The role of transoesophageal echocardiography in adolescents and adults with congenital heart defects

Computed tomography of the coronary arteries in diagnosis

IMPORTANCE OF THE FIELD

Cardiac computed tomography (CT) has recently emerged as a non-invasive alternative to catheter angiography for the assessment of coronary artery disease. Rapid technological advances have rendered coronary CT angiography to a robust, accurate and fast imaging modality to assess coronary artery disease in selected patients. The list of further indications in which cardiac CT is an appropriate test remains a topic of discussion.

AREAS COVERED IN THIS REVIEW

This review discusses the main literature available on the use of cardiac CT in the indications considered appropriate in the 2006 Appropriateness Criteria by the American College of Radiology with special emphasis on the temporal trends in the utilization of cardiac CT in clinical practice and in the opinion of the experts, and provides an outlook on how cardiac CT might evolve in the future.

WHAT THE READER WILL GAIN

The reader will gain insight into the strengths and shortcomings of CT of the coronary arteries in coronary artery diagnosis and will learn why cardiac CT is appropriate in some indications but not in others.

TAKE HOME MESSAGE

Recent research in cardiac CT has substantially improved the evaluation of the coronary arteries with CT, and the list of indications cardiac CT is appropriate for might expand further in the coming years.

CT evaluation of congenital heart disease in adults

OBJECTIVE

The purpose of this article is to describe the spectrum of imaging findings of congenital heart disease in adults.

CONCLUSION

Continued advances in CT have facilitated evaluation of two important patient populations: adults with surgically palliated congenital heart disease and adults with previously undiagnosed congenital heart disease.

ACR appropriateness criteria on suspected congenital heart disease in adults

The number of adults with congenital heart disease is increasing in North America. This is attributable to a variety of factors, including improvements in surgical techniques and increases in immigration. Cardiac imaging is critical for the initial assessment of adults with newly suspected congenital heart disease as well as for the serial assessment of adults with known congenital heart disease. Chest radiography and echocardiography continue to be the initial tools used to evaluate adult congenital heart disease. However, cardiac computed tomography and magnetic resonance imaging have significantly improved over the years and have become integral to the evaluation of adult congenital heart disease, often precluding the necessity for invasive cardiac catheterization. Noninvasive imaging is particularly useful for the surveillance of patients with surgically corrected congenital heart disease, who often require 2 or more additional operations.

Noninvasive coronary artery imaging in the diagnosis and management of patients with ischemic heart disease

The inherent limitations of x-ray coronary angiography have led to the development for both noninvasive and minimally invasive techniques for imaging the coronary arteries to assist in the diagnosis and management of patients with ischemic heart disease. Significant advances in transesophageal echocardiography, electron beam computed tomography, and magnetic resonance imaging now permit imaging of the proximal to mid-coronary arteries. Moreover, results of initial studies demonstrate the promise of these methods to detect coronary artery stenoses. In addition, each of these methods provides biochemical or physiologic data about the stenoses that are not obtainable through x-ray angiography. Quantification of coronary calcification via electron beam computed tomography has shown promise as a surrogate marker of coronary atherosclerosis. Transesophageal echocardiography and magnetic resonance imaging appear useful in evaluating the physiologic significance of angiographically detectable coronary artery stenoses via assessment of coronary blood flow. However, it should be noted that significant improvements in technology or acquisition parameters must occur before these techniques can be used on a routine clinical basis for coronary artery imaging. The relative merits and ultimate clinical potential of each of these techniques are discussed in this article.

