A case of acute myocardial infarction after blunt chest trauma in a young man

Coronary artery injury rarely occurs after blunt chest trauma, but it can lead to extensive myocardial infarction and be frequently overlooked. A 16-yr-old man was presented with comatose mental state and rapid respiration rate. He ran into guard rail while riding a motorcycle. In routine examination, his electrocardiogram showed Q wave and 2 mm ST segment elevation in all precordial leads, I and aVL. The cardiac enzymes were also elevated: creatine kinase (CK)-MB was 300 U/L, and cardiac specific troponin I was 5.7 ng/mL. Two-dimensional echocardiography showed anteroseptal akinesia with severely depressed left ventricular function, ejection fraction of 28%. He could not receive any anticoagulation or thrombolytic therapy because of his brain lesion. Three weeks later, his mental state improved. A diagnostic coronary angiogram revealed total occlusion in the proximal left anterior descending artery (LAD) with collaterals from the right coronary artery and left circumflex artery. We successfully performed a percutaneous coronary intervention for the LAD lesion, and the final angiogram showed a good coronary flow without residual stenosis.     

实时三维超声心动图左心室重构指数评价冠心病患者左心室重构的研究

目的探讨实时三维超声心动图（RT-3DE）测量左心室重构指数（LVRI）评价冠心病患者左心室重构的价值。方法根据冠状动脉造影结果,将病变组分为左旋支或/和右冠支病变组（LCX/RCA组）24例,其中男性18例,女性6例,年龄38～76岁,平均年龄54.2岁;单纯左前降支病变组（LAD组）21例,其中男性16例,女性5例,年龄35～78岁,平均年龄53.5岁;包含LAD病变的双支或多支病变组（多支组）27例,其中男性20例,女性7例,年龄39～80岁,平均年龄56.2岁;正常对照组22例,其中男性17例,女性5例,年龄32～79岁,平均年龄55.2岁。行RT-3DE,应用软件自动测量左心室舒张末期容积（LVEDV）、舒张末期心外膜容积（LVEDVepi）、左心室射血分数（LVEF）;再计算左心室质量[LVM=1.05×（LVEDVepi-LVEDV）]、LVRI（LVM/LVEDV）,并采用二维超声心动图（2DE）双平面Simpson测量并计算上述各值。比较RT-3DE和2DE测量LVRI在组间的差异、组内的差异和相关性,以及LVRI与LVEDV、LVEF的相关性;并比较观察者间及观察者内两种方法测量LVRI的一致性和重复性。结果正常对照组、LCX/RCA组、LAD组、多支组两种方法测量的LVRI呈显著递减（P〈0.05或P〈0.01）。前两组两种方法间的LVRI差异无统计学意义（P〉0.05）,后两组有统计学意义（P〈0.05或P〈0.01）。相关性分析表明：①除多支组内两种方法间的LVRI无显著相关性（P〉0.05）外,余3组内均呈显著相关性（P〈0.01）;②病变组同种方法测量的LVRI与LVEDV呈显著负相关性、LVEF呈显著正相关性（P〈0.01）,但正常组内无显著相关性（P〉0.05）。RT-3DE测量的LVRI观察者间及观察者内一致性和重复性较2DE好。结论来源于RT-3DE的LVRI优于2DE,更能作为临床评价冠心病患者左心室重构的指标。     

A chronic heart failure model by coronary artery ligation in the goat

The availability of a reliable heart failure model in large animals is important. We report upon our efforts to develop a chronic heart failure model in seven goats using sequential ligation of the left anterior descending (LAD) coronary artery and its diagonal branch. After anesthesia and left thoracotomy, the LAD artery was ligated, and the diagonal vessel at the same level was ligated one hour later. Cardiac measurements were performed with a thermodilution catheter and by ultrasonography. Two months after the operation, the same measurements were made and animals were sacrificed for postmortem examinations of their hearts. Hemodynamic measurements, except cardiac output, showed no significant changes immediately after the coronary artery ligation. Echocardiographic measurements showed significant changes in the ejection fraction and fractional shortening without changes in left ventricular dimensions. Wall motion analyses demonstrated variable degrees of anteroseptal dyskinesia and akinesia in all animals immediately after coronary artery ligation. Five animals have undergone hemodynamic and ultrasonographic studies 2 months after coronary artery ligation. The results obtained from these animals showed significant increases in central venous pressure, right ventricular pressure, pulmonary artery pressure, and pulmonary artery capillary wedge pressure, and a significant decrease in cardiac output. Increases in left ventricular dimensions and decreases in ejection fraction with fractional shortening in ultrasonographic studies were also observed. Pathologically, well-demarcated thin-walled anteroseptal infarcts, with chamber enlargement, were clearly seen with dilatation of the heart chambers in all specimens. Based on this study, we conclude that goats, like sheep, can provide a reliable model of chronic heart failure by coronary artery ligation and in view of the many advantages offered by goats, we believe that this animal model will be useful for cardiac experimentation.     

