Cost-effective applications of cardiac computed tomography in coronary artery disease

Computed tomography has been introduced as a noninvasive imaging modality used for coronary artery calcium scoring in asymptomatic individuals and contrast-enhanced coronary angiography in symptomatic individuals. As the rising costs of healthcare reflect, in part, the development of these types of new expensive technologies for cardiac diagnosis, the economic considerations that surround them should be of interest to clinicians and payers alike. In this review, we discuss basic principles underlying economic efficiency analyses of medical products, using computed tomography in coronary artery disease as a case in point.     

Functional assessment of coronary artery disease by cardiac computed tomography

Introduction: Rapid technological advances in computed tomography (CT) have allowed CT coronary angiography (CTCA) to be delivered at low radiation dose and high diagnostic accuracy. Due to its high negative predictive value for coronary artery disease, it has become a gatekeeper for the assessment of patients with chest pain of recent onset. Second line functional assessment of a detected coronary stenosis relies mostly on other imaging modalities. Functional assessment of coronary artery disease by CT is therefore an attractive addition to CTCA.

Areas covered: This review will discuss the current evidence base and future development for CT perfusion imaging. Furthermore, this review will discuss CT-derived fractional flow reserve and CT coronary plaque characteristics as alternative approaches for functional evaluation of coronary artery disease. Finally, combining coronary anatomy and functional assessment of coronary flow with myocardial tissue characterization by CT may be attractive allowing triple assessment by CT.

Expert commentary: The combined use of CTCA and functional assessment of coronary artery stenosis by CT perfusion or CT-derived fractional flow reserve is an attractive diagnostic pathway that requires further evaluation.     

冠心病左心室能量和能量效率与心脏功能之间的关系

目的：研究冠心病左心室能量（LVE）及能量效率（EE）与心力储备之间的关系。方法：根据心导管压力-容积势能理论建立心超声技术下LVE和EE的改良模型，采用心超声法与心导管法对比对70例冠心病人（按冠脉造影病变血管支数分3组和按NYHA心功能分级分4组）和28例正常人的LVE指标和射血分数（EF）进行对比研究，绘制不同NYHA分级的压力-容积环能量图。结果：超声法与导管法测得总能量（TE）、搏功（SW）、收缩末势能（ESE）、充盈能（FE）和EE均高度吻合及相关（r=0.80~0.91），随病变血管支数和心功能分级增加ESE、FE、TE逐渐递增、EE和EF逐渐降低，P-V环右上移位，EE在不同心功能分级异常的敏感性较EF显著增高（P<0.05）。结论：超声法LVE和EE评价冠心病人心力储备功能可靠易行，且较EF具有更大的优势。     

Association between changes in coronary artery circulation and cardiac venous retention: a lesson from cardiac computed tomography

To use computed tomography (CT) image data to measure a potential association between the implantation of coronary artery bypass grafts (CABG) and changes in the coronary venous system has not yet been examined. In 112 (aged 59.4 ± 9.0; 45F) patients (pts.), a 64-slice CT angiography was performed. Patients were divided into 2 groups: CABG (56 pts.) and control (56 pts.)—without changes in coronaries. In each case, ten multi-planar reconstructions (MPR) and 3D volume rendering reconstructions using a 2 mm layer with ECG-gating, helical pitch: 12.8; rotation time: 0.4 s and average tube voltage: 135 kV at 380 mA. The visualization of the coronary veins was independently graded by 2 experts trained in CT. In the CABG group, the average number of visible coronary veins was 5.3 ± 1.3, while in the control group it was 3.1 ± 1.1 (p < 0.001). Statistical differences were also observed for the following coronary veins: posterolateral (control 2.1 ± 1.9 vs. CABG 2.9 ± 1.9; p < 0.05), lateral (control 2.2 ± 1.7 vs. CABG 3.1 ± 1.3; p < 0.01) and anterolateral (control 0.5 ± 0.9 vs. CABG 1.3 ± 1.0; p < 0.001). Implantation of CABG influences the coronary venous system. In patients after CABG, the number of identifiable coronary veins is significantly higher as compared to that in subjects without changes in coronaries. This might suggest an association between changes in coronary artery circulation and cardiac venous retention.     

