脉动血流发生器非圆齿轮副模态分析

为进一步验证新型脉动血流发生器驱动机构的性能,对脉动血流发生器非圆齿轮—曲柄滑块式驱动机构中的非圆齿轮副进行模态分析。利用编制的可视化设计平台和Solid Works的三维建模软件获得非圆齿轮副三维实体模型,在研究齿轮模态振动理论的基础上,利用COMSOL软件得到主、从动非圆齿轮前6阶固有频率及其模态振型。结果表明:脉动血流发生器的工作频率远低于所设计非圆齿轮副的固有频率;非圆齿轮副前6阶固有频率随阶数的增加而增大,呈正相关性,为后续脉动血流发生器样机试制及优化提供理论依据。

脉动血流发生器非圆齿轮-曲柄滑块式驱动机构设计与分析

为使脉动血流发生器产生稳定的脉动性血流,提出了一种新型非圆齿轮-曲柄滑块式驱动机构,运用非圆齿轮副和曲柄滑块机构的组合传动来实现血流的脉动。在满足人体血流脉动前提下,为使设计的机构运行平稳,采用2段三次Hermite插值多项式来对该机构输出构件的加速度曲线进行拟合,再由加速度曲线方程及其边界条件推导出速度、位移和跃度曲线方程,运用拟合得到的输出构件运动学曲线方程推导出非圆齿轮副节曲线反求模型。根据实例求解分析得到的机构参数进行三维建模和虚拟样机实验,对比虚拟仿真实验和理论分析结果,发现所设计机构能够按照预期规律实现脉动血流,且该机构具有良好的运动学特性,同时验证了所构建的运动学曲线方程及所建立的运动学分析模型的正确性。

局部缓慢狭窄幅度径向振荡弹性直圆管内脉动血流的压强和压强梯度分析

文研究了脉动血流通过局部缓慢狭窄幅度径向振荡的弹性直圆管时压强和压强梯度的分布特征。分析表明在局部狭窄幅度径向振荡的弹性管中压强及压强梯度分布与在直圆管或局部狭窄静止的情况下明显不同、而且它与Ｗｏｒｍｅｒｓｌｅｙ数、管壁特征、及狭窄幅度振荡频率有密切关系。此项研究对进一步认识分析某些病理和治疗手法等有重要意义。

运动对动脉内皮功能的调控及血流剪切力的介导作用

正常的动脉内皮功能在调节血管通透性、维持正常的凝血功能以及免疫、炎症反应中起重要作用,受损的内皮功能则可引起血管的重构以及血栓、动脉粥样硬化等疾病的发生和发展。合理的运动训练能够通过促进一氧化氮(nitric oxide,NO)、前列环素(prostacyclin,PGI2)等物质的分泌来维持和改善动脉内皮功能,并预防动脉粥样硬化的发生。而高强度运动训练则会导致氧化应激的发生并降低NO的生物活性,从而造成内皮功能障碍及心血管疾病的发生。大量研究表明,运动引起的血流剪切力幅度及形式的变化在上述血管生物学响应中起重要的介导作用。本文综述了运动训练对动脉内皮功能的调控作用、血流剪切力的介导作用以及相关分子生物学机制等方面的研究进展,为进一步深入研究运动调控内皮功能的血流动力学机制特别是血流剪切力的重要介导作用提供参考,同时也为通过监控血流剪切力等血流动力学参数以选择最佳运动方式提供一定的科学依据。

体外反搏对犬血流脉动性和血管阻力的影响

为了评价体外反搏是否具有扩张血管和增加血流脉动性的作用 ,制造了犬急性心肌梗塞模型 ,并使犬存活 6周。麻醉后 ,测定左侧颈总动脉血流量和右侧颈总动脉血压。计算反搏前和反搏中脉压差、血压脉动指数、血压的标准差、流量差、流量脉动指数、流量标准差和平均血管阻力。结果显示脉压差、血压脉动指数和血压标准差三个血压脉动性指标分别由反搏前的 30± 9mm Hg、1.2 6± 0 .0 5、8.7± 2 .5 mm Hg升高到反搏中的 4 3± 8mm Hg(P<0 .0 5 )、1.5 4± 0 .13、12 .4± 2 .0 mm Hg (P<0 .0 5 )。流量差、流量脉动指数和流量标准差三个血流脉动性指标分别由反搏前的 317± 4 8ml/ min、2 .85± 0 .2 1、96± 2 1ml/ min升高到反搏中的 4 4 7± 88m l/ min、4 .5 6± 0 .90、131±39m l/ m in,P值均于小 0 .0 5。平均血管阻力由反搏前的 5 78± 72 Wood单位降低到反搏中的 4 76± 85 Wood单位(P<0 .0 5 )。这表明体外反搏可使血管阻力下降 ,血压和血流脉动性增强。