糖尿病合并冠状动脉狭窄患者左室造影前后左室舒张末压差值比较研究

目的 探讨糖尿病对合并冠状动脉狭窄患者左室造影前后舒张末压差值和左室功能的影响。方法 选择行冠状动脉造影及左室造影的患者834例，其中无冠脉病变的患者172例，冠状动脉狭窄的患者662例。根据其有无糖尿病，将之分为糖尿病合并冠状动脉狭窄组(DM组)110人，及单纯冠状动脉狭窄组(非DM组)552人，所有病人都进行左室造影，测定左室射血分数(EF)，造影前后左室舒张末压(D1、D2)。结果 DM组患者造影前后左室舒张末压的差值(D3)明显高于非DM组的患者，两组间的射血分数无明显差异，年龄增加、糖尿病、EF的降低，与造影前后左室舒张末压的差值呈负相关。结论 糖尿病合并冠状动脉狭窄患者可以在心脏的收缩功能发生异常之前，表现出对心脏舒张功能的损害，而造影前后，左室舒张末压的差值可以更为敏感地反映左室舒张功能的改变。     

Exercise thallium-201 scintigraphy in the localization of myocardial ischaemia

We performed a retrospective study in order to study the ability of thallium-201 exercise scintigraphy to detect and to localize coronary artery perfusion defects (in comparison with a recent coronary angiogram). We studied 81 patients (67 males); their average age was 52.3 years (men 50.5 and women 54.1 years). They performed a pulse-conducted cycle exercise test, and 2 min before end of exercise 75 MBq of thallium-201 was infused intravenously, and tomographic images were reconstructed by using a Siemens-Rota SPECT gamma camera immediately and 4 h after exercise. The thallium-201 uptake defects were attributed to different coronary arteries, and the results were compared with a coronary angiogram made afterwards in 48 patients. The groups of one-, two- and three-vessel disease were 27, 21, and 21 patients, and only 12 patients did not have significant (over 50%) stenoses. The latter had the highest ejection fraction and working capacity. Sensitivity of thallium-201 exercise scintigraphy was 65%, whereas that of exercise ECG was 41% in patients with a low ejection fraction, while in the whole material the sensitivity of thallium-201 scintigraphy was 91% and that of exercise ECG was 54%. A stenosis in the right coronary artery was best localized by the thallium-201 scintigram (86% correctly); a stenosis in the left anterior descending artery was localized correctly in 75% of the cases, but a stenosis in left circumflex artery was localized correctly only in 44%. We conclude that exercise thallium-201 scintigraphy is a useful method not only in detecting but also in localizing coronary artery disease.     

Rapid progression of nonculprit coronary lesions six weeks after successful primary PCI in culprit artery： a case report

We report a case of a 49-year-old man who was admitted with a 3-hour history of sudden onset of substemal chest pain. Coronary angiography revealed that the left circumflex artery （LCX） was acutely and totally occluded at the mid-portion. In addition, the proximal and mid-portion of the right coronary artery （RCA） had a 60% occlusion. We inferred that the LCX was the culprit artery and primary PCI was successfully performed. Six weeks later, the patient had an eventful course with recurrence of chest pain. Coronary angiography showed no significant ste- nosis in the previous LCX lesion, while the proximal and middle potion of the RCA had a 90% occlusion. Our case demonstrates the systemic nature of acute coronary syndromes and highlights the inherent instability of coronary artery disease.     

False lumen stent placement during iatrogenic coronary dissection

A 38-year-old woman without significant cardiovascular risk factors was admitted in the coronary care unit with the diagnosis of acute coronary syndrome without ST-segment elevation. In coronary angiography, left coronary artery system was normal in the first contrast injection, but acute occlusion of the left main coronary trunk (LCT) due to iatrogenic dissection was observed in the following. The patient presented marked ST elevation, severe hypotension, hemodynamic collapse, and loss of consciousness. Cardiopulmonary resuscitation (CPR) was initiated, and two drug-eluting stents were consecutively placed in the LCT and the left anterior descending coronary (LAD), but the patient died after 60 min of continuous CPR. The autopsy showed dissection of the LCT and LAD coronaries with both stents placed in the false lumen and hyperacute myocardial infarction in the anterior left ventricular free wall. This case underlines the importance of careful indication of invasive procedures and of taking in consideration their potential risks.     

