腹主动脉夹闭再灌注后多脏器血流量及血浆、淋巴液中TNFα和IL-8水平的变化

目的探讨腹主动脉阻断后肠道淋巴液成分的改变与多器官功能损伤的关系.方法通过夹闭腹腔动脉40min建立腹主动脉阻断再灌注(I/R)的模型,检测不同时间点多器官的血流量,用放射免疫分析法测定再灌3 h时血浆及淋巴液中肿瘤坏死因子(TNFα)和白细胞介素8(IL-8)水平的变化.结果腹主动脉夹闭40min时,肠、肝、肾及下肢肌肉的血液灌注量均较夹闭前明显减少(P＜0.05),上肢肌肉的血流量反而增加;再灌后与缺血期比较:再灌1 h,腹主动脉阻断平面以下主要脏器血液灌注量增加,以肠、肾增加明显(P＜0.05),到再灌3 h时又有所下降.再灌过程中,上肢血流量明显减少(P＜0.05).缺血再灌3 h时,淋巴液中TNF α和IL-8的水平明显高于血浆(P＜0.05),血浆和淋巴液中TNFα的水平均高于对照组(P＜0.05).结论腹主动脉夹闭再通过程中,全身的血液动力学发生了明显改变,推论肠源性TNF等细胞因子,主要通过肠道淋巴液入血,进而造成远隔部位器官的损伤.     

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。     

急性等容血液稀释联合腹主动脉球囊阻断在凶险性前置胎盘剖宫产手术中的应用研究

目的探讨急性等容血液稀释联合腹主动脉球囊阻断在凶险性前置胎盘剖宫产手术中的应用价值。方法选取2016年1月~2018年1月我院收治的100例凶险性前置胎盘剖宫产手术患者作为研究对象,随机将其分为实验组和对照组,对照组患者术前进行腹主动脉球囊阻断,实验组患者术前进行急性等容血液稀释联合腹主动脉球囊阻断。比较两组患者术中异体血输注例数、术后2小时血常规、外周血中炎性介质CD2、CD4、CD8水平及新生儿娩出后1、5minApgar评分。结果实验组异体血输注例数明显少于对照组,组间比较差异具有统计学意义(P0.05);实验组患者术后2小时HB、HCT值明显高于对照组(P0.05);两组新生儿娩出后1、5minApgar评分,组间比较差异无统计学意义(P0.05);两组产妇术后第3、5天炎性介质CD2、CD4、CD8值,组间比较差异具有统计学意义(P0.05)。结论在腹主动脉球囊阻断剖宫产术中应用急性等容血液稀释技术是一种创新,它不仅不影响腹主动脉球囊阻断效果,而且能够节约血液资源,减少异体血输注,是阻断技术的有效补充。     

腹主动脉缩窄大鼠血浆心房利钠肽水平的变化

目的:通过建立腹主动脉缩窄大鼠模型,观察腹主动脉缩窄大鼠血浆心房利钠肽(ANP)浓度的改变。方法:30只雄性SD大鼠随机分为假手术组(14只)和模型组(16只)。模型组根据Doering等的方法,用银夹造成腹主动脉部分狭窄(银夹内径0.7mm);8周后计算左室心肌质量指数(LVMI),胶原染色观察心肌病理形态,放射免疫法测定血浆ANP水平。结果:造模8周时左室心肌胶原染色显示模型组有大量鲜红色胶原纤维,较假手术组有明显改变;模型组LVMI及血浆ANP水平较假手术组显著升高(P<0.01)。结论:腹主动脉缩窄大鼠造模8周时心肌符合纤维化改变,ANP在其过程中发挥重要作用。     

成人降主动脉置换术中三种体外循环灌注技术的应用

目的总结分析成人降主动脉置换术中各种体外循环灌注的技术特点和管理方法。方法 2006年1月至2009年12月,共有60例患者行降主动脉置换手术。按体外循环灌注技术类型分为3组:左心转流组4例,股动静脉转流组37例,上下半身分别灌注组19例。三组预充均采用勃脉力A和胶体,常规加入白蛋白和激素,监测混合静脉氧饱和度和血细胞压积,积极应用超滤技术和自体血液回收技术。结果术中转流平稳,血流动力学稳定,监测指标均在正常范围,仅出现9例并发症(截瘫、偏瘫、谵妄、苏醒延迟、低氧血症)。结论成人降主动脉置换术中根据不同的手术方式,正确选择和熟练应用相应的灌注技术是决定手术成功的重要因素。     

