Anatomic correlations of the long-axis views in biplane transesophageal echocardiography

Transesophageal multiplane imaging of the human pulmonary artery: a comparison of MRI and multiplane transesophageal two-dimensional echocardiography

OBJECTIVE

To evaluate the anatomical relationship between the esophagus and pulmonary artery including assessment of the correct transesophageal Doppler insonation angle into the mid-pulmonary artery trunk.

METHODS

We evaluated the anatomical relationship between the esophagus and pulmonary artery (PA) from comparable magnetic resonance (MR) and transesophageal echocardiographic (TEE) multiple two-dimensional images (0 degree, 45 degrees, 90 degrees and 135 degrees clockwise rotation of the standard transverse scanning plane when seen bearfrom the esophagus) obtained in 10 healthy, young volunteers.

RESULTS

The main PA could be visualized with both techniques in all 10 volunteers and provided highly identical images of good quality. A mean insonation angle of 35 degrees (range 26 degrees-46 degrees) for a fictive esophageal Doppler beam into the main PA was disclosed. The PA trunk was short with a mean length of 23.4 mm (range 17-30 mm).

CONCLUSIONS

These anatomical data contradict the general assumption of alignment of the pulmonary artery and the transesophageal Doppler beam. Angle correction should be applied in the clinical setting using MTEE by rotation of the scanning plane to approximately 45 degrees. Ignoring the insonation angle of approximately 35 degrees may cause 20% underestimation of blood flow velocity and cardiac output in the PA.

Detection of intraoperative segmental wall-motion abnormalities by transesophageal echocardiography: the incremental value of additional cross sections in the transverse and longitudinal planes

Because biplane and multiplane transesophageal echocardiography (TEE) are more complex and expensive than single-plane TEE, we performed this study to determine whether the use of multiple single-plane (transverse) cross sections is as reliable for detection of left ventricular segmental wall-motion abnormalities (SWMA) as biplane TEE. We used biplane TEE to acquire nine standard cross sections of the left ventricle in 41 consecutive adults undergoing cardiac or vascular surgery. Six of these cross sections were in the transverse plane (i.e., achievable with single-plane TEE) and three in the longitudinal plane (i.e., achievable only with biplane or multiplane TEE). Each cross section was divided into myocardial segments for analysis. A total of 1810 segments were analyzed by independent investigators using a standardized evaluation system. Seventeen percent of all SWMA detected in this study were in the midpapillary transverse-plane cross section, an additional 48% in other transverse-plane cross sections, and 35% exclusively in the longitudinal-plane cross sections. Thus, most (65%), but not all, SWMA were in cross sections achievable with single-plane TEE. We conclude that the MP-T cross section should be the foundation for assessment of segmental function, but additional cross sections in the transverse and longitudinal planes are required for detection of the majority of segmental wall-motion abnormalities.

Transesophageal Echocardiographic Assessment of Lesions of the Right Ventricular Outflow Tract and Pulmonic Valve

To establish the role of biplane transesophageal echocardiography (TEE) in the assessment of congenital and acquired lesions involving the right ventricular outflow tract (RVOT) and pulmonic valve (PV), 28 consecutive RVOT and PV lesions in 22 consecutive patients were studied by two-dimensional and color Doppler transthoracic echocardiograms (n = 22), horizontal (n = 22) and vertical (n = 22) plane TEEs, cardiac catheterization (n = 15), cardiac surgery (n = 6), and magnetic resonance imaging (n = 1). Sixteen patients had congenital lesions, and six had acquired lesions. Longitudinal TEE clearly imaged 25 of 28 abnormalities, transverse TEE clearly imaged 12 of 28, and transthoracic echocardiography clearly imaged 9 of 28. Two-dimensional TEE scanning revealed the lesion or site of stenosis. Color Doppler revealed conspicuous mosaic jets in relation to a structural abnormality in most cases. Longitudinal TEE was more sensitive in the detection of small vegetations of the PV, in the depiction of PV doming in cases of valvar pulmonic stenosis, and in the display of the RVOT and PV so that the longitudinal extent of involvement of larger masses could be appreciated. However, longitudinal TEE was not able to assess the gradient of a stenosis at the RVOT or PV level in any case. Biplane TEE is helpful in the anatomic assessment of congenital and acquired lesions of the RVOT and PV in adults. (ECHOCARDIOGRAPHY, Volume 13, January 1996)

Reference values for normal adult transesophageal echocardiographic measurements

Normal transesophageal echocardiographic measurements have not been presented previously relative to the effects of age, sex, and body surface area. This comparison was obtained by measuring cardiac and aortic dimensions in 60 patients (20 to 75 years old; 33 women) with normal transesophageal echocardiograms. We found a variable and usually important relationship between body surface area and 11 of 20 structures measured. A gender effect was not significant after indexing for body surface area for all but one structure. Age correlated with the diameter of the aortic root, descending aorta, superior vena cava, and right pulmonary artery. Similar dimensions were noted for certain paired structures as the two atria, the mitral and tricuspid annuli, and the aortic root and right ventricular outflow tract. Although multiple factors underlie what is normal in a given individual, our reference values serve to facilitate recognition of cardiac and aortic disease.

