同种异体人心脏主动脉与肺动脉瓣膜的生物力学比较

背景:目前同种心脏瓣膜已成熟应用于瓣膜替换手术及复杂先天性心脏病矫治手术中,但人心脏肺动脉瓣膜与主动脉瓣膜生物力学特性的对比研究报道较少。目的:对比分析深低温液氮保存人心脏主动脉瓣膜和肺动脉瓣膜的生物力学特性。方法:对比观察试验于2004-03/07在中国医学科学院心血管病研究所先天性心脏病研究室完成。取深低温液氮保存的健康成年男性脑死亡6h内志愿捐献者的人心脏主动脉瓣膜和肺动脉瓣膜各6例,符合医学伦理学要求。应用HD-10型厚度仪测定瓣膜组织的厚度,应用Instron拉伸机测定周向瓣膜组织的生物力学参数:瓣膜组织的断裂强度、应力应变曲线的斜率及伸长比。结果与结论:与人主动脉瓣膜相比,人肺动脉瓣膜组织厚度明显变薄;但二者的生物力学参数瓣膜组织的断裂强度、应力应变曲线的斜率及伸长比差异均无显著性意义(P0.05)。结果提示,人主动脉瓣膜与肺动脉瓣膜的生物力学特性基本相似,从瓣膜水平上分析,人肺动脉瓣膜可满足主动脉瓣位生物力学的需要。     

经导管主动脉瓣及肺动脉瓣置换的应用解剖

目的为经导管瓣膜置换提供正常人主动脉瓣膜及肺动脉瓣膜的相关应用解剖.方法解剖测量40例(男28,女12)外形大小正常的成年人心标本.结果测得主动脉瓣、肺动脉瓣周径分别为(63.25±8.43)mm、(66.52±11.25)mm;瓣膜游离缘长度分别为(26.25±3.84)mm、(27.51±5.15)mm;瓣膜附着缘长度分别为(20.36±3.51)mm、(21.27±4.64)mm;游离缘距窦底的距离分别为(15.15±2.67)mm、(16.54±4.33)mm左、右冠状动脉开口距主动脉根部距离分别为(16.59±4.16)mm、(17.23±3.26)mm.主肺动脉长度(33.54±8.15)mm.结论带瓣膜支架的大小和形状的设计应根据主动脉以及主肺动脉开口的大小及与周边结构的关系来选择.     

家犬主动脉窦影像分析和主动脉瓣支架瓣膜的研制

目的:观察家犬主动脉窦造影特点,研制可经导管植入主动脉瓣支架瓣膜的可行性.方法:选用健康杂种犬10只,行左心室造影,对主动脉窦部造影影像分析.将新鲜的猪心包经脱细胞处理后给予0.6%戊二醛浸泡36 h,缝合在瓣膜环上,制成主动脉瓣支架瓣膜.并将瓣膜支架经动脉植入家犬心脏主动脉瓣位置.经胸超声评价瓣膜功能.结果:左室造影可清晰显示主动脉窦部宽度和高度;升主动脉直径(1.73±0.15)mm,主动脉窦部直径(2.15+0.24)mm,冠脉开口至窦部的距离(1.12+0.14)mm.经胸超声检查示人工瓣膜瓣叶功能正常,无返流.结论:主动脉瓣支架瓣膜设计合理,功能正常,可用于经导管主动脉瓣膜置换的实验研究.     

主动脉与肺动脉半月瓣的测量

用50例经福尔马林固定过的正常成人离体心脏(其中男性47例,女性3例),切开主动脉、肺动脉,观察测量主、肺动脉口的周径和主、肺动脉瓣高、游离缘长度、瓣环长度,最后以求积仪测量瓣膜面积。一、主、肺动脉口的周径:主动脉口(平主动脉瓣环的最低点)的周径平均为6.02±0.53(5.0～7.0)cm,肺动脉口(肺动脉瓣环的最低点)的周径平均为6.45±0.85(5.0～8.5)cm,由此可见肺动脉口稍大于主动脉口。     

