Effects of antioxidants on coronary microvascular spasm induced by epicardial coronary artery endothelial injury in pigs

OBJECTIVES: The effect of oxidative stress on coronary microvascular disease is unknown. We investigated whether chronic administration of ascorbic acid (ASC) or glutathione (GSH) prevents microvascular dysfunction and remodeling induced by upstream repeated coronary artery endothelial injury. METHODS: Balloon endothelial injury was repeated at the left anterior descending coronary artery (LAD), just distal to an implanted flow meter, every 2 weeks for 6 weeks in pigs. Changes in LAD blood flow induced by acetylcholine (ACh) and 5-hydroxytryptamine were assessed before each endothelial injury and at 8 weeks after the first endothelial injury in pigs without treatment (endothelial injury group, n = 12) and in pigs treated with oral ASC (3 g/day) (ASC group, n = 12) and ASC (3 g/day) plus GSH (1 g/day) (ASC + GSH group, n = 12). RESULTS: In the endothelial injury group, reduced blood flow in response to ACh was augmented from a decrease of 18 +/- 17% to a decrease of 100% (that is, zero flow, 8 weeks, P < 0.01), accompanied by an increase of ascorbyl free radicals (AFRs) in coronary sinus blood. In contrast, in the ASC + GSH group, blood flow response to ACh was altered to a decrease of 45 +/- 17% (8 weeks, P < 0.01 compared with the endothelial injury group), coronary sinus blood AFRs did not change (8 weeks, 21.4 +/- 12.5 signal intensities, P < 0.01 compared with the endothelial injury group) and the rate of platelet aggregation induced by adenosine diphosphate was small (8 weeks, 56 +/- 17%, P < 0.01 compared with the endothelial injury group). CONCLUSIONS: Chronic administration of antioxidants suppressed microvascular hypercontraction, suggesting that it may be a promising therapeutic strategy for treating coronary microvessel disorders, including microvascular angina.     

Substance P dilates epicardial coronary arteries and increases coronary blood flow in humans

The effects of intracoronary infusions of substance P in conscious humans on epicardial vessel diameter and coronary sinus oxygen saturation were investigated in 13 patients who had angiographically normal coronary arteries. The dose of substance P ranged from 2.8 to 89.6 pmol/min, starting at 2.8 pmol/min and rising by doubling increments. All infusions were performed for 2-minute periods. Epicardial vessel diameter was measured by a computerized analysis system (CAAS) of the angiogram performed at the end of each infusion period. Coronary sinus oxygen saturation (CSO2) was measured continuously by a fiber-optic oximeter catheter in the coronary sinus. A reduction of arterial pressure, indicative of a systemic effect of substance P, occurred only when infusions were 44.8 pmol/min or more. At considerably smaller dosages, a dose-dependent increase in the left anterior descending artery diameter was seen with substance P; maximal dilation occurred at a dosage of 11.2 pmol/min. The percent increase in vessel diameter for this dosage was 29.4 +/- 19.8% (mean +/- SD) at the distal site of analysis and 16.7 +/- 10% at the proximal site of analysis. CSO2 rose in a dose-dependent manner and was maximal at a dosage of 11.2 pmol/min, which caused a 14.6 +/- 7.2% O2 rise above the preinfusion saturation of 43.5 +/- 11.1% O2. As the heart rate-blood pressure double product showed no change, it is argued that these changes in CSO2 probably reflect rises in coronary flow that were seen with dosages of substance P without systemic effect. In three patients, preconstriction induced by ergonovine was reversed by substance P infusions, which produced a degree of dilation equivalent to that of isosorbide dinitrate. We conclude that substance P at very small dosages, which are without peripheral effects, causes in vivo epicardial coronary artery dilatation as well as resistive vessel dilatation in humans.     

