Atherosclerosis suppression in the left anterior descending coronary artery by the presence of a myocardial bridge: an ultrastructural study

Ultrastructural changes of the left anterior descending coronary artery (LAD) by the presence of myocardial bridge (MB) were studied. In contrast with various atherosclerotic lesions in the intima both proximal to MB and in the whole length of the LAD having no MB, intimal thickness beneath MB was remarkably thin. Neither lipid deposition nor foam cells were present there even in the aged. The intima beneath MB consisted of only normal smooth muscle cells (SMCs) in some layers. Collagen fibrils loosely stuffed among SMCs showed a spiraled appearance. The intima distal to MB was thicker than that beneath MB. Modified SMCs were present along with normal SMCs, and foam cells were intermingled with them. By scanning electron microscopy, endothelial cells proximal to MB were arranged in a pavement-like appearance, and they were polygonal and flat. Endothelial cells beneath MB became spindle-shaped and regularly engorged along the direction of blood flow. Such regularity was lost in endothelial cells distal to MB. These endothelial changes indicate that the intima beneath MB is stressed by high shear and that intima proximal or distal to MB is stressed by low shear. It is, thus, suggested that alteration of hemodynamic factors that arise from contraction of MB greatly affects the evolution of atherosclerosis through the regulation of intimal lipid infiltration within the LAD.     

The significance of myocardial bridge upon atherosclerosis in the left anterior descending coronary artery

The relation between myocardial bridges (MB) and atherosclerosis in the left anterior descending coronary artery (LAD) was explored using morphometric methods in 642 hearts. The location of myocardial bridges in the LAD was classified according to distribution as proximal, middle and distal. Myocardial bridges were found in 48 per cent of males and 36 per cent of females. When proximal myocardial bridging was present intimal thickening and macroscopic raised lesion were increased just before the bridge as compared with the corresponding site in the other two categories. Underneath bridges eccentric plaques and raised lesions are absent although there is often concentric intimal thickening. The overall frequency of myocardial infarction was the same in patients with and without myocardial bridges. However, when infarction occurred in the patients having bridges, it was almost confined to those in the proximal group despite this being infrequent in the general distribution of myocardial bridges in the left anterior descending artery. It is postulated that hypertension may enhance infarction in the case of myocardial bridges in the very proximal left anterior descending artery. It is concluded that the location of myocardial bridges greatly alters the distribution of physical force against the arterial wall and influences the extent of atherosclerosis.     

Die koronare Muskelbrücke des Ramus descendens anterior

Zusammenfassung 711 menschliche Herzen wurden makroskopisch und teilweise auch angiographisch und histologisch auf koronare Muskelbrücken des Ramus descendens anterior untersucht. Bei 22,9% aller Herzen fanden sich derartige Brücken. Der durchschnittliche Abstand vom Hauptstamm der linken Kranzarterie betrÄgt 33,6 mm, die mittlere LÄnge 22,5 mm und die mittlere Dicke 2,8 mm. Zwischen den überbrückten KoronargefÄ\en und der Muskulatur liegt zumeist eine feine Fettgewebsverschiebeschicht. Geschlechts- und Altersverteilung sowie durchschnittliche Körpergrö\e und mittleres Herzgewicht sind für die Patientengruppe mit bzw. ohne Muskelbrücke des Ramus descendens anterior gleich.Die statistische Auswertung ergab, da\ sich proximal einer Muskelbrücke des Ramus descendens anterior signifikant mehr Koronararteriensklerose als unter und distal dieser Brücke finden. Herzen mit einer Muskelbrücke des Ramus descendens anterior haben signifikant weniger Koronararteriensklerose im gesamten Verlauf dieses Kranzarterienastes als Herzen ohne derartige Brücken; die Folge davon ist ein Trend zu weniger Vorderwandinfarkten bei Patienten mit Muskelbrücke am Ramus descendens anterior.Die Ursache für die Koronarsklerose-Protektion des Koronararterienastes unter der Muskelbrücke ist unklar.

