BACKGROUND The natural history of unilateral moyamoya disease (MMD) progressing to bilateral MMD remains an enigma in modern vascular neurosurgery. Few, small series with limited follow-up have reported relatively high rates of contralateral stenosis progression. OBJECTIVE To review our large series of unilateral MMD patients and evaluate radiographic and surgical progression rates, and identify any factors associated with progression. METHODS We included all unilateral MMD cases treated from 1991 to 2017 in an observational study. We examined time to contralateral radiographic progression and contralateral progression requiring surgery. Using Cox regression analysis, we evaluated factors potentially associated with contralateral progression. RESULTS There were 217 patients treated for unilateral MMD. About 71% were female, and the average age at first surgery was 33.8 yr. Average follow-up was 5.8 yr (range 1-22 yr). A total of 18 patients (8.3%) developed contralateral progression. And 8 of these (3.7%) developed progression requiring bypass surgery. Baseline stenosis and hyperlipidemia (HLD) were significantly associated with radiographic progression (hazard ratio [HR] = 9.7, P = .006; HR = 4.0, P = .024). Baseline stenosis was associated with surgical progression (HR = 44.2, P = .002). Results were similar when controlling for possible confounders using multivariate regression. CONCLUSION Previous series showed relatively high rates of progression in unilateral MMD (15%-30%), but these studies were small and long-term follow-up was rarely available. Our large series indicates that the rate of progression is lower than previously reported but still warrants yearly noninvasive screening. These data may provide indirect support for statin therapy in MMD.

中文翻译：

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单侧烟雾病临床病程

背景 单侧烟雾病 (MMD) 发展为双侧 MMD 的自然病程在现代血管神经外科中仍然是一个谜。很少有随访有限的小系列报道相对较高的对侧狭窄进展率。目的 回顾我们的大量单侧 MMD 患者并评估放射学和手术进展率，并确定与进展相关的任何因素。方法 我们在一项观察性研究中纳入了 1991 年至 2017 年治疗的所有单侧 MMD 病例。我们检查了对侧放射学进展和需要手术的对侧进展的时间。使用 Cox 回归分析，我们评估了可能与对侧进展相关的因素。结果 有 217 名患者接受了单侧 MMD 治疗。大约 71% 是女性，首次手术的平均年龄为 33.8 岁。平均随访时间为 5.8 年（范围 1-22 年）。共有 18 名患者 (8.3%) 出现对侧进展。其中 8 人 (3.7%) 进展需要搭桥手术。基线狭窄和高脂血症 (HLD) 与影像学进展显着相关（风险比 [HR] = 9.7，P = .006；HR = 4.0，P = .024）。基线狭窄与手术进展相关（HR = 44.2，P = .002）。当使用多元回归控制可能的混杂因素时，结果是相似的。结论 先前的系列研究显示单侧 MMD 的进展率相对较高 (15%-30%)，但这些研究规模较小，并且很少获得长期随访。我们的大型系列研究表明，进展速度低于之前报告的，但仍需要每年进行无创筛查。这些数据可能为 MMD 中的他汀类药物治疗提供间接支持。