Massive inferior wall aneurysm presenting with ventricular tachycardia and refractory cardiomyopathy requiring multiple interventions:A case report

BACKGROUND Inferior wall left ventricular aneurysms are rare,they develop after transmural myocardial infarction(MI)and may be associated with poorer prognosis.We present a unique case of a large aneurysm of the inferior wall complicated by ventricular tachycardia(VT)and requiring surgical resection and mitral valve replacement.CASE SUMMARY A 59-year-old male was admitted for VT one month after he had a delayed presentation for an inferior ST-segment elevation MI and was discovered to have a large true inferior wall aneurysm on echocardiography and confirmed on coronary computed tomography(CT)angiography.Due to the sustained VT,concern for aneurysm expansion,and persistent heart failure symptoms,the patient was referred for surgical resection of the aneurysm with patch repair,mitral valve replacement,and automated implantable cardioverter defibrillator insertion with significant improvement in functional and clinical status.CONCLUSION Inferior wall aneurysms are rare and require close monitoring to identify electrical or contractile sequelae.Coronary CT angiography can outline anatomic details and guide surgical intervention to ameliorate life-threatening complications and improve performance status.

Effects of Elasticity on Wall Shear Stress in Patient-Specific Aneurysm of Cerebral Artery

The behavior of wall shear stress (WSS) was previously reported in a deformable aneurysm model using fluid-structure interactions. However, these findings have not been validated. In the present study, we examined the effect of elasticity (i.e., deformation) on wall shear stress inside a cerebral aneurysm at the apex of a bifurcation using particle image velocimetry in vitro. The flow model simulated a human patient-specific aneurysm at the apex of the bifurcation of the middle cerebral artery. Flow characteristics by wall elasticity were examined for both elastic and non-deformable aneurysm models with pulsatile blood flow. The absolute temporally- and spatially-averaged WSS along the bleb wall was smaller in the elastic model than that in the non-deformable model. This small WSS may be related to attenuation of the WSS. Further, the WSS gradient had a finite value near the stagnation point of the aneurysm dome. Finally, the WSS gradient near the stagnation point was slightly smaller in the elastic model than that in the non-deformable model. These data suggest that elasticity of the aneurysm wall can affect the progression and rupture of aneurysms via hemodynamic stress.

Wall shear stress in intracranial aneurysms and adjacent arteries

Hemodynamic parameters play an important role in aneurysm formation and growth. However, it is difficult to directly observe a rapidly growing de novo aneurysm in a patient. To investigate possible associations between hemodynamic parameters and the formation and growth of intracranial aneurysms, the present study constructed a computational model of a case with an internal carotid artery aneurysm and an anterior communicating artery aneurysm, based on the CT angiography findings of a patient. To simulate the formation of the anterior communicating artery aneurysm and the growth of the internal carotid artery aneurysm, we then constructed a model that virtually removed the anterior communicating artery aneurysm, and a further two models that also progressively decreased the size of the internal carotid artery aneurysm. Computational simulations of the fluid dynamics of the four models were performed under pulsatile flow conditions, and wall shear stress was compared among the different models. In the three aneurysm growth models, increasing size of the aneurysm was associated with an increased area of low wall shear stress, a significant decrease in wall shear stress at the dome of the aneurysm, and a significant change in the wall shear stress of the parent artery. The wall shear stress of the anterior communicating artery remained low, and was significantly lower than the wall shear stress at the bifurcation of the internal carotid artery or the bifurcation of the middle cerebral artery. After formation of the anterior communicating artery aneurysm, the wall shear stress at the dome of the internal carotid artery aneurysm increased significantly, and the wall shear stress in the upstream arteries also changed significantly. These findings indicate that low wall shear stress may be associated with the initiation and growth of aneurysms, and that aneurysm formation and growth may influence hemodynamic parameters in the local and adjacent arteries.

Experimental and computational studies on the flow fields in aortic aneurysms associated with deployment of AAA stent-grafts

Pulsatile flow fields in rigid abdominal aortic aneurysm （AAA） models were investigated numerically, and the simulation results are found in good agreement with particle image velocimetry （PIV） measurements. There are one or more vortexes in the AAA bulge, and a fairly high wall shear stress exists at the distal end, and thus the AAA is in danger of rupture. Medical treatment consists of inserting a vascular stent-graft in the AAA, which would decrease the blood impact to the inner walls and reduce wall shear stress so that the rupture could be prevented. A new computational model, based on porous medium model, was developed and results are documented. Therapeutic effect of the stent-graft was verified numerically with the new model.