非体外循环下冠状动脉旁路移植围术期血浆脑钠肽释放及其相关性研究

背景：B型脑钠肽已成为心血管疾病诊断重要的血清标志物,作为心血管疾病危险因素分层的重要因子。 目的：分析冠状动脉旁路移植前后B型脑钠肽与各项血流动力学参数的关系。 方法：选择30例冠心病行冠脉旁路移植患者,分为左室射血分数≥ 50%心功能正常患者13例;左室射血分数< 50%心功能不全患者17例。观察患者移植前1 d、移植后7 h、移植后1,3,5,7 d血浆B型脑钠肽水平变化趋势,分析移植前后B型脑钠肽与心功能各项指标的相关关系。 结果与结论：左室射血分数≥ 50%组患者冠脉旁路移植前后血浆B型脑钠肽水平显著低于左室射血分数< 50%组;组内比较移植后血浆B型脑钠肽水平均显著高于移植前(P < 0.05或P < 0.001)。患者冠脉旁路移植前B型脑钠肽水平与纽约心脏病协会心功能分级、左房内径、左室内径呈正相关(r=0.61;r=0．34;r=0．67);与左室射血分数、心排血量呈负相关(r=-0.75;r=-0.70)。患者移植后B型脑钠肽峰值浓度与出院前纽约心脏病协会心功能分级、超声心动图左室舒张末期内径、肺动脉压力呈正相关(r=0.72;r=0.70;r=0.45)。结果说明冠心病患者冠脉旁路移植前血浆B型脑钠肽质量浓度与左心室射血分数及左心室舒张末期内径有很好的相关性,能准确反映冠脉旁路移植前后的心功能状态。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Surgical Myocardial Revascularization of Patients with Ischemic Cardiomyopathy and Severe Left Ventricular Disfunction

OBJECTIVE:

To determine long-term survival, identify preoperative factors predictive of a favorable outcome, and assess functional improvement after coronary artery bypass grafting in patients with advanced left ventricular dysfunction.

METHODS:

Between 1995 and 2001, 244 patients who underwent coronary artery bypass grafting and had a preoperative left ventricular ejection fraction less than or equal to 35% were included. left ventricular ejection fraction was determined by uniplanar or biplanar ventriculography during left heart catheterization. Indication for surgery was predominance of tissue viability. Functional improvement was evaluated through echocardiography and gated scintigraphy at exercise/rest. Survival was determined by Kaplan-Meier analysis.

RESULTS:

Mean left ventricular ejection fraction was 29±4% (ranged from 9% to 35%). An average of 3.01 coronary bypass grafts per patient were performed. In-hospital mortality was 3.7% (9 patients). The 4-year survival rate was 89.7%. Multivariate correlates of favorable short- and long-term outcome were preoperative New York Heart Association Funcional classification for congestive heart failure class I/II, lower PAsP, higher left ventricular ejection fraction and gated left ventricular ejection fraction Ex/Rest ratio >5%. Left ventricular ejection fraction rise from 32±5% to 39±5%, p <0.001. Gated left ventricular ejection fraction at exercise/rest increased markedly after surgery: from 27±8%/23±7% to 37±5%/31±6%, p <0.001.

CONCLUSIONS:

In selected patients with severe ischemic left ventricular dysfunction and predominance of tissue viability, coronary artery bypass grafting may be capable of implement preoperative clinical/functional parameters in predicting outcome as left ventricular ejection fraction and gated left ventricular ejection fraction at exercise/rest.     