孙氏手术治疗头臂血管严重受损的A型主动脉夹层过程中血液动力学参数的意义

目的:探讨孙氏手术治疗头臂血管严重受损的A型主动脉夹层对血液动力学参数的影响。方法:选取125例头臂血管严重受损的A型主动脉夹层患者,对其行孙氏手术,观察体外循环时间、主动脉阻断时间、低流量选择性脑灌时间以及同期合并手术;并发症及30 d内死亡发生率;手术前后左室舒张末期内径（LVEDD）、心指数（CI）、中心静脉压（CVP）。结果:患者体外循环时间、主动脉阻断时间以及低流量选择性脑灌时间平均分别为（194.32±52.64）、（103.66±33.07）、（23.15±7.29） min,同期合并手术主要有Bentall手术、升主动脉替换、主动脉瓣成形;19例（15.20%）发生并发症,主要有神经系统并发症、多脏器功能不全甚至衰竭、肾功能不全甚至衰竭,8例（6.40%）30 d内死亡,主要死于多脏器功能不全甚至衰竭;与手术前比较,手术后患者LVEDD显著降低,CVP、CI显著升高,差异有统计学意义（P<0.05）。结论:孙氏手术治疗头臂血管严重受损的A型主动脉夹层不仅能够降低并发症发生率和死亡率,而且还能改善血液动力学参数,对临床治疗A型主动脉夹层有积极意义。     

轴流血泵对心衰动物的辅助试验研究

选择 2 0只雄性健康成年绵羊 ,采用结扎冠脉方法建立心衰模型后 ,随机分为两组 ;心衰后实验组运用自制轴流血泵进行左心辅助 ,分别在结扎冠脉前、心衰后和左心辅助 1h测量两组动物各项血液动力学参数 ,探讨血泵的动力学输出和对衰竭心脏的辅助功能 ,并取标本进行光、电镜检查。通过测试实验组血液的FHB、Fib和主要器官的栓塞情况 ,观察血泵对血液的破坏程度。结果得出 :(1)选择性结扎冠脉比较适合作为LVAD的左心衰动物模型。 (2 )血泵的压力、流量输出能够达到辅助要求 ,血泵辅助流量可占总流量的 10 0 %。 (3)并联于左心房和腹主动脉的血泵是通过部分分流和提高主动脉舒张压方式促进心肌的恢复 ;病理检查结果与血液动力学结果推测一致。 (4 )实验组短期在体试验辅助 2 4h ,标准溶血指数NIH为 0 .0 8g/ 10 0L ,试验结束肾脏有散在白色斑块 ,血泵的进、出口与管道接口处覆盖一层薄薄白膜 ;血泵表面温度变化较小。     

体液免疫在异品系大鼠腹主动脉移植硬化中的作用

目的： 探索体液免疫在移植动脉硬化演变过程中的作用。方法: 建立大鼠腹主动脉移植硬化模型，HE染色和光镜下检查植入的腹主动脉病理学改变，计算机图像分析系统自动测出其管腔面积、内膜面积和中膜面积。间接免疫荧光法检测植入的腹主动脉壁IgG、IgM、C3沉积情况。结果: 异品系移植组术后60 d腹主动脉管腔明显缩小，内膜显著增厚，中膜变薄。增生的腹主动脉内膜主要由单核/巨噬细胞和平滑肌细胞构成，中膜层平滑肌细胞坏死，数量减少，弹力膜断裂。IgM、C3在术后各组各时点动脉壁上均未见沉积现象。IgG在异品系移植组术后7 d、15 d时动脉中膜层呈强荧光沉积，30 d后IgG荧光消失。结论: 体液免疫因子IgG可能参与了异品系大鼠移植腹主动脉硬化的过程。     

