钛合金表面微弧氧化涂层理化性能及表面形貌研究

目的研究Ti．6A1—4V合金表面微弧氧化（MAO）涂层的表面形貌及理化性能。方法将Ti-6A1-4V合金置于含0．02mol／Lβ-甘油磷酸二钠盐及0．2mol／L乙酸钙的电解液中进行MAO处理后,通过扫描电子显微镜（SEM）观察涂层表面形貌及截面形貌;X线能谱分析（EDX）检测涂层表面钙磷比;X射线衍射分析（XRD）检测涂层晶相构成;纳米压痕试验测量涂层的微弹性模量及微硬度。结果经MAO处理后,钛合金表面形成粗糙多孔的氧化膜;XRD显示涂层主要由锐钛矿相TiO2、金红石相Ti02和羟基磷灰石（HAP）构成;EDX及纳米压痕试验测得膜层的钙磷比为1．64,弹性模量和微硬度分别为（32．07±7．07）GPa和（1．49±0．68）GPa。结论通过MAO技术可制备出具备良好理化性能的含HAP的涂层。     

自体心包补片修补主动脉瓣环辅助主动脉瓣置换

背景：在主动脉置换过程中常遇到瓣环钙化、瓣周囊肿等特殊情况,这时一般应用特殊技术辅助主动脉瓣置换。 目的：观察自体心包补片修补主动脉瓣环辅助主动脉瓣置换治疗钙化性主动脉瓣狭窄并瓣环钙化的临床可行性。 方法：回顾性分析2009年1月至 2012年1月郑州大学第一附属医院42例钙化性主动脉瓣狭窄并瓣环钙化患者的临床资料,并通过统计学软件处理自体心包补片修补主动脉瓣环技术辅助主动脉瓣置换前后的主动脉瓣有效瓣口面积指数、最大跨瓣压差、血流峰值速度、左室射血分数等数据,分析自体心包补片修补主动脉瓣环技术辅助主动脉瓣置换的应用效果。 结果与结论：无置换中死亡病例,置换中主动脉阻断时间为52-88(63.0±18.1) min,体外循环时间为78-122(102.6±25.1) min,置换后1例患者出现急性肾功能衰竭,经床旁血透治疗后治愈。余患者无严重置换并发症。置换后住院天数为7-20(13.6±5.5) d。置换后多普勒超声心动图示：瓣膜功能良好,均未发现主动脉瓣周漏。置换后6个月的主动脉瓣有效瓣口面积指数、最大跨瓣压差、血流峰值速度、左室射血分数均有显著改善,与置换前比较差异均有显著性意义(P < 0.05)。证实对置换适应证合适的特殊换瓣患者,自体心包补片修补主动脉瓣环辅助主动脉瓣置换可取得满意的外科治疗效果,且操作安全简单,是一项可行的技术。     

脱细胞猪主动脉瓣叶的生物力学特性和免疫反应性

目的：探讨脱细胞猪主动脉瓣叶构建组织工程心脏瓣膜支架的可行性。方法：经胰酶-EDTA、表面活性剂、核酸酶处理，去除瓣叶的细胞成分，测定脱细胞瓣叶的生物力学特性，同时行大鼠皮下包埋实验，观察其免疫反应性。结果：瓣叶中的细胞成分能完全去除，获得无细胞的纤维网状支架。脱细胞瓣叶与新鲜瓣叶有基本相同的应力-应变曲线及应力-松弛曲线，而弹性模量、面积比、松弛强度、断裂强度和断裂伸长率两者无显著差异。脱细胞瓣叶的免疫反应性明显降低。结论：猪主动脉瓣叶经脱细胞处理后可以作为组织工程心脏瓣膜的支架材料。     

