Overview of stress echocardiography: uses, advantages, and limitations

An improved contrastive learning network for semi-supervised multi-structure segmentation in echocardiography

Cardiac diseases have high mortality rates and are a significant threat to human health. Echocardiography is a commonly used imaging technique to diagnose cardiac diseases because of its portability, non-invasiveness and low cost. Precise segmentation of basic cardiac structures is crucial for cardiologists to efficiently diagnose cardiac diseases, but this task is challenging due to several reasons, such as: (1) low image contrast, (2) incomplete structures of cardiac, and (3) unclear border between the ventricle and the atrium in some echocardiographic images. In this paper, we applied contrastive learning strategy and proposed a semi-supervised method for echocardiographic images segmentation. This proposed method solved the above challenges effectively and made use of unlabeled data to achieve a great performance, which could help doctors improve the accuracy of CVD diagnosis and screening. We evaluated this method on a public dataset (CAMUS), achieving mean Dice Similarity Coefficient (DSC) of 0.898, 0.911, 0.916 with 1/4, 1/2 and full labeled data on two-chamber (2CH) echocardiography images, and of 0.903, 0.921, 0.928 with 1/4, 1/2 and full labeled data on four-chamber (4CH) echocardiography images. Compared with other existing methods, the proposed method had fewer parameters and better performance. The code and models are available at https://github.com/gpgzy/CL-Cardiac-segmentation.

Automated diagnosis of cardiovascular diseases from cardiac magnetic resonance imaging using deep learning models: A review

In recent years, cardiovascular diseases (CVDs) have become one of the leading causes of mortality globally. At early stages, CVDs appear with minor symptoms and progressively get worse. The majority of people experience symptoms such as exhaustion, shortness of breath, ankle swelling, fluid retention, and other symptoms when starting CVD. Coronary artery disease (CAD), arrhythmia, cardiomyopathy, congenital heart defect (CHD), mitral regurgitation, and angina are the most common CVDs. Clinical methods such as blood tests, electrocardiography (ECG) signals, and medical imaging are the most effective methods used for the detection of CVDs. Among the diagnostic methods, cardiac magnetic resonance imaging (CMRI) is increasingly used to diagnose, monitor the disease, plan treatment and predict CVDs. Coupled with all the advantages of CMR data, CVDs diagnosis is challenging for physicians as each scan has many slices of data, and the contrast of it might be low. To address these issues, deep learning (DL) techniques have been employed in the diagnosis of CVDs using CMR data, and much research is currently being conducted in this field. This review provides an overview of the studies performed in CVDs detection using CMR images and DL techniques. The introduction section examined CVDs types, diagnostic methods, and the most important medical imaging techniques. The following presents research to detect CVDs using CMR images and the most significant DL methods. Another section discussed the challenges in diagnosing CVDs from CMRI data. Next, the discussion section discusses the results of this review, and future work in CVDs diagnosis from CMR images and DL techniques are outlined. Finally, the most important findings of this study are presented in the conclusion section.

Dobutamine Stress Echocardiography Safety in Chagas Disease Patients

BACKGROUND:

A few decades ago, patients with Chagas disease were predominantly rural workers, with a low risk profile for obstructive coronary artery disease (CAD). As urbanization has increased, they became exposed to the same risk factors for CAD of uninfected individuals. Dobutamine stress echocardiography (DSE) has proven to be an important tool in CAD diagnosis. Despite being a potentially arrhythmogenic method, it is safe for coronary patients without Chagas disease. For Chagas disease patients, however, the indication of DSE in clinical practice is uncertain, because of the arrhythmogenic potential of that heart disease.

OBJECTIVES:

To assess DSE safety in Chagas disease patients with clinical suspicion of CAD, as well as the incidence of arrhythmias and adverse events during the exam.

METHODS:

Retrospective analysis of a database of patients referred for DSE from May/2012 to February/2015. This study assessed 205 consecutive patients with Chagas disease suspected of having CAD. All of them had their serology for Chagas disease confirmed.

RESULTS:

Their mean age was 64±10 years and most patients were females (65.4%). No patient had significant adverse events, such as acute myocardial infarction, ventricular fibrillation, asystole, stroke, cardiac rupture and death. Regarding arrhythmias, ventricular extrasystoles occurred in 48% of patients, and non-sustained ventricular tachycardia in 7.3%.

CONCLUSION:

DSE proved to be safe in this population of Chagas disease patients, in which no potentially life-threatening outcome was found.