Effects of intracardiac radiofrequency current application on coronary artery vessels in young pigs

INTRODUCTION: Radiofrequency current is widely used in children to ablate accessory AV pathways. Previous data in a pig model demonstrated coronary artery obstruction adjacent to radiofrequency current lesions 48 hours and 6 months after energy delivery. In the present study, the long-term effects (>6 months) of radiofrequency current application on coronary artery vessels in young pigs are assessed. METHODS AND RESULTS: Radiofrequency current (500 kHz) was delivered over 30 seconds in ten piglets (mean body weight 12.8 kg) using a steerable 6-French catheter with a 4-mm thermistor tip electrode (target temperature 75 degrees C). Lesions were created under fluoroscopic and electrocardiographic guidance at the lateral right atrial (RA) wall above the tricuspid valve orifice, and at the lateral left atrial and left ventricular wall adjacent to the mitral valve orifice. Selective coronary angiography and intravascular ultrasound (IVUS) studies were performed 3, 6, 9, and 12 months after energy application. After 12 months, the lesions were studied pathohistologically. All lesions consisted of compact fibrous tissue. RA lesions extended to the adjacent right coronary artery and led to coronary artery involvement with increased fibrous tissue in the adventitia and media and intimal thickening in three animals. Coronary arterial narrowing was documented by IVUS during follow-up in all three cases 9 months after energy application. Angiography failed to demonstrate coronary pathology in any of the three animals. CONCLUSION: The risk of late coronary artery lesions must be considered when catheter ablation at the RA wall is planned in children with free-wall accessory AV pathways.     

Effects of mental stress on coronary epicardial vasomotion and flow velocity in coronary artery disease: relationship with hemodynamic stress responses

OBJECTIVES: This study examines the prevalence and hemodynamic determinants of mental stress-induced coronary vasoconstriction in patients undergoing diagnostic coronary angiography. BACKGROUND: Decreased myocardial supply is involved in myocardial ischemia triggered by mental stress, but the determinants of stress-induced coronary constriction and flow velocity responses are not well understood. METHODS: Coronary vasomotion was assessed in 76 patients (average age 59.9 +/- 10.4 years; eight women). Coronary flow velocity responses were assessed in 20 of the 76 patients using intracoronary Doppler flow. Repeated angiograms were obtained after a baseline control period, a 3-min mental arithmetic task and administration of 200 microg intracoronary nitroglycerin. Arterial blood pressure (BP) and heart rate assessments were made throughout the procedure. RESULTS: Mental stress resulted in significant BP and heart rate increases (p < 0.001). Coronary constriction (>0.15 mm) was observed in 11 of 59 patients with coronary artery disease (CAD) (18.6%). Higher mental stress pressor responses were associated with more constriction in diseased segments (rdeltaSBP = -0.26, rdeltaDBP = -0.30, rdeltaMAP = -0.29; p's < 0.05) but not with responses in nonstenotic segments. The overall constriction of diseased segments was not significant (p > 0.10), whereas a small but significant constriction occurred in nonstenotic segments (p = 0.04). Coronary flow velocity increased in patients without CAD (32.2%; p = 0.008), but not in patients with CAD (6.4%; p = ns). Cardiovascular risk factors were not predictive of stress-induced vasomotion in patients with CAD. CONCLUSIONS: Coronary vasoconstriction in angiographically diseased arteries varies with hemodynamic responses to mental arousal. Coronary flow responses are attenuated in CAD patients. Thus, combined increases in cardiac demand and concomitant reduced myocardial blood supply may contribute to myocardial ischemia with mental stress.     

心外膜脂肪体积与冠状动脉粥样硬化及左心室舒张功能的相关性研究

目的:通过双源64排CT对心外膜脂肪(EAT)进行三维立体重建,并测量其体积,探讨与冠心病发生、病变程度、斑块类型及早期心功能变化的关系。方法:临床疑诊冠心病(CAD)患者131例为研究对象,男性93例,女性38例,平均年龄(56±10)岁,收集所有病例一般临床资料,静脉取血行血脂、血常规及肝肾功能检查。超声心动图明确左心功能情况。所有患者均行冠状动脉64排双源CT血管成像检查,评价冠状动脉内斑块类型及稳定性,应用Vitrea FX(Vital Images)工作站的cardiac fat软件对EAT进行三维重建并测量其体积;根据冠状动脉造影结果确诊冠心病,并评价冠状动脉病变血管支数、病变部位及管腔狭窄程度。结果:冠心病组(n=63)EAT体积明显大于非冠心病组(n=68,P=0.003);冠状动脉3支病变者EAT体积,较1支及2支病变者明显增多(P<0.05);冠状动脉单纯低密度斑块者EAT体积较无斑块和单纯钙化者明显增大(P<0.001)。Pearson相关分析显示:EAT体积与腰围成正相关(r=0.475,P<0.001),与BMI成正相关(r=0.386,P<0.001)。Logistic回归分析显示EAT体积是冠心病的独立危险因素(OR=1.018,95%CI 1.004～1.033,P=0.011)。2组中左心室舒张功能减低者EAT体积均明显增加(P<0.05),EAT体积与左心室舒张末期内径明显正相关(r=0.331,P<0.001),与室间隔厚度正相关(r=0.195,P=0.031)。结论:EAT含量的增多与冠心病的发生、冠状动脉病变支数及易损斑块的形成密切相关,参与了左心室舒张功能的损伤过程,可能是冠心病新的危险因素,将可能是评价心血管疾病风险增加的新的无创指标,及潜在的治疗靶点。     