兔子宫壁组织力学特性的实验研究

目的 研究兔子宫壁组织的生物力学特性,并对分娩与未分娩组兔子宫壁力学特性进行比较.方法 以14只新西兰雌性大白兔为研究对象,取其子宫壁组织为拉伸试样,分娩与未分娩分组对照,用WDW4100微机控制电子万能实验机进行拉伸实验,测定其极限强度、应力应变关系;蠕变实验和应力松弛实验测定其黏弹性特征.结果 兔子宫壁组织表现出明显的黏弹性特征,应力应变呈指数关系;分娩组的平均极限应力为0.119MPa,未分娩组的平均极限应力为0.444MPa;分娩组的蠕变和松弛实验均明显比未分娩组低.结论 分娩与未分娩的兔子宫壁组织生物力学特性有明显的差别,对临床上研究人类子宫壁组织有一定的参考价值,有助于妇产科学的发展.     

大鼠死后胸主动脉生物力学特征变化规律的研究

取死后0～7 d大鼠胸主动脉进行单轴拉伸实验,观察各力学指标随死后经过时间(Post mortem interval,PMI)延长的演变,选取有明显变化趋势的力学指标进行统计分析.力学指标中最大值应力、最大值应变、能量与PMI有显著相关,其决定系数(R2)分别为0.822、0.716、0.669(P＜0.001).表明运用拉伸实验测量胸主动脉生物力学指标的变化可用于PMI推断.     

副冠状动脉变异

在解剖1个完好的成年男性心标本时,发现其右冠状动脉左上方发出1支副冠状动脉,现报道如下.△ 该动脉自右冠状动脉左上方3.74 mm处单独发出,右冠状动脉发出时外径5.40 mm,该副冠状动脉发出时外径1.34 mm.该副冠状动脉全程共有8条分支.在其发出时即有第一条分支通向肺动脉右侧根部心室壁中,并营养该处.此后该副主动脉向前绕肺动脉,在肺动脉与右心室相交处浅沟中左行,此段动脉外径为1.30 mm,沿途发出3条分支、通向动脉圆锥前侧的右心室壁中,营养相应部位心肌.     

瓣膜高度对移植主动脉瓣开闭性能的影响

临床上治疗主动脉瓣膜关闭不全的的手术多采用瓣膜移植,但术后患者重建的主动脉根部存在扩张现象,因此瓣膜高度的不足会致使主动脉瓣膜再次关闭不全。本文研究不同主动脉瓣膜高度设计对瓣膜开闭性能的影响,通过体外数值模拟,获取最佳手术方案,提供技术支持和理论依据。本文以根部直径26.0 mm、瓣膜高度14.0 mm为参照,建立瓣膜高度增量为±0.5 mm的六组三维几何模型。通过对模型最大应力、瓣口面积和接触力等参数的结构力学计算和分析,获得合理的几何尺寸。研究发现,六组模型的最大应力值范围在640～690 kPa之间,与文献的结果相符合;瓣膜高度分别为13.5、14.0、14.5 mm的三组模型的瓣口面积在合理范围内;六组瓣叶接触力随瓣膜高度增加呈增大趋势。研究表明主动脉瓣膜的高度对主动脉瓣膜关闭性能存在影响,太小或太大的瓣膜高度会减小主动脉收缩期的瓣口面积,影响主动脉开闭功能。     

左肺动脉瓣合并动脉壁缺损一例

女尸,约30岁,身高170cm,营养良好,他杀死亡.肺动脉直径2.0cm,左右肺动脉直径约1.1cm.左肺动脉起始部有一长1.0cm,宽0.5cm的瓣膜,瓣膜的游离缘上有一宽0.1cm的条带与其分离.窦腔内(瓣膜与左肺动脉壁之间)有两条细丝状结构.窦开口朝向肺门.从瓣膜的游离缘向左上方出现一中、内膜缺损区.该区梭形,长2.2cm,宽0.5cm,占左肺动脉周长的2/3.此区的动脉壁仅为疏松结缔组织构成.缺损区的边缘光滑,其中未见血栓存在.     

经皮心脏瓣膜置换术研究进展

经皮心脏瓣膜置换术是心血管疾病治疗领域中起步不久的新技术.随着生物工程学的发展,人体经皮肺动脉瓣膜、主动脉瓣膜置换取得了初步成功,它为微创治疗瓣膜疾病提供了一个崭新的思路.本文主要介绍这一技术的发展现状与未来的前景.     

