Tissue Doppler imaging in coronary artery diseases and heart failure

Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as coronary artery disease (CAD) and heart failure (HF). In these conditions, myocardial mitral annular systolic (S') and early diastolic (E') velocities have been shown to predict mortality or cardiovascular events. In heart failure non invasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/E') is a strong prognosticator, especially when E/E' is > or =15. Moreover, other parameters derived by TDI, as cardiac time intervals and Myocardial Performance Index, might play a role in the prognostic stratification in CAD and HF. Recently, a threedimensional (3-D) TDI imaging modality, triplane TDI, has become available, and this allows calculation of 3-Dvolumes and LV ejection fraction. We present a brief update of TDI.     

Tissue Doppler imaging for the pre-clinical diagnosis of cardiomyopathy.

This editorial refers to "Tissue Doppler imaging detects early asymptomaticmyocardial abnormalities in a dog model of Duchenne's cardiomyopathy"by V. Chetboul on page 1934 Duchenne muscular dystrophy is an important cause of cardiomyopathyin children and adolescents and is caused by mutations in thegene coding for the protein dystrophin [1]. Dystrophin participatesin linking the sarcomere to the sarcolemma and extracellularmatrix and plays a role in cell signalling [2]. The diseaseis characterised by skeletal and cardiac myopathies. Becauseit is inherited as an X-linked recessive disorder,     

Tissue Doppler echocardiographic evidence of atrial mechanical dysfunction in coronary artery disease

BACKGROUND: Atrial function is an integral part of cardiac function which is often neglected. The presence of coronary artery disease (CAD) may impair atrial function. This study investigated if atrial mechanical dysfunction was present in patients with CAD by tissue Doppler echocardiography (TDI). METHODS: Echocardiography with TDI was performed in 118 patients with CAD, and compared with 100 normal controls with comparable age and heart rate. Regional atrial function was assessed at the left (LA) and right (RA) atrial free wall and inter-atrial septum (IAS). The peak regional atrial contraction velocity of (V(A)) and the timing of mechanical events were compared. RESULTS: The V(A) in the LA (5.0+/-2.6 Vs 7.7+/-2.6 cm/s), IAS (4.8+/-1.7 Vs 5.7+/-1.5 cm/s) and RA (6.8+/-3.1 Vs 9.2+/-2.9 cm/s) were significantly decreased in patients with CAD when compared with controls (all p<0.001). Patients with impaired systolic function (ejection fraction50% (both p<0.001); and were lower in those with restrictive filling pattern (RFP) than non-RFP of diastolic dysfunction (both p<0.05). The V(A) in all the subgroups was lower than controls. In contrast, transmitral atrial velocity was unable to reveal any abnormality except in the subgroup with a RFP. The LA dimension, area and volume were increased in the disease groups, but were largely unchanged in the RA despite abnormal V(A). The physiological inter-atrial delay for the onset and peak atrial contraction between the RA and LA were unaffected by CAD. CONCLUSIONS: The atrial contractile function in both atria was impaired in the presence of CAD, especially in the LA. This was detected even in patients with preserved systolic function or mild diastolic dysfunction such as non-RFP. Direct assessment of atrial velocity by TDI may better reflect atrial mechanical function than transmitral atrial velocity.     

Environmental impact of cardiac imaging tests for the diagnosis of coronary artery disease

The use of cardiovascular imaging is growing inexorably and concerns have been expressed about its cost and radiation safety. In this study, the relative environmental impact of MRI, single photon emission tomography and cardiac ultrasound (echo) for the diagnosis of coronary artery disease were examined. The results emphasise that echo causes the least environmental impact at each stage of its life cycle. The effect of one echo on human health, ecosystem effects and resource use was of the order of 1-20% of those of the alternative methods. Although there are circumstances in which one imaging modality is preferred on clinical grounds, when everything else is equal, these results support the selection of echocardiography as the preferred test on environmental grounds.     