Relation of epicardial and pericoronary fat to coronary atherosclerosis and coronary artery calcium in patients undergoing coronary angiography

Fat surrounding coronary arteries might aggravate coronary artery disease (CAD). We investigated the relation between epicardial adipose tissue (EAT) and pericoronary fat and coronary atherosclerosis and coronary artery calcium (CAC) in patients with suspected CAD and whether this relation is modified by total body weight. This was a cross-sectional study of 128 patients with angina pectoris (61 +/- 6 years of age) undergoing coronary angiography. EAT volume and pericoronary fat thickness were measured with cardiac computed tomography. Severity of coronary atherosclerosis was assessed by the number of stenotic (> or =50%) coronary vessels; extent of CAC was determined by the Agatston score. Patients were stratified for median total body weight (body mass index [BMI] 27 kg/m(2)). Overall, EAT and pericoronary fat were not associated with severity of coronary atherosclerosis and extent of CAC. In patients with low BMI, those with multivessel disease had increased EAT volume (100 vs 67 cm(3), p = 0.04) and pericoronary fat thickness (9.8 vs 8.4 mm, p = 0.06) compared with those without CAD. Also, patients with severe CAC had increased EAT volume (108.0 vs 69 cm(3), p = 0.02) and pericoronary fat thickness (10.0 vs 8.2 mm, p value = 0.01) compared with those with minimal/absent CAC. In conclusion, EAT and pericoronary fat were not associated with severity of coronary atherosclerosis and CAC in patients with suspected CAD. However, in those with low BMI, increased EAT and pericoronary fat were related to more severe coronary atherosclerosis and CAC. Fat surrounding coronary arteries may be involved in the process of coronary atherosclerosis, although this is different for patients with low and high BMIs.     

外周血管动脉粥样硬化对年轻冠心病患者的预测意义

目的探讨外周血管颈动脉、股动脉粥样硬化对年轻冠状动脉性心脏病（冠心病）的预测作用。方法根据冠状动脉造影结果将58例≤40岁的患者分为冠心病组（37例）和非冠心病组（21例）,采用高分辨彩色多普勒超声同时检查颈动脉、股动脉,分别测量颈动脉内膜-中层厚度（carotid intima media thickness,CIMT）、股动脉内膜-中层厚度（femoral intima media thickness．FIMT）,以内膜-中层厚度（intima media thickness,IMT）≥1．2mm为粥样硬化斑块。比较两组的CIMT、FIMT及斑块检出率．计算斑块对年轻冠心病的预测值。结果冠心病组CIMT、FIMT高于非冠心病组[（1．36±0．51）mm比（0．84±0．38）mm,P〈0．05：（1．48±0．84）mm比（0.74±0．26）mm．P〈0．05]．冠心病组颈动脉、股动脉粥样硬化斑块形成检m牢均明显高于非冠心病组．差异有统计意义i62ck（23／37）比9．5％（2／21）．P〈0．05;57％（21／37）比14％（3／21）,P〈0．05]。颈动脉、股动脉粥样硬化斑块预测年轻冠心病的敏感性分别为62％、57％,特异性为90％、86％,阳性预测值分别为92％、88％,阴性预测值为58％、53％：颈动脉、股动脉联合检测未见明显提高预测值。结论外周血管颈动脉、股动脉粥样硬化与年轻冠心病相关,颈动脉、股动脉粥样硬化斑块对年轻冠心病患者均有预测作用,其特异性、阳性预测值均较高．     

Control of shear stress in the epicardial coronary arteries of humans: impairment by atherosclerosis

