Supplementary Material for: Instant Reocclusion following Mechanical Thrombectomy of in situ Thromboocclusion and the Role of Low-Dose Intra-Arterial Tirofiban

Background: An in situ thromboocclusion (IST) is defined as an infarct extensively involving all or most of a stenosed arterial territory, which is one major stroke mechanism related to intracranial atherosclerosis (ICAS). We focused on ISTs occurring in major cerebral arteries and analyzed their rate of instant reocclusion during mechanical thrombectomy (MT) compared with non-ISTs. Also, we introduced a treatment strategy of low-dose intra-arterial tirofiban administration to prevent such reocclusion following repeat recanalization, and evaluated its safety and efficacy. Methods: We analyzed 168 consecutive patients treated with MT over a 2-year period from May 2011 to April 2013. During MT, if angiography following a successful recanalization showed stenosis at the occlusion site, we performed additional angiographic runs every 10 min for 30 min after the recanalization. Then, if angiography revealed reocclusion, we performed a repeat recanalization, using the same MT technique but additionally followed by low-dose intra-arterial tirofiban infusion. Time-of-flight MR angiography or CT angiography was performed to confirm any underlying ICAS at the occlusion site 5-7 days after the procedure. The patients who had confirmed underlying ICAS were included in the IST cohort. Results: Of 168 enrolled patients, we excluded 36 who could not be checked for underlying ICAS at the occlusion site for one of the following reasons: recanalization failure (n = 11), rescue stenting after tirofiban failure (n = 5) and lack of follow-up vascular imaging (n = 20). The incidence of IST was 30.3% (40/132). All IST patients were confirmed to have underlying ICAS by follow-up vascular imaging. Instant reocclusion after successful recanalization was significantly more frequent in the IST cohort [26/40 (65%) vs. 3/92 (3.3%); p Conclusions: In situ thromboocclusion was characterized by a significantly higher chance of instant reocclusion during MT. In such cases, low-dose intra-arterial tirofiban administration may be effective and safe. However, future confirmation by prospective multicenter trials seems necessary.

背景：原位血栓闭塞（in situ thromboocclusion, IST）指累及狭窄动脉供血区域全部或大部分的脑梗死，是与颅内动脉粥样硬化（intracranial atherosclerosis, ICAS）相关的主要卒中发病机制之一。本研究聚焦于发生于主要脑动脉的原位血栓闭塞病例，对比其与非原位血栓闭塞病例在机械取栓术（mechanical thrombectomy, MT）过程中的即时再闭塞发生率。此外，本研究引入低剂量动脉内替罗非班给药策略，以预防重复再通术后发生此类再闭塞，并评估该策略的安全性与有效性。

方法：本研究分析了2011年5月至2013年4月这2年间接受机械取栓术治疗的168例连续入组患者。在机械取栓术操作中，若成功再通后血管造影显示闭塞部位存在狭窄，则于再通术后每10分钟行一次血管造影检查，持续30分钟。若血管造影提示发生再闭塞，则采用相同的机械取栓技术实施重复再通，并于术后追加低剂量动脉内替罗非班输注。术后5~7天，采用飞行时间磁共振血管造影（time-of-flight MR angiography）或计算机断层血管造影（CT angiography）确认闭塞部位是否存在潜在颅内动脉粥样硬化。将经影像学证实存在潜在颅内动脉粥样硬化的患者纳入原位血栓闭塞队列。

结果：168例入组患者中，因以下原因无法评估闭塞部位潜在颅内动脉粥样硬化的36例患者被排除：再通失败（n = 11）、替罗非班治疗失败后行补救支架置入术（n = 5）以及缺乏随访血管影像学检查（n = 20）。原位血栓闭塞的发生率为30.3%（40/132）。所有原位血栓闭塞患者均经随访血管影像学证实存在潜在颅内动脉粥样硬化。成功再通后的即时再闭塞发生率在原位血栓闭塞队列中显著更高[26/40（65%） vs. 3/92（3.3%）；P

结论：原位血栓闭塞的特征为机械取栓术过程中即时再闭塞风险显著升高。此类病例中，低剂量动脉内替罗非班给药策略或具备有效性与安全性。不过，仍需未来多中心前瞻性试验进一步验证该结论。