FUNDAMENTO:

Até poucas décadas atrás, os pacientes chagásicos eram predominantemente trabalhadores rurais, com baixo perfil de risco para doença obstrutiva coronária. Com a crescente urbanização, passaram a ter os mesmos fatores de risco para doença aterosclerótica que indivíduos não infectados. O ecocardiograma sob estresse com dobutamina (EED) é uma importante ferramenta no diagnóstico de coronariopatia. É referido, porém, como um método potencialmente arritmogênico, mas seguro, em pacientes coronarianos não chagásicos. Entretanto, há insegurança na prática clínica de indicá-lo no paciente chagásico, devido ao potencial arritmogênico já intrínseco nesta cardiopatia.

OBJETIVOS:

Analisar a segurança do EED em uma população de chagásicos com suspeita clínica de coronariopatia.

MÉTODOS:

Análise retrospectiva de um banco de dados de pacientes encaminhados para a realização do EED entre maio/2012 e fevereiro/2015. Avaliou-se pacientes consecutivos portadores de doença de Chagas e com suspeita de coronariopatia. Confirmou-se a sorologia para doença de Chagas em todos os pacientes.

RESULTADOS:

A média etária dos 205 pacientes analisados foi de 64 ± 10 anos, sendo a maioria do sexo feminino (65,4%). Nenhum paciente apresentou eventos adversos significativos, como infarto agudo do miocárdio, fibrilação ventricular, assistolia, acidente vascular encefálico, ruptura cardíaca ou morte. Quanto às arritmias, extrassístoles ventriculares frequentes ocorreram em 48% dos pacientes, taquicardia ventricular não sustentada em 7,3%, bigeminismo em 4,4%, taquicardia supraventricular e taquicardia ventricular sustentada em 1% e fibrilação atrial em 0,5%.

CONCLUSÃO:

O EED mostrou ser um exame seguro nessa população de pacientes chagásicos, onde nenhum desfecho grave foi encontrado.

Prognostic utility of cardiovascular magnetic resonance upright maximal treadmill exercise testing

BACKGROUND

Left ventricular wall motion abnormalities (LVWMA) observed during cardiovascular magnetic resonance (CMR) pharmacologic stress testing can be used to determine cardiac prognosis, but currently, information regarding the prognostic utility of upright maximal treadmill induced LVWMA is unknown. Our objective was to determine the prognostic utility of upright maximal treadmill exercise stress CMR.

METHODS

One hundred and fifteen (115) men and women with known or suspected coronary arteriosclerosis and an appropriate indication for cardiovascular (CV) imaging to supplement ST segment stress testing underwent an upright treadmill exercise CMR stress test in which LVWMA were identified before and immediately after exercise. Personnel blinded to results determined the post-test incidence of cardiac events (cardiac death, myocardial infarctions [MI], and unstable angina warranting hospital admission or coronary arterial revascularization).

RESULTS

All participants completed the testing protocol, with 90% completing image acquisition within 60 s of exercise cessation. MI or cardiac death occurred in 3% of individuals without and 17% of individuals with inducible LVWMA (p = 0.024). The combination of MI, cardiac death, and unstable angina warranting hospitalization occurred in 14% of individuals without and 47% of individuals with inducible LVWMA (p = 0.002). The addition of CMR imaging identified those at risk for future events (p = 0.002), as opposed to the electrocardiogram stress test alone (p = 0.63).

CONCLUSIONS

In patients with or suspected of coronary arteriosclerosis and appropriate indication for imaging to supplement ST segment analysis during upright treadmill exercise, the presence of inducible LVWMA during treadmill exercise stress CMR supplements ST segment monitoring and helps identify those at risk of the future combined endpoints of myocardial infarction, cardiac death, and unstable angina warranting hospitalization.

[Biphasic reaction to dobutamine stress echocardiography as a predictor of coronary artery spasm: Apropos of 3 cases]

Dobutamine-related coronary spasm is a possible complication of dobutamine stress echocardiography potentially explaining a part of some erroneously labeled "false positive tests". Presently, there are no established echographic predictors of coronary spasm. We report 3 clinical cases in which dobutamine-induced spasm was strongly suspected on the basis of a biphasic reaction including an initial deterioration rapidly followed by a spontaneous recovery in well-defined echocardiographic territory. In all three cases, we were able to confirm spasm of angiography. The biphasic reaction may constitute a potential predictor of spasm in patients with positive dobutamine stress tests.

Prognostic value of PET myocardial perfusion imaging in obese patients

OBJECTIVES

This study sought to determine and compare the prognostic and incremental value of positron emission tomography (PET) in normal, overweight, and obese patients.