Tissue Doppler imaging in Fabry disease

PURPOSE OF REVIEW: The development of effective enzyme replacement/enhancement therapy makes of clinical relevance considering Fabry disease in the differential diagnosis of patients with hypertrophic cardiomyopathy. In particular the opportunity to significantly modify the clinical progression of the disease has reinforced the need for early diagnosis of Fabry cardiomyopathy. RECENT FINDINGS: The study with tissue Doppler of Fabry patients with endomyocardial biopsy-proven cardiac involvement showed a reduction of both diastolic and systolic myocardial velocities recorded at septal and lateral corners of mitral annulus. Tissue Doppler abnormalities were present not only in patients with left ventricular hypertrophy but also in younger patients with normal cardiac wall thickness and represent the first sign of myocardial damage. Furthermore tissue Doppler studies have been shown useful in detecting cardiac involvement in female carriers with no systemic manifestations of Fabry disease. In patients already submitted to enzyme-replacement therapy tissue Doppler and strain rate imaging represent useful noninvasive tools in assessing treatment efficacy. SUMMARY: Tissue Doppler imaging can provide early detection of cardiac involvement in Fabry disease and represents the most accurate and sensitive noninvasive tool for the diagnosis of myocardial dysfunction and for the assessment of cardiac improvement during enzyme replacement therapy. The detection of tissue Doppler abnormalities in female carriers may represent a hint for an invasive assessment of cardiac involvement.     

Tissue Doppler imaging (TDI) for on-line detection of regional early diastolic ventricular asynchrony in patients with coronary artery disease

Diastolic filling of the left ventricle is often impaired in patients with coronary artery disease (CAD) in the absence of systolic wall motion abnormalities or previous myocardial infarction. The current study was designed to assess the ability of tissue Doppler imaging (TDI) for on-line detection of regional diastolic wall motion abnormalities to identify CAD in patients with preserved systolic function. 20 normal subjects (age 51 ± 13years) and 17 CAD patients with normal systolic function and 70% luminal narrowing of the LAD (age 56 ± 11years) were included. Coronary anatomy was unknown to the echocardiographer. In the parasternal short axis and the apical 4-chamber-view, peak tissue velocities of the anterior/inferior and the midseptal/midlateral LV segments during rapid ejection (RE), isovolumic relaxation (IR), rapid filling (RF) and atrial contraction (AC) were analyzed by color-M-Mode-TDI. In the apical view, in 13 of 35 (37%) patients with adequate recordings, myocardial asynchrony was detected during IR: while the septum was moving inwards (red color-coding), the lateral wall was moving outwards (blue/green coding). In the remaining 22 patients (63%) a slow, synchronous outward motion of septum and lateral wall with homogeneous color-coding (blue/green) was seen. Unblinding of the coronary status revealed a critical LAD stenosis in all 13 patients (100%) with myocardial asynchrony. Analysis of midseptal peak velocities during IR revealed positive velocities (1.22 ± 1.64cm/s) in CAD patients and negative velocities (–1.39 ± 0.81cm/s) in normal subjects. Thus, TD1 allowed for the on-line detection of early diastolic asynchrony in 13 of 16 (82%) patients with critical LAD-narrowing. Due to the rapid assessment of regional wall motion abnormalities, TDI might help to identify CAD in patients with normal systolic function.     

Tissue factor and coronary artery disease

Plaque disruption with superimposed thrombosis is the main cause of acute coronary events such as acute myocardial infarction and unstable angina. Among other factors, tissue factor seems to play an important role determining plaque thrombogenicity. Tissue factor is a potent initiator of the coagulation cascade situated within the vessel wall and is highly exposed to the blood after plaque rupture. Several mediators involved in the process of atherosclerotic plaque formation are capable of inducing tissue factor expression in cells such as monocytes, macrophages and endothelial cells, which under normal conditions do not express tissue factor or to a limited extent only. The increased expression of tissue factor is not limited to the plaque but is also found in circulating monocytes in patients with acute coronary syndromes. In addition, studies have shown an important contribution of tissue factor in the pathogenesis of thrombosis and restenosis after balloon angioplasty. Recent basic studies focus on the therapeutic inhibition of tissue factor. Specific and non-specific inhibitors of tissue factor or the tissue factor/factor VIIa complex have been developed or identified, and have been tested in experimental studies. Clinical studies are currently being initiated. In this review, we present the current knowledge on the role of tissue factor in atherosclerosis, arterial intervention and potential pharmacological approaches, with focus on acute coronary syndromes.     

