腹主动脉瘤血管力学研究新方法简介

腹主动脉瘤(abdominal aortic aneurysms,AAA)是一种常见的动脉扩张性疾病,往往因破裂出血导致患者死亡。对AAA的治疗方法较为复杂,并有相当的风险。为了很好地预防并及时发现AAA,世界各国的研究者正在致力于寻找AAA的发病原因。目前AAA的形成机制尚不明确,多数学者认为是血管力学、遗传学、环境学及生物化学等因素导致动脉结构改变和负载的加重相互作用的结果。     

腹主动脉瘤炎症机制的研究进展

腹主动脉瘤是血管外科最高危的血管退化性疾病之一,其最严重的后果是由于薄弱的动脉管壁无法承受血流冲击,导致动脉瘤壁破裂,引起的猝死。随着我国人口老龄化形势日趋严峻,腹主动脉瘤的发病率也逐年上升,成为威胁我国人民生命健康的重要疾病之一。随着对腹主动脉瘤认识的进步,影像学检查手段的增多,该疾病的确诊率已大大提高,但其具体的发病机制仍不完全清楚。目前已知腹主动脉瘤的发生与吸烟、性别、氧化应激、基质蛋白酶、血脂等多种因素相关,最新的研究显示炎症反应在腹主动脉瘤的发生发展过程中起到重要作用,本文主要对腹主动脉瘤与白细胞相关的炎症反应机制的最新研究进展予以综述。     

腹主动脉瘤形成机制中血流动力学的作用

随着生活水平的改善和老龄化程度的提高,腹主动脉瘤(AAA)的发病率逐年升高。目前对于AAA的形成机制尚不明确,大多数学者认为是遗传学、环境学、生物化学及血流动力学诸因素导致动脉壁结构改变和承受负载加重相互长时间作用的结果。 研究表明,主动脉瘤的好发部位主要集中在肾下腹主动脉段,而此段与其余主动脉相比最为特殊的是其血流动力学因素,对于     

家兔肾下腹主动脉瘤模型的建立

目的:建立简易、稳定性高的家兔肾下腹主动脉瘤模型.方法:选取健康雄性家兔32只设立盐水灌注对照,采用弹力蛋白酶灌注肾下腹主动脉的方法进行模型制作,利用不同染色方法,分别于术后2天,7天取标本观察灌注段腹主动脉的成瘤情况,形态学变化及病理改变.结果:8只弹力蛋白酶灌注术后7天组有6只存活,腹主动脉直径扩张均大于100%,与各对照组相比差异有统计学意义.病理改变体现为炎性细胞浸润,血管中层弹力组织破坏.结论:家免腹主动脉瘤模型操作简易,病理特征稳定,建模成功率较高.     

腹主动脉瘤腔内旁路术的应用研究

在50岁以上人群中,腹主动脉瘤(AAA)的发病率为3％。由于老龄化和诊断水平的不断提高,AAA的发现率还在日益升高。AAA的主要威胁是突发性破裂。破裂时手术死亡率在最有经验的医师手中也仍高于90％。传统的选择性切除手术已被广泛接受,虽然无症状的AAA早期手术死亡率只有5％,但对高龄、肥胖、糖尿病及心、肺、肾并存的患者,选择性切除术的死亡率可高达60％。对这些患者,AAA腔内旁路术既可明显减轻手术创伤,又可降低手术死亡率,从而成为一种新术式。     

腹主动脉瘤的流固耦合分析方法研究

目的:将流固耦合分析方法运用于血流动力学的研究,可以获得更加准确的结果,为临床诊断和治疗提供有效的指导.方法:本文运用ANSYS和CFX对腹主动脉瘤(Abdominal Aortic Aneurysm,AAA)进行流固耦合模拟分析,以便获得动脉瘤的血流速度和瘤壁的应力分布,判断易破裂危险区域.结果:实验结果表明,本例的腹部主动脉瘤应力峰值位于瘤体颈部.结论:流动和壁面切应力分布揭示动脉瘤颈部为破裂的危险区域.     

