OCT和IVUS在血流导向装置植入动脉瘤动物模型后贴壁及内皮化评估中的应用价值研究

OCT and IVUS evaluating stent apposition and endothelialization after FD implantation in aneurysm animal models

目的探讨光学相干断层扫描(OCT)和血管内超声(IVUS)对动脉瘤动物模型中血流导向装置(FD)贴壁和内皮化评估的应用价值,同时分析贴壁不全(ISA)对瘤腔愈合和支架内皮化进程的影响。方法采用外科方式建立小型猪颈总动脉侧壁动脉瘤模型并植入FD。术后即刻使用OCT和IVUS分别记录ISA发生部位和程度,并比较二者在FD贴壁评估中差异。术后第12周末通过DSA检查评估动脉瘤闭塞程度(Kamran分级)及支架通畅情况;通过OCT和IVUS观察支架内皮化情况并通过组织病理学结果对比分析ISA对瘤腔愈合和内皮化进程的影响。结果共建立6头小型猪颈总动脉侧壁动脉瘤模型并成功植入6枚国产Tubridge FD。相对于IVUS,OCT能发现更多的ISA(6枚,14处vs 3枚,4处);血管管径变化区(7处)、瘤颈区(4处)和FD头尾端(3处)是ISA高发部位,支架编织丝与管壁距离为(560.14±101.48)μm。术后第12周末DSA显示1例动脉瘤瘤颈处少许对比剂残存(Kamran分级3级),余5例动脉瘤完全闭塞(Kamran分级均为4级);1枚FD管腔中度狭窄,余5枚FD管腔通畅。OCT提示支架内大部分急性ISA消失,残留未贴壁的比例降至3/14,其中2处位于瘤颈区,1处位于支架局部;组织病理学结果显示支架编织丝裸露,未见明显血管内皮覆盖;1枚管腔狭窄的FD增生内膜主要由血管平滑肌细胞和细胞间质构成。结论相对于IVUS,OCT能在颈动脉动脉瘤FD植入模型中发现更多的ISA;大部分急性的ISA在12周后有较好的转归,而严重的ISA将造成FD内皮化延迟,动脉瘤闭塞延迟。

Objective To investigate the application value of optical coherence tomography(OCT)and intravascular ultrasound(IVUS)in evaluating flow diverter(FD)apposition and endothelialization in aneurysm animal models,and analyze the effect of incomplete stent apposition(ISA)on aneurysm lumen healing and stent endothelialization.Methods Lateral common carotid artery aneurysm models in swines were established by surgical method and then FD was implanted.Immediately after surgery,OCT and IVUS were used to evaluate the locations and degrees of ISA,and difference between these 2 methods in evaluating FD apposition was compared.DSA was performed at 12 weeks after surgery to evaluate the aneurysm occlusion(Kamran grading)and stent patency.OCT and IVUS were used again to observe the stent endothelial situation;by comparing with histopathologic results,effect of ISA on aneurysm healing and stent endothelialization was analyzed.Results Lateral common carotid artery aneurysm models in 6 swines were established,and 6 Tubridge FDs were successfully implanted.Compared with IVUS(3 stents,4 locus),OCT could detect more ISA(6 stents,14 locus);and the vascular diameter change area(7 locus),aneurysm neck area(4 locus)and the head and tail of FD(3 locus)were the main sites of FD malapposition;average distance between stent wire and vessel wall was(560.14±101.48)μm.At 12 weeks after surgery,DSA showed that 1 patient had a little residual contrast agent at the aneurysm neck(Kamran grading 3),and the remaining 5 had complete aneurysm occlusion(Kamran grading 4).One FD had moderate lumen stenosis,and the other 5 FDs had lumen patency.OCT indicated mostly disappeared acute ISA;ISA proportion decreased to 21.4%(3/14),including 2 in the aneurysm neck and 1 in the partial stent.Histopathological results showed bare stent woven silk,without obvious endothelial coverage;in one FD with luminal stenosis,intimal hyperplasia was mainly composed of vascular smooth muscle cells.Conclusion In carotid artery aneurysm model with FD implantation,OCT can detect more ISA than IVUS;most acute ISA have good outcome at 12th week of follow-up,while severe ISA can cause delayed FD endothelialization and delayed aneurysm occlusion.