Combining myocardial perfusion imaging with computed tomography for diagnosis of coronary artery disease

PURPOSE OF REVIEW: To illustrate where the integration of computed tomography with myocardial perfusion single photon tomography may improve current diagnostic imaging paradigms and allow for enhanced risk stratification. RECENT FINDINGS: Computed tomography has the advantage of detecting coronary atherosclerosis at its earliest stages and also identifying patients at high risk for having underlying myocardial ischemia, allowing initiation of appropriate therapeutic measures well before development of obstructive coronary artery disease. Single photon computed tomography can, conversely, clarify the anatomic findings of computed tomography, based on a functional assessment of myocardial blood flow, thereby guiding antiischemic and interventional therapies. SUMMARY: Hybrid imaging with single photon tomography and computed tomography angiography may prove important from a diagnostic and therapeutic viewpoint in several clinical scenarios. It is likely that fusion imaging may more precisely tailor therapy, reduce healthcare costs and improve patient outcome over the next decade.     

Clinical application of echocardiographic imaging to diagnosis of coronary artery disease

Ergometer two-dimensional echocardiography was performed in 28 subjects complaining of chest pain but without myocardial infarction. Sequential ergometer loading was initiated at 50 or 75 watts, and increased in several stages. Apical four-chamber view two-dimensional echocardiograms were recorded onto video tape, and video images were converted into digital computer signals. After cine-loop display, computer image processing included noise reduction and edge enhancement, M-mode measurements were made at a designated level on the two-dimensional echo images. Wall motion was also analyzed directly from the two-dimensional echo images, using an auto-edge detection method. The derived data were compared with results from coronary angiograms. No echo abnormality was observed at rest, whereas during exercise wall motion was depressed at the diseased site of the angiogram; the amplitude of excursion and the changes in systolic and diastolic velocity were disturbed at the septum in LAD-involved patients, and in the posterolateral wall in both Cx and RCA patients. The imaging success rate using the computer-aided analysis was found to be 92.9%. Sensitivity for diagnosis of coronary artery disease was 82.1% and specificity 89.3%. Ergometer two-dimensional echocardiography with assisted computer image processing appears to be one of the most valuable tools for clinical real time evaluation of coronary artery disease.     

Doppler spectrum analysis and vascular imaging in the diagnosis of extracranial carotid artery disease

Ultrasound methods are well suited for the exploration of the carotid system. High resolution echography can visualize atheromatous defects on the vessels walls with a resolution better than one mm, whereas Doppler examination detects haemodynamic disturbances due to these plaques. Conventional Doppler examination can reveal moderate or severe stenosis (greater than 60%); the recent development of frequency analysis of the Doppler audio signal makes now possible the detection of very light haemodynamic disturbances due to low grade stenosis even as small as 15%. Spectral distribution abnormalities have been classified in four grades according to their amplitude. The combination of the morphological and functional data provided by echography and Doppler spectrum analysis has drastically increased the diagnostic possibilities of the ultrasound methods in the field of the extracranial vascular pathology. With a new duplex system which combines echography and C.W. Doppler examination (duplex probe) it is possible to detect, and quantify carotid stenosis (in percentage of the lumen reduction), and to evaluate blood flow volume in ml/mn.     

双源CT冠脉成像与冠脉造影诊断冠心病的对比研究

目的：评价双源CT（DSCT）冠状动脉成像与冠状动脉造影（CAG）在冠心病诊断中的价值。方法：对38例临床疑诊冠心病患者169支冠状动脉同时进行了DSCT冠状动脉成像和CAG检查,以CAG诊断冠心病为标准分析DSCT冠状动脉成像诊断冠心病的各项指标的表现。结果：DSCT冠状动脉成像判断冠脉中、重度狭窄（狭窄≥50％）的敏感度、特异度、准确度、阳性预测值、阴性预测值分别为93．75％（45／48）,99．17％（120／121）,97．63％（165／169）,97．83％（45／46）,97．56％（120／123）。DSCT冠状动脉成像与CAG对各支冠状动脉狭窄程度的显示具有较好的一致性（Kappa=0．921,P〈0．001）。两种检查方法在发现冠状动脉疾病方面无显著差异（P〉0．05）。结论：双源CT冠状动脉成像显示冠脉病变具有较高的敏感性和特异性,已成为冠心病诊断的一种可靠、无创的有效方法。     