Morphometric study of the human fetal heart. I. Arterial segment

This study measured the dimensions of the great arteries of normal human fetal hearts at an early fetal stage (between 13-20 weeks post-fertilization) in 103 fetuses obtained by necropsy. Different segments of the aorta and the pulmonary artery were dissected and their external diameters measured under stereoscopic magnification. All segments showed linear growth during this period of fetal development. Ranges in median values of external diameters associated with the pulmonary artery were: 2.1-4.2 mm for the valve ring; 2.2-4.2 mm for the main pulmonary trunk; 1.2-2.5 mm for the right pulmonary artery; 0.9-2.18 mm for the left pulmonary artery; and 4.0-8.0 mm for the length of the main pulmonary trunk. Similarly, in the aorta, median diameters were: 2.1-4.2 mm for the ascending aorta; 1.92-3.8 mm for the aortic arch; 1.45-3.0 mm for the aortic isthmus; and 1.75 -3.35 mm for the descending aorta. The diameter of the ductus arteriosus ranged between 1.2-2.45 mm. The growth rates of the pulmonary artery and the aorta were similar. The diameter of the ascending aorta was found to be greater than that of the descending aorta and the right pulmonary artery was wider than the left pulmonary artery. In addition, the magnitude of growth in the various aortic segments was different and the ratios obtained between the aortic isthmus and the ascending and descending aortae, ranged between 0.66-0.93. This study provides important morphometric reference information concerning the dimensions and growth of the great arteries of the fetal heart and has clinical application in pediatric cardiac surgery and echocardiography.     

The positions of coronary arterial ostia

The positions of the coronary arterial ostia were examined in the cadavers of 38 adults. All the ostia were related to the aorta and none to the pulmonary artery. The aortic valves in 37 specimens were normal and possessed three cusps, while one was bicuspid. In the normal specimens, the main right and left coronary ostia were confined to the anterior and left posterior aortic sinuses respectively, apart from one specimen in which the right ostium was related to the right posterior sinus. Six specimens had small accessory ostia, close to the main right ostium. The majority of ostia were situated on or immediately below the supravalvular ridge. Circumferentially, the ostia clustered near the maximum curvature of the sinus. In the single specimen where the aortic valve was bicuspid, both ostia lay more-or-less symmetrically in the sinus above an anterior cusp which showed evidence of formation from two components. The reasons for confinement of the coronary ostia to only two of the three aortic sinuses are not clear. Microscopic examination of serial sections through 22 human embryos of 5.0–17.5 mm CR length (Carnegie stages XIII–XIX) confirmed that the earliest vessels in the heart wall develop subepicardially near the apex at stage XV. The network extends centripetally and only at stage XVII could coronary arterial stems, communicating with the aortic lumen, be identified. The sequence suggests that confinement of the coronary ostia to the anterior and left posterior sinuses probably occurs because these represent the most accessible contact points for the centripetally growing vascular plexus. © 1996 Wiley-Liss, Inc.     

Observation of root variations in human coronary arteries

In dissection courses conducted from 1999 through to 2003, five specimens were found to have coronary arteries with variant roots and branches, as follows: in specimens 1-4, roots of the right coronary artery (RCA) and right conus branch arose independently from the right aortic sinus (RAS); in specimen 5, the RCA and left coronary artery (LCA) originated from the RAS. The LCA pierced the upper part of the muscular interventricular septum and appeared on the surface, then dividing into the anterior interventricular and the circumflex branches. In the present study, we considered that the right conus arteries in specimens 1-4 were the remnant blood capillaries around the aorta towards the RAS in the embryonic stage. In specimen 5, the vessel near the left aortic sinus was poorly developed as a small thin artery. Instead, the LCA was developed from the anterior and posterior interventricular septal branches.     