Altered arterial wall shear stress may adversely affect vascular endothelium and contribute to atherogenesis. This study examined the hypothesis that, in humans, dilation of normal coronary arteries with increased flow limits increases in shear stress and that loss of flow-mediated dilation in atherosclerosis results in failure to control shear stress. Coronary blood flow was increased by infusing adenosine (0.022 to 2.2 mg/min) through a 2.5F Doppler flow catheter positioned in the middle segment of the left anterior descending coronary artery in 8 patients with mild atherosclerosis but no flow-limiting stenosis and in 10 patients with entirely smooth coronary arteries. Quantitative angiography and coronary flow velocity were used to estimate shear stress in a proximal segment of the left anterior descending artery exposed to increased flow, but not to adenosine. The peak increase in blood flow was the same in smooth (371 +/- 65%) and irregular (377 +/- 50%) arteries. However, at peak flow, dilation was greater in smooth segments (16.3 +/- 2.7%) than in irregular segments (2.0 +/- 1.5%) (p less than 0.001). In each patient, smooth segments dilated with increasing shear stress (slope 7.4 +/- 0.9%), whereas irregular segments dilated less (slope 0.9 +/- 0.6%) and showed greater increases in shear stress (p less than 0.01). The peak increase in shear stress was less in smooth (189 +/- 23%) than in irregular (365 +/- 52%) segments (p less than 0.01). These results suggest a control mechanism in normal coronary arteries whereby increases in shear stress stimulate vasodilation and thus limit further increases in this force at the endothelial surface.(ABSTRACT TRUNCATED AT 250 WORDS)     

急性高血糖犬心表冠状动脉和心肌微血管的储备功能

应用血流仪和心肌对比超声心动图测量犬基础状态和高血糖状态冠状动脉前降支和心肌微血管的血流量,应用双嘧达莫后,前降支血流量和血流储备无明显变化,而心肌微血管的密度、血流量和血流储备明显下降。     

心血管病患者尸检中主动脉粥样硬化与冠状动脉粥样硬化程度的相关性分析

目的　了解心血管病患者的主动脉粥样硬化 (AAS)程度能否反映冠状动脉粥样硬化(CAS)程度。方法　在我院连续 30年尸检的 2 995例病例中 ,其中经临床诊断为高血压、冠心病或合并有糖尿病的患者 2 38例 ,男 185例 ,女 5 3例 ,年龄 4 3～ 97( 73 2± 9 9)岁 ,单纯患有原发性高血压的患者 70例 ,单纯患有冠心病的患者 81例 ,同时患有冠心病及高血压的患者 6 2例 ,同时患有冠心病、高血压及糖尿病三种疾病的患者 2 5例。将他们的尸检资料按以下标准分级 :AAS程度根据粥样硬化病变所占主动脉内膜面积的百分比并结合病变性质分为 0～Ⅳ级 ;CAS程度根据冠状动脉 3个主要分支中至少 1支的管腔狭窄程度分为 0～ 4级。所有病例资料经过分级评分后 ,进行AAS与CAS的相关分析 ,统计分析用SPSS 10 0 ,进行两因素直线相关分析及相关系数的显著性检验。结果　在2 38例尸检资料中 ,AAS与CAS程度呈显著正相关 (r =0 36 6 ,P <0 0 1) ,年龄分组 (≥ 6 5岁 ,<6 5岁组 )也显示AAS与CAS程度呈正相关 (分别为r =0 343,P <0 0 1;r =0 5 2 1,P <0 0 1) ;单纯高血压组 ,AAS与CAS程度呈显著正相关 (r =0 2 4 3,P <0 0 5 ) ;单纯冠心病组 ,AAS与CAS程度无显著相关 (r =0 0 72 ,P >0 0 5 ) ;高血压合并冠心病组 ,总体显示AA     

Evidence of pathological coronary flow patterns in patients with isolated coronary artery aneurysms

