Stroke and Dementia Research Centre, St George's University of London, Cranmer Terrace, London. SW17 0RE, United Kingdom.
Stroke. 2011 Oct;42(10):2819-24. doi: 10.1161/STROKEAHA.111.622514. Epub 2011 Aug 18.
Improved methods are required to identify patients with asymptomatic carotid stenosis at high risk for stroke. The Asymptomatic Carotid Emboli Study recently showed embolic signals (ES) detected by transcranial Doppler on 2 recordings that lasted 1-hour independently predict 2-year stroke risk. ES detection is time-consuming, and whether similar predictive information could be obtained from simpler recording protocols is unknown.
In a predefined secondary analysis of Asymptomatic Carotid Emboli Study, we looked at the temporal variation of ES. We determined the predictive yield associated with different recording protocols and with the use of a higher threshold to indicate increased risk (≥2 ES). To compare the different recording protocols, sensitivity and specificity analyses were performed using analysis of receiver-operator characteristic curves.
Of 477 patients, 467 had baseline recordings adequate for analysis; 77 of these had ES on 1 or both of the 2 recordings. ES status on the 2 recordings was significantly associated (P<0.0001), but there was poor agreement between ES positivity on the 2 recordings (κ=0.266). For the primary outcome of ipsilateral stroke or transient ischemic attack, the use of 2 baseline recordings lasting 1 hour had greater predictive accuracy than either the first baseline recording alone (P=0.0005), a single 30-minute (P<0.0001) recording, or 2 recordings lasting 30 minutes (P<0.0001). For the outcome of ipsilateral stroke alone, two recordings lasting 1 hour had greater predictive accuracy when compared to all other recording protocols (all P<0.0001).
Our analysis demonstrates the relative predictive yield of different recording protocols that can be used in application of the technique in clinical practice. Two baseline recordings lasting 1 hour as used in Asymptomatic Carotid Emboli Study gave the best risk prediction.
需要改进方法来识别无症状颈动脉狭窄患者中风风险高的患者。最近的无症状颈动脉栓塞研究表明，经颅多普勒检测到的栓塞信号（ES）在 2 次持续 1 小时的记录中独立预测 2 年的中风风险。ES 检测耗时，尚不清楚是否可以从更简单的记录方案中获得类似的预测信息。
在无症状颈动脉栓塞研究的预先定义的二次分析中，我们研究了 ES 的时间变化。我们确定了与不同记录方案相关的预测效果，以及使用更高的阈值（≥2 ES）来指示增加的风险。为了比较不同的记录方案，使用接收者操作特性曲线的分析进行了敏感性和特异性分析。
在 477 名患者中，467 名患者有基线记录可用于分析；其中 77 名患者在 2 次记录中的 1 次或 2 次记录中出现 ES。2 次记录中的 ES 状态显著相关（P<0.0001），但 2 次记录中的 ES 阳性一致性较差（κ=0.266）。对于同侧中风或短暂性脑缺血发作的主要结果，使用 2 次持续 1 小时的基线记录比单独使用第 1 次基线记录（P=0.0005）、单次 30 分钟记录（P<0.0001）或 2 次持续 30 分钟记录（P<0.0001）具有更高的预测准确性。对于同侧中风单独的结果，与所有其他记录方案相比，2 次持续 1 小时的记录具有更高的预测准确性（所有 P<0.0001）。
我们的分析证明了不同记录方案的相对预测效果，可以在临床实践中应用该技术。如无症状颈动脉栓塞研究中使用的 2 次持续 1 小时的基线记录提供了最佳的风险预测。