[Echocardiographic evaluation in unoperated congenital heart disease in adults]

Echo and Doppler echocardiographic procedures have gained special importance in the diagnostics of congenital diseases in adults. These procedures permit detailed visualization of the pathomorphology of the heart as well as reliable evaluation of the hemodynamic changes. There are differentiated indications for the various procedures, such as transthoracic and transesophageal echocardiography, Doppler and color-Doppler echocardiography, contrast echocardiography and 3-dimensional echocardiography. This article discusses the opposition of the various echo and Doppler echocardiographic procedures with respect to the diagnostics of the most frequent non-operated congenital diseases in adults. The pathomorphology of the various congenital diseases will be summarized and then the important echocardiographic criteria presented which are decisive for the diagnostic procedure. In simple congenital malformation of cardiac valves, such as bicuspid aortic valve (Figure 1: aortic ring abscess), pulmonary valve stenosis (Figure 2), Ebstein's anomaly (Figure 3) or malformations of the mitral valve (Figure 4: cleft in the anterior mitral cusp), the diagnosis can often be made using transthoracic echo and Doppler echocardiography, and the severity of the defect determined. However, the sonographic conditions, especially in adults, are frequently too limited to permit recognition of detailed smaller changes, so that transesophageal examination is required to finally confirm the diagnosis in these patients. In the diagnostics of diseases of the left ventricular outflow tract and the thoracic aorta, such as subvalvular aortic valve stenosis (Figure 5), the sinus of Valsalva aneurysm or the coarctation of the aorta (Figure 6), the left ventricular outflow tract can be evaluated morphologically from a transthoracic procedure and the accelerations of flow can be recorded by continuous wave Doppler. If there is no sclerosis of the fibrous membrane, these can often not be depicted by transthoracic procedures, so that a supplementary transesophageal examination is meaningful. This is required in any case for diseases of the descending thoracic aorta. In the case of congenital lesions, such as atrial septal defects (Figure 7: anomalous pulmonary venous return, Figure 8: 3-dimensional visualization of an atrial septal defect, Figure 9: sinus venosus defect), ventricular septal defect or a patent ductus arteriosus Botalli (Figure 10), color-Doppler and contrast echocardiography have become especially important. Transesophageal examination is also indicated for these congenital diseases for direct depiction of the defect as well as for precise evaluation of the shunt. Moreover, in atrial septal defects, it has been shown that a 3-dimensional echocardiography provides additional advantage with respect to spatial relationship of the defect to the other cardiac structures, as well as presenting dynamic changes during a heart cycle. Extensive knowledge of complex congenital heart disease, such as tetralogy of Fallot (Figure 11), complete transposition of the great arteries, congenitally corrected transposition of the great arteries (Figure 12), the double-outlet right ventricle, truncus arteriosus communis, the cor triatriatum, tricuspid atresia (Figure 13) or the univentricular heart (Figure 14) usually requires performance of a transthoracic echo- and Doppler echocardiographic examination to assess the pathomorphological changes and to examine hemodynamics. In the majority of patients, supplementary transesophageal echocardiography and an echo contrast examination are important. Initial examinations using 3-dimensional echocardiography are very promising in this connection and with respect to the exact spatial presentation of pathoanatomical structures.

Intraoperative transesophageal echocardiography using high-resolution biplane 7.5 MHz probes with continuous-wave Doppler capability in infants and children with tetralogy of Fallot

This study reports the role of biplane transesophageal echocardiography in monitoring surgical repairs of tetralogy of Fallot. In our patients, 3 repairs were revised based on transesophageal echocardiography and continuous-wave Doppler results, and intraoperative management was altered in 2 others.

Multiplane transoesophageal echocardiography is the only definitive ultrasound approach in adult supravalvular aortic stenosis

This report describes a rare case of isolated supravalvular aortic stenosis (SVAS) in a 28 year-old female patient. A congenital heart defect, diagnosed at birth, was until 1994 suspected to be a valvular aortic stenosis (VAS). Cardiac catheterization led to the diagnosis of supravalvular aortic stenosis, which could easily be confirmed by multiplane but not by monoplane transoesophageal echocardiography (TEE). Precordial examinations had not revealed the vitium, probably because the SVAS is a rare malformation of the ascending aorta, but with multiplane TEE the aortic narrowing could be imaged clearly and pressure gradients comparable to those found with invasive measurements were established. The advantage of this non-invasive method for diagnosis and preoperative preparation are discussed in detail.