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Muscle bridges over the left anterior descending coronary artery: Their influence on arterial disease

Summary A total of 711 hearts was studied and examined for coronary muscle bridges of the left anterior descending (LAD) macroscopically, angiographically and histologically.A muscular overbridging of the LAD was found in 22.9% of all hearts. The average distance from left artery bifurcation was 33.6 mm, the average length was 22.5 mm and the average thickness 2.8 mm. A thin layer of fat tissue is mostly to be found between the overbridged coronary artery and the myocardial bridge. The patient group with and without myocardial overbridging showed no difference in sex or age nor in average stature and the average heart weight.Statistically, there is significantly more atherosclerosis of the coronary artery proximal to the muscle bridge than there is under and distal to the bridge. A difference in frequency and extent of atherosclerosis in hearts with and without coronary muscle bridge could not be shown for this portion of the LAD. Nevertheless, there is a tendency for fewer anterior-wall infarctions in the patient group with a coronary muscle bridge of the LAD, because, when the whole branch is considered, there is a significantly lower incidence of atherosclerosis in hearts with myocardial overbridging of the LAD. The reason for the protective effect of a coronary muscle bridge is yet not clear.

Herrn Prof. Dr. Gerd Hegemann in Verehrung zum 65. Geburtstag     

The effect of myocardial bridging of the coronary artery on vasoactive agents and atherosclerosis localization

The relationship between alterations in the immunohistochemical expression of three vasoactive agents [endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), and angiotensin-converting enzyme (ACE)] and the occurrence human atherosclerosis was investigated in relation to the myocardial bridge (MB) of the left anterior descending coronary artery (LAD), an anatomical site that experiences increased shear stress. Five millimetre cross-sections of LADs with MB from 22 autopsied cases were taken from the left coronary ostium to the cardiac apex and were immunohistochemically stained with antibodies against eNOS, ET-1, and ACE. The extent of atherosclerosis in each section was calculated using the atherosclerosis ratio (intimal cross-sectional area/medial cross-sectional area) determined by histomorphometry. The results were analysed according to their anatomical location relative to the MB, either proximal, beneath, or distal. The extent of atherosclerosis was significantly lower beneath the MB, compared with proximal and distal segments. The expression of eNOS, ET-1, and ACE was also significantly lower beneath the MB. The expression of these agents correlated significantly with the extent of atherosclerosis. Because nitric oxide, after its production by eNOS, is believed to be degraded by superoxide radicals, the effect of eNOS expression on atherosclerosis remains controversial. However, the present findings clearly indicate that the expression of ET-1 and ACE is directly related to the development of human coronary atherosclerosis in vivo through shear stress.     

Absence of atherosclerosis evolution in the coronary arterial segment covered by myocardial tissue in cholesterol-fed rabbits

The evolution of atherosclerotic lesions is suppressed in the intima of the human coronary artery, beneath myocardial bridges. To elucidate the mechanism of the protective effect, we investigated morphological changes using the rabbit coronary artery as a model. Rabbits fed a 1%-cholesterol diet were killed at intervals up to 20 weeks. Two short segments of the left coronary arteries running in the epicardial adipose tissue (EpiLAD) and subsequently running in the myocardium (MyoLAD) were compared morphologically. The intima of the EpiLAD had flat endothelial cells with a polygonal shape, and demonstrated raised atherosclerotic lesions with increase in serum cholesterol level. In contrast, the intima of the MyoLAD was free of atherosclerotic lesions throughout the study, and the endothelial cells were spindle-shaped and engorged. While ferritin particles reached only the surroundings of the internal elastic lamina in the MyoLAD, they permeated into the media of the EpiLAD. We suggest that myocardial bridges suppress coronary atherosclerosis by an alteration of endothelial permeability, which may be due to changes in haemodynamic force tending towards a higher shear stress. The data provide an insight into the relationship between haemodynamics and the development of coronary atherosclerosis.     

壁冠状动脉与心肌桥的应用解剖学

本文在 50例心脏上测量了心肌桥位置的长、宽、厚度 ;并在光镜下观察了壁冠状动脉的结构。发现桥前段血管内膜较桥下、后段的内膜显著增厚 (P<0 .0 1) ,讨论了它与冠状动脉粥样硬化间的关系。     

Collagen alteration in vascular remodeling by hemodynamic factors

The collagen alterations in the vascular wall remodeled by hemodynamic change were investigated by electron microscopy and immunohistochemistry. The left anterior descending coronary artery (LAD) without a myocardial bridge (MB) showed both lower matrix metalloproteinase-1 (MMP-1) expression and a smaller extent of spiraled collagen (SC) distribution than the LAD wall with MB, in which the intima was influenced by high shear stress. In the wall of the varicose great saphenous vein (GSV) the expression of MMP-1 was lower, while the expression of prolyl 4-hydroxylase was higher, than in the normal GSV. The extent of SC distribution in the intima and media of the varicose GSV was smaller than that in the normal GSV. An analogous difference in results was demonstrated between the portal vein (PV) of patients with liver cirrhosis and normal PV. However, the levels of expression of MMP-2, MMP-9 and tissue inhibitors of MMP (TIMPs) in these pathologic vessels were not different from those in the corresponding normal vessels. The results indicate that hemodynamic forces such as shear stress and increased intravascular blood pressure contribute to the collagen alterations in the vascular wall, which may lead to vascular wall remodeling. Received: 22 October 1999 / Accepted: 20 January 2000     