Mechanics of formation and rupture of human aneurysm

The mechanical response of the human arterial wall under the combined loading of inflation, axial extension, and torsion is examined within the framework of the large deformation hyper-elastic theory. The probability of the aneurysm formation is explained with the instability theory of structure, and the probability of its rupture is explained with the strength theory of material. Taking account of the residual stress and the smooth muscle activities, a two layer thick-walled circular cylindrical tube model with fiber-reinforced composite-based incompressible anisotropic hyper-elastic materials is employed to model the mechanical behavior of the arterial wall. The deformation curves and the stress distributions of the arterial wall are given under normal and abnormal conditions. The results of the deformation and the structure instability analysis show that the model can describe the uniform inflation deformation of the arterial wall under normal conditions, as well as formation and growth of an aneurysm under abnormal conditions such as the decreased stiffness of the elastic and collagen fibers. From the analysis of the stresses and the material strength, the rupture of an aneurysm may also be described by this model if the wall stress is larger than its strength.

Study on hemodynamics in patient-specific thoracic aortic aneurysm

The objective of this study is to investigate the hemodynamics in patient-specific thoracic aortic aneurysm and discuss the reason for formation of aortic plaque.A 3-Dimensional pulsatile blood flow in thoracic aorta with a fusiform aneurysm and 3 main branched vessels was studied numerically with the average Reynolds number of 1399 and the Womersley number of 19.2.Based on the clinical 2-Dimensional CT slice data,the patient-specific geometry model was constructed using medical image process software.Unsteady,incompressible,3-Dimensional Navier-Stokes equations were employed to solve the flow field.The temporal distributions of hemodynamic variables during the cardiac cycle such as streamlines,wall shear stresses in the arteries and aneurysm were analyzed. Growth and rupture mechanisms of thoracic aortic aneurysm in the patient can be analyzed based on patient-specific model and hemodynamics simulation.

复合型形态学特征联合流体力学对肾下型腹主动脉瘤破裂风险的评估

目的探讨复合型几何形态学特征对腹主动脉瘤(AAA)破裂风险的影响,并进行流体力学分析。方法回顾性收集2019年6月—2023年8月行CTA检查的AAA未破裂患者25例(完整组)和同期检查进行性别和年龄1∶1配比的AAA破裂患者25例(破裂组)。比较两组患者之间AAA的形态学特征,筛选AAA破裂风险的影响因素,并进行流体力学分析。结果破裂组和完整组的瘤体最大直径(D_(max))、瘤颈直径(D_(neck))、瘤体最大直径/健康主动脉直径(D_(max)/DAO)、瘤体最大直径/瘤颈直径(D_(max)/D_(neck))、标准化动脉瘤范围(L_(nor))分别为(5.92±1.50)cm和(3.67±0.68)cm、(2.38±0.50)cm和(2.06±0.03)cm、(2.54±0.67)和(1.56±0.34)、(2.53±0.62)和(1.81±0.38)、(22.73±11.08)和(10.78±4.59);破裂组的形态学指标量值均高于完整组,其差异均具有统计学意义(t=6.947、2.563、6.567、4.952、4.982,P均<0.05)。其中D_(max)和D_(max)/DAO是AAA破裂风险的独立影响因素(OR分别为1.824、4.039,95%CI分别为1.459~6.251和3.261~9.155,P<0.05)。包含复合型形态学特征的多变量新模型对破裂风险分类的准确性高于仅包含D_(max)的常规模型(94%比88%)。破裂组和完整组AAA分别表现为Ⅲ型和Ⅱ型血流模式,并且破裂组AAA的低壁剪切力面积大于完整动脉瘤(73.9 cm^(2)比67.8 cm^(2))。结论结合形态学特征D_(max)、D_(max)/DAO和流体力学的血流模式和低壁剪切力面积有助于评估AAA的破裂风险。

