大脑中动脉狭窄患者脑血管反应性和储备能力研究

目的 :探讨大脑中动脉 (MCA)狭窄患者脑血管反应和储备能力。方法 :75例符合大脑中动脉(MCA)狭窄诊断标准的缺血性卒中患者入选试验组。常规经颅多普勒超声 (TCD)检查后 ,进入TCD8 0CO2 反应性监测软件 ,取双侧MCA作为监测血管 ,经改进的麻醉呼吸气囊接可充气呼吸面罩 ,使受检者吸入 5 %CO2 和 95 %O2 混合气体 1min诱发高碳酸血症 ,经过度换气试验诱发低碳酸血症 ,计算试验前后血流速度变化的百分比。结果 :常规TCD检查 :75例患者MCA狭窄 10 5条 ,其中轻度狭窄 4 4条 (41 9% ) ;中度狭窄 36条 (34 3% ) ;高度狭窄 2 5条 (2 3 8% )。 5 %CO2 吸入和过度换气后 ,2试验组狭窄MCA血流速度变化率与同年龄对照组比较 ,差异均有显著性意义 (P<0 0 1) ;随着MCA狭窄程度的加重 ,血流速度变化率逐渐减低。结论 :MCA狭窄的缺血性卒中患者由于MCA狭窄、血流受阻 ,使脑血管的反应性和储备能力降低 ;狭窄程度越重 ,脑血管的反应性和储备能力也越差 ,发生低灌注卒中的危险性也越大。

Evaluation of Cerebrovascular Reactivity and Reserve Capacity in Patients with Middle Cerebral Artery Stenosis

Objective: To investigate the cerebrovascular reactivity and reserve capacity in patients with middle cerebra l artery(MCA)stenosis. Methods: Seven ty-five ischemic stroke patients with MCAs stenosis were enrolled in this study . All the patients were routinely examined with transcranial Doppler (TCD), and then TCD 8.0 software was used to evaluate the cerebrovascular reactivity and re serve capacity. Hypercapnia was induced by inhaling the 5% CO 2 and 95% O 2 mixed gas from modified anesthesia air sac, and hypocapnia was induced by volunt ary hyperventilation. The changes of velocities were recorded in both sides of M CA. Results: Routine examination: 75 pa tients with 105 MCA stenoses, 44( 41.9% )of the MCA stenoses were mild grad e, 36(34.3%)of them were moderate and 25( 23.8% )of them were severe. Af ter 5% CO 2 inhalation and voluntary hyperventilation, the percentage of veloc ities in the both experiment groups was significantly lower than that of the two control groups ( P <0.01). With the aggravatio n of MCA stenosis, the changing rate of velocity gradually decreased. Conclusion: Because MCA stenosis, bloodstream is blocked in patients with MCA stenosis in ischemic stroke, both cerebrovascular r eactivity and reserve capacity decrease; the severer the stenostic grade, the lo wer the declination of cerebrovascular reactivity and reserve capacity, and the higher the risk of low perfusion stroke.