系统性红斑狼疮患者胎儿脐动脉血流彩色多普勒超声对早产的监测作用

目的探讨胎儿脐动脉彩色多普勒超声对系统性红斑狼疮(SLE)孕妇早产的监测作用。方法回顾性分析于中山大学附属第一医院、广州中医药大学附属第一医院活胎分娩的160例SLE孕妇。结果 SLE孕妇妊娠时平均年龄为(29.7±3.7)岁(20~37岁),早产52例(32.5%),未出现不良妊娠结局足月产76例(47.5%)。<34周的早产发生率为26.9%,≥34周的早产发生率为73.1%。早产原因依次为治疗性早产(30例)、自发性早产(12例)和未足月胎膜早破早产(10例)。胎儿脐动脉血流彩色多普勒超声检查提示早产组脐动脉血流搏动指数(PI)、阻力指数(RI)、S/D值均高于足月产组(P<0.05)。受试者运算特征曲线(ROC)中PI、RI、S/D曲线下面积分别为0.6(95%CI 0.5~0.7)、0.7(95%CI 0.6~0.8)、0.6(95%CI 0.5~0.7)。选取PI、RI、S/D的最佳截点:1.0、0.7、2.8,其敏感性分别为34.6%、50.0%、50.0%,特异性分别为84.2%、81.6%、81.6%。结论 SLE妊娠早产发生率较高。脐动脉血流多普勒彩超检查可作为SLE患者孕晚期的无创监测手段,对指导分娩时机有重要的临床意义。

基于指端容积血流脉动波形图的血流动力学分析

目的基于在指端采集并量化的容积血流脉动波形图进行血流动力学特性分析，研究与年龄和体育训练相关的循环状态变化。方法我们测试了61例样本（男性33例，女性28例，均没有心血管病病史），年龄19～80岁（其中19～29岁10例，30～39岁10例，40～49岁10例，50～59岁10例，60～69岁10例，70～79岁10例，80岁1例）。结果由HC2180无创血流参数检测仪量化的特征指标（Tg2-Tg）／（Tg-Tgl）与年龄显著相关（P〈0．001）。将额外10例运动员样本（男性7例，女性3例，年龄19～29岁）与其中相同年龄段的10例普通样本（男性7例，女性3例，年龄19～29岁）进行比较，结果显示长期从事体育训练的样本相对于普通样本的血流动力学特性出现了低龄化特征。结论该指标可用于针对不同人群的大样本量采集与统计学分析，作为方便快捷无创的血流动力学测量方法，以发现不同人群间血管与外周循环的细微差异及其与生理和病理状态之间的关系。

体外反搏对人血压脉动性测量的影响

脉动血流对维持正常的血管内皮细胞功能有重要作用 ,本研究拟建立血压脉动性的测量方法 ,并以此评价体外反搏对人血压脉动性的影响。健康青年男性志愿者 8名 ,局麻下穿刺桡动脉 ,送入 4F顶端测压导管至主动脉弓部 ,测量体外反搏前及体外反搏中的血压并计算脉压差、血压脉动指数和血压标准差。结果表明 ,脉压差、血压脉动指数和血压标准差 3个血压脉动性指标分别由反搏前的 47± 5 m m Hg、1.6 4± 0 .11、13.6± 1.5 m m Hg升高到反搏中的 77± 3mm Hg、2 .46± 0 .2 5、19.3± 2 .2 mm Hg,P值均小于 0 .0 5。因此 。

