新型多层裸支架治疗胸腹主动脉瘤的实验研究

发布时间：2018-06-16 08:51

本文选题：胸腹主动脉瘤 + 多层裸支架　；参考：《第二军医大学》2017年硕士论文

【摘要】：研究背景胸腹主动脉瘤(Thoracoabdominal aortic aneurysm,TAAA)常累及腹腔干动脉、肠系膜上动脉、肾动脉等重要分支动脉,外科手术难度大,目前仍没有公认的标准术式。传统开放手术需要联合开胸开腹,阻断并重建内脏动脉血供,手术创伤大,部分患者无法耐受。开窗、分支型支架以及烟囱技术等主动脉腔内修复术(Endovascular aortic repair,EVAR)具有明显的微创优势,减少了内脏缺血及脊髓并发症。但面临定制周期长、术中需要使用大剂量造影剂、内漏并发症高及手术费用大等劣势。在此背景下国内外尝试应用多层裸支架技术治疗累及重要分支动脉的复杂动脉瘤。初期结果,令人鼓舞。然而中长期临床随访发现有动脉瘤破裂及重要分支堵塞等严重并发症发生。研究目的探讨新型多层裸支架治疗胸腹主动脉瘤的临床可行性。本研究从血液动力学基本原理入手,并根据前期研究结果(裸支架孔隙率、渗透性)对裸支架血液动力学效应的影响,结合目前临床应用裸支架的缺点自主研发设计应用于胸腹主动脉瘤的新型裸支架腔内移植物。随后通过计算机模拟新型裸支架在胸腹主动脉瘤个体化3D模型中释放,观察其瘤腔内血液动力学变化,最后通过动物实验初步评估新型多层裸支架治疗胸腹主动脉瘤的安全性及有效性。研究方法1.根据新型裸支架的结构特征(螺旋直径、螺旋角度、线径长短、线径粗细等)构建新型多层裸支架的计算机模型。2.利用3D Slicer 4.5.0-1及血管建模工具包(The Vascular Modeling Toolkit,VMTK)构建胸腹主动脉瘤患者个体化3D动脉瘤模型。3.计算机模拟支架置入并分析新型多层裸支架置入后瘤腔内血液动力学变化:分析内容包括瘤腔内的管壁应力、血流流速以及管壁切应力等参数。4.建立一种形态学及血液动力学与累及分支动脉的复杂胸腹主动脉瘤相似,适用于新型多层裸支架研究的动物模型。5.将新型裸支架置入动物模型中,随访3个月复查CTA观察动脉瘤直径变化、瘤腔内血栓率变化及分支动脉通畅情况。研究结果1.计算机模拟新型裸支架置入个体化3D动脉瘤,显著增加瘤颈接触处的管壁应力,而瘤腔内壁的应力无明显变化;瘤腔内流速及切应力显著减低。2.建立动物模型18例,1例因麻醉过深死于呼吸抑制;2例术后发现分支动脉闭塞;其余15例均成功并且动物模型与临床胸腹主动脉瘤在形态和血液动力学上相似。3.动物模型置入新型裸支架后引起动脉瘤最大直径减小(15.8±0.7mm降低至15.3±0.9 mm)、诱导瘤腔内血栓进一步形成(12.6±4.2%增加至52.7±15.4%,p0.001)并保持分支动脉通畅(93.3%,14/15),达到治疗动脉瘤预期效果。结论新型多层裸支架引起瘤腔内血液动力学变化,降低瘤腔内血流速度和瘤壁切应力,在保持分支动脉通畅的同时诱导瘤腔内血栓形成,增加管壁有效厚度从而降低管壁应力,达到治疗效果。为累及分支动脉的胸腹主动脉瘤的腔内治疗提供了一种新的腔内移植物选择。同时新型多层裸支架治疗胸腹主动脉瘤的有效性、安全性有待于大规模体外、动物实验进一步的验证。
[Abstract]:Background Thoracoabdominal aortic aneurysm (TAAA) often involves an important branch of the abdominal dry artery, the superior mesenteric artery, and the renal artery. The surgical operation is difficult and there are still no recognized standard surgical procedures. Traditional open surgery requires open thoracotomy, blocking and reconstructing the blood supply of the visceral arteries. The surgical trauma is large. Endovascular aortic repair (EVAR), such as window opening, branching stents and chimney technology, has obvious minimally invasive advantages to reduce visceral ischemia and spinal cord complications. However, large dose contrast agents, high internal leakage complications and large surgical costs are needed during the long period of customization. In this context, it is an attempt to treat complicated aneurysms involving important branch arteries at home and abroad. Early results are encouraging. However, in the middle and long term clinical follow-up, severe complications such as aneurysm rupture and important branch blockage are found. This study is based on the basic principle of hemodynamics, and based on the effect of the previous study on the hemodynamic effect of bare stents, combined with the shortcomings of the present clinical application of bare scaffolds in the design of a new type of bare stent graft applied to the thoracic and abdominal aortic aneurysm. A new type of bare scaffold was released in the individualized 3D model of thoracic and abdominal aortic aneurysm, and the hemodynamic changes were observed in the aneurysm. Finally, the safety and effectiveness of the new type multi-layer bare stent in the treatment of thoracic and abdominal aortic aneurysm were evaluated by animal experiments. 1. according to the structural characteristics of the new naked support (spiral diameter, spiral angle, and line) A computer model of a new type of multilayer bare scaffold.2. is constructed by using 3D Slicer 4.5.0-1 and vascular modeling toolkit (The Vascular Modeling Toolkit, VMTK) to construct the individualized 3D artery aneurysm model for patients with thoracic and abdominal aortic aneurysm. Dynamic changes: the analysis includes the tube wall stress, flow velocity, and tube wall shear stress and other parameters.4. to establish a kind of morphological and hemodynamics similar to the complicated thoracic and abdominal aortic aneurysm involving the branch artery, which is suitable for the new type of bare scaffold model.5. to put new bare stents into the animal model and follow up 3 The changes in the diameter of the aneurysm, the change of thrombus rate in the lumen and the patency of the branch artery were observed at CTA months. Results 1. computer simulation of a new type of bare scaffold was implanted into the individual 3D aneurysm, which significantly increased the stress of the tube wall at the neck contact, but the stress of the inner wall of the tumor had no obvious change; the velocity of the tumor and the shear stress in the lumen were significantly reduced by.2.. Animal model 18 cases, 1 patients died of respiratory depression over deep anesthesia, 2 cases were found branch artery occlusion, the other 15 cases were successful and the animal model and Clinical Thoracic and abdominal aortic aneurysm resemble the shape and hemodynamics of.3. animal model after implantation of new bare scaffold to cause the largest diameter of aneurysm (15.8 + 0.7mm to 15.3 + 0.9 mm). The intravascular thrombus was further induced (12.6 + 4.2% to 52.7 + 15.4%, p0.001) and the branch patency (93.3%, 14/15) was maintained to achieve the expected effect of the aneurysm. Conclusion a new type of multi-layer bare stent was used to induce hemodynamic changes in the lumen of the tumor, to reduce the blood flow velocity and wall shear stress in the lumen, and to induce the patency of the branch artery at the same time. A new endovascular graft selection is provided for the intracavitary treatment of thoracic and abdominal aortic aneurysm involving branching arteries. The safety of new type multi-layer bare stents for the treatment of thoracic and abdominal aortic aneurysm needs to be safe in vitro and in vitro. The experiment is further verified.
【学位授予单位】：第二军医大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R543.16

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