不同钙化模式对经导管主动脉瓣膜植入效果影响的数值模拟研究

目的通过有限元方法评估不同钙化模式对经导管主动脉瓣膜植入效果的影响。方法根据钙化斑块在主动脉瓣叶上的位置不同,建立对合线钙化模型、附着线钙化模型和圆圈钙化模型3种不同钙化形式的主动脉根部模型。使用ABAQUS软件仿真自膨胀经导管主动脉瓣膜植入3个钙化模型中的过程,分析不同钙化模型对主动脉根部应力、瓣架变形以及瓣周间隙的影响。结果圆圈钙化模型中钙化斑块的最大主应力最大,为18.42 MPa,可能导致假体植入后发生脑卒中的风险更高;圆圈钙化模型的瓣架变形程度也最大,可能导致更差的假体耐久性;附着线钙化模型的瓣周间隙面积为37.2 mm~2,超过其他模型的2倍,植入后出现严重瓣周返流的风险可能性更高。结论不同的主动脉瓣叶钙化模式与经导管主动脉瓣膜植入后的主动脉根部应力、瓣架变形以及瓣周间隙有关,对术后并发症和假体耐久性产生影响。研究结果为临床上经导管主动脉瓣膜植入术术后效果的预测提供参考。     

髋关节软骨高、低负重区微纳结构的力学性质对比

文题释义：微纳层面：相对于宏观层面而言,是对宏观层面的一个补充,由肉眼可见的毫米级别到肉眼不可见的微米、纳米级别。分别使用微米级、纳米级原子力显微镜探针测量软骨微纳弹性模量,以揭示软骨在微纳层面力学性能的特点,以及与宏观层面力学性能的关系。 负重区：在日常活动运动中,由于机体力线等不同,势必造成软骨不同区域负重出现不同,不同的负重也会影响到胶原纤维等物质的重塑重构,引起软骨力学性能的改变。 背景：髋关节软骨具有高、低负重区域,既往研究表明2个区域的宏观弹性模量是不同的。然而在微米和纳米水平上的弹性模量尚不清楚,这些信息对于进一步理解软骨微米和纳米力学性质至关重要。此外,影响软骨2个区域机械性能的微纳结构至今仍有待阐明。 目的：探究微纳层面髋关节软骨高、低负重区力学性质与结构。 方法：取新鲜正常猪股骨头软骨,使用原子力显微镜直径为5 μm的球形尖端测量不同负重区微米级压缩弹性模量,使用曲率半径为5 nm的ScanAsyst-Air探针测量其纳米级压缩弹性模量、纳米结构和胶原纤维直径。扫描电子显微镜用于识别软骨不同负重区微米结构。 结果与结论：①股骨头软骨高负重区微米级弹性模量为(433.05±146.52) kPa,低负重区微米级弹性模量为(331.19±84.88) kPa,高负重区域在微米水平上的压缩弹性模量显著高于低负重区域(P=0.029 8);②股骨头软骨高负重区纳米级弹性模量为(1.24±0.42) GPa,低负重区纳米级弹性模量为(1.28±0.41) GPa,在纳米水平上2个区域的胶原纤维的压缩弹性模量差异无显著性意义(P=0.846 2);③在微米水平上,股骨头软骨高负重区域的胶原纤维排列更规则;在纳米水平上,2个负重区域的胶原纤维直径差异无显著性意义(P=0.926 4);④以上结果表明,股骨头软骨高负重区胶原纤维较低负重区交联更规则,使软骨高负重区微米级压缩弹性模量高于低负重区,与宏观上压缩弹性模量趋势一致,但高负重并没有影响到纳米层面单个胶原纤维。 ORCID: 0000-0001-7971-5372(郭江博) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

纳米压痕技术在骨组织微纳观结构研究中的应用

目的:纳米压痕技术测得骨的微观弹性模量及硬度反映骨的微观力学性能,在骨组织微结构研究中的应用已经日益广泛,本文的目的在于对纳米压痕技术在骨微结构研究中的应用进展过程进行回顾性的综述。方法:阅读相关文献分别对纳米压痕技术原理组成、使用及计算方法及其在骨力学、微结构、骨愈合、骨软骨组织研究中的应用等几个方面进行归纳总结性阐述,从而得出该技术在整个骨组织研究中的应用趋势及发展现状。结果:在骨研究中骨的整体宏观力学性能变化情况与纳米压痕技术所测得的微观力学性能可能并不一致。骨微结构研究中纳米压痕硬度能有效地反映骨材料的各向异性程度。纳米压痕技术可以将骨愈合潜在的生物学原理与机械性能逐渐恢复过程相联系起来。纳米压痕与原子力显微镜等技术相结合可以提高试验的准确度。结论:纳米压痕技术是作为测量骨表面和骨组织的纳米量级形貌特征和100 nm~600 nm下的凹痕压痕模量与硬度等力学性质的重要手段。纳米压痕技术在评价骨组织材料质量方面有着良好的应用前景,日渐成熟且仍有很大的发展空间。     

