颈动脉内Neuroform EZ支架置入后支架内再狭窄模型的建立及其影像学和病理学研究

Establishment of carotid artery in-stent restenosis models after Neuroform EZ stent implantation and their imaging and pathological studies

目的建立巴马猪颈动脉内Neuroform EZ支架置入后支架内再狭窄(ISR)模型,观察并总结其影像学和病理学特征改变。方法以13头健康广西巴马小型猪为研究对象,采用球囊过度扩张的方式损伤巴马猪颈动脉内膜后原位置入Neuroform EZ支架建立ISR模型。术后每2周通过床旁彩超监测巴马猪颈动脉支架置入区血流情况,如发现支架内血流增快或减慢,即刻行DSA、血管内超声(IVUS)、光学相干断层扫描(OCT)和高分辨MRI(HR-MRI)检查,明确支架内狭窄情况后处死巴马猪,取支架处组织,采用HE染色观察其病理学改变。结果13头巴马猪单侧颈动脉球囊扩张完成后共置入13枚Neuroform EZ支架,技术成功率为100%。术后(12.46±3.57)周(6~18周),13头巴马猪中监测到支架内血流增快10例,血流减慢3例;即刻DSA检查显示13头巴马猪的支架内均出现不同程度狭窄,狭窄率为(44.23±9.39)%;IVUS和OCT提示支架主体完全被增生的血管内膜覆盖,局部管腔的缩窄为明显增厚的内膜所致,而缩窄的管腔在HR-MRI上表现为管壁的明显强化;HE染色显示病变血管内弹力板断裂,内膜增生明显,增生的内膜以平滑肌细胞为主。结论通过球囊过度扩张撕裂血管内膜并原位置入颅内支架的方式,在12周左右可建立巴马猪颈动脉ISR模型,多种影像学和病理学检查均证实ISR为增生的内膜所致。

Objective To establish the carotid artery in-stent restenosis(ISR)models in Bama pigs after Neuroform EZ stent implantation,and observe and summarize their imaging and pathological characteristics.Methods Thirteen healthy Bama pigs from Guangxi Province were chosen;carotid artery intima was injuried by balloon over-dilation;Neuroform EZ stents were implanted at the vascular injury sites to establish ISR models.Blood flow at areas accepted carotid artery stent implantation in Bama pigs was monitored by bedside color ultrasound every 2 weeks after surgery;once hemodynamic changes(acceleration or deceleration of the blood flow)in stents were detected,DSA,intravascular ultrasound(IVUS),optical coherence tomography(OCT)and high-resolution MRI(HR-MRI)were performed immediately.Bama pigs were then sacrificed and tissues at the stents were taken;HE staining was used to observe the pathological changes.Results Thirteen Neuroform EZ stents were implanted into 13 Bama pigs after balloon over-dilation of the unilateral carotid arteries with a technical success rate of 100%.Hemodynamic changes in stents were detected in these 13 pigs(10 with acceleration and 3 with deceleration)at(12.46±3.57)weeks after stenting(ranged from 6-18 weeks);ISR of different degrees was found in all these 13 pigs by DSA with an average stenosis rate of(44.23±9.39)%.IVUS and OCT found that the main body of stents was covered by hyperplastic intima,and thickened intima resulted in local lumen stenosis;and obvious vascular wall enhancement in these lumens was shown on HR-MRI.HE staining showed rupture of intravascular internal elastic lamina and severely arterial intimal hyperplasia;and the hyperplastic intima was mainly composed of smooth muscle cells.Conclusion Carotid artery ISR models in Bama pigs can be accurately and reliably established at approximately 12 weeks by tearing endovascular intima with balloon over-dilation and implanting Neuroform EZ stents,and multiple imaging and pathology methods confirm that ISR is caused by hyperplastic intima.