赵国定益气化痰通络法治疗冠状动脉介入术后心肌微循环障碍经验

经皮冠状动脉介入治疗已成为冠心病常见且有效的治疗方法,但部分病人冠状动脉介入术后心肌血流灌注不足,此与冠状动脉微循环功能障碍相关。赵国定教授以益气化痰通络为法则,对治疗冠状动脉介入术后心肌微循环障碍有独特见解。     

冠状动脉血流与心肌灌注CT评估方法与进展

随着经皮冠状动脉介入治疗技术的普及与提高,对于缺血性心脏病的认识不断深入,冠状动脉微循环障碍得到日益的关注,无创心肌灌注评估方法的研究成为新的热点。本文在复习文献的基础上对冠状动脉血流与心肌灌注CT评估方法的临床应用价值及进展做一综述。     

冠状动脉微循环侵入性诊疗用于急性ST段抬高型心肌梗死患者的研究进展

对梗死相关冠状动脉行早期直接经皮冠状动脉介入治疗（PPCI）是指南推荐治疗急性ST段抬高型心肌梗死（STEMI）的常规手段,可以有效减少心肌梗死面积并保留左心室收缩功能。尽管PPCI可以成功恢复心外膜冠状动脉血流,但仍有部分患者因微循环功能障碍无法实现最佳心肌灌注并影响远期预后。因此,及时评估STEMI患者微循环功能并采取相应治疗策略至关重要。本文针对冠状动脉微循环侵入性诊断技术及治疗策略用于STEMI患者的最新研究进展进行综述。     

心脏磁共振在冠状动脉微循环障碍评估中的应用进展

冠状动脉微循环障碍指冠状动脉微循环的结构或功能异常所导致的冠状动脉血流储备降低,其是未来发生不良心血管事件的强预测因子。冠脉微循环的结构、功能完整性对存活心肌的恢复和永久性损伤的防止具有重要的意义。心脏磁共振近来被认为是无创评估心肌微循环功能的金标准,其无辐射、无衰减,具有良好的空间分别率及动态追踪对比剂分布的特点,有很好的发展潜力。     

冠状动脉微循环及微血管性心绞痛的研究进展

冠状动脉微循环在心肌的血供中起着重要作用。心肌声学造影是诊断微循环水平心肌灌注的新技术,可同时观察心脏的结构、心肌局部和整体功能以及心肌的各级血流灌注,有利于研究冠状动脉微循环的病理生理机制并可能检出早期微血管内皮功能不全。在正常健康人,肌源性血流依赖性微动脉扩张和微循环代谢产物导致的冠状动脉微循环收缩形成互相制约的平衡调节机制,保持正常血流灌注。在冠心病心肌缺血如劳力性心绞痛时由于心肌代谢增加氧耗增加导致心肌缺血时,微血管反而收缩加剧缺血。研究表明这类患者是由于小冠状动脉扩张储备减低或冠状动脉收缩而导致心肌缺血,冠状前小动脉是调节心肌血液灌注的主要功能部位。     

改善冠状动脉微循环,优化ST段抬高型心肌梗死再灌注治疗策略

目前,经皮冠状动脉介入治疗(PCI)是ST段抬高型心肌梗死(STEMI)患者的首选再灌注策略,旨在恢复心外膜梗死相关动脉血流,尽早实现微血管再灌注,从而抑制心肌不可逆性损伤.然而,相当比例的患者由于冠状动脉微循环障碍(CMD),初次PCI后并不能实现有效的心肌再灌注.既往心脏保护相关研究主要致力于保护心肌细胞和减小梗死...     