正常大鼠不同动脉血管应力-应变分布的比较

通过充压实验和无载荷状态及零应力状态,我们研究了16只雄性大鼠的胸主动脉、腹主动脉、左颈总动脉、左股动脉和左肺动脉的形态学和应力－应变分布特征,并比较了不同血管间的差异。结果表明,血管的内外周长、管壁和管腔面积、管壁厚度、管壁厚度与内半径之比以及在不同压力负荷下血管外直径的变化,五条动脉之间有显著差异（P＜0.01）。展开角在肺动脉最大,而胸主动脉最小（P＜0.01）。残余应变绝对值和残余应变梯度在股动脉最大,而在胸主动脉最小（P＜0.01）。应力－应变关系分析证明,在周向上,股动脉最硬;在轴向上,胸主动脉最硬。而在这两个方向上,肺动脉最软。本实验表明,无论在形态学指数方面,还是在生物力学特征方面,五条动脉血管间都有显著差异。     

SOST expression is restricted to the great arteries during embryonic and neonatal cardiovascular development.

Spatial-temporal regulation of bone morphogenetic protein (BMP) and Wnt activity is essential for normal cardiovascular development, and altered activity of these growth factors causes maldevelopment of the cardiac outflow tract and great arteries. In the present study, we show that SOST, a Dan family member reported to antagonize BMP and Wnt activity, is expressed within the medial vessel wall of the great arteries containing smooth muscle cells. The ascending aorta, aortic arch, brachiocephalic artery, common carotids, and pulmonary trunk were all associated with SOST expressing smooth muscle cells, while the heart itself, including the valves, and more distal arteries, that is, pulmonary arteries, subclavian arteries, and descending aorta, were negative. SOST was expressed from embryonic day 15.5 up to the neonatal period. SOST expression, however, did not correspond with inhibition of Smad-dependent BMP activity or beta-catenin-dependent Wnt activity in the great arteries. Activity of both signaling pathways was already down-regulated before induction of SOST expression.     

Coronary artery wall imaging in mice using osmium tetroxide and micro-computed tomography (micro-CT)

The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary artery disease models, it is highly desirable to image coronary artery walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO(4) ) solution. As a tissue-staining contrast agent, OsO(4) is retained in the vessel wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the artery wall visible in CT. Additionally, since OsO(4) preferentially binds to lipids, it highlights lipid deposition in the artery wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE(-/-) ) mice at 10 μm resolution. The results show that walls of coronary arteries as small as 45 μm in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO(4) and micro-CT permits the visualization of the coronary artery wall in intact mouse hearts.     

Topographic anatomy of the fetal inferior vena cava,coronary sinus,and pulmonary veins: Variations in Chiari's network

To understand anomalies in Chiari's network better, we assessed the topographical anatomy of the fetal inferior vena cava (IVC), coronary sinus, and atria. We examined sagittal serial paraffin sections of 15 human fetuses of crown–rump length 24–36 mm, corresponding to a gestational age of 8 weeks. Although their outflow tract morphologies were similar, these 15 specimens could be classified into two groups. In eight specimens, the left common cardinal vein reached the body wall, whereas in the other seven the vein was obliterated near the left pulmonary vein. Irrespective of the group in which the specimen was included, the anteroposterior arrangement of the coronary sinus, the sinus septum (septum), and the right sinus valve (right valve) could be classified into three types: the right valve–septum–coronary sinus arrangement in seven specimens; the right valve–coronary sinus–septum arrangement in five; and the coronary sinus–right valve–septum arrangement in three. Depending on differences in topographical anatomy, the sinus septum separated the coronary sinus opening from either the right or the left atrium. Likewise, the coronary sinus opening was either adjacent to or distant from the IVC terminal. Rather than the counter‐side position of the right valve being at the IVC terminal, the left sinus valve protruded leftward, forming an incomplete interatrial septum. Fetal variations seemed to be closely connected with individual variations and a high frequency of Chiari's network anomalies in adults. Clin. Anat. 28:627–637, 2015. © 2014 Wiley Periodicals, Inc.     

