Markus H, Cullinane M
Clinical Neuroscience, St George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.
Brain. 2001 Mar;124(Pt 3):457-67. doi: 10.1093/brain/124.3.457.
Cross-sectional studies suggest that impaired cerebral haemodynamics is associated with symptomatic status in patients with carotid stenosis and occlusion, but there is relatively little prospective data confirming this association. Transcranial Doppler ultrasonography was used to determine the reactivity of the middle cerebral artery to 8% carbon dioxide in air in 107 patients with either carotid occlusion (n = 48) or asymptomatic carotid stenosis (n = 59). Subjects were followed prospectively until stroke, transient ischaemic attack (TIA), death or study end. Mean duration of follow-up was 635 days. No patients dropped out due to operation before an end-point was reached, or were lost to follow-up. There were 11 ipsilateral ischaemic events during follow-up (six strokes, five TIAs). Exhausted ipsilateral middle cerebral artery reactivity (>20% increase in ipsilateral middle cerebral flow velocity in response to 8% carbon dioxide) predicted ipsilateral stroke and TIA risk in the whole group (P: < 0.00001) and in the carotid occlusion (P: = 0.019) and carotid stenosis (P: = 0.015) groups alone. It also predicted the risk of ipsilateral stroke alone in all three groups. Cox regression was performed, controlling for age, gender, hypertension, diabetes, smoking, ipsilateral CT infarct, degree of contralateral stenosis and the presence of ipsilateral stenosis versus occlusion. Exhausted reactivity remained an independent predictor of ipsilateral stroke and TIA (odds ratio 14.4, 95% confidence interval 2.63-78.74, P: = 0.0021). In contrast, the pulsatility index of the middle cerebral artery was a poor predictor of the risk of stroke. Reactivity to 6% carbon dioxide also predicted the risk of stroke and TIA, but slightly less effectively than reactivity to 8% carbon dioxide. Severely reduced cerebrovascular reactivity predicts the risk of ipsilateral stroke and TIA in patients with carotid occlusion, and to a lesser extent in asymptomatic carotid stenosis. Particularly in the former group, a study is required to determine whether revascularization reduces the risk of stroke in patients with exhausted reactivity.
横断面研究表明，脑血流动力学受损与颈动脉狭窄和闭塞患者的症状状态相关，但前瞻性数据相对较少能证实这种关联。对107例颈动脉闭塞（n = 48）或无症状性颈动脉狭窄（n = 59）患者，采用经颅多普勒超声检查来测定大脑中动脉对空气中8%二氧化碳的反应性。对受试者进行前瞻性随访，直至发生卒中、短暂性脑缺血发作（TIA）、死亡或研究结束。平均随访时间为635天。在达到终点前，没有患者因手术退出或失访。随访期间有11例同侧缺血性事件（6例卒中，5例TIA）。同侧大脑中动脉反应性耗竭（对8%二氧化碳反应时同侧大脑中动脉血流速度增加>20%）在整个组（P：<0.00001）以及单独的颈动脉闭塞组（P：=0.019）和颈动脉狭窄组（P：=0.015）中均能预测同侧卒中和TIA风险。它也能预测所有三组中单独同侧卒中的风险。进行了Cox回归分析，对年龄、性别、高血压、糖尿病、吸烟、同侧CT梗死、对侧狭窄程度以及同侧狭窄与闭塞的存在情况进行了控制。反应性耗竭仍然是同侧卒中和TIA的独立预测因素（比值比14.4，95%置信区间2.63 - 78.74，P：=0.0021）。相比之下，大脑中动脉搏动指数对卒中风险的预测效果较差。对6%二氧化碳的反应性也能预测卒中和TIA风险，但效果略逊于对8%二氧化碳的反应性。严重降低的脑血管反应性可预测颈动脉闭塞患者同侧卒中和TIA风险，对无症状性颈动脉狭窄患者的预测程度较小。特别是在前一组中需要进行一项研究，以确定血运重建是否能降低反应性耗竭患者的卒中风险。
