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）中术前脑血流动力学损伤和产生的活性氧是否与术后脑过度灌注的发生相关。方法：对90例因同侧伊卡狭窄（>70%）而接受CEA的患者的血清样本中的丙二醛修饰的低密度脂蛋白（MDA-LDL）浓度（氧化损伤的生化标志物）进行测定。在颈内动脉（伊卡）夹闭前、伊卡夹闭后10分钟以及伊卡开放后5分钟和20分钟，从插入同侧颈静脉球的静脉导管中采集血清样本。在CEA之前，还使用单光子发射计算机断层扫描测量脑血流量（CBF）和脑血管对乙酰唑胺的反应性（CVR）。此外，术后测量CBF。结果：12名患者（13%）在CEA后立即观察到高灌注（CBF增加>100%）。Logistic回归分析显示，术前CVR降低（95% CI，1.053 - 1.453 ; P=0.0097）和MDA-LDL增加伊卡解除夹闭后（计算为夹闭前值的百分比）（95%CI，0.862 - 0.980 ; P=0.0098）与术后脑灌注过度的发生显著相关。11例术前CVR降低和伊卡开放后MDA-LDL升高的患者中有10例发生了CEA后高灌注，其中2例发生了脑高灌注综合征。结论：术前脑血流动力学损伤和手术过程中产生的活性氧与CEA术后脑过度灌注的发展相关。

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.