急性心肌梗死血管重建后心肌灌注的评价和临床意义

经皮冠状动脉介入治疗开通梗死相关动脉、恢复正常心外膜血流的同时,心肌微循环的灌注也非常关键。本文详细介绍了再血管化后心肌灌注水平评价方法、疗效判断、临床症状及预后的评估。     

心肌微循环及微循环阻力指数研究近况

微循环是冠状动脉循环的重要组成部分。越来越多的研究显示,微循环结构和功能受损是冠心病患者不良预后的独立预测因素[1-3]。最早用于评估微循环状态的参数是冠状动脉血流储备（coronary flow reserve,CFR）,但CFR受血压、心率、心外膜狭窄病变及血流动力学等因素影响,重复性差,限制了其临床应用[4-5]。     

冠状动脉慢血流现象研究进展

冠状动脉（冠脉）慢血流现象是冠脉造影和介入治疗时的常见现象。心肌微循环障碍、冠脉循环前向阻力增加、内皮功能障碍、血管舒缩因子分泌失调、炎症和冠脉弹性改变等诸多因素与冠脉慢血流密切相关。     

冠状动脉慢血流现象研究进展

冠状动脉（冠脉）慢血流现象是冠脉造影和介入治疗时的常见现象。心肌微循环障碍、冠脉循环前向阻力增加、内皮功能障碍、血管舒缩因子分泌失调、炎症和冠脉弹性改变等诸多因素与冠脉慢血流密切相关。     

Coronary microcirculation. Physiologic and pathologic aspects]

The coronary circulation has a protective regulation system which, in extreme haemodynamic conditions, compensates increased myocardial oxygen demand. The coronary reserve, based on this concept defines the capacity of the system to increase flow temporally, and, thereby, myocardial oxygen supply. The introduction of new methods of investigating the coronary microcirculation has enabled the study of this phenomenon in several cardiovascular pathologies. Two types of investigation are used currently for studying the coronary microcirculation: 1) invasive methods, especially the recently developed intracoronary Doppler and pressure guide, 2) non-invasive methods, and, in particular, contrast echocardiography, position emission tomography and magnetic nuclear resonance. These investigations allow measurement of the coronary reserve or the assessment of the myocardial consequences of abnormalities of the microcirculation. Some workers use these methods to investigate pathological coronary microcirculation in different cardiomyopathies, in the presence of different cardiovascular risk factors (hypertension, diabetes, smoking, hypercholesterolaemia) and after cardiac transplantation.     

冠脉微循环再灌注的血流动力学研究进展

冠脉微循环血流灌注在冠心病血管再通治疗中有重要意义.现总结近年来在动物模型及临床观察中微循环再灌注的血流动力学特点,讨论微循环血流障碍导致心肌收缩功能异常和血流分布改变的作用机制,提出反映冠脉微循环功能改变的敏感指标和检测方法.     

Comparison of the effects of increased myocardial oxygen consumption and adenosine on the coronary microvascular resistance

The purposes of this study were to determine if coronary dilation secondary to an increase in myocardial oxygen consumption (MVO2) affects the microcirculation in a homogeneous or heterogeneous manner and to determine if comparable degrees of coronary dilation produced by increasing MVO2 or exogenous (intravenous adenosine) or endogenous (intravenous dipyridamole) adenosine have similar effects in the coronary microcirculation. The epimyocardial coronary microcirculation was observed through an intravital microscope by stroboscopic epi-illumination in anesthetized open-chest dogs. Aortic pressure and heart rate were controlled by an aortic snare and atrioventricular sequential pacing, respectively, during experimental procedures. In group 1 (n = 15), coronary arterial microvessel diameters were measured under control condition and during rapid pacing at 300 beats/min, which doubled MVO2. Increases in MVO2 caused heterogeneous vasodilation in coronary arterial microvessels (40-380 microns). There was an inverse relation between control diameter and percent increase in diameter. In group 2 (n = 15) or group 3 (n = 10), adenosine or dipyridamole was infused intravenously to increase myocardial perfusion to the same level as that obtained with rapid pacing. Adenosine and dipyridamole did not change MVO2. Adenosine and dipyridamole also caused heterogeneous vasodilation, but the effects of adenosine and dipyridamole were restricted to arterial microvessels smaller than 150 microns. From these results, we conclude that increases in MVO2 produce widespread but heterogeneous vasodilation, that is, greater dilation in smaller arterial microvessels. Comparable increases in coronary flow produced by increasing MVO2 or endogenous and exogenous adenosine do not produce identical changes in the distribution of coronary microvascular resistance.     