左心形态与冠状动脉狭窄程度的关系

目的 研究冠状动脉狭窄程度及分型与左心形态的关系.方法 对选择性冠状动脉造影的589例住院患者,去除风湿性心脏病、高血压性心脏病后,进行冠状动脉病变程度与左心形态及收缩功能关系的分析.并使用Spss 11.0统计软件分析包进行数据的R×C表卡方检验、均值的t检验(Independent-Sample T Test)、One-Way ANOVA方差分析和相关性分析(Bivariate Correlation).结果 冠状动脉病变积分、病变支数、病变分型与左房收缩末期内径(LADs)、左房舒张末期内径(LADd)、左室收缩末期内径(LVDs)、左室舒张末期内径(LVDd)呈正相关(P<0.01).冠状动脉造影阳性组中LADs、LADd、LVDs均值增高.而且冠状动脉病变支数越多及冠状动脉狭窄介入治疗的难度越高,LADs、LADd、LVDs、LVDd的均值升高越明显.结论 冠状动脉狭窄可引起心脏扩大,并随着狭窄程度的增高而加重.     

Impact of cardiac rehabilitation exercise program on left ventricular diastolic function in coronary artery disease: a pilot study

Diastolic dysfunction is common in coronary artery disease (CAD). Exercise-based cardiac rehabilitation (CR) improves survival and quality of life but its effect on diastolic function is unclear. We sought to determine the impact of CR on diastolic function. We conducted a prospective study of CAD patients referred for 3-month outpatient CR, with pre-CR and post-CR echocardiograms. Twenty-five outpatients (age [mean ± SD], 66 ± 11 years; 7 [28 %] women; 22 [88 %] with recent acute coronary syndrome) were recruited upon beginning CR; one patient lacking follow-up was excluded from analysis. Before CR, patients’ mean ejection fraction was 61 ± 7 %; regional wall motion score index was 1.18 ± 0.28; and left ventricular diastolic dysfunction existed in 21 (88 %). Of the 24 (96 %) patients with post-CR follow-up, 12 (50 %) had improved diastolic function, 2 of the 24 (8 %) had normal diastolic function throughout, nine (38 %) remained at the same grade, and one (4 %) had worsened diastolic function. The E/e′ ratio improved significantly after CR (11.9 ± 4.5 vs. 10.7 ± 4.5; P = .048). Fourteen patients with normal or improved diastolic function had a greater decrease in left atrial volume index (?4.2 ± 6.3 vs. 1.6 ± 6.3 mL/m²; P = .04) and a greater increase in peak untwisting rate (20 ± 36 vs. ?42 ± 45 °/s; P = .003) than did patients with no diastolic improvement. Three-month, exercise-based CR was associated with improved left ventricular diastolic function in half of our patients. Further large studies are needed to clarify the effect of CR on diastolic dysfunction in patients with CAD.     

Coronary computed tomography angiography investigation of the association between left main coronary artery bifurcation angle and risk factors of coronary artery disease

To explore the association between the left main coronary artery bifurcation angle and common atherosclerotic risk factors with regard to the development of coronary artery disease (CAD) using coronary computed tomography angiography (CCTA). A retrospective review of 196 CCTA cases (129 males, 67 females, mean age 58?±?10.5 years) was conducted. The bifurcation angle between the left anterior descending (LAD) and left circumflex (LCx) was measured on two-dimensional (2D) and three-dimensional (3D) reconstructed images and the type of plaque and degree of lumen stenosis was assessed to determine the disease severity. An association between bifurcation angle and patient risk factors [gender, body mass index (BMI), hypertension, cholesterol, diabetes, smoking and family history] of CAD was also assessed to demonstrate the relationship between these variables. The mean bifurcation angle between the LAD and LCx was 79.40°?±?22.97°, ranging from 35.5° to 178°. Gender and BMI were found to have significant associations with bifurcation angle. Males were at 2.07-fold greater risk of having a >80° bifurcation angle and developing CAD than females (P?=?0.003), and patients with high BMI (>25 kg/m²) were 2.54-fold more likely to have a >80° bifurcation angle than patients with a normal BMI (P?=?0.001) and thus were at greater risk of developing CAD. There is a direct relationship between the left main coronary artery bifurcation angle and patient gender and BMI. Measurement of the bifurcation angle should be incorporated into clinical practice to identify patients at high risk of developing CAD.     