指端容积血流脉动波、子宫动脉多普勒联合sFlt-1/PlGF比值对早发型子痫前期的预测

目的:探讨指端容积血流脉动波形图(PPG)、子宫动脉多普勒检查联合血清可溶性fms样酪氨酸激酶-1(sFlt-1)、胎盘生长因子(PlGF)检测对早发型子痫前期(PE)的预测价值。方法:选取500例符合纳入标准的早孕期妇女为研究对象,随访至产后6周,其中23例发生妊娠期高血压剔除,28例失访剔除,根据妊娠结局分为正常对照组(408例)、早发型PE组(22例)、晚发型PE组(19例)。收集所有研究对象在孕11~14周PPG反射指数(PPG RI)、孕20~24周PPG RI、子宫动脉(UtA)多普勒搏动指数(UtA PI)和阻力指数(UtA RI)及孕24~28周血清sFlt-1、PlGF检测值。统计分析各检测指标与早发型、晚发型PE发病的相关性。结果:相比正常对照组,早发型PE组及晚发型PE组UtA PI、UtA RI、PPG RI、PPG RI′数值明显升高,sFlt-1/PlGF比值明显升高;相比晚发型PE组,早发型PE组UtA PI、UtA RI数值更高,sFlt-1/PlGF比值更高。UtA PI、UtA RI、PPG RI、PPG RI′单独预测早发型PE的ROC曲线下面积(AUC)分别为0.826、0.819、0.798、0.833;单独预测晚发型PE的AUC分别为0.743、0.741、0.733、0.685,4个指标联合预测早发型PE的AUC分别为0.915、0.73、0.95;预测晚发型PE的AUC分别为0.757、0.90、0.73。结论:PPG、子宫动脉多普勒检查联合孕中期sFlt-1/PlGF比值检测显著提高早发型PE预测的准确性,值得临床推广。

0D-1D coupling model and 3D fluid-structure interaction model based on coronary CT angiography for displaying hemodynamic characteristics of coronary artery stenosis

Objective To observe value of 0D-1D coupling model and 3D fluid-structure interaction(FSI)model based on coronary CT angiography(CCTA)for displaying hemodynamic characteristics of coronary artery stenosis.Methods Based on CCTA data of the stenosed left anterior descending branch(LAD)in a patient with coronary heart disease,an 0D-1D coupling model and 3D FSI model were built,respectively.Then hemodynamic characteristic indexes,including the pressure,flow velocity and wall shear stress(WSS)were obtained in every 0.01 s during 1 s at 5 sampling points(i.e.sampling point 1—5)using these 2 models,respectively,and the consistencies of the results between models were evaluated with Spearman correlation coefficient r s.Results The time consuming for construction of 0D-1D coupling model and 3D FSI model was 0.033 min and 704 min,respectively.Both models showed basically distribution of the pressure,flow velocity and WSS of the stenosed LAD.For more details,the pressure at the stenosed segment of LAD and the proximal segment of stenosis were both higher,which gradually decreased at the distal segment of stenosis,and the flow velocity at the proximal segment of stenosis was in a relatively slow and uniform condition,with significantly increased flow velocity and WSS at the stenosed segment.Compared with 3D FSI model,0D-1D vascular coupling model was relatively unrefined and lack of distal flow lines when displaying blood flow velocity.For sampling point 2 at the stenosed segment of LAD,no significant consistency for pressure between 2 models was found(P=0.118),but strong consistency for the flow velocity and WSS(r s=0.730,0.807,both P<0.05).The consistencies of pressure,flow velocity and WSS between 2 models at the proximal and distal segment of stenosis,i.e.1,3—5 sampling points were week to moderate(r s=0.237—0.669,all P<0.05).Conclusion 0D-1D coupling model exhibited outstanding computational efficiency and might provide relatively reasonable results,while 3D FSI model showed higher accuracy for details and streamline when simulating LAD stenosis.

超声诊断双胎输血综合征的临床观察

目的:评价超声在诊断双胎输血综合征中的应用价值。方法:应用二维及多普勒超声测定168例孕31+1周～38周的双胎妊娠孕妇的胎儿生长指标及脐动脉血流PI值,RI值,S/D比值。结果:超声诊断双胎输血综合征12例,诊断准确率83%(10/12);结论:二维联合多普勒超声诊断双胎输血综合征有较高的准确率,是诊断双胎输血综合征的简便快捷方法之一。

Clinical application of hepatic CT perfusion

Complicated changes occur in hemodynamics of hepatic artery and vein, and portal vein under various kinds of pathologic status hepatic blood supply. This because of distinct double article reviews the clinical application of hepatic computed tomography perfusion in some liver diseases.

