Stress echocardiography for the detection and assessment of coronary artery disease

Stress echocardiography: An overview for use in pediatric and congenital cardiology

Currently, the role of stress echocardiography primarily resides in diagnosing acquired coronary artery disease (CAD) in adults. Besides an increasing concern for traditional CAD in young patients due to obesity and other chronic pediatric diseases, there is also a growing population of adolescents and young adults with "at risk" coronary arteries due to: reimplanted coronaries in congenital heart disease, anomalous origin of the native coronary arteries, coronary abnormalities in Kawasaki's disease, and posttransplant coronary vasculopathy. Stress echocardiography is well suited for routine screening and monitoring in these patients. Also, due to the ability of stress echocardiography to provide real-time cardiac imaging, it is useful in areas beyond coronary ischemia. Utilizing Doppler derived velocities and pressure gradients, one is able to further evaluate and risk-stratify patients with valvular heart disease. In addition, stress echocardiography is useful in evaluating other areas including ventricular and coronary reserve. The benefits of stress echocardiography are it is: readily available, portable, and relatively cheap. It can be performed without sedation or radiation exposure which becomes very important in younger patients that require periodic monitoring. Stress echocardiography can also evaluate functional abnormalities instead of relative perfusion defects. Overall, stress echocardiography is currently an underutilized imaging modality that has a wide, and expanding, range of application in the practice of pediatric and congenital cardiology.

Semi-supine exercise stress echocardiography in children and adolescents: feasibility and safety

Although exercise stress echocardiography (ESE) is a well-validated technique in adult population, its use in children is quite limited. We aimed to assess the feasibility, the safety and the reproducibility of ESE, using on-line scanning in semi-supine cyclo-ergometer protocol in a large pediatric population. Between July 2008 and January 2013, 42 patients (mean age 14 ± 3) were evaluated with a bicycle ESE performing 50 studies. ESE was successfully performed and well tolerated by all patients. None of the patients presented with adverse effects of stress-induced ischemia. HR was 82 ± 13 at rest, and 153 ± 19.1 during peak exercise. Among 544 views analyzed for grading of image quality, the visualization was optimal in 473 (87 %), suboptimal in 39, and inadequate in 32 (6 %). 37 tests were performed in patients with congenital or acquired coronary abnormality. Regional wall motion abnormalities (RWMA) were revealed in nine cases (24 %). The agreement between the two different observers showed a K index of 0.7276 (95 % CI 0.6497-0.8055) for the image quality and a K index of 0.5125 (95 % CI 0.4782-0.5468) for the RWMA analysis. Among ten patients with hypertrophic cardiomyopathy, we were able to demonstrate the new comparison of significant left ventricular outflow tract gradient (≥30 mmHg) during exercise in three patients (30 %). Bicycle stress echocardiography performed by on-line scanning during exercise is a feasible, safe, and reproducible modality in children. Further data to assess its diagnostic accuracy are, however, needed. Stress echocardiography provides a dynamic assessment of the myocardial structure and function under conditions of physiologic or pharmacologic stress.

[Diagnostic work-up of coronary artery disease: Clinical value of different imaging methods]

This continuing medical education (CME) article describes the different non-invasive imaging methods with the exception of positron emission tomography for ischemia and viability testing. While stress methods, such as myocardial scintigraphy, stress echo or stress magnetic resonance imaging can detect the functional relevance of coronary artery stenosis, multislice computed tomography allows the visualization of the coronary anatomy and potential stenoses. Recently developed hybrid imaging allows the coronary anatomy and simultaneous functional testing of ischemia to be depicted. The different imaging methods for ischemia and viability testing are described.