壁冠状动脉血流动力学体外模拟

目的 研究心肌桥压迫对壁冠状动脉内血流、正压力、周向应力、切应力的影响。方法 对原有的壁冠状动脉模拟装置进行较大改进,使其测量的血流动力学参数从单一应力（正应力）扩展到多种应力,以便更全面准确地模拟在正压力、周向应力、切应力共同作用下的真实血流动力学环境,从而综合考虑在多种应力共同作用下血流动力学规律与壁冠状动脉粥样硬化之间的关联。结果 壁冠状动脉模拟装置实验结果表明,应力的异常主要位于壁冠状动脉近端,随着心肌桥压迫程度加剧,近端的应力平均值与波动值明显增大,正应力平均值升高27.8%,波动值升高139%。结论 心肌桥压迫造成壁冠状动脉近端血流动力学发生异常,对认识冠脉粥样硬化发病的血流动力学机理具有重要意义,对于心肌桥的病理影响及治疗具有潜在的临床价值。     

多层螺旋CT评估心肌桥及伴发血管粥样硬化病变的诊断价值

目的 探讨256层螺旋CT评估心肌桥及伴发血管粥样硬化病变的诊断价值。方法 回顾性收集接受256层螺旋CT检查并于30 d内行选择性冠脉造影检查的（疑似冠心病患者）101例患者相关资料。统计多层螺旋CT和CAG对心肌桥的检出率及检出心肌桥的位置分布;并测量心肌桥的长度,CT血管成像评估载心肌桥-壁冠状动脉冠脉分支粥样硬化的狭窄程度。结果 256层螺旋CT检出16例患者共18段心肌桥,检出率为15.84%,其中最常见的心肌桥部位是前降支中段心肌桥为16段,出现率为88.89%（16/18）。CAG仅检出4例患者共4段心肌桥,检出率为3.96%。256层螺旋CT测量心肌桥的平均长度为（27.20±16.30）mm,CAG证实的CTA评价的载MB-MCA血管节段狭窄程度≥50%有5段（27.78%）,CAG证实的CTA评价的载MB-MCA血管节段近段狭窄程度≥50%有6段（33.33%）。结论 256层螺旋CT对心肌桥的检出率明显高于CAG;更清晰显示心肌桥形态结构,并可观察伴发血管的粥样硬化病变。     

心肌桥的形态特点与冠状动脉粥样硬化关系

目的　探讨心肌桥（MB）存在及与冠状动脉粥样硬化（AS）的关系。 方法　回顾性分析在法医尸解中发现的87例心肌桥的形态特点与AS的关系。 结果　MB检出率34.7％,并随年龄呈阶梯样增加,心肌桥主要出现在左冠状动脉前降支及右主干, 单个MB最多,占90.8％（79例）。MB桥前段发生AS有43.7％（38例）,管腔狭窄程度大多在Ⅲ级以上占86.8％（33例）;桥后段有8％（7例）发生AS,管腔狭窄程度均在Ⅱ级以下,二者有统计学意义（P<0.05）,桥下段无AS;存在AS的MB长度大多2.0cm以上。 结论　大多数MB是解剖变异,随着年龄增加可导致桥前段和桥后段AS,桥前段更易发生AS。     

