Department of Neurological Surgery, Washington University School of Medicine in St. Louis, Missouri 63110, USA.
J Neurosurg. 2013 Jan;118(1):25-33. doi: 10.3171/2012.9.JNS12551. Epub 2012 Oct 26.
The Carotid Occlusion Surgery Study (COSS) was conducted to determine if superficial temporal artery-middle cerebral artery (STA-MCA) bypass, when added to the best medical therapy, would reduce subsequent ipsilateral stroke in patients with complete internal carotid artery (ICA) occlusion and an elevated oxygen extraction fraction (OEF) in the cerebral hemisphere distal to the occlusion. A recent publication documented the methodology of the COSS in detail and briefly outlined the major findings of the trial. The surgical results of the COSS are described in detail in this report.
The COSS was a prospective, parallel-group, 1:1 randomized, open-label, blinded-adjudication treatment trial. Participants, who had angiographically demonstrated complete occlusion of the ICA causing either a transient ischemic attack or ischemic stroke within 120 days and hemodynamic cerebral ischemia indicated by an increased OEF measured by PET, were randomized to either surgical or medical treatment. One hundred ninety-five patients were randomized: 97 to the surgical group and 98 to the medical group. The surgical patients underwent an STA-MCA cortical branch anastomosis.
In the intention-to-treat analysis, the 2-year rates for the primary end point were 21% for the surgical group and 22.7% for the medical group (p = 0.78, log-rank test). Fourteen (15%) of the 93 patients who had undergone an arterial bypass had a primary end point ipsilateral hemispheric stroke in the 30-day postoperative period, 12 within 2 days after surgery. The STA-MCA arterial bypass patency rate was 98% at the 30-day postoperative visit and 96% at the last follow-up examination. The STA-MCA arterial bypass markedly improved, although it did not normalize, the level of elevated OEF in the symptomatic cerebral hemisphere. Five surgically treated and 1 nonsurgically treated patients in the surgical group had a primary end point ipsilateral hemispheric stroke after the 30-day postoperative period. No baseline characteristics or intraoperative variables revealed those who would experience a procedure-related stroke.
Despite excellent bypass graft patency and improved cerebral hemodynamics, STA-MCA anastomosis did not provide an overall benefit regarding ipsilateral 2-year stroke recurrence, mainly because of a much better than expected stroke recurrence rate (22.7%) in the medical group, but also because of a significant postoperative stroke rate (15%). Clinical trial registration no.: NCT00029146.
颈动脉闭塞手术研究（COSS）旨在确定在完全性颈内动脉（ICA）闭塞且闭塞远端大脑半球氧摄取分数（OEF）升高的患者中，在最佳药物治疗的基础上加用颞浅动脉-大脑中动脉（STA-MCA）旁路是否会降低随后的同侧卒中。最近的一篇出版物详细记录了 COSS 的方法，并简要概述了试验的主要发现。本报告详细描述了 COSS 的手术结果。
COSS 是一项前瞻性、平行组、1:1 随机、开放标签、盲法评估治疗试验。参与者通过血管造影显示 ICA 完全闭塞，在 120 天内导致短暂性脑缺血发作或缺血性卒中，并且通过 PET 测量的 OEF 增加表明存在血流动力学性脑缺血，被随机分配至手术治疗或药物治疗。195 名患者被随机分配：97 名至手术组，98 名至药物组。手术患者行 STA-MCA 皮质分支吻合术。
意向治疗分析中，手术组的 2 年主要终点发生率为 21%，药物组为 22.7%（p=0.78，对数秩检验）。93 名接受动脉旁路手术的患者中，有 14 名（15%）在术后 30 天内同侧半球发生原发性终点卒中，其中 12 名在术后 2 天内发生。术后 30 天访视时 STA-MCA 动脉旁路通畅率为 98%，末次随访时为 96%。STA-MCA 动脉旁路术显著改善了症状性大脑半球的 OEF 升高水平，但并未使其正常化。手术组中，5 名接受手术治疗的患者和 1 名未接受手术治疗的患者在术后 30 天之后发生了同侧半球原发性终点卒中。没有基线特征或术中变量能够揭示那些将经历与手术相关的卒中的患者。
尽管 STA-MCA 吻合术具有极佳的旁路移植通畅率和改善的脑血流动力学，但并未提供同侧 2 年卒中复发的整体获益，主要是因为药物治疗组的卒中复发率（22.7%）高于预期，同时也因为术后卒中发生率（15%）较高。临床试验注册号：NCT00029146。