血管壁面剪切应力对动脉粥样硬化和动脉瘤的影响

血管壁面剪切应力是血流动力学的重要参数,正常的壁面剪切应力维持了血管的生理状态,而异常的壁面剪切应力与动脉粥样硬化和动脉瘤的病理进展关系密切,是发生恶性心脑血管事件的危险因素之一。异常的壁面剪切应力通过不同发病机制破坏了内皮细胞的正常功能,介导这两种疾病的起始、演变。文章结合近几年来的文献研究,综述了壁面剪切应力对动脉粥样硬化和动脉瘤的影响。

高分辨磁共振血管壁成像评价未破裂颅内小动脉瘤的瘤壁特点

目的 使用高分辨磁共振血管壁成像(HRMR-VWI)评估未破裂颅内小动脉瘤(直径<7 mm)的瘤壁特点。方法 回顾性分析2019年6月至2023年9月首都医科大学附属北京友谊医院诊断的未破裂颅内小动脉瘤患者病例资料。共25例患者共计33处小动脉瘤纳入分析。评估动脉瘤位置、动脉瘤壁是否强化、瘤壁有无局部变薄,并测量动脉瘤的大小、瘤壁厚度等。并比较微小动脉瘤组(直径<3 mm)和小动脉瘤组(直径3~7 mm)上述特点的差异。结果 25例33处小动脉瘤,动脉瘤大小平均(3.3±1.5) mm,其中直径<3 mm和直径3~7 mm组分别为17处和16处,最大动脉瘤壁厚度为(0.9±0.3) mm。19处(57.6%)动脉瘤壁可见强化,9处(27.3%)可见动脉瘤壁局部变薄。根据动脉瘤直径分为微小动脉瘤组(n=17)和小动脉瘤组(n=16)。两组的动脉瘤位于前循环占比、动脉瘤位置分布、瘤壁强化程度、最大瘤壁厚度、局部动脉瘤壁变薄占比、腔内血栓占比比较,差异均无统计学意义(P>0.05);微小动脉瘤的动脉瘤直径、瘤壁强化占比分别为(2.2±0.5) mm、35.3%,均低于小动脉瘤组[(4.4±1.4)mm、81.3%],差异均有统计学意义(P<0.05)。结论 HRMR-VWI图像有助于全面评估颅内小动脉瘤壁及瘤腔的特点。超1/2的小动脉瘤可见瘤壁强化,且微小动脉瘤的瘤壁强化比例更低,超1/4小动脉瘤可见局部瘤壁变薄。

心肌梗死后左心室室壁瘤血栓形成与室壁增厚的相关性分析

目的:探讨心肌梗死后左心室室壁瘤(left ventricular aneurysm,LVA)患者血栓形成与室壁增厚率的相关性,为早期识别血栓形成高危患者提供依据。方法:回顾性纳入322例心肌梗死后LVA患者,根据左心室内是否发生血栓将患者分为血栓组(91例)和非血栓组(231例)。比较两组一般资料和临床指标的差异。通过二元Logistic回归分析筛选心肌梗死后LVA患者血栓形成的相关因素。应用受试者工作特性(receiver operating characteristic,ROC)曲线评估指标诊断价值。结果:血栓组的收缩压和LVEF低于非血栓组,血栓组的心力衰竭发病率、室壁瘤尺寸、室壁瘤颈宽度和室壁瘤面积指数高于无血栓组(P<0.05)。血栓组的左心室中间段前壁(Z=-2.301,P=0.021)、心尖段前壁(Z=-2.088,P=0.037)、心尖段间隔壁(Z=-2.296,P=0.022)、心尖段侧壁(Z=-2.824,P=0.005)的室壁增厚率低于非血栓组。Logistic回归分析发现,心尖段侧壁的室壁增厚率与心肌梗死后LVA患者血栓形成紧密相关(OR=0.983,95%CI:0.969~0.998,P=0.028)。ROC曲线结果显示心尖段侧壁的室壁增厚率的曲线下面积为0.61(95%CI:0.539~0.672)。结论:心尖段侧壁的室壁增厚率与心肌梗死后LVA患者血栓事件相关,在临床实践中监测室壁增厚率可为患者预后提供指导。