冠状动脉结扎与腹主动脉缩窄所致慢性心力衰竭大鼠模型比较

目的比较冠状动脉结扎术与腹主动脉缩窄术所建立的大鼠慢性心力衰竭(chronicheartfailure,CHF)模型在病理及病理生理学等方面的差别。方法实验大鼠随机分为三组:正常对照组(Control组)、冠状动脉结扎术组(A组)和腹主动脉缩窄术组(B组),8周后测定血流动力学变化,计算左、右心室重量指数,观察心肌组织形态学改变。结果A、B组死亡率分别为33%、17%;左、右心室重量指数(LVWI、RVWI)分别升高28%、40%和23%、40%,A组LVWI升高较B组更明显(P<0.05);两种CHF模型动脉收缩压(BPs)、动脉舒张压(BPd)、左室收缩压(LVSP)、左室压力上升和下降最大速率(+/-dp/dtmax)均较Control组显著降低(P<0.01),A组较B组降低更为显著(P<0.05)。光镜下A组梗死区纤维组织替代坏死心肌细胞,大量炎性细胞浸润,非梗死区心肌细胞肥大伴间质显著增生;B组心肌细胞肥大,排列紊乱,小血管壁增厚,间质增生伴少量炎细胞浸润。结论冠脉结扎术和腹主动脉缩窄术均是建立慢性心力衰竭大鼠模型的有效方法。两者的差别是:腹主动脉缩窄术建立的是压力超负荷型CHF模型,冠脉结扎术建立的是低心输出量型CHF模型,后者心衰程度更严重,其病理生理演变过程与充血性心力衰竭更接近。     

体外腹主动脉末端阻断辅助标准心肺复苏的影像解剖研究

目的　为体外腹主动脉末端阻断辅助标准心肺复苏（CPR）提供影像解剖学基础。 方法　75名患者的CT影像解剖图中,以脐为标志点,主要观测：①脐中点水平面对应椎体的位置;②腹主动脉末端与脐中点的关系;③腹主动脉下段、下腔静脉下段与腰椎的相对位置关系。 结果　腹主动脉末端、腰椎与脐标志点基本重叠于人体正中线位置：①脐中点位于腰4椎体下缘以上40.31mm,以下32.82 mm范围内;②腹主动脉末端在脐上、下35 mm范围内;③腹主动脉末端所在的横切面上腹主动脉位于脊柱椎体前略偏左侧,下腔静脉在此平面位于椎体前偏右侧。 结论　可以脐为重要的标志点定位腹主动脉末端以进行体外腹主动脉远端阻断,辅助标准CPR改善血流动力学机制,保证心脑等重要器官血供,从而增高冠状动脉灌注压和CPR成功率。     

牙髓牙本质复合体中VIP阳性神经纤维的研究

目的:研究血管活性肠肽(VIP)在牙髓牙本质复合体中的表达,探讨其功能。方法:收集人前磨牙,石蜡包埋切片,作免疫组织化学和图象定量分析。结果:VIP阳性神经纤维自根尖孔呈束状进入牙髓,至颈部扇形分开,在冠髓大量分支,部分围绕在血管周围,部分终止于牙髓基质,部分参与形成成牙本质细胞层下Raschkow神经丛,然后发出分支伸入成牙本质细胞层和前期牙本质,但不进入成熟牙本质。VIP阳性神经纤维在冠髓的积分光密度为12.74±1.807,体密度为0.0192±0.0127,线密度为0.0046±0.0029,在前期牙本质的积分光密度为13.07±1.927,线段长度为(19.60±8.597)mm。结论:VIP阳性神经纤维存在于人牙髓牙本质复合体,部分纤维围绕血管,部分纤维止于牙髓基质和前期牙本质,这种分布提示该纤维除与血管运动有关外,可能还与感觉有关,在痛觉传导、血管调节等方面发挥重要作用。     

Evaluation of the appropriate root pressure for maintaining heartbeat during an aortic cross-clamp for primary repair of the aortic arch in premature infants with associated cardiac anomalies

We developed a new cardiopulmonary bypass (CPB) method to minimize myocardial damage during aortic arch reconstruction. In this method, coronary flow and heartbeat were stabilized by maintaining the aortic root pressure with an adjusted preload of the ventricle during aortic cross-clamping. This study was performed to determine the appropriate root pressure to maintain the heartbeat without causing deterioration of ventricular function. Study 1. Under partial CPB, the ascending aorta was cross-clamped in 6 pigs (group 1). Experimental data at various systolic aortic root pressures was analysed to determine the appropriate root pressure. Study 2. In group 2 (control, n＝6), the aorta was not clamped, while in group 3 (n＝6), the aorta was cross-clamped for 60 min and the systolic aortic root pressure was maintained at the pressure determined in study 1. Study 1. The diastolic coronary flow was stabilized at values comparable to that before initiation of CPB (6.6±1.4 ml/beat) when the systolic aortic root pressure was above 80 mmHg. Intracardiac pressure and the myocardial oxygen consumption (MvO2) seemed to be acceptable when the systolic aortic root pressure was below 100 mmHg. Therefore, 90 mmHg was selected for study 2. Study 2. Perioperative cardiac function did not differ between the groups. We concluded that 90 mmHg was the systolic aortic root pressure appropriate for this method.     

