Introduction

Revascularization procedures in carotid artery stenosis have shown a positive effect in the restoration of cerebral oxygen metabolism as assessed by T2’ (T2 prime) imaging as well as capillary homeostasis by measurement of capillary transit time heterogeneity (CTH); however, data in patients with asymptomatic carotid stenosis without manifest brain lesions are scarce.

Patients and Methods

The effect of revascularization on the hemodynamic profile and capillary homeostasis was evaluated in 13 patients with asymptomatic high-grade carotid stenosis without ischemic brain lesions using dynamic susceptibility contrast perfusion imaging and oxygenation-sensitive T2’ mapping before and 6–8 weeks after revascularization by endarterectomy or stenting. The cognitive performance at both timepoints was further assessed.

Results

Perfusion impairment at baseline was accompanied by an increased CTH (p = 0.008) in areas with a time to peak delay ≥ 2 s in the affected hemisphere compared to contralateral regions. Carotid intervention improved the overall moderate hemodynamic impairment at baseline by leading to an increase in normalized cerebral blood flow (p = 0.017) and a decrease in mean transit time (p = 0.027), oxygen extraction capacity (OEC) (p = 0.033) and CTH (p = 0.048). The T2’ values remained unchanged.

Conclusion

This study presents novel evidence of a state of altered microvascular function in patients with high-grade carotid artery stenosis in the absence of ischemic brain lesions, which shows sustained normalization after revascularization procedures.

中文翻译：

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无症状重度颈动脉狭窄血运重建的脑血流动力学和氧代谢综合评价

介绍

颈动脉狭窄的血运重建手术通过 T2' (T2 prime) 成像评估以及通过测量毛细血管通过时间异质性 (CTH) 来评估毛细血管稳态，在恢复脑氧代谢方面显示出积极作用；然而，没有明显脑损伤的无症状颈动脉狭窄患者的数据很少。

患者和方法

在通过动脉内膜切除术血运重建之前和之后 6-8 周，使用动态磁敏对比灌注成像和氧合敏感 T2' 标测评估了 13 名无症状性高级别颈动脉狭窄且无缺血性脑损伤的患者的血运重建对血流动力学特征和毛细血管稳态的影响或支架。进一步评估了两个时间点的认知表现。

结果

 与对侧区域相比，受影响半球达到峰值延迟时间≥2 s 的区域的基线灌注损伤伴随着 CTH 增加 ( p = 0.008)。颈动脉干预通过增加标准化脑血流量 ( p  = 0.017) 和减少平均通过时间 ( p  = 0.027)、氧气提取能力 (OEC) ( p  = 0.033) 和CTH ( p  = 0.048)。T2'值保持不变。

结论

这项研究提供了新的证据，表明在没有缺血性脑损伤的情况下，高级别颈动脉狭窄患者的微血管功能状态发生了改变，这表明血运重建手术后持续正常化。