冠状动脉病变程度与血清胆红素及左心功能的相关性研究

目的 探讨冠状动脉病变程度与血清胆红素水平及左心功能的关系.方法 对206例冠心病患者进行血生化、心脏彩超、冠状动脉造影等检查,采用Gemini评分将入选患者按积分由低到高分成4组.结果 总胆红素(TBIL)、左房内径(LAD)、左室内径(LVD)、左室射血分数(LVEF)在不同的组间差异均有统计学意义(P<0.05或P<0.01).Gensini积分与各变量间Spearman相关性比较:LAD(r=0.280,P=0.000)、LVD(r=0.176,P=0.011)与积分呈显著正相关,TBIL(r=-0.541,P=0.000)、LVEF(r=-0.222,P=0.001)与积分呈显著负相关.Gensini积分与各参数多元线性回归分析TBIL(P=0.000)、LVD(P=0.002)与积分呈独立相关.结论 TBIL、LVD与冠脉狭窄程度的积分呈独立相关,是Gemini积分的独立影响因子.LVEF与冠脉病变程度呈负相关,对冠心病的病变程度具有预测价值.     

64排螺旋CT检测冠状动脉病变与同型半胱氨酸水平的相关性研究

目的 探讨64排螺旋CT(MSCT)检测冠状动脉病变与同型半胱氨酸水平的相关性.方法 入选研究对象87例,均未接受叶酸和(或)维生素B12等治疗,分为急性冠状动脉综合征(ACS)组33例、稳定型心绞痛(SAP)组29例和正常对照组25例,均行冠状动脉MSCT成像检查,根据CT值进一步将ACS和SAP患者分为易损斑块组26例,混合斑块组19例,钙化斑块组17例;对所有研究对象检测血清同型半胱氨酸(Hcy)浓度.结果 3组间血清Hcy浓度按ACS组(16.44±5.48) μmol/L、SAP组(13.06±5.80) μmol/L、正常对照组(9.94±4.23) μmol/L顺序递减(均P＜0.01);易损斑块组和混合斑块组血清Hcy浓度均高于钙化斑块组,为(16.50±5.24) μmol/L、(15.51±6.24) μmol/L vs(11.63±5.21) μmol/L(均P＜0.01);ACS组与SAP组斑块构成比不同(x2=7.628,P＜0.05);ACS组易损斑块检出率(42.4％)高于SAP组(17.2％),ACS组钙化斑块检出率(18.2％)低于SAP组(48.3％)(均P＜0.05);斑块的不同性质与血清Hcy浓度间存在相关关系(rs=0.467,P＜0.01).结论 冠状动脉MSCT联合血清Hcy化验检查可作为诊断冠心病并预测其严重程度的无创方法在临床上得以应用.     

Complex coronary artery fistulas in adults: evaluation with multidetector computed tomography

Coronary artery fistulas (CAFs) are rare congenital or acquired abnormalities that have anomalous terminations of the coronary arteries. Although many patients with CAFs are asymptomatic, they can display various clinical features associated with ischemic heart disease or heart failure. Making an early diagnosis is important for the proper management and prevention of late symptoms and complications. Conventional coronary angiography and cardiac CT have been commonly performed to diagnose CAFs, but multi-detector computed tomography (MDCT) is now being widely applied for diagnosing cardiovascular anomalies, and the number of incidentally detected CAFs on MDCT has been increasing. Therefore, we have to be familiar with the image findings of CAFs, and especially the image findings of MDCT for making the correct diagnosis of CAFs. In this article, we illustrate the MDCT findings of various types of CAFs in adults and we review the pathophysiology and clinical features of CAFs.     