Positron emission tomography to assess the haemodynamics of the coronary circulation.

Positron emission tomography (PET) allows the non-invasive measurement of absolute myocardial blood flow (ml/min/g of myocardium) in man. This has made possible the measurement of myocardial blood flow and the coronary vasodilator reserve (an index of the ability of the coronary microcirculation to dilate) in healthy volunteers to establish the normal values and ranges of these parameters. This technique allows the assessment of the functional significance of epicardial coronary stenoses as well as the investigation of the function of the coronary microcirculation in patients with and without coronary artery disease.     

Coronary flow velocity immediately after reperfusion reflects myocardial microcirculation in canine models of acute myocardial infarction

Recent reports indicate that the coronary microcirculation is sometimes injured, despite successful reperfusion in acute myocardial infarction (AMI). However, it is difficult to evaluate the coronary microcirculation immediately after reperfusion by using only angiography. The purpose of this study was to examine the relationship between the pattern of coronary blood flow velocity and myocardial microcirculatory injury immediately after reperfusion in AMI. The authors recorded the left circumflex coronary flow velocity by using the Doppler guide wire method 10 minutes after reperfusion in a canine model of AMI. In addition, myocardial contrast echocardiography was performed with the injection of contrast medium into the left circumflex coronary artery before clamping of the coronary artery and 15 minutes after release of the clamp. From these images, the ratio of the normalized gray-level postreperfusion to preclamping in the contrast-enhanced area was determined. It was compared with coronary flow velocity variables. In the 10 dogs with a diastolic-to-systolic velocity ratio (DSVR) < 4.0, this velocity ratio 10 minutes after reperfusion correlated positively (r = 0.75, p < 0.01) with the normalized gray-level ratio. However, the remaining three dogs with a DSVR > or = 4.0 markedly deviated from this pattern. Coronary flow velocities in the three dogs were characterized by a greater decrease in systolic flow velocity and occurrence of early systolic retrograde flow. Myocardial contrast echocardiographic images in these three dogs demonstrated a lower normalized gray-level ratio. In conclusion, the coronary flow velocity pattern immediately after reperfusion may reflect myocardial microcirculatory injury.     

The coronary circulation and blood flow in left ventricular hypertrophy

Two distinct types of left ventricular hypertrophy (LVH) have been described: the so called "physiologic" hypertrophy, which is normally found in professional athletes, and "pathologic" LVH which is found in patients with inherited heart muscle disease such as hypertrophic cardiomyopathy (HCM) or patients with cardiac and systemic diseases characterized by pressure or volume overload. Patients with pathologic LVH have often symptoms and signs suggestive of myocardial ischemia despite normal coronary angiograms. Under these circumstances ischemia is due to coronary microvascular dysfunction (CMD). The abnormalities of the coronary microcirculation may be unrelated to the degree of LVH and cause a reduction in maximum myocardial blood flow which, in the absence of epicardial stenoses, is suggestive of CMD. There is no technique that enables direct visualization of coronary microcirculation in vivo in humans. Therefore, its assessment relies on the measurement of parameters which reflect its functional status, such as myocardial blood flow and coronary flow reserve which is an integrated measure of flow through both the large epicardial coronary arteries and the microcirculation. In this review article we discuss the pathophysiological mechanisms responsible for CMD in patients with primary and secondary LVH and how the recognition of this phenomenon is providing new important information on patient stratification and prognosis. Finally, we discuss how assessment of CMD may be used as a valuable surrogate marker to test the efficacy of old and new drugs. This article is part of a Special Issue entitled "Coronary Blood Flow".     