彩色多普勒超声诊断老年性主动脉瓣钙化的临床应用

目的 应用彩色多普勒超声(CDFI)探讨老年性主动脉瓣钙化的超声表现及其临床价值.方法 回顾性探讨170例50岁以上老年性主动脉瓣钙化表现与年龄、心功能的相关性.结果 退行性变发病率随年龄增大而增高.右冠瓣、无冠瓣的钙化比左冠瓣多发;心功能低下(P＜0.01).结论 CDFI能无创地准确观察瓣膜的形态变化及多项心功能的监测,为临床的诊断、治疗提供有价值依据.     

年龄与位置对牙本质力学性质的影响

目的研究人牙本质弹性模量和硬度随年龄和位置的变化情况。方法采集下颌无龋坏第3磨牙,按照年龄分为青年、中年、老年3组。采用纳米压痕对牙本质切片的多个位置进行力学测试。结果外层和中层牙本质的弹性模量和硬度大于内层牙本质的弹性模量和硬度;随着年龄的增长,各个区域的牙本质弹性模量和硬度都增大。结论牙本质具有梯度力学特性,外层和中层牙本质具有很高的刚度,其抵抗变形的能力要强于内层牙本质。同时,随着年龄增长牙本质弹性模量和硬度增大。     

遗传性乳光牙与正常恒牙牙本质表面形貌及元素分布和显微硬度的差异

背景:目前国内外对遗传性乳光牙本质的研究主要集中于牙本质发育异常家系调查和表型分析,对遗传性乳光牙本质的物理性能的研究鲜有报道。目的:对比研究遗传性乳光牙与正常恒牙的牙本质的表面形貌,元素分布以及显微硬度的差异。方法:收集3例遗传性乳光牙本质患者需要拔除的牙齿,共5颗。选择年龄、性别相匹配的无龋坏的正畸牙作为对照的正常恒牙。采用扫描电镜,X射线能量色谱仪,纳米压痕仪对遗传性乳光牙和正常恒牙的牙本质进行表面形貌观察,元素分布以及显微硬度进行测试。结果与结论:遗传性乳光牙的牙本质结构松散,牙本质小管结构改变;遗传性乳光牙的牙本质中钠、锌、硫、钙含量显著高于正常恒牙,而镁、磷、氯降低正常恒牙(P0.01);遗传性乳光牙的牙本质中钙/磷比值为1.76,明显高于正常恒牙(P0.01)。遗传性乳光牙的牙本质的显微硬度是(1.18±0.18)GPa,明显低于正常恒牙牙本质的显微硬度(1.72±0.48)GPa(P0.01)。因此,说明遗传性乳光牙本质小管结构发生改变,其硬度低于正常恒牙牙本质的硬度,这可能与遗传性乳光牙本质元素分布有关。     

儿童主动脉瓣单叶置换术后瓣叶适应性的数值分析

目的 探究儿童主动脉瓣单叶置换（single aortic valve replacement, SAVR）术后主动脉瓣关闭不全（aortic insufficiency, AI）的生物力学机制,并提出应对措施。方法 构建理想化主动脉瓣模型及术后生长模型。改变置换瓣叶游离缘长度、瓣叶高度以及改进设计的一种凹型结构,比较不同结构尺寸对术后主动脉瓣运动同步性和关闭性能的影响。结果 置换瓣叶的闭合滞后于自体瓣叶,自体瓣叶贴合于置换瓣叶游离缘下方2 mm处。术后6年出现明显AI。增加瓣叶高度不能改善术后效果,且会增加瓣叶的最大应力。增加游离缘长度10%能够改善术后效果,当游离缘增加15%,会造成主动脉瓣过长,导致主动脉瓣产生不良的贴合。凹型主动脉瓣较传统结构更有利于瓣叶对合,能够有效降低最大应力20%,效果最佳。结论 儿童行SAVR术后,会使瓣叶运动不同步,对合点发生偏移,术后6年出现AI现象。建议裁剪为增加游离缘长度10%的凹型结构,不建议增加瓣叶高度。     

