眼动脉侧支循环对颈内动脉闭塞患者的脑血流代偿作用

Cerebral blood flow compensation in patients with occlusion of internal carotid artery by collateral circulation of ophthalmic artery

目的探讨眼动脉(OA)侧支循环对颈内动脉颅外段闭塞患者的脑血流代偿作用。方法选择在开滦总医院经MRI血管成像和颈部血管彩色双重功能超声检查均证实的单侧颈内动脉颅外段完全闭塞患者96例,其中男性81例,女性15例;平均年龄61.64岁。均为右利手,其中左侧颈内动脉闭塞46例,右侧颈内动脉闭塞50例。应用彩色经颅多普勒超声(TCD)检测OA和Willis环侧支循环开放情况,大脑中动脉(MCA)收缩期峰值血流速度(Vs)、舒张末期血流速度(Vd)、平均血流速度(Vm)、搏动指数(PI)的血流动力学状态,观察颅脑MRI中脑梗死和临床眼部缺血的发生情况。结果颈内动脉颅外段完全闭塞96例患者中OA侧支循环开放60例(62.50%),OA侧支循环未开放36例(37.50%);两者比较,差异有显著统计学意义(χ~2=11.406,P=0.001)。OA侧支循环开放组有Willis环侧支循环开放者52例(86.67%),OA侧支循环未开放组有Willis环侧支循环开放者36例(100.00%);两组比较,差异有显著统计学意义(χ~2=11.847,P=0.001)。MCA血流动力学指标Vs、Vd、Vm、PI,两组比较,差异无统计学意义(P> 0.05)。MCA供血区有脑梗死灶者,OA侧支循环开放组34例(56.67%),OA侧支循环未开放组24例(66.67%);两组比较,差异无统计学意义(χ~2=2.122,P=0.145)。眼部缺血体征,OA侧支循环开放组11例(18.33%),OA侧支循环未开放组9例(25.00%);两组比较,差异无统计学意义(χ~2=1.452,P=0.228)。结论慢性颈内动脉颅外段闭塞患者可通过启动OA侧支循环,弥补Willis环侧支循环代偿作用衰减引起的部分血流灌注不足,但OA和Willis环侧支循环代偿能力依然有限,仍然具有较高的MCA供血区脑梗死发病率和一定程度的眼部缺血病变发生。

Objective To investigate the cerebral blood flow compensatory effect of occlusion of the ocular artery(OA)on the extracranial occlusion of internal carotid artery.Methods A total of 96 patients with complete occlusion of unilateral internal carotid artery confirmed by MRI angiography and cervical vascular color dual-function ultrasound examination were enrolled,which included 81 males and 15 females and mean age of 61.64 years old.All of the patients were right-handed;46 cases had left internal carotid artery occlusion and 50 of right internal carotid artery occlusion.The color transcranial Doppler ultrasound(TCD)was used to detect OA and Willis ring collateral circulation,middle cerebral artery(MCA)systolic peak blood flow velocity(Vs),end-diastolic blood flow velocity(Vd),mean blood flow velocity(Vm)and pulsatility index(PI),and occurrence of cerebral infarction and ocular ischemia in brain MRI were observed.Results Of all the 96 patients with complete occlusion of internal carotid artery,60 cases(62.50%)were OA collateral patency,while 36(37.50%)were OA non-collateral patency,and the difference was statistically significant(χ^2=11.406,P=0.001).There were 52 cases(86.67%)with collateral patency of Willis ring in OA collateral patency group,and 36(100.00%)in OA non-collateral patency group,and there was significant difference between 2 groups(χ^2=11.847,P=0.001).The MCA hemodynamic parameters of Vs,Vd,Vm,and PI of 2 groups were no significantly different(P>0.05).For cerebral infarction of MCA supplied area,there were 34 cases(56.67%)in OA collateral patency group and 24(66.67%)in OA non-collateral patency group,and there was no significant difference between 2 groups(χ^2=2.122,P=0.145).For ocular ischemic signs,there were 11 cases(18.33%)in OA collateral patency group and 9(25.00%)in OA non-collateral patency group,and there was no significant difference between 2 groups(χ^2=1.452,P=0.228).Conclusion It is demonstrated that patients with chronic internal carotid artery occlusion could initiate partial vascular stenosis by attenuation of Willis ring collateral circulation in initiating OA collateral circulation,but OA and Willis ring collateral compensatory ability are limited,which may cause higher incidence of cerebral infarction in MCA supplied area and a certain degree of ocular ischemic lesions.