients who were consecutively registered in a tertiary hospital between 2002 and 2010 with infarctions in the middle cerebral artery territory and a corresponding M1 occlusion confirmed by magnetic resonance angiography, computed tomography angiography, or conventional angiography were enrolled. Patients with a high-risk cardioembolic source, clear recanalization, concurrent infarct in an arterial territory other than the occlusion site, or no prior occlusion in a previous imaging within 1 month were assigned to the embolic occlusion group, and the remaining patients were assigned to the thrombotic occlusion group. The infarct pattern was categorized into seven groups: scattered, territorial, lenticulostriatal, scattered-territorial, scattered-lenticulostriatal, territorial-lenticulostriatal, and scattered-territorial-lenticulostriatal. Data of stroke recurrence and mortality were collected through electronic medical record and the National Vital Statistics System. <b><i>Results:</i></b> Of 114 patients, 54 (47.4%) were classified as having an embolic occlusion. When infarct patterns were compared between the groups, any-scattered infarct pattern was more common in the thrombotic occlusion group (71.2% vs. 40.7%, p = 0.002), and any-territorial infarct pattern was more prevalent in the embolic occlusion group (55.6% vs. 28.8%, p = 0.005). In addition, scattered-without-territorial pattern was higher in the thrombotic occlusion group (OR: 0.25; CI: 0.11-0.57; p = 0.001). Any-territorial infarct pattern was also related to initial stroke severity (NIHSS on admission, OR: 400.98; CI: 2.94-54,741.32; p = 0.017) and poor functional outcome (modified Rankin Scale score ≥4) at discharge (OR: 14.40; CI: 1.37-152.00; p = 0.027) independent of other parameters. However, no association was found between stroke recurrence, mortality and occlusion mechanism. <b><i>Conclusion:</i></b> This study shows that specific infarct patterns are related to cerebral arterial occlusion mechanisms and are correlated with functional outcome. Otherwise, the results of our study indicates that infarct patterns on DWI might be a clue for determining ischemic stroke etiology on patients with major cerebral artery occlusion.

<b><i>背景：</i></b> 脑动脉闭塞（cerebral arterial occlusion）通过两种截然不同的机制发生：血栓形成（thrombosis）与栓塞（embolism）。区分血栓形成与栓塞是明确患者脑卒中病因的关键环节之一。本研究评估了伴有相关动脉闭塞的急性脑卒中患者的梗死模式与预后，重点关注两种闭塞机制各自的特征性表现。<b><i>方法：</i></b> 本研究纳入2002年至2010年间于某三级医院连续登记的急性缺血性脑卒中患者，所有患者均存在大脑中动脉供血区梗死，且经磁共振血管造影（magnetic resonance angiography, MRA）、计算机断层血管造影（computed tomography angiography, CTA）或常规血管造影证实存在M1段闭塞。存在高风险心源性栓塞来源、明确血管再通、闭塞部位以外动脉供血区并发梗死，或1个月内既往影像学未显示闭塞的患者被归入栓塞性闭塞组，其余患者则被分配至血栓性闭塞组。梗死模式被分为7类：散在型、供血区全域型、豆纹动脉型、散在-供血区全域型、散在-豆纹动脉型、供血区全域-豆纹动脉型以及散在-供血区全域-豆纹动脉型。通过电子病历与国家生命统计系统收集脑卒中复发率与死亡率数据。<b><i>结果：</i></b> 114例患者中，54例（47.4%）被归类为栓塞性闭塞。对比两组梗死模式可见，伴散在成分的梗死模式在血栓性闭塞组中更为常见（71.2% vs. 40.7%，p=0.002），而伴供血区全域成分的梗死模式在栓塞性闭塞组中更为普遍（55.6% vs. 28.8%，p=0.005）。此外，单纯散在（无供血区全域）梗死模式在血栓性闭塞组中的占比更高（比值比[OR]: 0.25；95%置信区间[CI]: 0.11-0.57；p=0.001）。伴供血区全域成分的梗死模式还与初始脑卒中严重程度（入院时美国国立卫生研究院卒中量表[National Institutes of Health Stroke Scale, NIHSS]评分，OR: 400.98；CI: 2.94-54741.32；p=0.017）以及出院时不良功能预后（改良Rankin量表[modified Rankin Scale, mRS]评分≥4）独立相关（OR: 14.40；CI: 1.37-152.00；p=0.027）。然而，未发现脑卒中复发率、死亡率与闭塞机制之间存在关联。<b><i>结论：</i></b> 本研究表明，特定的梗死模式与脑动脉闭塞机制相关，且与功能预后存在关联。此外，本研究结果提示，弥散加权成像（diffusion-weighted imaging, DWI）上的梗死模式或可为伴有大脑血管闭塞的缺血性脑卒中患者明确病因提供线索。