心包横窦的范围、通连及其变异

目的：明确正常心包横窦的范围、通连及变异,为临床影像学及心脏外科疾病的诊断及治疗提供依据。方法：选用正常成人胸部连续断层标本４０例及心包完整的离体心脏１０例。对横窦的形态、通连关系、毗邻关系及变异进行观察。结果：５０例标本中,２例可见前垂中与主动脉上窦后部直接延续,未见中间水平部;４８例可见中间水平部或／及后垂直部,其中２４％（１２例）中间水平部延续到右肺动脉前下方,３０％（１５例）延续到右肺动脉     

Rat pulmonary artery wall injury by chronic intermittent infusions of Escherichia coli endotoxin. Obliterative vasculitis and vascular occlusion

To examine the effect of intermittent endotoxemia on rat pulmonary artery structure and hemodynamic function we infused purified Escherichia coli endotoxin on four occasions over 3 weeks (at 7-day intervals), through an indwelling catheter placed in the external jugular vein. The fourth infusion of endotoxin was associated with widespread but focal alveolar consolidation, reduced perfusion of small pulmonary arteries by lumen occlusion and obliteration, pulmonary vascular wall injury, and a peripheral leukocytosis (mean +/- SEM total leukocytes, endotoxin 133.5 +/- 23 X 10 mm3, control 12.2 +/- 1.2 X 10 mm3, p less than 0.001) in which polymorphonuclear (PMN) leukocytes predominated at the expense of lymphocytes (p2x less than 0.01). The alveolar wall was thickened and the alveolar space was consolidated by degenerating polymorphonuclear leukocytes, mononuclear cells, lipid laden alveolar macrophages, erythrocytes, fibrin, and cell debris. In regions of alveolar consolidation vessel lumens were either narrowed by subendothelial cell collections that consisted either of mononuclear cells or degenerating mural and inflammatory cells, or they were occluded by degenerating inflammatory cells and cell debris. The walls of occluded vessels were evident only by their residual elastic laminae: remnants of lysed endothelial cells lined the intima and the media consisted of degenerating mural and inflammatory cells. Capillary endothelial cells showed extensive hydropic degeneration and lysis of cell contents. Intimal precursor smooth muscle cells were hypertrophied but were not associated with the appearance of mature smooth muscle cells in the walls of small pulmonary arteries. In regions of less severe alveolar consolidation by inflammatory cells, vessel wall injury was still evident but less marked; precursor smooth muscle cells were hypertrophied; subepithelial and subendothelial collections of fluid and fibrin were present; and plasma membranes of endothelial cells were disrupted. Despite extensive pulmonary vascular injury, chronic intermittent endotoxemia did not produce the structural changes associated with pulmonary hypertension (medial thickening and appearance of medial muscle in previously nonmuscular arteries) nor a significant change in pulmonary artery pressure.     

The origin of the epicardium and the embryonic myocardial circulation in the mouse

The origin of the epicardium and the formation of the early blood vessels of the heart prior to the opening of the coronary arteries from the aorta have been studied in the 9–13.5 day post coitum (dpc) mouse embryo heart. The epicardium begins to appear by 9 dpc. The majority of the epicardial cells derive from the somatopleural investment of the septum transversum, from where they migrate, associated to form vesicles, to the dorsal aspect of the ventricles and atria. The epicardial cells then migrate over the lateral surfaces and the AV sulcus to the ventral aspect of the heart. In the subepicardial space around the sulcuses, the proliferating epithelial tissue is found, also in vesicular form, for a time. The ventrally migrating primordial epicardial tissue ensheaths lastly the truncus arteriosus, while the sinus venosus is coated with epicardium ab initio, where (and also in the SA sulcus) the epicardial cells derive in part from the cuboidal cells of the pleuroperitoneal canal and in part from the somatopleural cells. The early blood vessel formation follows in space and time the development of the epicardium. The first blood vessels appear by 10 dpc by the invagination of the endocardium into the early sinus muscle, and at the same time in the ventricular chamber by the encasing of the endocardium, as the trabeculae become consolidated into the myocardial walls. By this process sinusoids are formed, some of which penetrate through the myocardium and which, by rapid proliferation, form an interconnected subepicardial plexus. These capillaries proliferate ventrally in the wide subepicardial space, reaching the septating truncus, in which the aorta and pulmonary artery are developing. The definitive coronary artery openings appear by 13 dpc, allowing the high pressure blood from the aorta to flow into a preexisting vascular bed.