BACKGROUND

Cardiac rubidium 82 (Rb-82) PET is increasingly being used for myocardial perfusion imaging (MPI). A strength of PET is its accurate attenuation correction, thereby potentially improving its diagnostic accuracy in obese patients. The prognostic value of PET in obese patients has not been well studied.

METHODS

A total of 7,061 patients who had undergone Rb-82 PET MPI were entered into a multicenter observational registry. All patients underwent pharmacologic Rb-82 PET and were followed for cardiac death and all-cause mortality. Based on body mass index (BMI), patients were categorized as normal (<25 kg/m(2)), overweight (25 to 29.9 kg/m(2)), or obese (≥30 kg/m(2)). Using a 17-segment model and 5-point scoring system, the percentage of abnormal myocardium was calculated for stress and rest patients categorized as normal (0%), mild (0.1% to 9.9%), moderate (10% to 19.9%), and severe (≥20%).

RESULTS

A total of 6,037 patients were followed for cardiac death (median: 2.2 years) and the mean BMI was 30.5 ± 7.4 kg/m(2). A total of 169 cardiac deaths were observed. PET MPI demonstrated independent and incremental prognostic value over BMI. Normal PET MPI conferred an excellent prognosis with very low annual cardiac death rates in normal (0.38%), overweight (0.43%), and obese (0.15%) patients. As well, both moderately and severe obese patients with a normal PET MPI had excellent prognosis (0.20% and 0.10%, respectively). The net reclassification improvement of PET was 0.46 (95% confidence interval [CI]: 0.31 to 0.61), and appeared similar in the moderately and severe obese patients which were 0.44 (95% CI: 0.12 to 0.76) and 0.63 (95% CI: 0.27 to 0.98), respectively.

CONCLUSIONS

Rb-82 PET has incremental prognostic value in all patients irrespective of BMI. In the obese population, where other modalities may have reduced diagnostic accuracy, cardiac PET appears to be a promising noninvasive modality with prognostic value.

Prognostic value of normal stress echocardiography in obese patients

BACKGROUND

Chest pain is a common problem in obese patients. Because of the body habitus, the results of noninvasive evaluation for CAD may be limited in this group.

METHODS

We reviewed the records of 1446 consecutive patients who had undergone clinically indicated stress echocardiography (SE). We compared major adverse cardiac events (MACE; myocardial infarction, cardiac intervention, cardiac death, subsequent hospitalization for cardiac events, and emergency department visits) at 1 year in normal weight, overweight, and obese subjects with normal SE.

RESULTS

Excluding patients with an abnormal and indeterminate SE and those who were lost to follow-up, a retrospective analysis of 704 patients was performed. There were 366 obese patients (BMI ≥ 30), 196 overweight patients (BMI 25-29.9), and 142 patients with normal BMI (18.5-24.9). There was no MACE in the groups at 1-year follow-up after a normal SE.

CONCLUSIONS

In obese patients including those with multiple risk factors and symptoms concerning for cardiac ischemia, stress echocardiography is an effective and reliable noninvasive tool for identifying those with a low 1-year risk of cardiac events.

[Coronary artery spasm during dobutamine stress echocardiography: prevalence, clinical and echocardiographic characteristics and prognosis]

OBJECTIVES

To assess the prevalence of coronary artery spasm during dobutamine stress chocardiography (DSE), to describe clinical and echocardiographic characteristics and prognosis.

PATIENTS AND METHODS

We evaluated all the patients with known or suspected coronary artery disease (CAD) referred to our echocardiography laboratory for dobutamine stress test between January 2004 and June 2012, (10013 exams). Those with abnormal DSE underwent coronary angiograms with a systematic methylergometrine intracoronary injection in case of absence of significant coronary stenosis or spontaneous occlusive coronary spasm. Patients who had spontaneous occlusive coronary spasm or positive methylergometrine test but no significant stenoses were included.

RESULTS

One thousand and four patients had abnormal DSE, 78 (7.7%) fulfilled the inclusion criteria. There were 57 males and 21 females, mean age was 57.9 years, 37 patients had a known history of CAD. Twenty-four patients had a spasm on the left anterior artery (31%), 37 on the right coronary artery (47%) and 17 on the circumflex (22%). There was a good correlation between spastic arteries and dobutamine induced wall motion abnormalities territories. No complications occurred during the exams or during the provocation test. After 46 months mean follow up; one case of myocardial infarction with normal coronary arteries was noted and six patients experienced recurrent angina responding to treatment intensification.