电子束CT冠状动脉血管造影与冠状动脉造影结果的关联性研究

目的　探讨电子束CT冠状动脉血管造影 (eletronbeamcomputedtomographicangiography ,EBA)与冠状动脉造影结果的关联性。方法　 2 4例临床怀疑冠心病患者分别行EBA及冠状动脉造影 (coronaryangiography,CAG) ,所有EBCT图像均经三维重建显像 ,按照AHA分段方法进行分段 ,每套重建显像血管分成左主干 (leftmainartery ,LM)及前降支 (leftanteriordescendingcoronaryartery ,LAD)、左旋支 (leftcircumflexartery ,LCx)、右冠脉 (rightcoronaryartery,RCA)各近、中、远三段共 10段血管 ,由 2名医生对LM和LAD、LCx、RCA的近、中段共 16 8段血管进行分析 ,其结果与CAG结果对比 ,比较EBA与CAG所示冠状动脉狭窄间的关系。结果　在 16 8个近段和中段血管中有 147段 (87.5 0 %)EBA能够清楚显像 ,其中LAD近段和中段清晰显像的百分比都为 95 .83%,而RCA近段和中段分别为 91.6 7%和 5 8.33%,LCx近段和中段为 91.6 7%、79.17%,而在 16 8个近段和中段血管中CAG全部清晰显像 ;如果以 >5 0%狭窄作为有意义狭窄 ,则EBA与CAG比较发现狭窄的敏感性和特异性是 83.33%和 92 .13%,其中LM是 10 0 .0 0%和 95 .6 5 %,LAD近段是 10 0 .0 0 %和 75 .0 0 %,LAD中段是 82 .35 %和 6 6 .6 7%,RCA近段是 80 .0 0 %和 71.43%,RCA中段是 5     

壁冠状动脉周向应力体外加载装置的研制

目的设计并研制壁冠状动脉周向应力体外模拟装置,实现不同程度心肌桥压迫下壁冠状动脉周向应力的体外加载。方法利用心肌桥冠状动脉血液动力学体外模拟装置,实现壁冠状动脉周向应力的体外测量。依托上述实验数据,实现不同程度心肌桥压迫下壁冠状动脉周向应力的体外加载。结果通过体外测量实验发现,壁冠状动脉近心段周向应力最大值、平均值以及波动值都会随着心肌桥压迫程度的增加而显著增大。通过壁冠状动脉周向应力的体外加载实验,验证加载波形与周向应力体外测量实验波形基本吻合。结论该装置可以实现壁冠状动脉周向应力的体外加载,为探究壁冠状动脉近端血液动力学异常对动脉粥样硬化产生及斑块破裂的影响,提供一个尽量接近在体环境、多种参数可调控的体外模拟平台。     

Left main or proximal left anterior descending coronary artery disease: detection by echocardiographic evaluation of interventricular septal function during exercise

Forty patients with coronary artery disease were studied prospectively to investigate whether stenosis of the left main (LMCA) or left anterior descending coronary artery, proximal to the first septal branch (proximal LAD), could be detected by M-mode echocardiography during exertion. The interventricular septum was visualized in 30 of the patients during bicycle exercise in the semisupine position, all with simultaneous occurrence of electrocardiographic evidence of myocardial ischaemia. Fifteen of these had LMCA or proximal LAD stenosis. Systolic motion and thickening of the septum decreased significantly from rest to peak exercise in patients with LMCA or proximal LAD disease while it increased in those without. The results suggest that M-mode echocardiography during exercise in patients with coronary artery disease might identify those with LMCA or proximal LAD stenosis.     

The relationship of myocardial bridges to coronary artery dominance in the adult human heart

Myocardial bridging is recognized as an anatomical variation of the human coronary circulation in which an epicardial artery lies in the myocardium for part of its course. Thus, the vessel is 'bridged' by myocardium. The anterior interventricular branch of the left coronary artery has been reported as the most common site of myocardial bridges but other locations have been reported. The purpose of this study was to provide more definitive information on the vessels with myocardial bridges, the length and depth of the bridged segment, and the relationship between the presence of bridges and coronary dominance. Two hundred formalin-fixed human hearts were examined. Myocardial bridges were found in 69 (34.5%) of the hearts with a total of 81 bridges. One bridge was found in 59 of these hearts and multiple bridges were observed in ten (eight with double bridges and two with triple bridges). Bridges were most often found over the anterior interventricular artery (35 hearts). Bridges were also found over the diagonal branch of the left coronary artery (14), over the left marginal branch (five) and over the inferior interventricular branch of the left coronary artery (six). Bridges were also found over the right coronary artery (15 hearts), over the right marginal branch (four) and over the inferior interventricular branch of the right coronary artery (two). The presence of bridges appeared to be related to coronary dominance, especially in the left coronary circulation. Forty-six (66.6%) of the hearts with bridges were left dominant. Forty-two of these had bridges over the left coronary circulation and four over the right coronary circulation. Seventeen hearts (24.6%) were right dominant. Eleven of these had bridges over the right coronary circulation and six over the left coronary circulation. The remaining six hearts were co-dominant with four having bridges over the left coronary circulation and two over the right coronary circulation. The mean length of the bridges was 31 mm and the mean depth was 12 mm. The possible clinical implications of myocardial bridging may vary from protection against atherosclerosis to systolic vessel compression and resultant myocardial ischaemia.     

