个性化主动脉夹层及其搭桥术的流固耦合数值模拟

目的 研究不同搭桥方式对不同假腔型式的Debakey III型主动脉夹层模型治疗效果的影响。方法 依据主动脉夹层患者的CT图像,采用Mimics医学图像处理软件进行模型重建,并利用计算机辅助手段建立升-腹和锁-腹两种方式的旁路搭桥模型,进行流固耦合数值模拟计算,比较不同模型的血流动力学差异。结果实施两种方式的旁路搭桥转流术后,通腔型式模型的血液流量、血流平均与最大速度均有不同程度的降低。同时升-腹搭桥后血液最大压力和血管壁位移均减小,而锁-腹搭桥后却增加;盲腔型式模型的上述血流动力学参数在搭桥后均降低,且升-腹搭桥式模型的降幅更大。结论 升-腹搭桥方式对通腔和盲腔两种假腔型式主动脉夹层有更好的治疗效果,借助数值模拟的结果可以更好地解释搭桥手术对主动脉夹层的影响,并确立搭桥手术的科学有效性和临床实用性。     

改良B-T手术与中央分流术的血流动力学比较

目的对比分析改良B-T手术(modified B-T shunt,MBTS)和中央分流术(central shunt,CS)两种手术方式的血流动力学特征。方法采集法洛氏四联症(tetralogy of fallot,TOF)病人的医学图像,三维重建真实的解剖模型;对模型进行虚拟血管搭桥等操作,模拟手术过程;采集病人的生理数据,建立集中参数模型(lumped parameter mod-el,LPM);通过LPM计算提供计算流体力学仿真模型的边界条件;利用ANSYS软件对模型的血流动力学进行数值模拟。结果无论是快速射血期还是舒张期,MBTS和CS模型中搭桥管内的血液始终流向肺循环,但是两个模型中的血液最高流速明显不同。CS模型中分流管两端的压差相比MBTS模型较大。MBTS模型中分流管的壁面切应力分布不均匀,在0.025～340 Pa。而CS模型中分流管上的壁面切应力分布相对较均匀,约在32.2～72.6 Pa。结论两种手术方式都提供了足够的肺动脉血流量;MBTS方式对右上肢的血液供应有较大影响;CS方式分流率偏高;两个模型前端吻合口部位压力梯度很大,应引起临床重视。本研究为临床治疗TOF的手术术式决策提供了重要的理论依据。     

法洛四联症根治术后对左肺动脉狭窄影响机理的数值分析

目的 利用计算流体力学(CFD)方法分析法洛四联症(TOF)根治术后不同的左肺动脉狭窄率（50%,20%,0%）模型的局部血流动力学改变。方法 通过对患者CT数据处理,完成3组左肺肺动脉狭窄几何的全三维数字化重构;结合主肺动脉血流量等临床数据,对3组模型中肺动脉分叉区的血液流动速度场、压力、壁面剪切应力等进行记录。结果 在3组模型的非定常模拟中,左肺动脉起始端均存在与狭窄率相关的反流和血流分布,右肺动脉血流分布规则。3组模型的静态压力、压力损失、壁面剪切力等也不同。结论 肺动脉分支的合理扩大在TOF根治术中有重要意义;术后左肺动脉狭窄是造成肺动脉反流的早期和重要因素;通过CFD模拟术后患者的三维模型可以对手术的效果提供早期参考。     

主动脉夹层及其移植管搭桥术的二维数值模拟

目的探讨搭桥术对主动脉夹层假腔内血流动力学参数的影响及该术式的治疗有效性。方法利用AutoCAD软件构建DeBakeyⅢ型主动脉夹层及其移植管搭桥术的理想化二维几何模型,然后利用ANSYS软件进行数值模拟,分析计算结果的血流动力学特性。结果在实施搭桥手术后,假腔内的血流速度与压力均小于实施搭桥手术前的值。结论利用旁路搭桥转流术可有效地降低主动脉弓的血压,减轻血流对夹层病变的冲击和压力。由此推之到其对防止夹层破裂,促进夹层局部病变愈合,是一种有效的手术方式。     

