Int J Stroke. 2009 Oct;4(5):398-405. doi: 10.1111/j.1747-4949.2009.00339.x.
Better methods of identifying which patients with asymptomatic carotid stenosis will develop stroke, are required to improve the risk-benefit ratio of carotid endarterectomy. A promising method is the detection of asymptomatic embolic signals using transcranial Doppler. Embolic signals predict stroke risk in symptomatic carotid stenosis, but their predictive role in asymptomatic carotid stenosis is uncertain.
The Asymptomatic Carotid Emboli Study is a prospective observational study in patients with asymptomatic carotid stenosis> or =70%.
Two 1-h transcranial Doppler recordings from the ipsilateral middle cerebral artery are performed at baseline, and a single-hour recording is performed at 6, 12 and 18 months. Follow-up is for 2 years. All recordings are centrally blinded to subject identity during analysis. The primary hypothesis is: do embolic signals on either of two 1-h recordings at entry predict ipsilateral transient ischaemic attack and stroke risk over the following 2 years? The major secondary hypothesis is: does the presence of embolic signals on a single-hour-long recording at baseline or at 6, 12 or 18 months predict ipsilateral transient ischaemic attack and stroke risk over the subsequent 6-month period?
Recruitment was completed in October 2007 with 482 subjects. At the baseline, the proportion of subjects with embolic signals was 10.7% on recording 1, 10.8% on recording 2 and 16.7% on either of the two recordings. Embolic signal prevalence on the two recordings was significantly associated (chi(2) 27.48, P<0.0005). Patients without embolic signals were more likely to be treated with antiplatelets (90.8 vs 76.9%, P<0.0005) and this difference persisted on multivariate analysis.
Asymptomatic Carotid Emboli Study will determine whether embolic signal is a useful predictor in asymptomatic carotid stenosis, and detection allows its predictive value to be compared with clinical features, imaging parameters and ultrasound plaque morphology. Baseline data show antiplatelet therapy is associated with fewer embolic signals.
需要更好的方法来识别哪些无症状性颈动脉狭窄患者会发生中风，以提高颈动脉内膜切除术的风险效益比。一种有前景的方法是使用经颅多普勒检测无症状性栓塞信号。栓塞信号可预测有症状性颈动脉狭窄的中风风险，但其在无症状性颈动脉狭窄中的预测作用尚不确定。
无症状性颈动脉栓子研究是一项针对无症状性颈动脉狭窄≥70%患者的前瞻性观察性研究。
在基线时对同侧大脑中动脉进行两次1小时的经颅多普勒记录，并在6、12和18个月时进行一次1小时的记录。随访2年。所有记录在分析过程中对受试者身份进行集中盲法处理。主要假设是：入组时两次1小时记录中的任何一次出现的栓塞信号是否能预测接下来2年同侧短暂性脑缺血发作和中风风险？主要次要假设是：基线时或6、12或18个月时1小时记录中出现的栓塞信号是否能预测随后6个月同侧短暂性脑缺血发作和中风风险？
2007年10月完成了482名受试者的招募。在基线时，记录1中出现栓塞信号的受试者比例为10.7%，记录2中为10.8%，两次记录中任何一次出现栓塞信号的比例为16.7%。两次记录中栓塞信号的患病率显著相关（χ² 27.48，P<0.0005）。无栓塞信号的患者更有可能接受抗血小板治疗（90.8%对76.9%，P<0.0005），且这种差异在多变量分析中持续存在。
无症状性颈动脉栓子研究将确定栓塞信号在无症状性颈动脉狭窄中是否为有用的预测指标，并通过检测将其预测价值与临床特征、影像学参数和超声斑块形态进行比较。基线数据显示抗血小板治疗与较少的栓塞信号相关。
