Supplementary Material for: Clinical Relevance of Computed Tomography Perfusion-Estimated Infarct Volume in Acute Ischemic Stroke Patients within the 6-h Therapeutic Time Window

<b><i>Introduction:</i></b> Although the estimated infarct volume on baseline computed tomography perfusion (CTP) can identify patients who are likely to benefit from endovascular thrombectomy (EVT) in late time window strokes, the role of CTP imaging in early time windows has not been established. We assessed the clinical impact of CTP-estimated infarct volume on long-term prognosis after EVT, particularly in patients with early time window stroke. <b><i>Methods:</i></b> We retrospectively reviewed patients who underwent pretreatment CTP and EVT for large vessel occlusion in the anterior circulation within 6 h after symptom onset between March 2014 and February 2019. The infarct volume at baseline CTP was estimated using commercially available software (RAPID, iSchemaView, Menlo Park, CA, USA) with a cerebral blood flow threshold &lt;30% of the normal brain. Risk factors for poor outcome after EVT were evaluated, and a receiver operating characteristic (ROC) curve analysis was used to identify CTP-estimated infarct volumes that optimally predicted the development of symptomatic intracranial hemorrhage (sICH) and poor outcomes (modified Rankin Scale [mRS] 3–6) at 90 days. <b><i>Results:</i></b> Of 120 patients, successful recanalization was achieved in 89 (74.2%) patients, while 61 (50.8%) showed poor outcomes at 90 days. Among 89 patients with successful recanalization after EVT, age, diabetes, clinical stroke severity, CTP-estimated infarct volume, and sICH development were independently associated with 90-day clinical outcomes. ROC analysis identified infarct volumes of ≥88.5 mL and ≥74 mL as the optimal thresholds for predicting poor outcome and development of sICH, respectively. Patients with large infarct volumes showed poorer outcomes (odds ratio [OR], 7.704; 95% confidence interval [CI], 1.528–38.839) and higher rates of sICH development (OR, 10.857; 95% CI, 1.835–64.235). Among patients with large infarction volumes (≥88.5 mL), the 90-day mRS demonstrated a shift toward better outcomes in patients with successful recanalization. <b><i>Conclusion:</i></b> Larger initial infarct volumes are significantly associated with worse clinical outcomes in patients who underwent EVT because of early time window stroke. Furthermore, our study of 6-h data demonstrated that an initial infarction of more than a certain volume might be an independent risk factor for sICH development and poor outcomes even in patients with successful recanalization. However, we still observed benefits of EVT in patients with large ischemic cores. The CTP-estimated infarct volume might be an important prognostic factor after EVT rather than a biomarker predicting treatment effectiveness.

引言：尽管基线CT灌注成像（computed tomography perfusion, CTP）所估算的梗死体积，可识别出在晚期时间窗卒中中有望从血管内取栓术（endovascular thrombectomy, EVT）中获益的患者，但CTP成像在早期时间窗卒中中的应用价值尚未明确。本研究旨在评估CTP估算的梗死体积对EVT术后长期预后的临床影响，尤其针对早期时间窗卒中患者。

方法：本研究回顾性分析了2014年3月至2019年2月期间，症状发作后6小时内接受术前CTP检查并因前循环大血管闭塞行EVT的患者。基线CTP的梗死体积采用商用软件（RAPID、iSchemaView，美国加利福尼亚州门洛帕克市）进行估算，以脑血流量低于正常脑组织30%作为阈值。本研究评估了EVT术后不良预后的危险因素，并通过受试者工作特征曲线（receiver operating characteristic, ROC）分析，筛选出可最优预测症状性颅内出血（symptomatic intracranial hemorrhage, sICH）发生以及90天改良Rankin量表（modified Rankin Scale, mRS）评分3~6分的不良预后的CTP估算梗死体积界值。

结果：本研究共纳入120例患者，其中89例（74.2%）实现成功再通，61例（50.8%）在90天随访时出现不良预后。在89例EVT术后成功再通的患者中，年龄、糖尿病、临床卒中严重程度、CTP估算的梗死体积以及sICH发生情况均与90天临床预后独立相关。ROC曲线分析显示，预测不良预后和sICH发生的最优梗死体积阈值分别为≥88.5 mL和≥74 mL。梗死体积较大的患者预后更差（比值比[OR]=7.704；95%置信区间[CI]：1.528~38.839），且sICH发生率更高（OR=10.857；95%CI：1.835~64.235）。在梗死体积≥88.5 mL的患者中，成功再通者的90天mRS评分分布向更优预后方向偏移。

结论：对于因早期时间窗卒中接受EVT的患者，初始梗死体积越大，临床预后越差，二者存在显著相关性。此外，基于6小时时间窗数据的本研究显示，即使在成功再通的患者中，初始梗死体积超过特定界值仍可能是sICH发生和不良预后的独立危险因素。但本研究仍观察到EVT对大缺血核心区患者的获益。CTP估算的梗死体积或许可作为EVT术后重要的预后预测因子，而非仅用于预测治疗有效性。