顿抑心肌的微循环障碍机制研究

目的 :探讨顿抑心肌微循环改变及机制。方法 :制备左前降支冠脉(LAD)阻断不同时间 ( 15和 60min)后再灌注 2h犬心肌顿抑模型 ,在不同观察时间点行静脉心肌声学造影 (MCE) ,计算心肌视频密度峰值(PVI)、MCE曲线上升斜率 (α)和曲线早期下降斜率 ( β) ,分别代表心肌血流灌注量、灌注速度和排空速度。测定相应时间点冠状静脉窦血乳酸浓度。结果 :⑴心肌顿抑早期PVI显著增高 ,1h后恢复至结扎前水平 ;⑵再灌注期顿抑区与正常区PVI比值、α比值、β比值显著高于LAD结扎前 ,随着再灌注时间的延长比值逐渐回降 ;⑶再灌注期冠状静脉窦血乳酸浓度明显增高。结论 :心肌顿抑早期心肌微循环处于“高动力”状态 ,血流灌注增加与排空加快并存 ;顿抑心肌缺氧代谢加强 ;心肌内微循环短路可能是心肌顿抑微循环障碍的机制。     

冠心病患者心肌声学造影定量分析的初步研究

拟探讨MCE定量分析在缺血性心脏病上的诊断价值。对10例临床诊断冠心病的患者行MCE,从时间-强度曲线中获得造影剂再灌注强度峰值(SIpeak),再灌注时间(Rt),再灌注率(b)和心肌血流量(SI×b)。同一检查对象不同心肌节段的4个参数(SIpeak、Rt、b和SI×b)均有统计学上的差异(P<0.05),对照组和观察组SIpeak具有统计学上的差异,SIpeak预测缺血性心脏病的ROC曲线下面积(AUC)为0.782,最佳临界值为64.4,以SIpeak≤64.4来预测缺血性心脏病,敏感性83.3%,特异性69.0%。利用超声造影匹配成像技术能够较满意地显示心肌灌注状态,初步研究表明通过MCE及Qontrast多参数定量分析软件可以评价心肌梗死区和缺血区的血流灌注缺损。SIpeak是预测缺血性心脏病的敏感指标。     

择期经皮冠脉介入术对急性心肌梗死心肌微循环的作用

目的应用心肌声学造影(MCE)评价急性心肌梗死(AMI)患者择期经皮冠脉介入术(PCI)前后的心肌微循环。方法选择20例AMI患者,在择期PCI治疗前、后分别应用声诺维(SonoVue)静脉注射,行间歇触发、二次谐波MCE检查,应用声学密度分析软件(AD)定量测定心肌微循环内造影剂的声学峰值强度(PI)、曲线下面积(AUC)。结果治疗前梗死相关节段的PI、AUC明显低于正常灌注节段(P<0.001);择期PCI治疗后梗死节段的PI、AUC仍明显低于正常节段(P<0.001),但较PCI前明显升高(P<0.001),校正后的PIr、AUCr亦明显升高(P<0.001);而正常灌注节段的PI、AUC在PCI前后无明显变化(P>0.05)。结论MCE可定量评定AMI患者的心肌微循环;择期PCI可改善AMI患者梗死节段的微循环。     

心肌造影超声心动图定量分析软件系统的设计与实现

心肌声学造影是当前超声心动图学的国际研究热点。本文设计的心肌造影超声心动图(M CE)定量分析软件系统,通过非线性回归分析方法计算出正常、缺血、梗死、存活心肌区域内微血管血流量、血容量、血流分布和血流储备等冠状动脉微循环血流动力学临床诊断指标,从而使M CE上升到定量评价心肌灌注的新水平。本文软件系统的设计完全遵从D ICOM国际标准,可无缝接入PACS系统。     