中央分流术中血管弹性壁和刚性壁对血管中血流动力学的影响

目的 通过数值模拟仿真研究中央分流手术（central shunt, CS）的血流动力学环境,并分别研究弹性与刚性血管壁条件对其血管内血流动力学参数分布的影响。方法 建立两个理想化的CS搭桥模型,其中一个假设为刚性血管壁,另一个为弹性血管壁。利用有限元方法进行数值计算,其中弹性血管壁模型采用流固耦合方法。结果 两个模型中的流速和压力分布总体大致相同。刚性血管壁模型中大约有68.9%血液从主动脉分流进入肺动脉中,弹性血管壁模型中该值增加到了70%。弹性模型和刚性模型中搭桥血管两端的压降分别为7.668 8 kPa和7.222 3 kPa。弹性模型中搭桥管各处的横截面积有一定变化,最大变化率约为2.2%,出现在近心端吻合口处。提取两个模型中的5个关键区域进行壁面切应力比较,其数值差别最多约为16.1%。结论 总体来说两个模型的血液流动形态没有大的改变;血管的弹性因素轻微影响了流量的分布和搭桥管两端的压降;搭桥管上血管的弹性对近心段吻合口处的影响高于对远心端吻合口处的影响。在CS术治疗法洛四联症的数值模拟仿真中血管壁为刚性这一假设是可以接受的,而流固耦合的数值模拟将得到更为可信的仿真结果。     

右冠状动脉开口异位1例

在局部解剖的过程中,发现右冠状动脉开口位置异常1例(附图),报道如下:下,动脉口直径为0.4cm,其主干先在升主动脉根部与肺动脉干之间紧贴升主动脉壁向右行走0.9cm距离,继行于肺动脉与右心耳下方的右冠状沟内,向右绕过右缘至膈面走行于后室间沟,于心尖处与前室间支末梢吻合,沿途分支有:右圆锥支、右室支、右缘支、右房支、房事结支。左冠状动脉开口于左主动脉窦内,动脉口直径为0.4cm,心脏其它部位未见异常。 本例右冠状动脉分支和分布虽属正常,但其始段贴着升主动脉壁行走,当主动脉充盈扩张时,可能影响到右冠状动     

搭桥术治疗DeBakey Ⅲ型主动脉夹层的流固耦合数值模拟

目的研究旁路搭桥转流术治疗DeBakey Ⅲ型主动脉夹层的力学机理,并探讨该术式的有效手术方案。方法构建升-腹搭桥和锁-腹搭桥前后通腔型式和盲腔型式的DeBakey Ⅲ型主动脉夹层个性化模型,利用计算流体力学的方法,在生理流动条件下进行流固耦合数值模拟。结果搭桥后假腔的血液流动速度、压力和血管壁位移分别平均下降38.86%、15.347 kPa和39.46%。结论搭桥手术是一种在特定情况下治疗DeBakey Ⅲ型主动脉夹层的有效手术方式,具有很好的临床应用前景。     

一侧肺动脉起源于升主动脉的外科处理

目的探讨一侧肺动脉起源于升主动脉的外科处理方法.方法自1993年3月～2001年8月共收治5例一侧肺动脉起源于升主动脉患者,其中4例为右肺动脉起源于升主动脉,合并动脉导管未闭4例、卵圆孔未闭2例及室间隔缺损1例;另1例为左肺动脉起源于升主动脉合并法乐氏四联症.均在全麻低温低流量下行根治术.结果1例因呼吸衰竭、弥散性血管内凝血(DIC)术后24天死亡,4例治愈.结论一侧肺动脉起源于升主动脉手术效果良好.     

改良B-T手术不同搭桥方式的血流动力学比较

目的 通过数值模拟的方法对比分析端对边（end-to-side, ETS）与边对边（side-to-side, STS）两种不同搭桥方式的改良B-T手术（modified blalock-taussig shunt, MBTS）对血流动力学的影响,为临床治疗单心室心脏缺陷综合征提供参考。方法 采集单心室心脏缺陷综合征病人的医学图像,重建病人心脏真实的几何模型;基于虚拟手术操作系统模拟手术过程;采集病人的生理数据,建立病人的集中参数模型（lumped parameter model, LPM）;通过LPM计算提供计算流体力学（computational fluid dynamics, CFD）仿真模型的近生理边界条件;利用有限体积法对模型进行数值仿真。结果 分别获取了ETS模型和STS模型的血液流速以及壁面切应力分布。ETS模型和STS模型的吻合口部位振荡剪切系数（oscillatory shear index, OSI）分别为3.058×10-3和13.624×10-3,能量损失分别为116.5 和94.8 mW,右、左肺动脉流量比RRPA/LPA分别为0.8和1.72。结论 两个模型的能量损失相差不大,对手术的影响相对较小。STS搭桥方式左右肺动脉流量分布均匀,吻合口位置OSI值较小,优于ETS搭桥方式,应着重考虑。本研究为临床治疗单心室心脏缺陷综合征提供重要的理论支持和参考。     