LOW OR UNRECORDABLE PULSATILE OCULAR BLOOD FLOW MAY BE RELAT-ED TO SEVERE STENOSIS OF THE IPSI-TATERAL INTERNAL CAROTID ARTERY

Purpose: To examine the relationship between stenosis of the internal carotid artery (ICA) and pulsatile ocular blood flow (POBF). Methods: In 57 eyes of 30 patients who were referred for doppler ultrasound examination of the ICA we measured POBF and analyzed the correlation with degree of ipsilat-eral ICA stenosis. Results: There was a significant negative correlation between POBF and ipsilateral ICA stenosis (Pearson correlation coefficient, r =-0.516, P< 0.0001). In 14

Simulation of Variable Viscosity and Jeffrey Fluid Model for Blood Flow Through a Tapered Artery with a Stenosis

Non-Newtonian fluid model for blood flow through a tapered artery with a stenosis and variable viscosity by modeling blood as Jeffrey fluid has been studied in this paper. The Jeffrey fluid has two parameters, the relaxation time A1 and retardation time A2. The governing equations are simplified using the case of mild stenosis. Perturbation method is used to solve the resulting equations. The effects of non-Newtonian nature of blood on velocity profile, temperature profile, wall shear stress, shearing stress at the stenotsis throat and impedance of the artery are discussed. The results for Newtonian fluid are obtained as special case from this model.

Clinical and hemodynamic profiles of elderly patients with pulmonary arterial hypertension： a single center, prospective study

Backgrounds Pulmonary arterial hypertension （PAH） was previously considered an illness that affects mostly the young, but now it is also increasingly recognized in the elderly. The aim of this study was to compare the features of elderly versus younger patients diagnosed with PAH, and to define the prognostic factors which affect their long-term survival. Methods In this prospective, single center study, the clinical, echocardiographic, hemodynamic characteristics, and the outcomes of younger （18-65 years） and elderly （〉 65 years） patients with definitive diagnosis of precapillary PAIl were compared. Results A total of 119 patients were analyzed in this study; 43 were elderly （mean age： 71.5 ± 5.5 years）, while 76 were non-elderly （mean age 44.5 ±15.2 years）. During the mean follow-up duration of 26.8 ±25.0 months, 43 deaths occurred, 17 of which were among the elderly group, with 28 among non-elderly group. Comparison of baseline parameters showed that 6 min walking distance, hemoglobin levels, pulmonary artery pressures and pulmonary vascular resistance were significantly lower; and estimated glomerular filtration rate, body mass index, E/e＇ and pulmonary capillary wedge pressure were significantly higher in the elderly group than in the younger group. Survival analysis demonstrated that the independent predictors of death were tricuspid plane annular systolic excursion （TAPSE; HR： 1.272, 95% CI： 1.079-1.499, P = 0.004） and uric acid （HR： 1.291, 95% CI： 1.042-1.600, P = 0.019） in the elderly group. In contrast, in the non-elderly group, higher brain natriuretic peptide （HR： 1.002, 95% CI： 1.001-1.004, P 〈 0.001） and higher right atrial pressure （HR： 1.128, 95% CI： 1.026-1.241, P = 0.013） values were the only parameters associated with mortality. Conclusions Our data suggest that elderly PAH patients have a unique clinical and hemodynamic profile, with totally different prognostic markers compared to younger PAH patients.

Effect of a distal protection device on epicardial blood flow and myocardial perfusion in primary percutaneous coronary intervention

Objective: The beneficial effect of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has been well established, but there is the problem of no-reflow phenomenon which is an adverse prognostic factor in primary PCI. In the present study the effect of a distal protection device (PercuSurge GuardWire; GW) on epicardial blood flow and myocardial perfusion was evaluated. Methods and Results: Patients with AMI were randomly divided into 2 groups, the GW and the control groups. The GW group included 52 patients with AMI who underwent primary PCI with GW protection and the control group included 60 patients who underwent primary PCI without GW protection. Epicardial blood flow in the infarct-related artery (IRA) and myocardial perfusion were evaluated according to the thrombolysis in myocardial infarction (TIMI) flow grade and the myocardial blush grade (MBG). We found TIMI score of 3 was obtained significantly more frequently in the GW group (96%) than in the control group (80%). The MBG score of 3 was obtained also significantly greater in the GW group (65%) than in the control group (33%). Conclusion: Primary PCI with GW protection can significantly improve epicardial blood flow and myocardial perfusion.