OBJECTIVES: Aim of our study was to evaluate the coronary flow patterns and therapeutic effects of nitroglycerin (NTG) in patients with isolated large coronary artery aneurysms (CA). CA are defined as nonobstructive lesions of the epicardial coronary arteries with a luminal dilation >or=two-fold of the normal diameters. The pathophysiology of a potential coronary insufficiency in this entity is still unknown. METHODS: A coronary sinus study with incremental atrial pacing before and after the administration of 0.2 mg NTG was performed in 19 patients with bilateral large fusiform nonstenotic CA to evaluate an exercise-induced myocardial ischemia. The average peak velocity in the aneurysmatic segment of the proximal left anterior descending artery was simultaneously measured by a 14/1000 inch Doppler flow wire. The coronary flow volumes and vascular resistances were calculated. RESULTS: Evidence of exercise-induced myocardial ischemia was found in all patients presenting with a frank cardiac lactate production (10.2+/-3.3%) which was significantly aggravated by NTG (26.0+/-7.5%, P<0.003). 0.2 mg NTG provoked a long-lasting and significant decrease in coronary flow volume (from 140.2+/-34.2 to 91.2+/-21.8 ml/min, P<0.002), a marked increase in coronary vascular resistance (from 0.62 to 0.92 mmHG x ml/min(-1), P<0.002) and an inadequate increase in coronary flow volume under cardiac pacing. CONCLUSION: CA were identified as an entity of nonobstructive ischemic coronary artery disease with an exercise-induced myocardial ischemia and impaired flow volume. NTG exerted an adverse vasoactive effect in CA.     

Transmural perfusion gradients distal to various degrees of coronary artery stenosis during resting flow or at maximal vasodilation

Summary Regional myocardial perfusion (assessed by 15 tracer microspheres) was determined at various levels of stenosis of the left circumflex coronary artery in anesthetized dogs. Measurements during control and at three levels of stenosis produced by a micrometer-driven mechanical occluder were made in each heart. No change was found in the transmural distribution of coronary blood flow until 93% stenosis. At levels above 93% stenosis there was a linear decrease in subendocardial perfusion with only minor changes in subepicardial perfusion. During maximal vasodilation produced by reactive hyperemia, the decrease in subendocardial flow was observed at levels greater than 60% stenosis. It is concluded that the subendocardium of the left ventricle has a large vasodilator reserve and severe stenoses are required to disrupt flow when autoregulation is intact. When autoregulation is abolished, reduction in subendocardial flow occurs at lesser degrees of stenosis.

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Transmurale Durchblutungsverteilung im stenoseabhängigen Myokard unter Ruhebedingungen und bei maximaler Koronardilatation

Zusammenfassung Die regionale Myokarddurchblutung, mit 15 microspheres gemessen, wurde bei unterschiedlichen Stenosegraden des R. circumflexus der linken Koronararterie bei narkotisierten Hunden gemessen. Die Messungen wurden in Kontrolle und bei 3 Stenosegraden (mit Mikrometerschraube angetriebene mechanische Drossel) ausgeführt. Die transmurale Durchblutungsverteilung blieb unverändert bis zu einer Stenose von 93%. Oberhalb dieses Wertes sank die subendokardiale Durchblutung linear, die subepikardiale Durchblutung änderte sich nur wenig. Bei maximaler Vasodilatation (reaktive Hyperämie) wurde die Abnahme der subendokardialen Durchblutung schon bei >60% Stenose festgestellt. Es wird daraus geschlossen, daß das Subendokard eine große Vasodilatationsreserve hat und daß erst hochgradige Stenosen, die Durchblutung bei intakter Autoregulation beeinflussen. Bei ausgeschalteter Autoregulation erfolgt die Verminderung der subendokardialen Perfusion schon bei geringeren Stenosegraden.

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With 3 figures and 4 tables

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This study was supported in part by grants from the U.S. Public Health Service HL 08311, the Wisconsin Heart Association and the Deborah Hospital Foundation.

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Dr.Gross is a recipient of a Pharmaceutical Manufacturers Association Foundation Faculty Development Award.     

Effects of insulin on coronary blood flow in anesthetized pigs

Insulin can influence the vasculature by a sympathetically mediated vasoconstriction and a vasodilatation; the latter effect predominates in the renal circulation of anesthetized pigs. We determined the effect of intravenous infusion of insulin on coronary blood flow in pentobarbitone-anesthetized pigs at constant heart rate, arterial pressure and blood levels of glucose and potassium. In 6 pigs, infusion of 0.004 IU kg(-1) min(-1) of insulin decreased coronary flow despite increasing left ventricular dP dT(max)(-1); when the latter was abolished by propranolol, the coronary flow response was augmented. The mechanisms of this response were examined in 22 pigs given propranolol. Phentolamine changed coronary flow response to an increase (6 pigs) and this was abolished by intracoronary injection of N(omega)-nitro-L-arginine methyl ester (L-NAME; 5 pigs). L-NAME augmented coronary flow response (6 pigs) and this was abolished by phentolamine (5 pigs). In 18 pigs given propranolol, three incremental doses of insulin caused graded coronary flow decreases whether L-NAME was given (6 pigs) or not (6 pigs) beforehand, and caused graded coronary flow increases after phentolamine (6 pigs). Thus insulin caused a coronary vasoconstriction mediated by sympathetic alpha-adrenergic effects and a vasodilatation related to the release of nitric oxide. The net effect was a coronary vasoconstriction.     