冠脉造影脉冲响应原理评价心肌微循环

本方法采用冠脉造影脉冲响应原理,建立冠脉造影心肌微循环分析系统。结合定量冠脉造影(QCA),该系统提供有关心肌微循环(Tmicro-1)、冠脉几何形态(MLD)和血流动力学(mAP、CFV、Rcor)等定量指标,用以评价冠状动脉和心肌微循环,并临床应用20例。结果显示:随着近段冠脉狭窄MLD缩小,Tmicro-1减少;PCI治疗后,随着MLD增加,Tmicro-1增加,两者之间呈良好相关(r=0.87,P<0.001),并且CFV、Rcor均得到一致改善。因此,冠脉造影脉冲响应分析系统所提供的Tmicro-1、CFV等定量分析指标,可作为评估冠脉血流和心肌微循环功能状态的敏感参数,结合定量冠脉造影分析指标,有利于提高常规冠脉造影解剖形态与生理功能相结合,分析冠脉狭窄和介入治疗前、后心肌微循环和大-小循环动力学之间的变化关系。     

心肌声学造影的发展及在冠心病诊治中的运用

心肌声学造影(Myocardial Contrast Echocardiography，MCE)在评价心肌微循环血流灌注，评定冠脉储备及冠脉血运重建后的疗效等方面的运用已成为一项十分重要的研究课题。MCE是指将含有微气泡的造影剂直接经冠状动脉或外周静脉注入，当微气泡通过心肌微血管床时，应用二维或多普勒超声技术使含血心肌的微气泡显像，以观察心肌血流灌注、冠脉血流储备。目前，它被认为是无创性评定心肌微循环灌注的最有潜力的工具。本文就近年来心肌声学造     

心肌声学造影在冠状动脉微血管疾病中的临床应用进展

冠状动脉微血管疾病是心肌微循环异常的临床综合征,其出现打破了以往对心脏疾病认识的局限,正引起越来越多的关注。心肌声学造影是评估心肌微循环灌注情况的新技术,有望成为该病的重要检查方法。本文简要综述心肌声学造影的作用机制、冠状动脉微血管疾病的相关概念以及心肌声学造影在冠状动脉微血管疾病的临床诊断、治疗及预后评估方面的作用。     

心肌微循环的基本特点

为了适应心脏功能、代谢的特殊需要,心肌微循环在长期的进化演变过程中,从无到有、从简单到复杂,逐渐完善,发展到哺乳类动物心脏,心肌微循环已形成了一些独特的基本特点,正确认识这些特点,对于理解心脏病理生理现象和疾病防治均有重要意义。结合我们的工作分析文献,心肌微循环的基本特点可以归纳为四点:     

心肌核素断层显像定量分析系统

介绍了开发设计的计算机心肌核素断层显像定量分析系统.该系统可进行原始数据的读取和格式转换,自动分割左心室,完成SPECT心肌灌注靶心图定量分析、PET心肌代谢靶心图定量分析,对病人数据进行9分区靶心图定量计算等临床数据处理任务.并将结果同医师半定量诊断结果进行对比.     

冠状造影脉冲响应分析评价心肌微循环

目的探讨冠脉造影脉冲响应分析评价心肌微循环的价值。方法数字血管造影脉冲响应函数分析系统 ,分析视频时间密度曲线 ,测定造影剂平均通过微循环时间倒数(Tmicro -1),作为评价局部心肌微循环灌注指标。结合定量冠脉造影(QCA)、计算机测量冠脉血流速度并计算冠脉血流动力学参数来评价冠脉狭窄和介入治疗前、后心肌微循环和大小循环动力学之间的变化关系。结果随着近段冠脉狭窄MLD缩小 ,Tmicro-1 减少 ;PCI治疗后 ,随着MLD增加 ,Tmicro -1增加 ,两者之间呈良好相关(r=0.87,P<0.001)。示意Tmicro -1可作为评估冠脉狭窄程度的临床指标 ;急性冠脉综合征PCI治疗后 ,随着狭窄MLD增加 ,Tmicro-1 和CFV、Rcor均得到一致改善 ,但PCI前Tmicro-1 与CFV之间并非线性相关(r=0.18,P>0.05) ,可能与大、小循环之间存在不同的影响因素有关 ,但Tmicro -1更能反应局部心肌灌注。结论QCA结合Tmicro -1、CFV等定量指标 ,有利于提高常规冠脉造影解剖形态与生理功能相结合、大(体循环)、小(微循环)循环相关联的综合诊断水平     

