Gupta Ajay, Marshall Randolph S
Department of Radiology, Weill Cornell Medical College, New York, N.Y., USA.
Cerebrovasc Dis. 2015;39(5-6):253-61. doi: 10.1159/000381108. Epub 2015 Apr 8.
With progressive improvements in medical therapy and resultant reductions in stroke risk, luminal stenosis criteria are no longer adequate to inform decisions to pursue surgical revascularization in patients with asymptomatic carotid artery stenosis.
In this evidence-based review, we discuss the imaging-based risk stratification strategies that take into account factors beyond luminal stenosis measurements, including cerebral hemodynamics and plaque composition. The existing literature lends support to the use of certain imaging tests in patients with asymptomatic carotid stenosis including cerebrovascular reserve testing, MRI of plaque composition, ultrasound of plaque echolucency, and transcranial Doppler evaluation for microemboli. The highest quality evidence thus far in the literature includes only systematic reviews and meta-analyses of cohort studies with no randomized trials having yet been performed to show how these newer imaging biomarkers could be used to inform treatment decisions in asymptomatic carotid stenosis. Beyond the need for randomized trials, there are additional important steps needed to improve the relevance of evidence supporting risk assessment strategies. Imaging studies evaluating the risk of stroke in carotid disease should clearly define asymptomatic versus symptomatic disease, use uniform definitions of clearly defined outcome measures such as ipsilateral stroke, ensure that imaging interpretations are performed in a manner blinded to treatments and other risk factors, and include cohorts which are on modern intensive medical therapy. Such studies of risk stratification for asymptomatic carotid stenosis will be most valuable if they can integrate multiple high-risk features (including clinical risk factors) into a multi-factorial risk assessment strategy in a manner that is relatively simple to implement and generalizable across a wide range of practice settings. Key Messages: Together, modern imaging strategies allow for a more mechanistic assessment of stroke risk in carotid disease compared to luminal stenosis measurements alone, which, with further validation in randomized controlled trials, may improve current efforts at stroke prevention in asymptomatic carotid stenosis.
随着医学治疗的不断进步以及中风风险的相应降低，管腔狭窄标准已不足以指导无症状性颈动脉狭窄患者进行手术血运重建的决策。
在本循证综述中，我们讨论了基于影像的风险分层策略，该策略考虑了管腔狭窄测量之外的因素，包括脑血流动力学和斑块成分。现有文献支持对无症状性颈动脉狭窄患者使用某些影像检查，包括脑血管储备测试、斑块成分的磁共振成像、斑块回声的超声检查以及微栓子的经颅多普勒评估。迄今为止，文献中质量最高的证据仅包括队列研究的系统评价和荟萃分析，尚无随机试验表明这些新的影像生物标志物如何用于指导无症状性颈动脉狭窄的治疗决策。除了需要进行随机试验外，还需要采取其他重要步骤来提高支持风险评估策略的证据的相关性。评估颈动脉疾病中风风险的影像研究应明确界定无症状与有症状疾病，对同侧中风等明确界定的结局指标使用统一的定义，确保在对治疗和其他风险因素不知情的情况下进行影像解读，并纳入接受现代强化医学治疗的队列。如果无症状性颈动脉狭窄的风险分层研究能够将多个高风险特征（包括临床风险因素）整合到一个多因素风险评估策略中，且该策略实施相对简单且可在广泛的实践环境中推广，那么这些研究将最有价值。关键信息：与仅测量管腔狭窄相比，现代影像策略能够更深入地评估颈动脉疾病的中风风险，在随机对照试验中进一步验证后，可能会改善目前无症状性颈动脉狭窄的中风预防工作。