VWI-MRI评估颅内未破裂动脉瘤稳定性的价值研究

目的探讨磁共振血管壁成像(VWI-MRI)评估颅内未破裂动脉瘤稳定性的价值。方法选取2021年1月—2023年1月就诊的120例颅内未破裂动脉瘤,根据动脉瘤稳定性将其分为稳定组(n=64)和不稳定组(n=56),均行VWI-MRI检查,比较2组及5年内不同生长、破裂风险未破裂动脉瘤患者VWI-MRI参数,分析VWI-MRI参数与颅内未破裂动脉瘤稳定性和5年内生长、破裂风险相关性。结果稳定组与不稳定组、5年内生长风险低高危和破裂风险低高危未破裂动脉瘤患者是否为分叉动脉瘤、形态、强化形式、瘤壁强化分级和强化指数比较差异具有统计学意义(P<0.05,P<0.01);颅内未破裂动脉瘤稳定性和5年内生长、破裂风险与分叉动脉瘤、形态、强化形式、瘤壁强化分级和强化指数均呈正相关(P<0.01)。结论VWI-MRI检查可用于评估颅内未破裂动脉瘤稳定性,并为临床早期评估动脉瘤生长、破裂风险提供参考。

切应力在血流动力学因素影响颅内动脉瘤形成和破裂中的作用

颅内动脉瘤是颅内动脉管壁病理性局限性扩张产生的脑血管瘤样突起,位居脑血管疾病病因的第3位,是造成蛛网膜下腔出血的首位病因。颅内动脉瘤的发生、发展和破裂受多种因素影响,其病理机制尚不十分明确。近年来,随着计算机模拟重建、流体力学等诊断技术的不断进步,越来越多的研究表明,血流动力学因素在动脉瘤的形成、生长及破裂过程中起着重要作用。其中,切应力被认为起主导作用。本文通过回顾近年来国内外关于血流动力学的文献,就切应力在血流动力学因素影响颅内动脉瘤发病机制中的作用展开综述。

高分辨磁共振血管壁成像在评估颅内动脉瘤中的初步应用

目的探讨高分辨磁共振血管壁成像(high-resolusion magnetic resonance vessel wall imaging,HR-VWI)评估颅内动脉瘤的可行性。方法根据动脉瘤是否破裂,将接受HR-VWI检查的颅内动脉瘤分为破裂组(n=12)和未破裂组(n=88),对比两组动脉瘤的部位、大小、瘤颈宽度、高/颈比(aspect ratio,AR)、子囊和瘤壁强化等级。以动脉瘤是否破裂为因变量,以上各因素为自变量进行单因素和多因素Logistic回归分析。未破裂动脉瘤中,对症状性亚组(n=8)和无症状亚组(n=80)进行对比分析。结果破裂组的动脉瘤大小(t=2.187,P=0.031)、AR(t=3.164,P=0.002)、子囊比例(P=0.012)和瘤壁强化分级(P<0.001)大于未破裂组。多因素Logistic回归提示瘤壁强化等级是破裂动脉瘤的独立危险因素(P=0.002)。未破裂动脉瘤中,症状性亚组瘤壁强化分级(P<0.001)和AR(t=3.939,P<0.001)大于无症状亚组。结论破裂动脉瘤中HR-VWI瘤壁强化分级高于未破裂动脉瘤,症状性未破裂动脉瘤存在瘤壁强化现象。有必要获得瘤壁的组织学标本,与HR-VWI结果对照分析,进一步研究瘤壁强化的机制和意义。

左心室下侧壁室壁瘤行左心室重建术后的近中期结果

目的:评价左心室下侧壁室壁瘤行左心室重建术后的近中期结果。方法:我院1999-11至2013-05间,共有11例左心室下侧壁室壁瘤患者行左心室成形术,男8例,女3例。11例患者同期8例行冠状动脉旁路移植术,2例行二尖瓣成形手术,1例行二尖瓣替换术。对所有患者进行回顾性分析并进行近中期随访。结果:手术早期死亡1例。术后行主动脉球囊反搏(IABP)支持1例,左心室辅助1例,因窦房结功能障碍行永久起搏器置入术1例。随访期死亡1例。随访期内无再入院,无二次手术,无不良心脑血管事件。结论:左心室下侧壁室壁瘤行左心室重建术手术安全,近中期结果良好。