Depressed Systemic Arterial Compliance is Associated with the Severity of Heart Failure Symptoms in Moderate-to-Severe Aortic Stenosis: a Cross-Sectional Retrospective Study

Background: Patients with aortic stenosis (AS) may develop heart failure even in the absence of severe valve stenosis. Our aim was to assess the contribution of systemic arterial properties and the global left ventricular afterload to graded heart failure symptoms in AS.Methods: We retrospectively reviewed medical records of 157 consecutive subjects (mean age, 71±10 years; 79 women and 78 men) hospitalized owing to moderate-to-severe degenerative AS. Exclusion criteria included more than mild aortic insufficiency or disease of another valve, atrial fibrillation, coronary artery disease, severe respiratory disease or anemia. Heart failure symptoms were graded by NYHA class at admission. Systemic arterial compliance (SAC) and valvulo-arterial impedance (Zva) were derived from routine echocardiography and blood pressure.Results: Sixty-one patients were asymptomatic, 49 presented mild (NYHA II) and 47 moderate-to-severe (NYHA III-IV) heart failure symptoms. Mild symptoms were associated with lower SAC and transvalvular gradients, while more severe exercise intolerance coincided with older age, lower systolic blood pressure, smaller aortic valve area and depressed ejection fraction. By multiple ordinal logistic regression, the severity of heart failure symptoms was related to older age, depressed ejection fraction and lower SAC. Each decrease in SAC by 0.1 ml/m² per mmHg was associated with an increased adjusted odds ratio (OR) of a patient being in one higher category of heart failure symptoms graded as no symptoms, mild exercise intolerance and advanced exercise intolerance (OR: 1.16 [95% CI, 1.01-1.35], P=0.045).Conclusions: Depressed SAC may enhance exercise intolerance irrespective of stenosis severity or left ventricular systolic function in moderate-to-severe AS. This finding supports the importance of non-valvular factors for symptomatic status in AS.     

Left ventricular response to isometric exercise in aortic valve diseases and its value in the optimal timing of aortic valve replacement

In order to evaluate the left ventricular response to isometric exercise in different types of aortic valve disease, isometric exercise tests were performed during cardiac catheterization in 14 patients with pure aortic stenosis, 20 with combined aortic stenosis and regurgitation, and 18 with pure aortic regurgitation. Patients with angina pectoris in whom coronary angiography had not been performed were excluded. Thirty-seven patients were recatheterized 12 months after aortic valve replacement, and the ventricular response to exercise was re-evaluated. Preoperatively, the ejection fraction did not change significantly during exercise in patients with aortic stenosis, tended to decrease in patients with combined valve lesion, and decreased significantly in patients with aortic regurgitation (p less than 0.001). In the three patients whose ejection fraction during preoperative exercise decreased to below 0.40, it remained below 0.50 after successful aortic valve replacement. It appears possible to reveal left ventricular dysfunction in many patients with aortic regurgitation and in some with combined aortic valve disease by means of isometric exercise. The severely depressed ventricular dysfunction during exercise does not appear to correct totally after surgery.     

Improved global and regional left ventricular function after angioplasty for chronic coronary occlusion

Percutaneous transluminal coronary angioplasty can be performed safely and effectively in patients with chronic total coronary occlusion. To investigate the effect on left ventricular function, global and regional left ventricular ejection fraction were analyzed by contrast angiography in 49 patients before and 10±6 weeks after successful recanalization. Coronary angiography at follow-up showed reocclusion in 12 patients (24%). In 37 patients with patent arteries global ejection fraction increased from 55.8±7.1% at baseline to 62.5 ± 11.3% at follow-up (P < 0.001), and regional wall motion assessed by the centerline method improved from –1.7 + 1.0 to – 0.6 ± 1.5 standard deviations/chord (P<0.001). In contrast, in patients with reocclusion neither global ejection fraction nor regional wall motion were significantly different at follow-up compared with baseline. Changes in global or regional left ventricular function after coronary recanalization were unrelated to other parameters such as severity of angina, duration of occlusion, history of myocardial infarction, presence or absence of visible collaterals, or baseline left ventricular function. Thus in patients with primarily successful recanalization of chronically occluded coronary arteries persistent vessel patency is the major determinant of global and regional improvement of left ventricular function.Abbreviation PTCA percutaneous transluminal coronary angioplasty Correspondence to: W. Terres     

冠心病不同程度冠脉狭窄时红细胞变形性和心功能变化及其意义

对冠心病（ＣＨＤ）按冠脉主要分支狭窄程度不同分组，测定红细胞变形指数（ＤＩ）和心功能参数（ＥＦ、ＦＳ）。结果表明，ＣＨＤ二亚组ＤＩ、ＥＦ、ＦＳ显著低于对照组（Ｐ＜００１或００５），ＣＨＤ冠脉明显狭窄组ＤＩ及ＥＦ、ＦＳ显著低于轻度狭窄组（Ｐ＜００５）。提示ＤＩ、ＥＦ、ＦＳ可能对于区别ＣＨＤ有或无意义冠脉狭窄具有一定预示价值。     