代谢重编程对腹主动脉瘤的影响

腹主动脉瘤(abdominal aortic aneurysm, AAA)早期起病隐匿,急性破裂时常危及患者生命。目前,AAA缺乏有效的药物治疗手段,深入探索其发病机制成为解决问题的关键。代谢重编程是细胞为满足自身物质和能量需要而改变代谢模式的过程,主要包括糖代谢、脂质代谢和氨基酸代谢三个方面,其在心血管疾病尤其是AAA中的调节作用近年来备受关注。本文聚焦近年血管平滑肌细胞(vascular smooth muscle cells, VSMCs)和巨噬细胞的代谢重编程对AAA发生、发展的影响的研究进展,特别是其在VSMCs凋亡和表型转化、细胞外基质重塑、氧化应激和炎症反应等主要病理过程中的作用,以期从代谢角度为AAA的机制研究和临床治疗提供新思路。     

腔内修复术治疗腹主动脉瘤的临床疗效分析

目的:评价腔内修复术(EVAR)治疗腹主动脉瘤(AAA)的临床疗效及安全性。方法:选择2008年12月至2013年12月收治的29例AAA患者,给予EVAR治疗,观察其围术期的疗效及血管破裂死亡、伤口愈合情况、截瘫、腔内隔绝术后并发症的发生情况和随访期疗效及血管破裂死亡、截瘫及内漏的发生情况。结果:29例手术均成功,1例术后3天出现右髂动脉支架内血栓、消化道出血及肝肾功能衰竭,行持续性血液净化好转出院。2例术区切口愈合延迟,9例术后发热,无在院死亡及截瘫病患。随访期间,1例术后30天死亡,死于肝肾功能衰竭;1例3个月出现肾功能不全;1例双下肢乏力,无截瘫发生。存活的28例患者复查增强CT见支架位置、形态良好,无移位及内漏发生。结论:EVAR具有成功率高、创伤小、恢复快等特点,且并发症少,治疗AAA安全有效。     

不同体重对正常饮食下小鼠腹主动脉瘤进展影响的回顾性研究

目的 分析正常饮食情况下,术前体重对猪胰弹性蛋白酶(PPE)诱导的小鼠腹主动脉瘤进展的影响。方法 回顾分析本实验室最近半年44例PPE诱导的小鼠腹主动脉瘤模型中,术前不同体重对后期腹主动脉直径和腹主动脉瘤进展的影响,分析两者的相关性。对术前体重低于25 g的8例入选小鼠(模型组1)和术前体重高于30 g的8例入选小鼠(模型组2)进行体重、脂肪分布、腹主动脉直径、腹主动脉直径变化、腹主动脉瘤病变组织学和免疫组织化学比较。正常阴性对照小鼠未给与任何处理。结果 44例小鼠腹主动脉瘤血管直径和术前体重的相关系数为0.005,未发现体重对腹主动脉瘤进展有显著影响。进一步分析发现,模型1组和模型2组在术后14 d血管直径(1.35 mm vs 1.27 mm)和血管直径变化上(0.85 mm vs 0.72 mm)差异没有显著性。相比正常血管,模型组1和模型组2小鼠在术后14 d,腹主动脉肾下灌注段直径显著增加,全部形成动脉瘤。组织学呈弹性纤维断裂、平滑肌细胞耗竭、炎症反应增加和血管新生异常等典型的腹主动脉瘤病变特征。结论 在正常饮食小鼠,体重未见影响腹主动脉瘤的进展。     

Predictors of post-operative mortality following treatment for non-ruptured abdominal aortic aneurysm

The aim of this prospective study of patients undergoing repair of non-ruptured abdominal aortic aneurysm between 1999 and 2003 was to evaluate and compare risk factors for mortality after surgery, to determine a complex of informative factors for lethal outcome, and to define patient risk groups. Logistic regression analysis revealed a complex of informative factors, including female gender, previous myocardial infarction, age greater than 75 years, and clinical course of abdominal aortic aneurysm as important indicators for lethal outcome. A risk score model identified low-, moderate- and high-risk groups with mortality rates of 2.9%, 8.0% and 44.4%, respectively.     