颅内未破裂动脉瘤形态学对高分辨率MR管壁成像瘤壁强化的影响因素分析

目的探讨颅内未破裂动脉瘤形态学对高分辨率磁共振管壁成像下瘤壁强化的影响因素。方法回顾性连续纳入2015年1月至2016年12月第二军医大学附属长海医院颅内未破裂动脉瘤患者68例(共86个动脉瘤)的临床及影像资料,应用MR管壁成像技术进行动脉瘤扫描,并通过对比剂增强前后影像学特征以判断瘤壁强化。根据是否存在瘤壁异常强化分为强化组(32例,34个动脉瘤)与非强化组(45例,52个动脉瘤)。因部分患者同时存在强化和非强化动脉瘤,故两组按强化与否的病例数分别计算。应用三维影像数据计算动脉瘤的形态学参数,包括动脉瘤大小、高宽比、体积比、体颈比、横长比、瓶颈因子及入射角度。运用单因素分析与多因素Logistic回归分析,明确瘤壁强化的形态学影响因素。结果 (1)共34个(39.5%)动脉瘤存在瘤壁强化,52个(60.5%)动脉瘤无瘤壁强化。两组性别、年龄、高血压病、糖尿病、吸烟、蛛网膜下腔出血家族史、动脉瘤部位的差异均无统计学意义(均P>0.05)。(2)强化组动脉瘤大小、高宽比、体积比、体颈比、瓶颈因子水平均大于非强化组,组间差异均有统计学意义[9.19(6.54,11.40)mm比5.31(4.17,7.37)mm,1.18(1.01,1.69)比0.91(0.72,1.25),3.62(2.30,4.63)比2.18(1.37,2.76),1.52(1.25,1.99)比1.19(1.03,1.51),1.21(1.11,1.69)比1.05(0.94,1.31);均P<0.01];强化组不规则形态动脉瘤比例高于非强化组,组间差异有统计学意义[55.9%(19/34)比17.3%(9/52),P<0.01];组间动脉瘤纵横比及入射角度的差异均无统计学意义(均P>0.05)。(3)由于高宽比、体积比、体颈比及瓶颈因子与瘤体大小有关联,故将动脉瘤大小、入射角度和不规则形态纳入多因素Logistic回归分析,结果显示动脉瘤大小(OR=3.727,95%CI:1.993~6.971,P<0.01)、不规则形态(OR=3.990,95%CI:1.219~13.065,P=0.022)为动脉瘤瘤壁强化的独立危险因素。结论颅内未破裂动脉瘤的大小与不规则形态是瘤壁异常强化的独立危险因素,高分辨率MR管壁成像可能成为颅内动脉瘤破裂风险评估的有效无创影像学方法。

高分辨率核磁共振在椎-基底动脉夹层动脉瘤诊治中的作用

目的探讨高分辨率核磁共振(HR-MRI)在椎-基底动脉夹层动脉瘤(VBDA)诊疗中的作用。方法回顾性分析首都医科大学宣武医院2016年1月至12月收治的使用3.0 T HR-MRI检查时间飞跃法血管成像等序列,并经DSA确诊的VBDA患者62例,根据病史将其分为无症状组18例和症状组44例,分析其临床特点、影像学特点及与预后的关系。结果 HR-MRI显示,双腔征/内膜瓣在无症状组和症状组中分别占27.8%(5例)和54.5%(24例),壁间血肿在两组中分别占22.2%(4例)和43.2%(19例),瘤壁强化在两组分别占33.3%(6例)和77.3%(34例),以上特征两组比较差异均有统计学意义(均P<0.05)。症状组中18.2%(8例)的患者出现复发,明显高于无症状组的5.6%(1例),两组差异有统计学意义(P<0.05)。结论 HR-MRI能够较好显示VBDA的病变特点。症状性VBDA中瘤壁强化和复发比例均较高,提示HR-MRI可在一定程度上评估瘤壁的稳定性并判断预后。

基于CT的三维颈内动脉瘤手术前后的血流动力学分析

目的研究颈内动脉瘤术后血流动力学因素对动脉瘤复发的影响,为临床了解动脉瘤术后复发机制提供帮助。方法应用计算机软件Mimics重建颈内动脉瘤术前、术后三维模型,通过有限元软件ANSYS与大型流体力学软件CFX进行非定常流动计算与分析,通过有限元方法获得颈内动脉瘤手术前后的血流动力学参数。结果颈内动脉瘤瘤体内形成漩涡区,复发病例术后原载瘤动脉处压力明显降低,原载瘤动脉处剪切应力明显增大,血流速度明显增大。结论血管响应血流动力学变化,在功能与结构方面发生适应性反应,为分析研究动脉瘤生长、破裂、术后复发提供了新的研究思路和理论方法。