Continuous cerebral and myocardial perfusion during aortic arch repair in neonates and infants

To minimize myocardial ischemia, we repaired aortic arch obstruction with ventricular septal defect, using two different techniques of cerebral and myocardial perfusion. Seventy-one infants, ages 3 to 137 days, underwent primary repair of coarctation of the aorta (n = 49)/interruption of the aortic arch (n = 22) with ventricular septal defect. In 65 patients, an end-to-end arch anastomosis was performed with cerebral and myocardial perfusion through the innominate or the ascending arterial cannula (non-working beating heart: NWBH). In the remaining 6 patients, an arterial cannula was placed into the innominate artery. With partial cardiopulmonary bypass, the innominate artery was snared proximal to the cannulation site and the ascending aorta was cross-clamped. An extended arch anastomosis was carried out with cerebral perfusion and a working beating heart (WBH). Ten patients (15%) undergoing aortic arch repair with the NWBH technique required cardioplegic arrest to complete a proximal anastomosis, whereas in all 6 repairs with the WBH technique, the extended anastomoses were completed without myocardial ischemia. One hospital death and late death occurred, with an overall survival of 98%. End-to-end arch reconstruction is feasible without myocardial ischemia, using the NWBH technique in patients without hypoplastic arch and using the WBH technique in patients with hypoplastic arch.     

Augmentation of abdominal organ perfusion during cardiopulmonary bypass with a novel intra-aortic pulsatile catheter pump

BACKGROUND: Current pulsatile pumps for cardiopulmonary bypass (CPB) are far from satisfactory because of the poor pulsatility. This study was undertaken to examine the efficiency of a novel pulsatile catheter pump on pulsatility and its effect on abdominal organ perfusion during CPB. METHODS: Twelve pigs weighing 89+/-11 kg were randomly divided into a pulsatile group (n=6) and a non-pulsatile group (n=6). All animals had a CPB for 120 min, aorta clamped for 60 min, temperature down to 32 degrees C, and a perfusion flow of 60 ml/kg/min. In the pulsatile group, a 21 Fr intra-aortic pulsatile catheter, which was connected to a 40 mL membrane pump, was placed in the descending aorta and activated by a balloon pump driver during the first 90 minutes of CPB until aortic declamping. Hemodynamics, organ blood flow, body metabolism, and blood trauma were studied during experiments. RESULTS: Compared with the non-pulsatile group during CPB, the pulsatile group had a higher systolic blood pressure (p<0.01), higher mean arterial pressure (p<0.05), and higher blood flow to the superior mesenteric artery (p<0.05). The hemodynamic energy, indicated by the energy equivalent pressure (EEP) was higher in the gastrointestinal tract and kidney in the pulsatile group (p<0.01, p<0.01). Abdominal organ perfusion status, as indicated by SvO 2 in the inferior vena cava, was higher in the pulsatile group (p<0.05) 30 min after cessation of CPB. Hemolysis indicated by release of free hemoglobin during CPB was similar in the two groups. CONCLUSION: Applying the pulsatile catheter pump in the descending aorta is effective in supplying the pulsatile flow to the abdominal organs and results in improved abdominal organ perfusion during the ischemic phase of CPB.     

Local and regional wave speed in the aorta: effects of arterial occlusion

Arterial wave speed is widely used to determine arterial distensibility and has been utilised as a surrogate marker for vascular disease. A comparison between the results of the traditional foot-to-foot method for measuring wave speed to those of the pressure-velocity loop (PU-loop) method is one of the primary objectives of this paper. We also investigate the regional wave speed along the aorta, and the effect of arterial occlusion on the PU-loop measured in the ascending aorta. In 11 anaesthetised dogs, a total occlusion lasting 3 min was produced at four sites: upper thoracic, diaphragm, abdominal and left iliac artery. Pressure and flow in the ascending aorta and pressure proximal to the occlusion site were measured, and data were collected before, during the occlusion and after the occlusion had been removed. In control conditions, the wave speeds determined by the PU-loop in the aortic root were systematically lower than those measured by the foot-to-foot method. During thoracic and diaphragm occlusions, mean aortic pressure and wave speed increased significantly but returned to control values after each occlusion had been removed. The PU-loop is an objective and easy to use method for determining wave speed and can be advantageous for use in short arterial segments when local measurements of pressure and velocity are available.     

