Importance Intimal hyperplasia and subsequent saphenous vein graft failure may have significant adverse clinical effects in patients undergoing coronary artery bypass surgery. External support of saphenous vein grafts has the potential to prevent vein graft dilation and hence slow the rate of intimal hyperplasia and increase long-term vein patency. Objective To determine efficacy, as measured by intimal hyperplasia, and safety of an external saphenous vein graft support device in patients undergoing a coronary bypass graft procedure. Design, Setting, and Participants This within-patient randomized, open-label, multicenter study was conducted at 17 Cardiothoracic Surgical Trials Network centers in North America. Between January 2018 and February 2019, 224 patients with multivessel coronary artery disease undergoing isolated bypass surgery were enrolled. For each patient, 1 of 2 vein grafts was randomized to receive external support or no support. Interventions External vein graft support or no support. Main Outcomes and Measures The primary efficacy end point was intimal hyperplasia area assessed by intravascular ultrasound at 12 months postrandomization for each study graft. Secondary confirmatory end points were lumen diameter uniformity assessed by angiography and graft failure (≥50% stenosis) by quantitative coronary angiography. Major cardiac and cerebrovascular events were collected through month 12. Results Among 224 patients (mean [SD] age, 65.8 [8.3] years; 178 [79.5%] male), 203 (90.6%) were eligible for intravascular ultrasound, of which 85 (41.9%) had at least 1 study graft occluded or severely diseased at 12 months (55 supported, 56 unsupported). After imputation of data missing because of graft occlusion or severe disease, the estimated mean (SE) intimal hyperplasia area was 5.11 (0.16) mm2 in supported grafts and 5.79 (0.20) mm2 in unsupported grafts (P = .07). In a sensitivity analysis of 113 patients with both grafts imaged, the mean intimal hyperplasia area was 4.58 (0.18) mm2 and 5.12 (0.23) mm2 in supported and unsupported grafts, respectively (P = .04). By 12 months, 5 patients (2.2%) died and 16 patients (7.1%) experienced a major cardiac or cerebrovascular event. Conclusions and Relevance The 12-month difference in intimal hyperplasia area between supported and unsupported grafts did not achieve statistical significance. Cumulative mortality and major cardiac or cerebrovascular events rates were similar to those in other randomized coronary artery bypass trials. Further investigation to assess the effect of external graft support devices on long-term graft patency and clinical outcomes is warranted. Trial Registration ClinicalTrials.gov Identifier: NCT03209609.

中文翻译：

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冠状动脉旁路手术中隐静脉移植物的外部支持：一项随机临床试验。

重要性 内膜增生和随后的隐静脉移植失败可能对接受冠状动脉旁路手术的患者产生显着的不良临床影响。隐静脉移植物的外部支持有可能防止静脉移植物扩张，从而减缓内膜增生的速度并增加长期静脉通畅。目的 确定外隐静脉移植支持装置在接受冠状动脉旁路移植术患者中的疗效（通过内膜增生测量）和安全性。设计、设置和参与者 这项患者内随机、开放标签、多中心研究在北美的 17 个心胸外科试验网络中心进行。2018年1月至2019年2月期间，纳入了 224 名接受孤立搭桥手术的多支冠状动脉疾病患者。对于每位患者，2 个静脉移植物中的 1 个被随机分配接受外部支持或不接受支持。干预 外部静脉移植支持或不支持。主要结果和测量 主要疗效终点是在随机化后 12 个月对每个研究移植物通过血管内超声评估的内膜增生面积。次要确认性终点是通过血管造影评估的管腔直径均匀性和通过定量冠状动脉造影评估的移植失败（≥50% 狭窄）。收集第 12 个月的主要心脏和脑血管事件。结果 在 224 名患者（平均 [SD] 年龄，65.8 [8.3] 岁；178 名 [79.5%] 男性）中，203 名 (90.6%) 符合血管内超声检查条件，其中 85 名(41. 9%）在 12 个月时至少有 1 个研究移植物发生阻塞或严重病变（55 个支持，56 个不支持）。由于移植物闭塞或严重疾病而缺失数据后，估计的平均 (SE) 内膜增生面积在支撑移植物中为 5.11 (0.16) mm2，在无支撑移植物中为 5.79 (0.20) mm2 (P = .07)。在对 113 名接受两种移植物成像的患者进行的敏感性分析中，支撑和未支撑移植物的平均内膜增生面积分别为 4.58 (0.18) mm2 和 5.12 (0.23) mm2 (P = .04)。到 12 个月时，5 名患者 (2.2%) 死亡，16 名患者 (7.1%) 经历了重大心脏或脑血管事件。结论和相关性 支持和非支持移植物之间内膜增生面积的 12 个月差异没有达到统计学意义。累积死亡率和主要心脏或脑血管事件发生率与其他随机冠状动脉搭桥试验中的相似。需要进一步调查以评估外部移植物支持装置对长期移植物通畅率和临床结果的影响。试验注册 ClinicalTrials.gov 标识符：NCT03209609。