PET measurement of the coronary flow reserve and microcirculatory function

This review article discusses some of the potentially beneficial effects of calcium antagonists on the coronary microcirculation. These include their vasodilating action on coronary resistance vessels as well as their effects on extravascular resistance (i.e. intramyocardial pressure). Examples are presented of how the non-invasive measurement of myocardial blood flow and flow reserve by means of positron emission tomography (PET) can contribute to the understanding of the effects of drug treatment on the coronary microcirculation. The action of calcium antagonists on the coronary microcirculation can contribute to explain the efficacy of these drugs against ischemia and ischemia-reperfusion damage.     

Inhibition of iron-catalyzed oxidative reactions restores mathcing between coronary blood flow and myocardial metabolic demand in type 2 diabetes

In diabetes, endothelium-dependent dilation of large and small coronary arteries is impaired, which results in a mismatch between myocardial metabolic demand and coronary blood flow. It has been proved that deferoxamine, an iron chelator that inhibits Fenton and Haber-Weiss reactions, restores a normal response to cold pressor test and flow increase in angiographically normal epicardial coronary arteries of diabetic patients. This result suggests that nitric oxide could be inactivated by reactive oxygen species. The aim of this study was to assess the effects of deferoxamine on coronary microcirculation vasomotion when myocardial oxygen demand is increased by sympathetic stimulation elicited by cold pressor test in type 2 diabetic patients. In 17 patients with angiographically normal coronary arteries and without any other coronary risk factors, coronary blood flow has been measured using quantitative angiography and intracoronary Doppler at baseline and during a cold pressor test, before and after intravenous administration of 500 mg deferoxamine. Increase in rate-pressure product, an estimate of myocardial metabolic demand, was similar before and after deferoxamine (+21.1 +/- 8.7% vs +20.5 +/- 8.9%, respectively), but coronary blood flow increase was significantly higher after deferoxamine (+6.3 +/- 12.9% vs +31.8 +/- 16.7%, respectively, p < 0.001), and coronary resistance was increased before deferoxamine and decreased after (+14.8 +/- 21.9% vs -7.9 +/- 10.9%, respectively, p < 0.001). Moreover, before deferoxamine, the negative correlation between coronary blood flow and rate-pressure product changes before deferoxamine (R = 0.518, P < 0.05) was turned in a positive relationship after deferoxamine (r = 0.546, p < 0.05). In conclusion, in type 2 diabetic patients, endothelium-dependent dilation of the coronary microcirculation is restored when iron-catalysed oxidative reactions are inhibited by deferoxamine, which restores the normal matching between myocardial oxygen demand and coronary blood flow.     

Transmural myocardial ischemia due to slow coronary flow

Slow coronary flow phenomenon(SCFP) is an angiographic observation characterized by delayed distal vessel opacifi-cation in the absence of significant epicardial coronary disease. Only limited studies have been focused on the etiologies,clinical manifestations and treatment of this unique angiographic phenomenon. In our case report,we described an 85-year-old man who came with significant ST segment elevation in leads V1-V4 and V3R-V5R without increase in myocardial enzyme. The patient also developed respiratory failure requiring intubation and mechanical ventilation. Coronary angiography revealed only mild atherosclerosis without spasm or thromboembolic occlusion. Slow flow was seen in all coronary arteries,especially in the left anterior descending and right coronary arteries. This case speculated that transmural myocardial ischemia with ST segment elevation might be resulted from slow coronary flow. Transmural myocardial ischemia can occur owing to abnormalities of the coronary microcirculation.     

急性心肌梗死经皮冠脉介入治疗后无再流现象的研究进展

急性心肌梗死的急诊经皮冠脉介入治疗可并发无再流现象,是目前再灌注治疗时代的难点。已成为界内人士研究和关注的焦点。本文综述了无再流现象以下几个方面:(1)无再流的定义;(2)检测方法,其中介绍了心肌分级、心肌声学造影等;(3)临床相关因素,包括梗死面积、血脂、梗死前心绞痛的发生时间、血管斑块成分及血液的抗氧化因子;(4)可能的发生机制,主要是冠脉微循环在缺血时的变化和远端的栓塞;(5)最新的治疗方法。由此,我们对冠脉介入治疗中的无再流现象有一系统了解。