PREVALENCE AND RISK FACTORS OF PERIPHERAL ARTERIAL DISEASE IN DIABETIC PATIENTS OVER 50 YEARS OLD IN CHINA

Objective To investigate the prevalence of peripheral arterial disease (PAD) in China type 2 diabetic patients and to demonstrate the relationships between putative risk factors and PAD. Methods In total 1 397 type 2 diabetic patients aged 50 years and older were enrolled and determined ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) in 15 Class III Grade A hospitals in 7 major cities of China. Results Mean patient age was 63.7±8.2 years and mean duration of diabetes mellitus was 9.39±7.4 years. Two hundreds and seventy-two (19.47%) patients were diagnosed as PAD by ABI <0.9, 122 (18.37%) in male and 150 (20.46%) in female. PAD patients had a significantly longer duration of diabetes mellitus, higher hemoglobin Alc, and a significantly lower mean body mass index than non-PAD ones. Aging, smoking, and systolic blood pressure were found to be positively related with the prevalence of PAD. In terms of lipid profiles, no variable was found to relate with PAD. Notably, baPWV showed as the same significant guiding index for PAD, almost matched with ABI. Conclusions PAD is a common complication in China type 2 diabetic patients. Therefore, PAD screening and treatment should be emphasized for diabetic patients with high risk factors.

Bleeding outcomes after non-emergency percutaneous coronary intervention in the very elderly

Background Octogenarians constitute an increasing proportion of patients presenting for non-emergency percutaneous coronary intervention （PCI）. Methods This study evaluated the in-hospital procedural characteristics and outcomes, including the bleeding events of 293 octogenarians presenting between January 2010 and December 2012 for non-emergency PCI to a single large volume tertiary care Aus- tralian center. Comparisons were made with 293 consecutive patients aged less than or equal to 60 years, whose lesions were matched with the octogenarians. Results Non-ST elevation myocardial infarction was the most frequent indication for non-emergency PCI in octoge- narians. Compared to the younger cohort, they had a higher prevalence of co-morbidities and more complex coronary disease, comprising more type C and calcified lesions. Peri-procedural use of low molecular weight heparin （LMWH; 1.0% vs. 5.8%; P 〈 0.001） and glycopro- tein IIb/IIIa inhibitors （2.1% vs. 9.6%; P 〈 0.001） was lower, while femoral arterial access was used more commonly than in younger patients （80.9% vs. 67.6%; P 〈 0.001）. Overall, there was a non-significant trend towards higher incidence of all bleeding events in the elderly （9.2% vs. 5.8%; P = 0.12）. There was no significant difference in access site or non-access site bleeding and major or minor bleeding between the two cohorts. Sub-analysis did not reveal any significant influence on bleeding rates by the use of LMWH, glycoprotein IIb/IIIa inhibitors or femoral arterial access. In addition, there were no significant differences in the rates of in-hospital mortality, stroke or acute stent thrombosis between the two groups. Conclusions In this single center study, we did not observe significant increases in adverse in-hospital outcomes including the incidence of bleeding in octogenarians undergoing non-emergency PCI.

Clinical applications of fractional flow reserve in bifurcation lesions

Pereutaneous coronary intervention （PCI） for coronary bifurcation lesions has been associated with lower procedural success rates and worse clinical outcomes compared with PCI for simple coronary lesions. Angiographic evaluation alone is sometimes inaccurate and does not reflect the fimctional significance of bifurcation lesions. The fractional flow reserve （FFR） is an easily obtainable, reliable, and reproducible physiologic parameter. This parameter is epicardial lesion specific and reflects both degree of stenosis and the myocardial territory supplied by the specific artery. Recent studies have shown that FFR-guided provisional side branch intervention strategy for bifurcation lesions is feasible and effective and can reduce unnecessary complex interventions and related complications. However, an adequate understanding of coronary physiology and the pitfalls of FFR is essential to properly use FFR for PCI of complex bifurcation lesions.

RELATIONS OF ENDOTHELIAL FUNCTION AND BLOOD FLOW IN BRACHIAL ARTERY AND CORONARY ARTERY

Objective:To determine the relations between endothelium-dependent vasodilator function and blood flow in the brachial and coronary arteries in patients with suspected coronary artery disease.Methods:Twenty-eight patients with suspected coronary artery disease underwent brachial artery endothelial function test by using high-resolution B-mode ultrasound before coronary angiography(CAG)and coronary flow reserve(CFR)test by using intracoronary Doppler technique.The correlation of coronary artery dilatation induced by an increase in blood flow after intracoronary adenosine infusion and brachial artery flow-mediated dilatation(FMD) following reactive hyperemia was evaluated.The relation between the change of brachial artery blood flow and CFR was also studied.Results:There was a positive correlation between brachial FMD and percent change of coronary diameter after adenosine infusion(12.50%±9.35% vs 11.38%±7.55%,r=0.425,P=0.02).There was also a weak negative relation between brachial flow change following reactive hy-peremia and CFR(r=-0.397,P=0.04).Conclusion:There is a correlation between the coronary endo-thelial function and the CFR by ultrasonic determination of brachial flow changes following reactive hyperemia.