左心室辅助装置与主动脉吻合角度对主动脉瓣膜影响的血流动力学研究

目的 探究左心室辅助装置(left ventricular assist device, LVAD)与主动脉吻合角度对主动脉瓣膜的血流动力学影响。方法 分别构建LVAD与主动脉吻合角度为45°、60°、90°的3个主动脉模型和主动脉瓣膜模型,搭建体外搏动台用于体外实验。运用粒子图像测速(particle image velocimetry, PIV)系统,选取心动周期中的3个时刻(T₁收缩峰值期,T₂瓣膜快速闭合时期和T₃舒张峰值期)探究主动脉瓣膜处血流动力学状态。结果 采用速度矢量、涡量、黏性剪切力指标评价LVAD吻合角度对主动脉瓣膜血流动力学的影响。瓣膜快速闭合时期,吻合角度增大时,瓣膜近壁面血流速度、平均涡量和最大黏性剪切力均增大。结论 吻合角度较低时,血流对主动脉瓣膜的冲击速度较小,瓣膜受到较小的剪切力,使瓣膜处于较好的血流动力学环境。研究结果为临床手术中吻合角度的选择提供参考。     

The site of origin of nonconfluent pulmonary arteries from a common arterial trunk or from the ascending aorta: its morphological significance

There are three possible embryological derivatives for nonconfluent pulmonary arteries which arise from a common arterial trunk or from the ascending aorta. We considered the feasibility of identifying these derivatives on the basis of the site of origin. We examined 15 specimens, in which both pulmonary arteries arose by separate orifices from a common arterial trunk (persistent truncus arteriosus), and 3 specimens, in which one pulmonary artery arose from the ascending aorta, the other being connected to the morphologically right ventricle (hemitruncus). Measurements were made for both the upper and lower margins of the orifices of the pulmonary arteries and then expressed as a percentage of the length of the ascending common trunk or aorta. The position of origin ranged from 39 to 100% for the upper margin and from 17 to 90% for the lower margin, without significant difference between left and right arteries. Since the range varied so widely, we contend that it is not possible to make a morphological identification of the pulmonary artery under consideration simply on the basis of the location of the site of origin.     

正常成人膈下动脉的超声观测

目的：观察膈下动脉的超声解剖及血流参数。方法：应用二维及多普勒超声观测100例正常成人的膈下动脉的起源、直径、血流参数（包括收缩期峰值速度、阻力指数、搏动指数）,并提出正常值范围。结果：超声能够显示起始于腹腔动脉干和腹主动脉的膈下动脉,右侧膈下动脉显示率（83％）较左侧（62％）高。正常成人膈下动脉直径左侧为（2．03±0．28）mm,右侧（2．07±0．30）mm,95％可信度上限值左侧2．58mm,右侧2．66mm;最大流速左侧为（45．95±12．65）cm／s,右侧（42．85±10．31）cm／s,95％可信区间左侧21．16～70．74cm／s,右侧22．64～63．16cm/s;阻力指数左侧为（0．78±0．04）cm/s,右侧（0．77±0．04）,95％可信区间：左侧0．70～0．86,右侧0．69～0．85。结论：超声能在一定程度上显示膈下动脉,评价膈下动脉起源及其血流参数.     

经右股动脉行肾动脉下腹主动脉腔内球囊阻断血流的应用解剖学研究

目的探讨经右股动脉入路应用球囊导管阻断肾动脉下腹主动脉的可行性。方法解剖50例健康成人尸体标本（其中男性33例,女性17例）,测量身高;分别经血管腔内测量肾动脉下腹主动脉至右股动脉腹股沟韧带平面的长度,采用sPSs12．0统计学软件分析身高与血管长度之间的关系。结果身高与肾动脉下腹主动脉至右股动脉腹股沟韧带平面的长度之间存在直线回归及较强的相关关系。结论经右股动脉入路行血管腔内球囊阻断肾动脉下腹主动脉对于腹主动脉瘤,特别是破裂腹主动脉瘤是一个可行的安全阻断血流的方法,为临床工作提供了一个新的思路和方法。     

Gut blood flow in the estuarine crocodile, Crocodylus porosus.