Group B streptococcus mycotic aneurysm of the abdominal aorta: report of a case and review of the literature

Mycotic aneurysm of the aorta is an uncommon condition, and Group B Streptococcus (GBS) is exceedingly rare in this setting. We present the first reported case of a GBS-infected abdominal aortic aneurysm (AAA) in North America. Key clinical and imaging findings and pathologic correlation are highlighted. A relevant review of the literature is discussed, which will bring the reader up to date with this specific disease entity.     

Numerical identification of the rupture locations in patient-specific abdominal aortic aneurysmsusing hemodynamic parameters

The rupture of an abdominal aortic aneurysm (AAA) is generally an unexpected event. Up to now, there is no agreement on an accurate criteria to predict the rupture risk of AAAs. This paper aims to numerically investigate the hemodynamics of three ruptured and one non-ruptured patient-specific AAA models to correlate local hemodynamic parameters with the rupture sites, and for the first time, this study introduced helicity as a potential index for the rupture potential of AAAs.3D reconstructions from CT scans were done. The simulation revealed that all the rupture sites were in regions of stagnation with near zero wall shear stress (WSS) but large WSS gradient (WSSG), which may explain the observation by the former researchers that the rupture site in the ruptured AAA has the lowest recorded wall thickness compared to other non-ruptured regions. Moreover, all the ruptures occurred at regions of zero helicity which represents a purely axial or circumferential flow. In addition, this study revealed that the double low region for the non-ruptured AAA was present with a thick layer of plaques, it suggests that the AAA rupture and the formation of atherosclerotic plaques may share a lot common physiological features. However, the fact that there are no plaques present in the walls of three RAAAs also indicates that AAA is not always a result of atherosclerosis. The current computational study may complement the maximum diameter, peak wall stress and other clinically relevant factors in AAA ruptures to identify the rupture sites of AAAs.     

Hemodynamic investigation of a patient-specific abdominal aortic aneurysm with iliac artery tortuosity

Abstract

This paper describes a systematic investigation on the hemodynamic environment in a patient-specific AAA with tortuous common iliac artery(CIA) and external iliac artery (EIA). 3D reconstructions from CT scans and subsequent computational simulation are carried out. It is found out that the Newtonian and non-Newtonian models have very similar flow field and WSS distribution. More importantly, it is revealed that the torturous CIA maintained its helical flow. It is concluded that the assumption of Newtonian blood is adequate in capturing the intra-aneurysmal hemodynamics. Moreover, it is speculated that the physiological spiral flow protects the twisted CIA from the thrombosis formation.     

Photobiomodulation and estrogen stabilize mitochondrial membrane potential in angiotensin–II challenged porcine aortic smooth muscle cells

Rupture of Abdominal aortic aneurysm (AAA) is among the 15 leading causes of death after age 65. Using high frequency ultrasound, we showed that photobiomodulation (PBM) prevents formation and progression of AAA in the angiotensin-II (Ang-II)-infused, apolipoprotein-e-deficient mouse model. In the current study we report that while challenge of porcine aortic Smooth Muscle Cells (SMCs) with Ang-II (1 μM) resulted in a marked decay in mitochondrial membrane potential (MitMP) vs non-challenged cells, treatment with PBM (continuous diode laser, 780 nm, 6.7 mW/cm², 5 minutes, 2 J/cm²) or pre-incubation with estrogen (50 nM, 1 hour) significantly attenuated this deterioration in MitMP. We also report that PBM and estrogen markedly affected porcine aortic SMC contraction and modified mitochondrial dispersion reflecting important influence on SMC function. These studies provide strong evidence of the important underlying role of mitochondria in the preventive effect of PBM on formation and progression of AAA and its reduced incidence and delayed onset in women.