颈内动脉严重狭窄时脑部症状与Willis环侧支循环建立的关系

The relationship between Willis circle and collateral circulation with brain symptom in severe stenosis at internal carotid artery

目的 应用经颅超声多普勒 (TCD)检测颈内动脉 (ICA )严重狭窄 ,探讨 Willis环的侧支循环与临床症状之间的相关性。方法 分析 34例 ICA严重狭窄患者 (其中有症状组 16例和无症状组 18例 )侧支循环的类型、大脑中动脉 (MCA)的平均血流速度 (Vm)、脉动指数 (PI)及频谱改变 ,并与 30例正常人进行对照。结果 存在 3种侧支循环类型 :前交通动脉 (ACOA)型 ,后交通动脉 (PCOA)型 ,眼动脉 (OA)型。无症状组的侧支循环中 ,ACOA型占 88.9% ,狭窄侧 MCA Vm为 5 9.1± 8.7cm / s;有症状组 ACOA型占 5 0 % ,有 4例未检出侧支循环 ,狭窄侧 MCAVm为 4 8.6± 7.3cm/ s(P<0 .0 0 1)。所有患者狭窄侧的 MCA PI减低 (P<0 .0 0 1) ,且频谱低平呈波浪状 ,波峰变钝 ,失去收缩峰的特征。结论 TCD可以发现 ICA严重狭窄患者 Willis环侧支循环的显著异常改变 ,研究 Willis环的侧支循环对 ICA严重狭窄患者治疗和预后的判断具有重要的临床价值。

Objective Using transcranial Doppler(TCD) ultrasonography to evaluate the patients with severe stenosis at internal carotid artery (ICA) and analyze the relationship between circle of Willis collateral circulation and clinical manifestation. Methods 34 cases with severe stenosis at ICA were devided into symptomatic and asymptomatic groups (18 of them had been admitted to MRA). The patterns of collateral circulation,flow velocities(Vm),pulsatility index(PI) and spectral waveforms of the MCA distal were also assessed. Results There were three patterns of collateral circulation:Anterior communicating artery (ACOA),Posterior communicating artery (PCOA) and Ophthalmic artery (OA). Among them,in asympotomatic group,88.9% of cases were in ACOA pattern,whose MCA Vm of stenosis was 59.1±8.7cm/s. In sympotomatic group 50% was ACOA and there was no collateral circulation in 4 cases. The Vm of MCA at stenosis side was decreased compared with normal control (48.6±7.3cm/s,P<0.001). Blunted Doppler flow waveforms (reduced systolic flow velocity and pulsatility) of the MCA inferred to reflect hemodynamic impairment. Conclusion TCD can detect the changes of circle of Willis collateral circulation in patients with severe extracranial ICA. It is suggested that searching for circle of Willis collateral circulation is significant to evaluate severe extracranial ICA.