Elastic Modulus of Cetacean Auditory Ossicles

In order to model the hearing capabilities of marine mammals (cetaceans), it is necessary to understand the mechanical properties, such as elastic modulus, of the middle ear bones in these species. Biologically realistic models can be used to investigate the biomechanics of hearing in cetaceans, much of which is currently unknown. In the present study, the elastic moduli of the auditory ossicles (malleus, incus, and stapes) of eight species of cetacean, two baleen whales (mysticete) and six toothed whales (odontocete), were measured using nanoindentation. The two groups of mysticete ossicles overall had lower average elastic moduli (35.2 ± 13.3 GPa and 31.6 ± 6.5 GPa) than the groups of odontocete ossicles (53.3 ± 7.2 GPa to 62.3 ± 4.7 GPa). Interior bone generally had a higher modulus than cortical bone by up to 36%. The effects of freezing and formalin‐fixation on elastic modulus were also investigated, although samples were few and no clear trend could be discerned. The high elastic modulus of the ossicles and the differences in the elastic moduli between mysticetes and odontocetes are likely specializations in the bone for underwater hearing. Anat Rec, 297:892–900, 2014. © 2014 Wiley Periodicals, Inc.     

Mast Cells in Human Stenotic Aortic Valves Are Associated with the Severity of Stenosis

Aortic valve stenosis (AS) is characterized by extensive calcification of the aortic valve leaflets and infiltration of inflammatory cells. Activated mast cells (MCs) may participate in the induction of fibrosis and calcification with ensuing valve stiffening. We sought to investigate whether the number of MCs within stenotic aortic valves is associated with the severity of AS. We studied 43 patients (19 men, 24 women) with dominant AS (age, 64.2?±?5.9 years; mean transvalvular pressure gradient, 62.11?±?24.47 mmHg) without atherosclerotic vascular disease, undergoing elective aortic valve replacement. MCs were detected in the excised valves by immunostaining. Aortic valves from five healthy subjects obtained on autopsy served as negative controls. The number of tryptase- and chymase-positive MCs was increased in AS valves compared with the control valves (6.9 [2.3–18.9]/mm² vs. 0.7 [0–2.2]/mm², P?=?0.0001 and 3.2 [2.1–9.4]/mm² vs. 0.3 [0–1.9]/mm², P?=?0.002, respectively). MCs that colocalized with macrophages and neovessels were detected mainly in the calcified regions of the leaflets. The number of MCs positively correlated with maximal (r?=?0.73, P?<?0.0001) and mean (r?=?0.78, P?<?0.0001) gradients and maximal aortic jet velocity (r?=?0.68, P?=?0.0005). An inverse correlation with aortic valve area (r?=??0.71, P?=?0.0001) was also observed. Multivariate regression analysis revealed that MC number and valve thickness were significantly associated with mean transvalvular gradient (R ²?=?0.74, P?<?0.000001) in AS patients. Increased MC number within human stenotic aortic valves is associated with the severity of AS.     

In vivo evaluation of an in-body, tissue-engineered, completely autologous valved conduit (biovalve type VI) as an aortic valve in a goat model

Using simple, safe, and economical in-body tissue engineering, autologous valved conduits (biovalves) with the sinus of Valsalva and without any artificial support materials were developed in animal recipients’ bodies. In this study, the feasibility of the biovalve as an aortic valve was evaluated in a goat model. Biovalves were prepared by 2-month embedding of the molds, assembled using two types of specially designed plastic rods, in the dorsal subcutaneous spaces of goats. One rod had three projections, resembling the protrusions of the sinus of Valsalva. Completely autologous connective tissue biovalves (type VI) with three leaflets in the inner side of the conduit with the sinus of Valsalva were obtained after removing the molds from both terminals of the harvested implants with complete encapsulation. The biovalve leaflets had appropriate strength and elastic characteristics similar to those of native aortic valves; thus, a robust conduit was formed. Tight valvular coaptation and a sufficient open orifice area were observed in vitro. Biovalves (n = 3) were implanted in the specially designed apico-aortic bypass for 2 months as a pilot study. Postoperative echocardiography showed smooth movement of the leaflets with little regurgitation under systemic circulation (2.6 ± 1.1 l/min). α-SMA–positive cells appeared significantly with rich angiogenesis in the conduit and expanded toward the leaflet tip. At the sinus portions, marked elastic fibers were formed. The luminal surface was covered with thin pseudointima without thrombus formation. Completely autologous biovalves with robust and elastic characteristics satisfied the higher requirements of the systemic circulation in goats for 2 months with the potential for valvular tissue regeneration.     