The size of human coronary arteries depending on the physiological and pathological growth of the heart the age,the size of the supplying areas and the degree of coronary sclerosis

Summary In 300 human hearts of all age groups (pre-natal to senescence) postmortem angiographs were performed under a pressure of 100 mmHg. The largest diameters of the three coronary arteries (i.e. the right coronary artery, the left descending and the left circumflex branch) were determined.In our material we did not find ectatic coronary arteries in old age in the absence of atherosclerosis. We suggest that as a rule the larger diameters of the dissected coronary arteries in older hearts may be a postmortem phenomenon, due to the decreased elasticity of the vascular walls, which manifests itself as a progressive loss of retraction.In female hearts the cross-sectional areas of the coronary arteries were a little smaller than in male hearts of same age groups (statistically not significant). In postmortem hearts of normal weights the diameters of the coronary arteries exceeded intravital measurements of other authors by nearly 15%, but there is good correlation between our postmortem findings and intravital measurements after application of nitroglycerin. It seems that the postmortem diameters of coronary arteries after filling under physiological pressure correspond with the maximal intravital diameters.In our material we found that even in hearts beyond the critical weight coronary arteries are able to grow. Because of the limited number of hearts with an excessive weight and healthy coronary arteries we cannot decide whether under pathological conditions the growth of the coronary arteries corresponds harmonically with the growth of the myocardium.There were large variations in coronary artery diameters during the physiological and pathological growth of the heart. If only the sum of the right coronary artery and the common stem of the left main coronary artery were considered the variations were smaller.On the average the largest diameters of coronary arteries with atherosclerosis were smaller than the diameters of healthy coronary arteries. We found a good correlation between the thickening of the intima of sclerotic vessels and the decrease in their diameters. Therefore we cannot support the view that coronary arteries of hearts with infarctions are smaller before the onset of atherosclerotic lesions.Furthermore we compared the cross-sectional areas of the coronary arteries with their supplying areas. We found the best correlation for the right coronary artery.During late fetal development and childhood there was a nearly linear correlation between the increase in the sum of cross-sectional areas of the three coronary arteries and the weight of the heart. During later physiological and pathological growth of the hearts there was a progressively slower increase of the cross-sectional areas. These differences were not present when the diameter of the healthy coronary arteries was compared with the diameter of the ventricular muscle mass (calculated as the cube root of the weight of the ventricular part = WVP). The closest correlation of all was found between these two linear parameters.Supported by the Deutsche Forschungsgemeinschaft (Ho282/8)Our morphometric investigations of the thickness of the intima at the widest part of the atherosclerotic and non-atherosclerotic arteries speak for the fact that the diameters of the vessels were the same in both groups before atheroma developed and that patients with myocardial infarction did not have pre-existing abnormally narrow coronary arteries.     

Aortic intimal sarcoma with acute myocardial infarction

An autopsy case of aortic sarcoma who died of acute myocardial infarction caused by coronary involvement is reported. The patient was a 54 year old woman who was admitted because of an undiagnosed fever and general fatigue of 6 months duration. Magnetic resonance imaging (MRI) showed a tumor in the aortic arch. Total aortic arch replacement was performed, it was diagnosed as a malignant mesenchymal tumor of the aorta. The patient died of acute myocardial infarction 10 months after the operation. At autopsy, the tumor had invaded the luminal surface and intima of the proximal anastomosis (the remnant ascending aorta and the graft), the aortic valves, the distal anastomosis (surgical line of the thoracic aorta plus the graft), and the coronary arteries. The left main coronary artery showed complete obstruction by fibrin thrombus with tumor invasion in the intima, which was responsible for acute myocardial infarction. Primitive and bizarre tumor cells proliferated with many slit-like tissue spaces. Most of the tumor except for its luminal surface showed necrosis. Ultrastructurally, there were spaces between tumor cells, suggesting lumen formation, and some of them had microvilli. This sarcoma was considered to be the so-called aortic intimal sarcoma.     

