大脑中动脉狭窄支架成形术后狭窄段血流动力学异常的可能机制

The potential causes of abnormal hemodynamical changes after stenting in selected patients with symptomatic middle cerebral artery stenosis

目的探讨大脑中动脉(MCA)支架成形术后短期内的血流动力学变化规律,分析术后狭窄段异常动力学改变的可能原因。方法对于抗栓治疗期间仍有症状发作的MCA中重度狭窄患者,完成MCA支架成形术。应用经颅多普勒超声(TCD)技术,系统评价术前及术后3d内的血流动力学变化。根据血流动力学的变化,并结合临床及影像学改变分析血流动力学异常的可能机制。结果29例患者(31条MCA中)完成了支架成形术,27条动脉支架术后3d内狭窄段的TCD频谱恢复至接近正常的水平。4例患者(4条动脉)3d在狭窄段又出现了狭窄样频谱,2例CT显示颅内出血。可能的原因:3例考虑过度灌注综合征,1例MCA下干狭窄加重。结论对于MCA支架成形术后血管开通良好但TCD提示仍然存在或再次出现狭窄样频谱的患者,过度灌注综合征及其它部位的狭窄可能是常见原因。

Objective To analyze the potential causes of abnormal hemodynamic changes after stenting in selected patients with symptomatic middle cerebral artery （MCA） stenosis. Methods Patients with symptomatic MCA stenosis underwent MCA stenting if they bad recurred symptoms of cerebral ischemia while receiving antiplatelet therapy. Transcranial Doppler（TCD） examination was performed before and 3 days after stenting. The causes of abnormal hemodynamics were analyzed by TCD spectra,clinical symptoms and neuroimaging. Results Among the 29 patients （31 stenotic MCA） ,TCD spectra in 27 MCA restored to nearly normal level after stenting. The stenosis-like spectra at stenotic segment appeared in four patients （four MCA） within 3 days after stenting and 2 patients occurred intracranial hemorrhagic changes on CT scans. The potential causes were hyperperfusion syndrome with 3 patients,and another severe stenosis was found at down branch of MCA in 1 patient. Conclusion The potential causes may be hyperperfusion syndrome or phenomenon and stenosis of other branch of MCA in patients with stenosis removing on angiography but stenosis-like spectra on TCD after stenting.