Application of dynamic computed tomography for measurements of local aortic elastic modulus

A novel computed tomographic (CT) technique used for the instantaneous measurement of the dynamic elastic modulus of intact excised porcine aortic vessels subjected to physiological pressure waveforms is described. This system was comprised of a high resolution X-ray image intensifier based computed tomographic system with limiting spatial resolution of 3.2mm⁻¹ (for a 40mm field of view) and a computer-controlled flow simulator. Utilising cardiac gating and computer control, a time-resolved sequence of 1 mm thick axial tomographic slices was obtained for porcine aortic specimens during one simulated cardiac cycle. With an image acquisition sampling interval of 16.5 ms, the time sequences of CT slices were able to quantify the expansion and contraction of the aortic wall during each phase of the cardiac cycle. Through superficial tagging of the adventitial surface of the specimens with wire markers, measurement of wall strain in specific circumferential sectors and subsequent calculations of localised dynamic elastic modulus were possible. The precision of circumferential measurements made from the CT images utilising a cluster-growing segmentation technique was approximately ±0.25mm and allowed determination of the dynamic elastic modulus (E_dyn) with a precision of ±8kPa. Dynamic elastic modulus was resolved as a function of the harmonics of the physiological pressure waveform and as a function of the angular position around the vessel circumference. Application of this dynamic CT (DCT) technique to seven porcine thoracic aortic specimens produced a circumferential average (over all frequency components) E_dyn of 373±29kPa. This value was not statistically different (p<0.05) from the values of 430±77 and 390±47kPa obtained by uniaxial tensile testing and volumetric measurements respectively.     

Alteration of dentin–enamel mechanical properties due to dental whitening treatments

The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation analysis with the Oliver–Pharr model provided elastic modulus and hardness across the dentin–enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0 GPa versus 113.4 GPa), while smaller increases were observed in the dentin (17.9 GPa versus 27.9 GPa). Likewise, there was an increase in the hardness of enamel (2.0 GPa versus 4.3 GPa) and dentin (0.5 GPa versus 0.7 GPa) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in the literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips?, Opalescence? or UltraEtch? caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips? showed a reduction in the elastic modulus of enamel (55.3 GPa to 32.7 GPa) and increase in the elastic modulus of dentin (17.2 GPa to 24.3 GPa). Opalescence? treatments did not significantly affect the enamel properties, but did result in a decrease in the modulus of dentin (18.5 GPa to 15.1 GPa). Additionally, as expected, UltraEtch? treatment decreased the modulus and hardness of enamel (48.7 GPa to 38.0 GPa and 1.9 GPa to 1.5 GPa, respectively) and dentin (21.4 GPa to 15.0 GPa and 1.9 GPa to 1.5 GPa, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy.     

New evidence for a critical role of elastin in calcification of native heart valves: immunohistochemical and ultrastructural study with literature review

Perrotta I, Russo E, Camastra C, Filice G, Di Mizio G, Colosimo F, Ricci P, Tripepi S, Amorosi A, Triumbari F & Donato G
(2011) Histopathology 59 , 504–513 New evidence for a critical role of elastin in calcification of native heart valves: immunohistochemical and ultrastructural study with literature review Aims: Calcific aortic stenosis is a progressive disease characterized by massive fibrosis andmineralization of the valve leaflets. The aim of this study was to determine whether the onset of native calcific aortic stenosis is associated primarily with matrix remodelling events, and particularly with elastin degradation. Methods and results: The immunohistochemical expression profile of matrix degradating enzymes and tenascin‐C was investigated in both healthy and native calcified aortic valves. Collagen and elastic tissue were studied by light microscopy and electron microscopy. Immunophenotypic analysis of inflammatory cells was carried out by using monoclonal antibodies to macrophages, T and B lymphocytes. Immunoreactivity for tenascin‐C and matrix metalloproteinase‐12 (MMP‐12) was associated with areas of dense mineralization, which were characterized by fibrosis, fragmentation and calcification of elastic fibres a positive reaction was also found around small islands of calcification. MMP‐11 was not detected in the diseased valves. Osteopontin and osteonectin were also found at sites of mineralization. All calcified valves examined showed inflammatory cell infiltration. Conclusions: Our results demonstrate the direct involvement of MMP‐12 in native aortic valve stenosis. MMP‐mediated degradation of elastic fibres might contribute actively to valve mineralization by inducing calcium deposition onto fragmented elastin.     