CONCLUSION

Coronary artery spasm during DSE but is a rare and under-diagnosed finding; it has, though, to be recognized as it may partly explain some erroneously labelled "false positive" exams. Methylergometrine provocation test should be performed in such a situation to establish the diagnosis. Prognosis appears favourable.

Stress echocardiography vs nuclear stress imaging in clinical cardiology

Stress echocardiography and nuclear stress imaging are important non-invasive tools in clinical cardiology. This review discusses the uses, strengths and limitations of these imaging modalities and looks at whether stress echocardiography can actually replace nuclear stress imaging.

Coronary artery spasm and dobutamine stress echocardiography

AIMS

The aim of this article was to assess whether abnormal dobutamine stress echocardiography (DSE) can be due to a dobutamine-induced coronary spasm in patients with angiographically documented vasospastic coronary arteries.

METHODS AND RESULTS

Between January 2004 and April 2008, we prospectively evaluated all patients with known or suspected coronary artery disease (CAD) referred to the echocardiography laboratory for dobutamine stress tests (6061 examinations). Those with abnormal DSE underwent coronary angiogram with a systematic methylergometrine intracoronary injection in the case of absence of significant coronary stenosis or spontaneous occlusive coronary spasm. Patients who had spontaneous occlusive coronary spasm or positive methylergometrine test, but no significant stenoses, were ultimately included in this study. About 581 patients had abnormal DSE, among them only 20 (3.4%) fulfilled the inclusion criteria. There were 15 males and 5 females, and mean age was 64.35 years (range 52-85); 8 patients had a known history of CAD and all of them had at least two established cardiovascular risk factors. The culprit vessel was the left anterior descending artery in 10 cases (50%), right coronary artery in 8 cases (40%), and left circumflex in 2 cases (10%). There was a systematic correspondence between the culprit arteries and dobutamine-induced wall motion abnormality territories. No complications occurred during examination or during the provocation test. All the patients were discharged with a calcium channel blocker and were doing well after 13 months of mean follow-up.

CONCLUSION

Coronary artery spasm can be induced at DSE, but is a rare finding; it could, though, be clinically relevant as it may partly explain some erroneously labelled 'false-positive' examinations. Methylergometrine provocation test is a safe and advisable approach in such situations.

Why to screen heart disease in diabetes

The expanding diabetic epidemic and the high risk of cardiovascular events in diabetic patients suggest that screening heart disease in this population is an important issue. Nonetheless, the advisability of large-scale screening in asymptomatic individuals with diabetes is debated, because available techniques are expensive and have suboptimal diagnostic accuracy. Moreover, all diabetic patients should be treated aggressively as if they all had a positive screening test, because diabetes could be considered a coronary risk equivalent. In this article, we underline the importance of an early diagnosis of coronary artery disease and heart failure in diabetic patients, suggesting that positive screening tests have significant implications in clinical management.

Nuclear Cardiology: Present and Future

Nuclear cardiology has made significant advances since the first reports of planar scintigraphy for the evaluation of left ventricular perfusion and function. While the current "state of the art" of gated myocardial perfusion single-photon emission computed tomographic (SPECT) imaging offers invaluable diagnostic and prognostic information for the evaluation of patients with suspected or known coronary artery disease (CAD), advances in the cellular and molecular biology of the cardiovascular system have helped to usher in a new modality in nuclear cardiology, namely, molecular imaging. In this review, we will discuss the current state of the art in nuclear cardiology, which includes SPECT and positron emission tomographic evaluation of myocardial perfusion, evaluation of left ventricular function by gated myocardial perfusion SPECT and gated blood pool SPECT, and the evaluation of myocardial viability with PET and SPECT methods. In addition, we will discuss the future of nuclear cardiology and the role that molecular imaging will play in the early detection of CAD at the level of the vulnerable plaque, the evaluation of cardiac remodeling, and monitoring of important new therapies including gene therapy and stem cell therapy.

The potential of myocardial perfusion scintigraphy for risk stratification of asymptomatic patients with type 2 diabetes

Patients with diabetes, in particular patients with type 2 diabetes, are at a 2- to 4-fold higher risk of cardiovascular mortality compared with their nondiabetic peers. Patients with diabetes are also more likely to have silent ischemia and less likely to survive a myocardial infarction than nondiabetic patients. Recent studies with electron beam computed tomography (EBCT) have shown that subclinical atherosclerosis is common in patients with diabetes, and studies with myocardial perfusion scintigraphy (with single-photon emission computed tomography) or stress echocardiography have demonstrated that between 25% and 50% of asymptomatic diabetic patients have ischemia during exercise or pharmacological stress and that a substantial proportion of these patients go on to develop major cardiovascular events within several years. Clearly, asymptomatic diabetic patients include a subset of individuals at high risk of cardiovascular disease who would benefit from improved risk stratification beyond that possible with risk factor scoring systems alone. Single-photon emission computed tomography, stress echocardiography, and possibly EBCT or multi-slice computed tomography, are emerging as valuable diagnostic tools for identifying asymptomatic diabetic patients who might require early and aggressive intervention to manage their cardiovascular risk.