Ventricular septal rupture caused by myocardial bridge,solved by interventional closure device

Myocardial bridging is a common coronary anomaly, which is generally described as a benign phenomenon. However, a growing number of studies consider this anomaly a relevant pathophysiological phenomenon with serious pathological consequences. Here we report on the case of an 88-year-old woman suffering from myocardial infarction and ventricular septal rupture, lacking any recognizable coronary disease except for a myocardial bridge causing the systolic compression of the left anterior descending coronary artery. A wide range of diagnostic procedures, including coronarography, echocardiography, and magnetic resonance imaging were used. The septal rupture was finally closed by using a percutaneous closure device. This event indicates that myocardial bridges – at least in some cases – may have notable clinical relevance.Some epicardial coronary arteries may have an intramyocardial segment referred to as a myocardial bridge (MB). This condition is generally described as a benign vascular anomaly. However, in some cases it has been reported to cause acute coronary syndrome, malignant ventricular arrhythmia, and sudden cardiac death (1). Research based on coronary angiography, a gold standard for diagnosing myocardial bridging, reports that this anomaly occurs in 1.5%-16% of members of Caucasian population (2). On the other hand, pathologists find myocardial bridging in up to 80% of all examined hearts (1). The relevance of the limitation of myocardial perfusion by compression of the anomalous vessel during the systole is often brought into question. At the same time, some studies report relevant asynergy in the contraction of the bridge during the diastolic blood flow (1). It has been well established that the proximal segment of the MB is more prone to atherosclerosis, while the tunneled coronary segment is spared (1). Plaques within the distal segment also seem to be less frequent (3). This is likely to be related to the higher proximal and lower distal intracoronary pressure-oscillation, which also implies shear stress (4). The tunneled segment is described as being prone to vasospasm (1).     

犬左冠状动脉前室间支心肌桥的形态学特征

目的探讨犬壁冠状动脉和心肌桥的形态学特点,为比较解剖学提供资料。方法取犬心41例,10%甲醛溶液固定,解剖显示冠状动脉及其分支,观测心肌桥及壁冠状动脉的出现率。结果犬冠状动脉心肌桥多出现于前室间支、后室间支和左室前支。心肌桥出现率70.7%,前室间支79.3%,心肌桥厚度为0.56±0.61 mm。前室间支前段内径1.64±0.46 mm,厚度0.18±0.06 mm;壁冠状动脉内径1.35±0.46 mm,厚度0.13±0.04 mm。心肌桥近段距第一对角支距离为19.78±8.20 mm,距前室间支起始部距离为24.49±12.37mm,距右冠起始部距离为24.21±5.80 mm。心肌桥纤维走向与壁冠状动脉夹角为68.94±14.38。结论犬冠状动脉心肌桥出现率及位置与人相似,可作为科研动物模型。     

冠脉CT与冠脉造影诊断心肌桥的临床价值比较

目的:比较冠脉CT与冠脉造影诊断心肌桥的临床价值。方法:收集2015年7月~2020年7月苏州大学第二附属医院心内科收治的107例疑似冠心病患者临床资料。依次进行冠脉CT和冠脉造影检查,计算壁冠状动脉（MCA）狭窄程度,观察前降支、对角支、钝缘支、后降支和回旋支冠脉分布走行以及与心肌的关系,测量心肌桥长度和厚度。比较两种检查方法图像质量优良率、心肌桥检出率以及心肌桥测量指标。分析两种检查方法显示MCA狭窄程度和诊断心肌桥的一致性。以冠脉造影为金标准,计算敏感度、特异度、准确度、阳性预测值、阴性预测值,评估冠脉CT判断MCA中重度狭窄和诊断心肌桥的价值。结果:两种检查方法图像质量优良率均较好,冠脉CT心肌桥检出率显著高于冠脉造影（25.23% vs 14.02%, P<0.05）;冠脉CT测得心肌桥长度大于冠脉造影,MCA狭窄程度低于冠脉造影,差异具有统计学意义（P<0.05）;冠脉CT和冠脉造影显示MCA狭窄程度的一致性较好（Kappa=0.832, P<0.05）;与冠脉造影比较,冠脉CT判断MCA中重度狭窄的敏感度、特异度、准确度、阳性预测值、阴性预测值分别为90.63%、86.67%、74.36%、95.59%、87.85%;冠脉CT和冠脉造影诊断心肌桥的一致性较好（Kappa=0.815, P<0.05）;与冠脉造影比较,冠脉CT诊断心肌桥的敏感度、特异度、准确度、阳性预测值、阴性预测值分别为64.29%、73.33%、69.23%、68.75%、68.97%。结论:冠脉CT与冠脉造影对心肌桥诊断均具有一定价值,而冠脉CT具有无创性、图像质量优良率高,且对心肌桥位置及分布显示佳,并对MCA狭窄具有较高敏感度和特异度,更具临床应用优势。