经颅多普勒超声检测颈内动脉狭窄患者脑血管反应性和微栓子信号的研究

目的:探讨经颅多普勒超声(TCD)检测颈内动脉狭窄(ICA)患者脑血管反应性(CVR)和微栓子信号(MES)的应用价值。方法:纳入ICA≥50%患者92例,并根据是否伴有临床症状分为症状组55例和无症状组37例。采用TCD检查评估ICA狭窄程度及斑块形态,评估血管运动反应性(VMR)、脑血管运动储备(CRC)、呼吸抑制指数(BHI)等参数和MES监测。并根据TCD检测结果分为ICA狭窄50%~69%组和ICA狭窄≥70%组;根据斑块灰度中位数(GSM),分为低回声(GSM≤25)斑块组和高回声(GSM>25)斑块组;根据有无溃疡斑块,分为溃疡性斑块组和非溃疡性斑块组。结果:与无症状组比较,症状组ICA狭窄≥70%及溃疡性斑块发生率显著升高(均P<0.01)。症状组、ICA狭窄≥70%组、溃疡性斑块组及低回声斑块组的MES检出率较无症状组、ICA狭窄50%~69%组、非溃疡性斑块组、高回声斑块组均增高(均P<0.05)。症状组VMR、CRC显著低于非症状组(均P<0.05);ICA狭窄≥70%组VMR、CRC和BHI显著低于ICA狭窄50%~69%组(均P<0.05)。结论:MES是不稳定颈动脉粥样硬化斑块的超声特征之一;CVR降低与ICA狭窄程度及临床症状相关。

Assessment of Cerebral Vascular Reactivity and Microembolic Signal in Patients with Internal Carotid Artery Stenosis by Transcranial Doppler

Objective: To assess the value of monitoring cerebral vascular reactivity(CVR) and microembolic signal(MES) by transcranial doppler(TCD) in patients with internal carotid artery(ICA) stenosis. Methods:We recruited 92 patients with ICA ≥50% to the study. Based on the presence of clinical symptoms, patients were placed into the symptomatic group(55 patients) or asymptomatic group(37 patients). The degree of stenosis,atherosclerotic plaque morphology, vascular motor reactivity(VMR), cerebrovascular reserve capacity(CRC),breath holding index(BHI), and MES monitoring were assessed by TCD. Based on TCD results, patients were divided into the 50%-69% ICA stenosis group and ≥70% ICA stenosis group;according to the plaque grey-scale median(GSM), they were divided into the hypoechogenic(GSM≤25) plaque group and hyperechogenic(GSM>25) plaque group;based on ulceration on plaques, they were divided into the ulcerated plaque group and non-ulcerated plaque group. Results: In the symptomatic group,≥70% ICA stenosis and ulcerated plaques occurred significantly more often than in the asymptomatic group(both P<0.01). MES were recorded significantly more often in the symptomatic,≥70% ICA stenosis, ulcerated plaque, and hypoechogenic plaque groups compared to that in the asymptomatic, 50%-69% ICA stenosis, non-ulcerated plaque, and hyperechogenic plaque groups, respectively(all P<0.05). VMR and CRC in the symptomatic group were significantly lower than that in the asymptomatic group(both P<0.05). VMR, CRC, and BHI in the ≥70% ICA stenosis group were significantly lower than that in the 50%-69% ICA stenosis group(all P<0.05). Conclusion: In patients with symptomatic ICA, MES are one of the ultrasound features of unstable carotid stenosis. CVR decrease is related to the degree of ICA stenosis and the presence of clinical symptoms.