冠状动脉内注入麦角新碱建立猪冠状动脉痉挛模型

目的探讨冠状动脉内注入麦角新碱构建猪冠状动脉痉挛模型及可能引起的心律失常事件。方法18只猪随机分成实验组（n=10）和对照组（n=8），麻醉后经右侧股动脉置入冠状动脉球囊导管至左前降支开1：3，实验组冠状动脉内注入麦角新碱0．3mg／kg，对照组注入等量的生理盐水。结果实验组均出现心电图胸导联ST段明显抬高，其中4例伴有严重室性心律失常，包括频发室性早搏2例、室性早搏合并非持续性室性心动过速1例、持续性室性心动过速合并心室扑动及颤动1例。冠状动脉造影提示血管痉挛致左前降支中远段血管明显狭窄8例、血管闭塞2例；对照组未见明显变化。结论冠状动脉内注入麦角新碱法可简单方便的建立猪冠状动脉痉挛模型。     

Exercise-induced ischemia in mildly symptomatic patients with coronary-artery disease and preserved left ventricular function. Identification of subgroups at risk of death during medical therapy

To determine prospectively whether the severity of reversible left ventricular ischemia provides prognostic information in mildly symptomatic patients with coronary-artery disease and preserved left ventricular function at rest (ejection fraction greater than 40 per cent), we studied 117 patients by means of exercise electrocardiography and radionuclide angiography. No patient had stenosis of the left main coronary artery. Mortality during subsequent medical therapy was significantly associated (by univariate life-table analysis) with three-vessel coronary-artery disease and the magnitude of the ejection fraction during exercise. In patients with three-vessel disease who had both ST-segment depression of 1 mm or more and a decrease in ejection fraction during exercise, in association with an exercise tolerance of 120 W or less, the probability of survival at four years was only 71 +/- 11 per cent (S.E.). All deaths occurred in this subgroup. Thus, objective evidence of left ventricular ischemia during exercise and exercise capacity identify one subgroup of minimally symptomatic patients with three-vessel disease with an excellent prognosis and another subgroup at relatively high risk of dying during subsequent medical therapy.     

血管内支架治疗鼻咽癌放疗后颈部血管狭窄或闭塞病变的效果

目的探讨血管内支架置入术治疗鼻咽癌放疗后的颈动脉狭窄或闭塞病变的疗效。方法对3例鼻咽癌患者放疗后出现严重动脉狭窄或闭塞病变的颈部血管行球囊成形术及支架置入术并进行随访。结果 3例患者均为男性,其中1例为双侧颈动脉闭塞,进行了一侧颈动脉闭塞病变再通术;1例为双侧颈动脉重度狭窄,进行了左侧颈动脉支架成形术;1例右颈内动脉起始段严重狭窄,左侧颈动脉闭塞,对右侧颈动脉严重狭窄处进行了血管内支架治疗;经过随访并未发现有支架内再狭窄。结论血管内支架置入术是治疗鼻咽癌放疗后颈部血管重度狭窄或闭塞病变的有效手段。     

High admission levels of γ-glutamyltransferase predict poor myocardial perfusion after primary percutaneous intervention

OBJECTIVE:

This retrospective study aimed to investigate the relationship between admission levels of serum γ-glutamyltransferase and poor myocardial perfusion after primary percutaneous coronary intervention in patients with acute myocardial infarction.

INTRODUCTION:

Reperfusion injury caused by free radical release and increased oxidative stress is responsible for the pathophysiology of the no-reflow phenomenon in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention. Serum γ-glutamyltransferase is an established marker of increased oxidative stress.

METHODS:

The study population consisted of 80 patients (64 men and 16 women, mean age = 67.5±6.6 years) with thrombolysis in myocardial infarction 0/1 flow pre-procedurally. The patients were divided into two groups according to thrombolysis in myocardial perfusion grades that were assessed immediately following primary percutaneous coronary intervention. The two groups (group 1 and group 2) each consisted of 40 patients with thrombolysis in myocardial perfusion grades 0-1 and thrombolysis in myocardial perfusion grades 2-3, respectively.