A novel crosslinking method for improved tear resistance and biocompatibility of tissue based biomaterials

Over 300,000 heart valve replacements are performed annually to replace stenotic and regurgitant heart valves. Bioprosthetic heart valves (BHVs), derived from glutaraldehyde crosslinked (GLUT) porcine aortic valve leaflets or bovine pericardium are often used. However, valve failure can occur within 12–15 years due to calcification and/or progressive degeneration. In this study, we have developed a novel fabrication method that utilizes carbodiimide, neomycin trisulfate, and pentagalloyl glucose crosslinking chemistry (TRI) to better stabilize the extracellular matrix of porcine aortic valve leaflets. We demonstrate that TRI treated leaflets show similar biomechanics to GLUT crosslinked leaflets. TRI treated leaflets had better resistance to enzymatic degradation in vitro and demonstrated better tearing toughness after challenged with enzymatic degradation. When implanted subcutaneously in rats for up to 90 days, GLUT control leaflets calcified heavily while TRI treated leaflets resisted calcification, retained more ECM components, and showed better biocompatibility.     

A human pericardium biopolymeric scaffold for autologous heart valve tissue engineering: cellular and extracellular matrix structure and biomechanical properties in comparison with a normal aortic heart valve

The objective of our study was to compare the cellular and extracellular matrix (ECM) structure and the biomechanical properties of human pericardium (HP) with the normal human aortic heart valve (NAV). HP tissues (from 12 patients) and NAV samples (from 5 patients) were harvested during heart surgery. The main cells in HP were pericardial interstitial cells, which are fibroblast-like cells of mesenchymal origin similar to the valvular interstitial cells in NAV tissue. The ECM of HP had a statistically significantly (p < 0.001) higher collagen I content, a lower collagen III and elastin content, and a similar glycosaminoglycans (GAGs) content, in comparison with the NAV, as measured by ECM integrated density. However, the relative thickness of the main load-bearing structures of the two tissues, the dense part of fibrous HP (49 ± 2%) and the lamina fibrosa of NAV (47 ± 4%), was similar. In both tissues, the secant elastic modulus (Es) was significantly lower in the transversal direction (p < 0.05) than in the longitudinal direction. This proved that both tissues were anisotropic. No statistically significant differences in UTS (ultimate tensile strength) values and in calculated bending stiffness values in the longitudinal or transversal direction were found between HP and NAV. Our study confirms that HP has an advantageous ECM biopolymeric structure and has the biomechanical properties required for a tissue from which an autologous heart valve replacement may be constructed.     

Simulation of Self Expanding Transcatheter Aortic Valve in a Realistic Aortic Root: Implications of Deployment Geometry on Leaflet Deformation

Self expanding Transcatheter Aortic Valve Replacements (TAVR) can conform to the geometry of the aortic annulus and the calcified leaflet complex, which may result in leaflet distortion and altered leaflet kinematics, but such changes have not yet been characterized. In this study we developed a computational model to investigate the deployment of a self expanding TAVR in a realistic aortic root model derived from multi-slice computed tomography (MSCT) images. We simulated TAVR crimping/deployment in realistic and idealized aortic root models, followed by diastolic loading of the TAVR leaflets in its final deployed configuration. The TAVR deployed in a realistic aortic root had increased peak loading in the commissural region of the leaflets compared to TAVRs under idealized circular deployment conditions (2.97 vs. 1.52 MPa). Furthermore, orientation of the TAVR in the asymmetric aortic annulus such that the commissures of the TAVR are aligned with the native valve commissures minimized the effect of TAVR stent distortion on peak stresses in the TAVR leaflets (2.97 vs. 2.35 MPa). We propose that preoperative planning of the orientation of the TAVR in the aortic root annulus might minimize the impact of potential stent distortion on leaflet function and may in turn increase long term leaflet durability.