Diagnostic accuracy of transesophageal echocardiography for detecting patent ductus arteriosus in adolescents and adults

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of patent ductus arteriosus (PDA) in the adolescent and the adult, 40 patients with PDA and 50 patients with other congenital heart diseases were studied. All echocardiograms were recorded before cardiac catheterization and surgery. The echocardiographic diagnosis of PDA was made by direct visualization of a shunt flow in the duct. A mosaic flow in the pulmonary artery without direct visualization of the duct was considered possible but not definitely diagnostic of PDA. TEE showed greater sensitivity and negative predictive value than TTE (97% vs 42%, and 98% vs 68%, respectively; p < 0.001) in confirming the diagnosis of PDA. The specificity and positive predictive value in establishing the diagnosis of PDA were the same for both techniques. In the subgroup of patients with Eisenmenger's syndrome, the sensitivity of TEE and TTE in confirming diagnosis of PDA was 100% and 12% (p < 0.01), respectively. The sensitivity of monoplane and biplane TEE in the diagnosis of PDA was comparable (95% and 100%, respectively; p = NS). In conclusion, TEE was highly sensitive and specific in detecting PDA in adolescents and adults. It was also highly valuable for detecting the cause of pulmonary hypertension in patients with Eisenmenger's syndrome.

Transesophageal echocardiography to evaluate patients with severe pulmonary hypertension for lung transplantation

The surgical approach to lung transplantation for patients with severe pulmonary hypertension will be dependent on the primary disease and specific cardiac anatomy. To determine the safety and utility of transesophageal echocardiography in the management of patients with severe pulmonary hypertension who are being evaluated for lung transplantation, we studied 48 consecutive patients, aged 38 +/- 11 years, with pulmonary artery systolic pressure of 70 mm Hg or greater. All patients previously underwent left and right heart catheterization, transthoracic echocardiography, and radionuclide ventriculography. Transesophageal echocardiography was tolerated well by all patients. Additional data that significantly altered surgical therapy was found in 12 of 48 patients (25%): proximal pulmonary artery thrombi (3), patent foramen ovale with significant right to left shunting (2), atrial septal defect (2), double-outlet right ventricle (2), ventricular septal defect (2), and exclusion of atrial septal defect (1). These findings were confirmed surgically in all patients except 3, who died awaiting transplantation. Transesophageal echocardiography is useful in the evaluation of patients with severe pulmonary hypertension.

Diagnosis in adolescents and adults with congenital heart disease. Prospective assessment of individual and combined roles of magnetic resonance imaging and transesophageal echocardiography

BACKGROUND

The inability to obtain complete diagnoses with transthoracic echocardiography in many adults with congenital heart disease provided the incentive to evaluate prospectively the individual and combined roles of magnetic resonance imaging (MRI) and transesophageal echocardiography (TEE) as "second-line" techniques for unresolved diagnostic problems.

METHODS AND RESULTS

Eighty-five patients were studied; 81 had MRI with a 0.5-T magnet to obtain spin-echo images, cine-MRI, and flow-velocity maps. Seventy-nine patients had TEE (37 biplane). A simple score (range, 0 to 1) was used for quantification of the results of MRI and TEE alone, for their comparison (in the 75 patients who had both), and for assessment of their combination. MRI, TEE, or their combination achieved a score of at least 0.75 in 18 of 25 diagnostic categories. A summary of the scores showed that for intracardiac anatomy. MRI scored 0.34, TEE scored 0.71 (P < .0001), and MRI plus TEE scored 0.84 (P < .003); for extracardiac anatomy, MRI scored 0.76, TEE scored 0.23 (P < .0001), and MRI plus TEE scored 0.84 (P = NS); and for hemodynamics and function, MRI scored 0.58, TEE scored 0.41 (P < .05), and MRI plus TEE scored 0.67 (P = NS). Total scores were MRI, 0.52; TEE, 0.50 (P = NS); and MRI plus TEE, 0.80 (P < .0001). MRI and TEE were inadequate for collateral and coronary arteries and pulmonary vascular resistance. Cine-MRI and flow-velocity maps comprised 43% of the MRI scores. Biplane TEE was better than single plane (scores of 0.59 versus 0.42, P < .0001).