RESULTS:

Admission pain to balloon time, γ-glutamyltransferase and creatine kinase-MB isoenzyme levels of group 1 patients were significantly higher than those of group 2 patients. Pain to balloon time, γ-glutamyltransferase, peak creatine kinase-MB isoenzyme, low left ventricular ejection fraction and poor pre-procedural thrombolysis in myocardial infarction grade were significantly associated with poor myocardial perfusion by univariate analysis. However, only pain to balloon time and γ-glutamyltransferase levels showed a significant independent association with poor myocardial perfusion by backward logistic regression analysis. Adjusted odds ratios were calculated as 4.92 for pain to balloon time and 1.13 for γ-glutamyltransferase.

CONCLUSION:

High admission γ-glutamyltransferase levels are associated with poor myocardial perfusion in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention, particularly in patients with prolonged pain to balloon time.     

Theoretical estimation of cannulation methods for left ventricular assist device support as a bridge to recovery

Left ventricular assist device (LVAD) support under cannulation connected from the left atrium to the aorta (LA-AA) is used as a bridge to recovery in heart failure patients because it is non-invasive to ventricular muscle. However, it has serious problems, such as valve stenosis and blood thrombosis due to the low ejection fraction of the ventricle. We theoretically estimated the effect of the in-series cannulation, connected from ascending aorta to descending aorta (AA-DA), on ventricular unloading as an alternative to the LA-AA method. We developed a theoretical model of a LVAD-implanted cardiovascular system that included coronary circulation. Using this model, we compared hemodynamic responses according to various cannulation methods such as LA-AA, AA-DA, and a cannulation connected from the left ventricle to ascending aorta (LV-AA), under continuous and pulsatile LVAD supports. The AA-DA method provided 14% and 18% less left ventricular peak pressure than the LA-AA method under continuous and pulsatile LVAD conditions, respectively. The LA-AA method demonstrated higher coronary flow than AA-DA method. Therefore, the LA-AA method is more advantageous in increasing ventricular unloading whereas the AA-DA method is a better choice to increase coronary perfusion.     

Radionuclide ventriculography and hemodynamic evaluation by right heart catheterization with exercise for assessing the functional significance of coronary artery stenoses

Summary A series of 13 patients with significant coronary stenoses but without prior myocardial infarction were simultaneously studied by right heart catheterization and radionuclide ventriculography to determine the extent to which abnormal responses in left ventricular ejection fraction and wall motion to maximum exercise are paralleled by abnormal left ventricular filling pressures. The correlations of the filling pressure as evaluated by the diastolic pulmonary artery pressure with both the exercise ejection fraction and the rest-to-exercise change in ejection fraction were high (r=–0.89,P<0.01 andr=–0.76,P<0.01, respectively). In addition, the filling-pressure response to stress separated the patients into distinct radionuclide categories. All the 7 patients with grossly abnormal filling pressures (P30 mmHg) developed regional wall motion abnormalities with exercise as evaluated by visual interpretation or quantitative phase analysis. These patients also had a decrease in ejection fraction from rest to exercise ranging from –9% to –32% together with an exercise ejection fraction below 50%. Conversely, these abnormalities were never found in patients with filling pressures below this threshold level. The data suggest that radionuclide ventriculography and measurement of left ventricular filling pressure with exercise yield corresponding results when assessing the functional significance of coronary stenoses in normotensive patients without prior myocardial infarction and normal global left ventricular function at rest.     

Acute geometric changes of the mitral annulus after coronary occlusion: a real-time 3D echocardiographic study

We performed real-time 3D echocardiography in sixteen sheep to compare acute geometric changes in the mitral annulus after left anterior descending coronary artery (LAD, n=8) ligation and those after left circumflex coronary artery (LCX, n=8) ligation. The mitral regurgitation (MR) was quantified by regurgitant volume (RV) using the proximal isovelocity surface area method. The mitral annulus was reconstructed through the hinge points of the annulus traced on 9 rotational apical planes (angle increment=20 degrees). Mitral annular area (MAA) and the ratio of antero-posterior (AP) to commissure-commissure (CC) dimension of the annulus were calculated. Non-planar angle (NPA) representing non-planarity of the annulus was measured. After LCX occlusion, there were significant increases of the MAA during both early and late systole (p<0.01) with significant MR (RV: 30+/-14 mL), while there was neither a significant increase of MAA, nor a significant MR (RV: 4+/-5 mL) after LAD occlusion. AP/CC ratio (p<0.01) and NPA (p<0.01) also significantly increased after LCX occlusion during both early and late systole. The mitral annulus was significantly enlarged in the antero-posterior direction with significant decrease of non-planarity compared to LAD occlusion immediately after LCX occlusion.