缺血预适应促发心肌毛细血管床功能性开放

目的:探讨反复短暂缺血剌激导致缺血预适应(IP)对心肌毛细血管床功能的影响。方法:复制套扎前降支冠状动脉犬模型。IP组给予缺血5min,灌注5min,反复4次;假手术组不予缺血与灌注剌激,观察40min。分别于实验前、第1次缺血与再灌注及第4次缺血与再灌注末行心肌声学造影,最后对心肌毛细血管进行超微结构观察,并定量分析,做组内及组间比较。结果:第4次缺血较第1次缺血其声学显影最小缺损面积百分比(ADmin%)由32.6%±5.7%降至21.8%±5.2%(P＜0.05),定量分析指标峰值(PI)、曲线下面积(AUC)、峰减半时间(HT)均增高;心肌毛细血管数、管腔内径、内皮细胞厚度及内皮细胞超微结构均无明显差别。结论:反复短暂缺血增加心肌微循环血液灌注但无毛细血管超微结构改变,提示IP促发心肌毛细血管床功能性开放。     

Optical Flow Analysis of Left Ventricle Wall Motion with Real-Time Cardiac Magnetic Resonance Imaging in Healthy Subjects and Heart Failure Patients

In cardiology, magnetic resonance imaging (MRI) provides a clinical standard for measuring ventricular volumes. Owing to their reliability, volumetric measurements with cardiac MRI have become an essential tool for quantitative assessment of ventricular function. However, as volumetric indices are indirectly related to myocardial motion that drives ventricular filling and ejection, cardiac MRI cannot provide comprehensive evaluation of ventricular performance. To overcome this limitation, the presented work sought to measure ventricular wall motion directly with optical flow analysis of real-time cardiac MRI. By modeling left ventricle (LV) walls in real-time images based on myocardial architecture, we developed an optical flow approach to analyzing LV radial and circumferential wall motion for improved quantitative assessment of ventricular function. For proof-of-concept, a cardiac MRI study was conducted with healthy volunteers and heart failure (HF) patients. It was found that, as real-time images provided sufficient temporal information for correlation analysis between different LV wall motion velocity components, optical flow assessment detected the difference of ventricular performance between the HF patients and the healthy volunteers more effectively than volumetric measurements. We expect that this model-based optical flow assessment with real-time cardiac MRI would offer intricate analysis of ventricular function beyond conventional volumetric measurements.

     

心肌超声造影心动图对高强度聚焦超声左心室心肌消融心肌坏死范围的评价

目的探讨心肌超声造影心动图评价高强度聚焦超声（HIFU）左心室心肌消融心肌坏死范围的可行性。方法新西兰兔9只,兔龄8～12个月,体质量（3.0±0.2）kg（2.8～3.5 kg）。HIFU治疗频率1.5 MHz,强度9.64 kW/cm2,脉冲照射方式,Ton=0.2 s、0.3 s,Toff=1.0 s、1.5 s,重复次数20次,靶区范围3 mm×2 mm。照射后行左心室心肌超声造影心动图,然后取下心脏,做2mm心肌切片,用2,3,5-三苯基氯化四氮唑（TTC）染色。测量造影剂充盈缺损面积及与之相对应心肌切片TTC染色心肌坏死面积,并计算其占整个心肌的面积百分比。结果造影剂充盈缺损面积百分比（13.7%±6.7%）与TTC染色心肌坏死面积百分比（15.5%±4.9%）间差异无统计学意义（P〉0.05）;两者间呈显著相关（r=0.94,P〈0.05）。结论心肌超声造影心动图可用于评价HIFU左心室心肌消融心肌坏死范围。     

超声二次谐波声面声学造影评价冠脉的微血管血流灌注

目的：本文获取冠状动脉血流变化所致的心肌灌注类型,以了解冠脉的微血管血流灌注变化。方法：36人先后完成冠状动脉影,静脉注射声学造影剂利声显（Levovist),通过超声二次谐波技术获取心肌灌注图像,按心肌灌注积分指数将病人分为三组。结果：三组病人的冠状动脉狭窄程度、心肌灌注积分指数明显差异（P＜0．001）,冠状动脉狭窄波＜75％者,病人心肌灌注多为正常,随着冠状动脉狭窄程度加重,出现不同程度的心肌灌注异常。8例完全阻塞的冠状动脉有不同的冠状动脉侧支循环表现为不同的心肌灌注类型。结论：静脉心肌声学造影是反映心肌灌注的有效方法,能够反应冠状动脉血流的改变及微循环结构的完整性变化,从而弥补冠状动脉造影仅能显示心外膜下的冠状动脉而无法观察毛细血管水平的心肌灌注之缺限。当心肌灌注不良时,MCE能提示冠状动脉病变的存在,及其严重性,但要注意侧支循环对心肌灌注之影响,可影响对冠脉病变程度判断的精确性。冠状动脉造影确定某支冠脉病变时,MCE心机灌注有助于评价侧支循环状态。     