CONCLUSIONS

MRI and TEE are important and complementary "second-line" investigations for congenital heart disease. Analysis of their performance in a wide range of diagnostic categories provides guidelines for their judicious application. Where both are available, diagnostic catheterizations are either obviated or simplified.

Echocardiographic assessment of adults with tetralogy of Fallot

Advances in medical and surgical management of congenital heart disease in the last three decades have resulted in a great many survivors to adulthood. Proper care requires intimate knowledge of the basic malformations and their surgical anatomy and results. Tetralogy of Fallot, the most common cyanotic malformation in adults, represents a spectrum from mild right ventricular outflow tract obstruction to complete pulmonary atresia. Evaluation of surgical residua and sequelae includes imaging of aortic-to-pulmonary arterial palliative shunts, detection of residual ventricular septal defect patch leaks or right ventricular outflow tract obstruction, definition of extracardiac conduit patency, and quantitation of ventricular function and valvular regurgitation. Refined echocardiographic imaging and hemodynamic definition is a mainstay in precise segmental anatomical and hemodynamic assessment. Transesophageal echocardiography is particularly important for intraoperative evaluation of surgical results.

Echocardiographic evaluation of isolated pulmonary valve disease in adolescents and adults

Congenital pulmonary valve disease is often not discovered until adolescence or adulthood. Transthoracic two-dimensional echocardiography can provide detailed information regarding right ventricular outflow anatomy, although images are often less satisfactory than those obtained in infants and children. The more recent addition of biplanar transesophageal echocardiography has enhanced our ability to image the right ventricular outflow tract, pulmonary valve, and pulmonary artery noninvasively. Pulsed and continuous-wave Doppler estimates of subvalvular and transvalvular gradients have proved to be accurate. Doppler color flow mapping has proved useful in determining the location and direction of stenotic and regurgitant flow. With no accepted standard for comparison, quantification of regurgitation remains problematic. In many cases, echocardiography has replaced catheterization and angiography in the evaluation and long-term follow-up of congenital pulmonary valve disease before and after intervention.

Echocardiography in the management of single ventricle: fetal through adult life

Echocardiography contributes to the management of patients with single ventricle by providing an initial comprehensive evaluation in fetal and neonatal life. This allows planning of the initial surgical palliation, usually without the need for cardiac catheterization. Serial surveillance for problems such as subaortic stenosis, valvar insufficiency, or complications of the mitral palliation aids in planning for the timing and type of subsequent surgical procedures. Evaluation of single ventricle size, shape, and mass provides some indication of risk for a Fontan procedure. Transesophageal echocardiography provides an excellent window for the evaluation of the interatrial baffle for shunts, thrombi, or occlusion in the early postoperative period. Later, studies of ventricular and valve function help to direct medical management such as afterload reduction and diuretic therapy.

Transesophageal echocardiography: state-of-the art and future directions

Transesophageal echocardiography complements transthoracic examination in 5-10% of patients referred to the echocardiographic laboratory. Clinical indications for performing this procedure are continually evolving. The semi-invasive nature of this procedure necessitates that it be judiciously used and that trained personnel undertake the procedure. Complications of the procedure need to be kept in mind. Future directions in the development of this technology involve newer, multiplanar, multifrequency transducers, digital archiving and retrieval, wide-field imaging, and 3-dimensional reconstruction. For the present, transthoracic echocardiography must remain the primary echocardiographic window imaging the heart, with defined clinical applications for transesophageal echocardiography.