Mechanisms of development of cerebral hyperperfusion following carotid endarterectomy and its influence on cerebral neuraltissue

背景和目的-本研究的目的是确定颈动脉内膜切除术(CEA)术前脑血流动力学损害和产生的活性氧与术后脑高灌流的发生是否相关。方法：检测90例同侧颈内动脉狭窄(70%)行CEA手术患者的血清丙二醛修饰低密度脂蛋白(丙二醛修饰低密度脂蛋白)浓度。分别在夹闭颈内动脉(ICA)前、夹闭ICA后10min、ICA开放后5min和20min，从同侧颈静脉球内插入静脉导管采集血清样本。CEA前应用单光子发射计算机断层扫描测定脑血流量(CBF)和脑血管反应性(CVR)。术后测量脑血流量。结果：12例患者(13%)在CEA术后即刻观察到高血流(CBF较术前增加100%)。Logistic回归分析显示，术前脑血管阻力降低(95%顺应值，1.053~1.453；P=0.0097)和颈内动脉开放后丙二醛-低密度脂蛋白升高(95%顺应值，0.862~0.980；P=0.0098)与术后脑高灌注量显著相关。术前CVR降低、ICA开放后MDA-LDL升高的11例患者中，有10例发生CEA术后高灌注，其中2例出现脑高灌注综合征。结论：术前脑血流动力学损害和术中产生的活性氧与CEA术后脑过度灌流的发生有关。

Background and Purpose-The purpose of the present study was to determine whether preoperative cerebral hemodynamic impairment and reactive oxygen species produced during carotid endarterectomy (CEA) correlate with development of postoperative cerebral hyperperfusion. Methods-Concentrations of malondialdehyde-modified low-density lipoprotein (MDA-LDL), a biochemical marker of oxidative damage, were measured in serum samples obtained from 90 patients undergoing CEA for ipsilateral ICA stenosis (>70%). Serum samples were obtained from a venous catheter inserted into the ipsilateral jugular bulb before clamping of the internal carotid artery (ICA), 10 minutes after clamping of the ICA, and 5 and 20 minutes after declamping of the ICA. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were also measured using single-photon emission computed-tomography before CEA. In addition, CBF was measured postoperatively. Results-Hyperperfusion (CBF increase >100% compared with preoperative values) was observed immediately after CEA in 12 patients (13%). Logistic regression analysis demonstrated that reduced preoperative CVR (95% CIs, 1.053 to 1.453 ; P=0.0097) and an increase in MDA-LDL (calculated as a percentage of the preclamp values) after ICA declamping (95% CIs, 0.862 to 0.980 ; P=0.0098) were significantly associated with development ofpostoperative cerebral hyperperfusion among the variables tested. Ten of 11 patients with reduced preoperative CVR and increased MDA-LDL after ICA declamping developed post-CEA hyperperfusion, and 2 of these patients developed cerebral hyperperfusion syndrome. Conclusions-Both preoperative cerebral hemodynamic impairment and reactive oxygen species produced during surgery correlate with development of cerebral hyperperfusion after CEA.