Noninvasive imaging for the diagnosis of coronary artery disease: focusing the development of new diagnostic technology

BACKGROUND: New tests, such as magnetic resonance imaging (MRI) and electron-beam computed tomography (CT), are being developed for the diagnosis of coronary artery disease. OBJECTIVE: To determine the conditions that a new test must meet to be a cost-effective alternative to established imaging tests. DESIGN: Decision model and cost-effectiveness analysis. DATA SOURCES: Literature review and meta-analysis. TARGET POPULATION: 55-year-old men and 65-year-old women presenting with chest pain. TIME HORIZON: Lifetime of the patient. PERSPECTIVE: Health care policy. INTERVENTIONS: MRI, electron-beam CT, exercise echocardiography, exercise single-photon emission CT, and coronary angiography. OUTCOME MEASURES: Target sensitivity and specificity values for a new noninvasive test. RESULTS OF BASE-CASE ANALYSIS: Assuming that society is willing to pay $75000 per quality-adjusted life-year (QALY) gained, a new test that costs $1000 would need a sensitivity of 94% and a specificity of 90% to be cost-effective. RESULTS OF SENSITIVITY ANALYSIS: Assuming that society is willing to pay $50000 per QALY gained, a new test that costs $1000 or more would never be cost-effective. For a test that costs $500, the sensitivity and specificity must each be 95%. CONCLUSIONS: New imaging techniques, such as MRI and electron-beam CT, must be relatively inexpensive and have excellent sensitivity and specificity to be cost-effective compared with other techniques for the diagnosis of coronary artery disease. Similar analyses in other areas of health care may help to focus the development of new diagnostic technology.     

Tissue Doppler imaging for predicting outcome in patients with cardiovascular disease

PURPOSE OF REVIEW: Tissue Doppler imaging is being increasingly used for assessing global ventricular function in systole and diastole, and for quantifying regional wall motion abnormalities both in systolic heart failure with mechanical dyssynchrony and ischemic heart disease. Its use as a predictive tool is recent and the authors review publications relating to this aspect. RECENT FINDINGS: Peak early diastolic mitral annular velocity is a powerful predictor of outcome in a variety of cardiovascular conditions and adds incremental value to clinical parameters and standard mitral Doppler inflow velocities. Tissue Doppler imaging can also predict the development of hypertrophic cardiomyopathy in asymptomatic individuals carrying the genetic mutation even before the onset of overt left ventricular hypertrophy. In addition, the standard deviation of the time to peak systolic velocity is a good marker of mechanical asynchrony and can predict reverse remodeling. It may also be useful in identifying individuals with ischemic heart disease and regional wall motion abnormalities who have an adverse outcome. SUMMARY: Tissue Doppler imaging is a powerful new echocardiographic tool that is now becoming the standard for assessing ventricular function in a variety of situations and diseases.     

128层螺旋CT冠状动脉成像在冠心病诊断中的应用价值

目的评价128层螺旋CT(128-SCT)冠状动脉成像在冠心病诊断中的应用价值。方法入选临床诊断为冠心病并行128-SCT冠脉成像检查的患者60例,在128-SCT检查后的4周内行冠状动脉造影(CAG)检查。以CAG检查结果为金标准,以冠状动脉节段为单位,对比分析各节段128-SCT及CAG检查结果,评估128-SCT诊断冠状动脉狭窄程度的准确性,同时计算128-SCT诊断冠心病的敏感性、特异性、阳性预测值、阴性预测值、诊断指数、诊断符合率及Kappa值等统计学指标。结果共评估60例患者的715个冠状动脉节段,对比CAG的结果,128-SCT有664个节段检查结果与CAG相符合,符合率达92.87%。128-SCT诊断冠心病的灵敏度为79.05%,特异度为98.52%,阳性预测值为90.22%,阴性预测值为96.47%,诊断符合率为95.66%,Kappa值为0.818。结论 128-SCT冠状动脉成像检出冠心病准确性较好,可作为诊断与排除冠心病的无创性检查方法。