Emergency cardiac imaging: state of the art

Multiple strategies and testing modalities are available to evaluate patients presenting to the emergency department with cardiac complaints. Many provide anatomic and prognostic information about coronary stenosis and long-term out-comes. Although nuclear and stress echo imaging have the ability to predict outcomes in patients in the emergency department population, the newer modalities of cardiac imaging (EBCT, MDCT,and CMR) continue to show promising results and may soon be incorporated into emergency department chest pain centers. Protocols can be developed within an institution to meet the needs of the patient population while minimizing risk and improving outcomes for all patients.

Noninvasive assessment of coronary artery disease in diabetic patients: The role of stress echocardiography

Diabetes mellitus is a frequently occurring disease, and its prognosis is essentially related to cardiac complications. Some have suggested that these patients should be considered as coronary artery disease (CAD)-equivalent and treated aggressively, accordingly. In addition, CAD in diabetes patients at the time of diagnosis is often more advanced, and is frequently associated with more extensive disease, a greater incidence of left ventricular dysfunction and higher rates of cardiac events. Unfortunately, the standard exercise treadmill stress test has important limitations, with a poor sensitivity for CAD detection if the patient has limited exercise capacity, which is the case for more than one-half of the diabetic patients in some series. The detection of regional wall motion abnormality with echocardiography permits the identification of the coronary territory involved. It can be used for CAD diagnosis, evaluation of myocardial viability, risk stratification following a myocardial infarction and assessment of preoperative risk before noncardiac surgery. The risk of CAD in patients with diabetes mellitus is reviewed, and the role of noninvasive testing with stress echocardiography in the diagnosis and risk stratification of these patients is discussed.

Feasibility to detect severe coronary artery stenoses with upright treadmill exercise magnetic resonance imaging

We performed treadmill exercise magnetic resonance imaging in 27 patients with exertional chest pain who were referred for contrast coronary angiography to determine the feasibility of this method to identify severe coronary artery stenoses. The sensitivity and specificity for detecting >70% coronary artery luminal diameter narrowings on contrast coronary angiography were 79% and 85%, respectively.

Cardiac catheterization in morbidly obese patients

The safety and findings of cardiac catheterization and coronary angiography in morbidly obese patients with suspected coronary heart disease (CHD) have not been fully examined in the modern era. From a database of 4,978 patients undergoing diagnostic cardiac catheterization, we identified 110 with morbid obesity (body mass > or = 145 kg and body mass index > or = 40 kg/m(2)). Relative to all the other patients in this database, morbidly obese patients had a lower prevalence of CHD (45% vs. 72%; P < 0.05), reflecting a higher prevalence of false positive noninvasive tests. Overall, noninvasive tests were only 75% sensitive and 39% specific for CHD in this group. Use of radial access (66%) and femoral closure devices (24%) was much more frequent in the morbidly obese cohort. Complications were no more frequent in the morbidly obese group, with major (0 vs. 0.9%) and minor (4.7% vs. 3.5%) adverse outcomes being similar to the rest of the database. We conclude that cardiac catheterization using the radial artery or a femoral closure device is a safe and effective method of evaluating CHD in morbidly obese patients. In contrast, noninvasive testing is frequently not definitive and may be misleading.

Stress radionuclide imaging versus stress echocardiography: a framework for comparisons

Comparisons of stress-imaging procedures require analyses based on their 2 principal applications: diagnostic and prognostic assessments. Besides comparing results reported in the literature--in which differences have been reported in the ability of stress nuclear versus stress echocardiographic imaging to predict a low risk of cardiac events-other factors often not reported may be important in discerning the relative efficacy of these tests. These include consideration of how these tests perform in specific, individualized patient scenarios; the effect of on-going technical advances on test usefulness; and evaluation of test worthiness according to such factors as cost-effectiveness and the magnitude of incremental test information that is provided. Furthermore, it is important to distinguish between a test's efficacy (ie, its intrinsic accuracy) and its effectiveness (ie, how it performs in the real world of clinical practice).