高分辨MRI颅内动脉瘤瘤壁环形强化的临床意义

目的探讨高分辨MRI（HR-MRI）中颅内动脉瘤瘤壁环形强化（CAWE）的临床意义。方法回顾性分析2014年10月至2015年7月收治的41例行钆剂增强3.0 T HR-MRI检查的颅内动脉瘤患者的影像及临床资料;由两名有经验的神经血管影像医师独立阅片,确定患者的颅内动脉瘤瘤壁是否出现CAWE。其中颅内不稳定动脉瘤患者25例,颅内稳定动脉瘤患者16例。对两名医师诊断CAWE结果的一致性进行kappa检验;比较两组患者颅内动脉瘤影像特征CAWE、个数、位置、大小等以及性别、年龄、吸烟史、饮酒史、高血压、糖尿病等,临床危险因素组间比较采用χ^2检验。结果 41例患者共发现颅内动脉瘤47个,其中颅内不稳定动脉瘤29个、颅内稳定动脉瘤18个;两名有经验的神经血管影像医师诊断CAWE结果的一致性较好（κ=0.828,95%CI：0.668～0.989）;颅内不稳定动脉瘤的CAWE明显较颅内稳定动脉瘤多,差异有统计学意义[75.9%（22/29）比33.3%（6/18）;χ^2=8.341,P=0.004];颅内不稳定动脉瘤患者的年龄〈60岁者较颅内稳定动脉瘤者多,差异有统计学意义[68.0%（17/25）比31.2%（5/16）;χ^2=5.299,P=0.021];而两组颅内动脉瘤均个数、位置、大小以及包括性别、吸烟史、饮酒史、高血压、糖尿病的差异均无统计学意义（P〉0.05）。结论 CAWE多明显见于颅内不稳定动脉瘤,能将症状性、形态改变及破裂的颅内动脉瘤与颅内稳定动脉瘤鉴别。

心肌梗塞患者左室壁应力和应变的研究

目的应用心室壁应力、应变对心肌梗死患者左室壁的生物力学变化进行探讨。方法选择30例健康人和30例心肌梗死患者,应用定量组织速度成像技术获取其左室前壁心肌5个取样点在长轴方向的应变峰值(PSS),计算左心室收缩期室壁径线峰值应力(Pσm)。结果①心梗组前壁五个心肌节段PSS显著下降,部分取样点应变峰值在心梗组和对照组均有显著性差异(P<0.05)。②Pσm在对照组和心梗组中分别为16.42±2.56和22.34±6.31,心梗组的Pσm明显高于对照组,两者比较具有显著性差异(P<0.05)。结论心肌梗死后室壁瘤的形成与室壁应力、应变密切相关。

高分辨MRI下颅内未破裂动脉瘤瘤壁环形强化的临床意义

目的探讨高分辨磁共振成像（HRMRI）下颅内未破裂动脉瘤瘤壁环形强化（CAWE）的临床意义。方法选取2014年10月至2015年6月收治的接受钆剂增强HRMRI检测的颅内未破裂动脉瘤患者28例，其中有症状患者13例（警示性头痛8例，患侧动眼神经麻痹5例），无症状患者15例。2名影像科医师独立阅片，确定是否出现CAWE。结果检测发现28例患者31枚颅内未破裂动脉瘤。根据Kappa一致性检验，2名影像科医师诊断CAWE结果有较高一致性（Kappa=0．7427，95％CI：0．51-0．98）。13例有症状患者14枚动脉瘤中11枚（11／14，78．6％）出现CAWE，15例无症状患者17枚动脉瘤中5枚（5／17。29．4％）出现CAWE，两者间差异有统计学意义（P=-0．0113）。结论钆剂增强HRMRI检测显示有症状颅内未破裂动脉瘤患者CAWE明显较无症状患者多见，提示动脉瘤未来破裂的可能性较高。