Supplementary Material for: Determination of the Onset-to-Reperfusion Time Threshold in Mechanical Thrombectomy Patients with Good Collateral Flow

Introduction: Mechanical thrombectomy (MT) is an effective treatment for acute ischemic stroke caused by large vessel occlusion. Prior investigations have shown that a well developed collateral circulation preserves the ischemic penumbra more effectively than inadequate collateral flow. As a result, stroke patients with robust collaterals generally achieve more favorable functional outcomes after MT. However, it remains unclear how long robust collateral flow can preserve the penumbra. This study aimed to determine the onset-to-reperfusion time threshold within which good collaterals improve outcomes.
Methods: We retrospectively analyzed patients with acute ischemic stroke who achieved successful reperfusion (expanded Thrombolysis in Cerebral Infarction ≥ 2b) after MT between 2017 and 2023. Collateral status was graded with the ASITN/SIR scale and categorizing patients into good collateral (grades 2–4) and poor collateral (grades 0–1) group. The primary endpoint was excellent functional outcome, defined as a 90 day modified Rankin Scale (mRS) score of 0–1. We used receiver operating characteristic curve analysis to predict excellent outcomes, determining cut-off points for onset-to-reperfusion time using the Youden index. Additionally, the onset-to-reperfusion time was divided into quartiles based on the distribution of all cases, and excellent outcome rates were compared across these quartiles.
Results: A total of 77 patients were included (good collateral group, 46; Poor collateral group, 31), with a median onset-to-reperfusion time of 310 min (interquartile range, 200–621 min). In the good collateral group, the cutoff time for achieving excellent outcomes was 235 min (sensitivity, 88%; specificity, 62%). The good collateral group showed significantly higher excellent outcome rates than the PC group at the shortest interval (< 200 min).
Conclusion: In patients with good collateral flow who achieved reperfusion after MT, the onset-to-reperfusion time threshold associated with an excellent outcome was 235 min. The 235 min cut off may serve as a practical target for onset to reperfusion timing in patients with favorable collateral circulation undergoing MT.

引言：机械取栓术（Mechanical thrombectomy, MT）是治疗大血管闭塞所致急性缺血性脑卒中的有效手段。既往研究表明，发育良好的侧支循环较侧支血流不足者，能更有效地挽救缺血半暗带。因此，侧支循环充足的脑卒中患者在接受MT治疗后，通常可获得更良好的功能预后。但目前尚不清楚充足的侧支血流能够维持半暗带的时长。本研究旨在明确可使良好侧支循环患者获益的发病至再灌注时间阈值。

方法：本研究回顾性分析了2017年至2023年间接受MT治疗后实现成功再灌注（扩展版脑梗死溶栓分级≥2b）的急性缺血性脑卒中患者。采用美国介入和治疗神经放射学学会/介入放射学学会侧支循环评分量表（ASITN/SIR scale）对患者侧支状态进行分级，并将患者分为良好侧支组（分级2~4级）与不良侧支组（分级0~1级）。本研究的主要终点为优良功能预后，定义为发病90天时改良Rankin量表（modified Rankin Scale, mRS）评分0~1分。采用受试者工作特征曲线分析预测优良预后，通过约登指数确定发病至再灌注时间的截断值。此外，基于所有病例的发病至再灌注时间分布将其分为四分位数组，并比较各组间的优良预后率。

结果：本研究共纳入77例患者，其中良好侧支组46例、不良侧支组31例；患者发病至再灌注时间的中位数为310min（四分位间距：200~621min）。在良好侧支组中，获得优良预后的截断时间为235min（灵敏度88%，特异度62%）。在最短时间间隔组（<200min）中，良好侧支组的优良预后率显著高于不良侧支组。

结论：对于接受MT治疗后实现再灌注且侧支循环良好的患者，与优良预后相关的发病至再灌注时间阈值为235min。该235min的截断值可作为侧支循环良好的MT治疗患者发病至再灌注时间控制的实用目标。