颈动脉粥样硬化与冠心病关系的研究

目的研究颈动脉粥样硬化与冠心病的关系。方法对301例冠状动脉造影的患者作双侧颈动脉超声检查，根据冠脉造影结果分为正常组及冠心病组，冠心病组根据冠状动脉病变支数再分为一支病变组，二支病变组，三支病变组3个亚组。测量颈总动脉后壁内中膜厚度(IMT)，斑块厚度，计算斑块积分及粥样斑块发生率。结果(1)冠心病组IMT，斑决积分及斑块发生率明显高于正常对照组(P＜0.01)。(2)随冠脉病变支数增加，斑块积分及IMT增加，亚组比较有显著性差异(P＜0.01)。(3)以IMT＞0.85mm和(或)出现粥样斑块预测冠心病，特异性75.3％，敏感性84.6％，阳性预测率88.4％。结论通过颈动脉超声检查可为冠心痛的诊断提供依据。     

颈动脉粥样硬化与冠心病关系的研究

目的:研究颈动脉粥样硬化与冠心病的关系。方法:对301例冠状动脉造影的患者作双侧颈动脉超声检查,根据冠脉造影结果分为正常组及冠心病组,冠心病组根据冠状动脉病变支数再分为一支病变组,二支病变组,三支病变组3个亚组。测量颈总动脉后壁内中膜厚度(IMT),斑块厚度,计算斑块积分及粥样斑块发生率。结果:(1)冠心病组IMT,斑块积分及斑块发生率明显高于正常对照组(P<0.01)。(2)随冠脉病变支数增加,斑块积分及IMT增加,亚组比较有显著性差异(P<0.01)。(3)以IMT>0.85mm和(或)出现粥样斑块预测冠心病,特异性75.3％,敏感性84.6％,阳性预测率88.4％。结论:通过颈动脉超声检查可为冠心病的诊断提供依据。     

Effects of atypical pneumonia agents on progression of atherosclerosis and acute coronary syndrome

BACKGROUND: The aim of this study was to investigate the presence of various atypical pneumonia agents (Chlamydia pneumoniae, cytomegalovirus, Mycoplasma pneumoniae), which are considered to have a role in the ethiopathogenesis of atherosclerosis, in aortic biopsies without macroscopically visible plaque and in internal thoracic artery biopsies. MATERIAL AND METHODS: Thirty-three patients (group 1), who had undergone coronary bypass operation and 10 non-atherosclerotic patients (group 2), were included in the study. Seventy-six tissue biopsies were taken. Biopsies from the patients in group 1 a were obtained from the atheroma plaque-free aortic tissue and 33 biopsies (group Ib) were obtained from their internal thoracic arteries. Following DNA extraction, nested PCR was used to detect Chlamydia pneumoniae DNA, and real time PCR was used to detect cytomegalovirus and Mycoplasma pneumoniae DNA. Blood parameters (lipid profile, CRP, fibrinogen) of the patients and operation characteristics were recorded. RESULTS: Chlamydia pneumoniae DNA was detected in 5 of 33 biopsy samples from coronary bypass patients, whereas none of the control patients (group 1b and group 2) were positive for this agent (P = 0.001). Neither CMV nor Mycoplasma pneumoniae was detected in IMA and aortic biopsies of both bypass and control patients. Elevated total cholesterol levels (P = 0.02) and positive CRP (P = 0.001) was found in C. pneumoniae positive patients. Prevalence of acute coronary syndrome was significantly higher in C. pneumoniae detected patients compared (P = 0.00 1). CONCLUSIONS: Detection of C. pneumoniae DNA in the atheroma free aortic biopsies might indicate that this micro-organism intervened in the progression of atheroma plaque. There was a strong relationship between the detection of this micro-organism in the aortic wall and acute coronary syndrome.The absence of DNA of the corresponding micro-organisms in the IMA wall may show its resistance to infective agents and in turn to atherosclerosis, which is a result of the prevailing endothelial functions of this artery.