Simultaneous recordings of blood flow in the right and left aorta and carotid and coeliac artery were made in the crocodile, Crocodylus porosus at rest and during various stimuli. In resting animals the right aorta and carotid artery flow profiles resembled the recordings obtained in the caiman (Axelsson et al. 1989a), with an anterograde blood flow throughout the cardiac cycle. As in the caiman, the left aorta flow profile was complex with both anterograde and retrograde blood flow during the cardiac cycle, and a net left aorta blood flow near zero at rest. The coeliac artery blood flow profile did not show the complex pattern seen in the upper aorta, immediately suggesting that most of the coeliac artery blood originates elsewhere. We believe that coeliac artery blood flow in the resting animal derives from the right aorta via the abdominal anastomosis between the two aortas. Feeding induced an increase in the coeliac artery and left aorta blood flow, probably due to a decrease in visceral vascular resistance, and hence coeliac arterial and the left aorta blood pressure, which facilitates blood flow (from right to left aorta) through the foramen of Panizza. During short 'fright dives', heart rate fell and there was a decrease in the recorded blood flows: carotid artery blood flow did not decrease to the same extent as the RAo and coeliac artery flow, indicating some capacity for redistribution of blood to the cephalic circuits during diving. Similarly, a near-unimpaired carotid artery blood flow was maintained after adrenaline injection. Substance P increased the coeliac artery blood flow and produced a right-to-left cardiac shunt, probably by construction of the pulmonary vasculature.     

右侧腋下小切口入路矫治法洛四联症的技术要点分析

目的 总结右侧腋下小切口剖胸矫治法洛四联症（TOF）的技术要点.方法 回顾性分析1997年1月-2013年10月346例TOF患儿的临床资料.均采用右侧腋下小切口入路行根治术治疗,其中男159例,女187例;平均年龄（1.9±1.2）岁;平均体质量（9.7±2.4） kg.合并卵圆孔未闭43例、房间隔缺损22例、动脉导管未闭10例、永存左上腔静脉10例、主动脉瓣下隔膜7例、二尖瓣关闭不全1例.全组跨环补片205例,右室流出道补片141例.结果 全组手术死亡7例（2.02％）,术中体外循环（90±24） min,主动脉阻断（64±17） min,术后机械通气4～165 h,监护室停留（3.2±1.7）d,术后当日胸腔引流量（138 ±91） ml,平均带胸管（2.5±0.9）d.术后出现并发症36例（1.04％）：低心排血量综合征17例（死亡5例）,严重肺部感染2例（死亡1例）,灌注肺5例（死亡1例）,右肺损伤7例,膈神经损伤4例,室间隔缺损残余分流2例,乳糜胸2例.结论 右侧腋下小切口配合有效的牵引显露行TOF根治安全可靠.     

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.     

Gut blood flow in the estuarine crocodile,Crocodylus porosus

Simultaneous recordings of blood flow in the right and left aorta and carotid and coeliac artery were made in the crocodile, Crocodylus porosus at rest and during various stimuli. In resting animals the right aorta and carotid artery flow profiles resembled the recordings obtained in the caiman (Axelsson et al. 1989 a), with an anterograde blood flow throughout the cardiac cycle. As in the caiman, the left aorta flow profile was complex with both anterograde and retrograde blood flow during the cardiac cycle, and a net left aorta blood flow near zero at rest. The coeliac artery blood flow profile did not show the complex pattern seen in the upper aorta, immediately suggesting that most of the coeliac artery blood originates elsewhere. We believe that coeliac artery blood flow in the resting animal derives from the right aorta via the abdominal anastomosis between the two aortas. Feeding induced an increase in the coeliac artery and left aorta blood flow, probably due to a decrease in visceral vascular resistance, and hence coeliac arterial and the left aorta blood pressure, which facilitates blood flow (from right to left aorta) through the foramen of Panizza. During short ‘fright dives’, heart rate fell and there was a decrease in the recorded blood flows: carotid artery blood flow did not decrease to the same extent as the RAo and coeliac artery flow, indicating some capacity for redistribution of blood to the cephalic circuits during diving. Similarly, a near-unimpaired carotid artery blood flow was maintained after adrenaline injection. Substance P increased the coeliac artery blood flow and produced a right-to-left cardiac shunt, probably by construction of the pulmonary vasculature.