Real-time myocardial contrast echocardiography as a useful tool to select candidates for coronary revascularization among patients with end-stage renal disease - a 3-year follow-up study

PurposeTo evaluate a real-time myocardial contrast echocardiography (MCE) as a tool to select candidates for coronary revascularization among patients with ESRD and to assess the rate of revascularization and mortality.Material / Methods58 ESRD patients were screened for CAD using MCE. We analyzed the rate of coronary revascularization during 3-year follow-up. Patients with and without perfusion disturbances on MCE were compared.ResultsCAD was found in 46.2% patients out of 39 who underwent coronary angiography. 11 (39.3%) patients out of 28 from the group with perfusion defects on MCE underwent revascularization procedure (21.4% - PCI, 17.9% - CABG). No one from the group without perfusion defects had revascularization procedure. Perfusion defect (OR 1.37 CI 1.37–1.86, p=0.022) was related to revascularization in multivariant analysis (OR 12.87, CI 1.86-89.21, p=0.025). There was no difference in mortality between the group which underwent invasive procedures and treated conservatively (p=0.6643). In ROC analysis defects on MCE and CAD on angiography were equally good in anticipating combined end-point (AUC 0.716, CI 95% 0.544–0.851 and AUC 0.747, CI 95% 0.577–0.875, p=0.701) and death (AUC 0.752, CI 95% 0.582–0.878 and AUC 0.729, CI 95% 0.558–0.861, p=0.805).ConclusionsOur results indicate that MCE is a safe and uncomplicated method which may help along with other methods to select candidates for coronary revascularization among ESRD patients. In our study coronary revascularization procedures were successful but they did not improve patients’ survival on 3-year follow-up.     

In vivo determination of acute myocardial ischemia based on photoacoustic imaging with a focused transducer

The location and ischemia extent are two important parameters for evaluating the acute myocardial ischemia (AMI). A focused-transducer-based photoacoustic imaging method was employed to assess time-dependent AMI. Our preliminary results show that the photoacoustic signal could identify the myocardium. The intensity and area of photoacoustic images of myocardium could be used for characterizing the ischemia extent and scope of myocardial ischemia. The results also imply that the intensity and area of photoacoustic images are the rapid fall of an exponential model with an increase of delaying time after the left anterior descending coronary artery (LAD) occlusion. These experimental results were consistent with the clinical characteristics. The findings suggest that the photoacoustic imaging be a potential tool for the real-time assessment of acute myocardial ischemia during surgical operation.     

Effect of buffered formalin on amplification of DNA from paraffin wax embedded small biopsies using real-time PCR

BACKGROUND: The isolation of good quality DNA from routinely fixed and processed biopsy samples is crucial for the success of subsequent molecular analysis. AIMS: To compare the amount of beta actin DNA extracted from upper gastrointestinal tract biopsies fixed in buffered and unbuffered formalin. METHODS: Amounts of beta actin DNA extracted from forceps biopsies of the upper gastrointestinal tract fixed in unbuffered (n = 22) and buffered formalin (n = 16) were estimated by quantitative real-time polymerase chain reaction. RESULTS: The yield of beta actin DNA was significantly higher in biopsies fixed in buffered formalin than in those fixed in unbuffered formalin (median 2.8 x 10(4) and 5.3 x 10(2) DNA molecules, respectively; p < 0.005). Furthermore, fixation in buffered formalin led to a more reproducible DNA extraction, as indicated by the coefficient of variation (1.0 and 2.2, respectively). CONCLUSIONS: This study indicates that tissue samples should be fixed in buffered formalin to facilitate the use of molecular pathology analysis in routine biopsy material.