Prevalence of left main coronary artery disease among patients referred to multislice computed tomography coronary examinations

We have evaluated the prevalence of left main coronary artery disease (LMCAD) among patients referred to multislice computed tomography (MSCT) coronary angiography examinations. The study Group comprised of 1,000 consecutive patients (750 male and 250 female; mean age 53±12 years) who underwent successful 64-slice MSCT examinations. Left main coronary artery (LMCA) was classified into three Groups: normal LMCA; nonsignificant LMCAD with coronary plaques resulting in obstructions ≤50%; and significant LMCAD corresponding to obstructions >50%. We have found that 24 patients (2.4%) had significant LMCAD. Additional 200 patients (20%) had nonsignificant LMCAD. Univariate analysis revealed that LMCAD was associated with age, male gender, diabetes, hypertension, hyperlipidemia, typical symptoms, history of previous myocardial infarction and previous percutaneous coronary intervention. Only age and male gender were found as independent predictors for LMCAD in multivariate analysis (P < 0.001 and P = 0.001, respectively,). Angiographic follow-up was avaliable for the 24 patients with significant LMCAD, and conventional coronary angiography confirmed the presence of significant LMCAD in all of these patients. Significant LMCAD was found in 2.4% of the 1,000 patients referred to 64-slice MSCT examinations. Age and male gender were the independent predictors for LMCAD.     

Coronary artery fistula in a patient with coronary artery disease: evaluation by coronary angiography and multidetector computed tomography

A 54-year-old man with acute miyocardial infarction was successfully treated with coronary artery stenting. Coronary angiography is the preferred diagnostic method for imaging the coronary arteries, but coronary artery fistulas origin and course may not be apparent. New tomographic cardiovascular imaging tests such as, multidetector computed tomography (MDCT) can be used to precise delineation of coronary fistulas. An erratum to this article can be found at     

原发性高血压左室构型变化与冠心病的关系

目的:探讨原发性高血压左室构型变化与冠心病的关系。方法:原发性高血压同时合并冠心病患者176例,均经超声心动图及冠状动脉造影检查。结果:原发性高血压左室可发生不同构型变化,并且不同的左室构型其冠心病的并发率不同,其中左室向心性对称肥厚并发冠心病的发生率最高。结论:左室向心性对称肥厚是冠心病独立的危险因素之一。     

Relationship between ventricular dyssynchrony and T-wave alternans in patients with coronary artery disease

Introduction: Coronary artery disease (CAD) is associated with increased dispersion of repolarization and sudden cardiac death. We sought to investigate whether ventricular dyssynchrony is associated with proarrhythmic repolarization dispersion as measured by T‐wave alternans (TWA) in patients with CAD. Methods and Results: We evaluated 154 patients (67 ± 9 years, 123 men) with documented CAD, who underwent exercise treadmill testing and echocardiographic examination. TWA was analyzed continuously during treadmill testing in all standard precordial leads by time‐domain method. Tissue Doppler imaging was performed to measure inter‐ and intraventricular dyssynchrony. Increased TWA ≥ 60μV was observed in 42 (27%) patients. There was higher prevalence of females (31 vs 16%, P = 0.04) and greater body mass index (25.7 ± 2.6 vs 24.6 ± 3.0 kg/m², P = 0.04) in the TWA ≥ 60μV group of patients than the TWA < 60μV group. The index of interventricular dyssynchrony, Ts‐RL, was significantly increased (75.6 ± 37.8 vs 59.9 ± 35.9 ms, P = 0.03) but not intraventricular dyssynchrony (all P > 0.05) in patients with TWA ≥ 60 μV compared with those with TWA < 60 μV. In addition, a weak but significant positive correlation was observed between TWA and Ts‐RL (r = 0.25, P = 0.003). Multivariate analysis revealed that only Ts‐RL (odds ratio 1.02, 95% confidence interval 1.00–1.03, P = 0.013) was independent predictor for increased TWA. Conclusions: Our results demonstrated that interventricular dyssynchrony in patients with CAD is associated with increased TWA. This suggests that interventricular dyssynchrony may contribute to proarrhythmic repolarization dispersion. (PACE 2011; 34:1503–1510)