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。     

Development of an animal experimental model for a bileaflet mechanical heart valve prosthesis

The objective of this study was to develop a pre-clinical large animal model for the in vivo hemodynamic testing of prosthetic valves in the aortic position without the need for cardiopulmonary bypass. Ten male pigs were used. A composite valved conduit was constructed in the operating room by implanting a prosthetic valve between two separate pieces of vascular conduits, which bypassed the ascending aorta to the descending aorta. Prior to applying a side-biting clamp to the ascending aorta for proximal grafting to the aortic anastomosis, an aorta to femoral artery shunt was placed just proximally to this clamp. The heart rate, cardiac output, Vmax, transvalvular pressure gradient, effective orifice area and incremental dobutamine stress response were assessed. A dose-dependent increase with dobutamine was seen in terms of cardiac output, Vmax, and the peak transvalvular pressure gradient both in the native and in the prosthetic valve. However, the increment was much steeper in the prosthetic valve. No significant differences in cardiac output were noted between the native and the prosthetic valves. The described pre-clinical porcine model was found suitable for site-specific in-vivo hemodynamic assessment of aortic valvular prosthesis without cardiopulmonary bypass.     

血流动力学的医学应用与发展

血流动力学是指血液在血管系统中流动的力学,主要研究血流量、血流阻力、血压、切应力、扰动流等,以及它们之间的相互关系,对人类生命健康具有重要的影响。血流动力学在血管的弯曲、狭窄、堵塞、分叉以及肿瘤的治疗等方面具有重要的临床研究意义。目前,血流动力学在动脉血管搭桥、冠状动脉狭窄、腹主动脉瘤、动脉粥样硬化、脑动脉肿瘤以及旋动流等方面引起广泛研究。伴随着血流动力学的深入研究,心脑血管的手术规划、介入治疗等得到快速发展,基于血流动力学的临床检测和治疗仪器也越来越多。血流动力学因素,如血管压力、血管阻力、血流量、壁面切应力、血液黏度、流动分离、湍流、涡流等对常见血管疾病以及术后并发症的影响机理正在逐步深入探索之中,并已经取得了一定成果。     

Temporary mechanical circulatory support for severe cardiac failure: experimental study

We describe a technique for mechanical cardiac assistance in an acute model of severe cardiac failure. Cardiac dysfunction was induced by a high dose of halothane in 13 dogs. Seven served as controls. Following median sternotomy, a pneumatically driven device was implanted in the other six dogs in a para-aortic position, using a simple surgical technique without cardiopulmonary bypass. The aorta was cross-clamped during cardiac assistance. During hemodynamic studies, the seven control animals with induced cardiac failure showed high end-diastolic left ventricular and right atrial pressures with low cardiac index and systolic left ventricular and aortic pressures. All dogs in this group died within 30 minutes. Use of a monovalvular cardiac assist device in the experimental group of six dogs to pump blood from the aortic root to the descending aorta in a counterpulsation manner, confirmed good preservation of systemic hemodynamic parameters after induction of heart failure. All animals in this treated group survived more than 45 minutes. Hemodynamically, the device acts as a new ventricle and the impaired left ventricle functionally becomes a left atrium. This condition is clinically appropriate for recovery of left ventricular function in severe acute myocardial failure.     

Lipid Deposition in Rat Aortas with Intraluminal Hemispherical Plug Stenosis : A Morphological and Biophysical Study

A new method was devised to create a stenosis in the rat abdominal aorta. To restrict blood flow, a hemispherical plug was inserted into the aorta through a renal artery. This type of intrinsic (intraluminal) stenosis minimizes possible intramural effects associated with external compression or ligation which severely deform the arterial wall. In the aorta of hypercholesterolemic rats, lipid deposits were distributed in crescent-shaped patches proximal and distal to the plug, whereas lipid deposition in the opposite aortic wall was inhibited. Based on enlarged physical scale models used to study the flow field, the regions of lipid deposition were found to coincide with regions of low shear stress, stagnation, and recirculation. Shear stress was elevated at the wall opposite the plug. These results show that when confounding mural effects are minimized, lipid deposition is promoted in regions of low shear stress with recirculation and inhibited in regions of elevated shear stress.