A prospective comparison of the multiplane probe with the biplane probe in structure visualization and Doppler examination during transesophageal echocardiography

To compare the imaging capability of the multiplane probe with that of the biplane probe, 317 consecutive patients were randomized to undergo transesophageal echocardiography with either probe. Images of 24 cardiac structures and nine Doppler signals were graded prospectively on a three-grade system. Both multiplane and biplane probes provided excellent visualization of cardiac structures and Doppler signals, but the multiplane probe was significantly superior to the biplane probe. There were no differences in the number of attempts at esophageal intubation, the amount of sedation used, and the examination time. The number of complications was similar, although all failed intubations occurred with the multiplane probe.

Visualization of sinus venosus-type atrial septal defect by biplane transesophageal echocardiography

In this article we describe three patients in whom biplane transesophageal echocardiography was useful in diagnosing sinus venosus type atrial septal defects. In two patients, diagnosis of anomalous pulmonary venous drainage was made correctly by biplane transesophageal echocardiography.

Multiplane transesophageal Doppler echocardiographic measurements of the velocity profile in the human pulmonary artery

Eight healthy, unsedated volunteers were studied to introduce a new non-invasive method for detailed blood velocity measurements and to evaluate flow patterns in the human pulmonary artery during end-expiratory apnea. With a multiplane transesophageal ultrasonic probe, spectral Doppler velocity registration was performed in nine different spatial locations across the vessel area. The pulmonary trunk could be visualized in all patients. The mean temporal velocity profile was virtually flat despite an instantaneous skewness that rotated counterclockwise up to 180 degrees. Furthermore, our data indicate that a good estimate of the temporal and spatial mean velocity can be obtained from velocity recordings based on centrally placed sample volumes. This makes the future application of Doppler-based measurement of cardiac output in the pulmonary artery hopeful. The ability of multiplane transesophageal echocardiography to estimate the area of the elastic human pulmonary artery, however, has to be evaluated more extensively before the clinical importance of this tool for measurement of cardiac output can be established.

Aorta: comprehensive evaluation by echocardiography and transesophageal echocardiography

The emergence of transesophageal echocardiography has made echocardiography a nearly ideal technique for evaluating the thoracic aorta. The echocardiographic anatomy of the aorta is reviewed. The role of echocardiography for evaluating aortic dissection, thoracic aortic aneurysm, aortic atherosclerosis, and thoracic aortic trauma is discussed. Comparison of echocardiography with other techniques for imaging the aorta (computed tomographic scan, nuclear magnetic resonance, and aortography) is presented.

Echocardiographic follow-up of atrial septal defect after catheter closure by double-umbrella device

BACKGROUND

Transcatheter device occlusion of atrial septal defects is an attractive approach, but its efficacy and place in patient management remain to be determined.

METHODS AND RESULTS

To evaluate the medium-term results of atrial septal defect device occlusion and factors influencing residual shunting, transesophageal and transthoracic echocardiograms of 49 patients were reviewed. Transesophageal echocardiograms on 48 patients immediately following surgical closure revealed residual shunting in 2% compared with 91% after device occlusion; this proportion decreased to 53% after a mean follow-up of 10 months. The actuarial analysis suggests a progressive resolution of shunting with time. One patient had residual shunting by transesophageal echocardiography immediately after surgical closure compared with 29 after a mean follow-up of 10 months after device occlusion. Residual shunting was not influenced by (1) dimension, location, or position with relation to the device as assessed by transesophageal echocardiography; (2) location of the defect; or (3) device size relative to the stretched dimension of the defect. In 15 patients, a poor correlation existed between transesophageal and transthoracic echocardiographic findings. Variability in serial transthoracic echocardiographic findings was observed in 14. Right ventricular dimension, heart size, and presence of a murmur at follow-up did not correlate with the presence or size of residual shunting after device occlusion.

CONCLUSIONS

These results suggest that ongoing spontaneous resolution of residual shunting occurs after device insertion. Factors related to the defect or device could not predict eventual resolution of residual shunting. Transthoracic echocardiography in the follow-up of these patients may not be reliable in determining presence of residual shunting.

Biplane transesophageal echo-Doppler studies of atrial septal defects: quantitative evaluation and monitoring for transcatheter closure

Forty-four patients with atrial septal defects, aged 7 months to 18 years (median 8.9), underwent biplane transesophageal (TEE) and transthoracic (TTE) echocardiography. The size of the defect and the shunt flow volume were measured by TEE and compared with the actual size at surgery (N = 14) or the shunt volume measured by the Fick method (N = 34), respectively. In all cases the location and morphology of the defect were clearly demonstrated by TEE; on the other hand, two patients with sinus venosus-type and multiple-type defects, respectively, and one with a small ostium primum defect did not have a complete diagnosis by TTE. The defect size determined by TEE correlated well with the surgical measurement. Similarly a significant correlation was demonstrated between the shunt volume measured by TEE and that obtained by the Fick method. In three patients transcatheter closure of the atrial septal defect by means of a clamshell device was accomplished successfully with TEE monitoring. We conclude that biplane TEE provides a better appreciation of cardiac anatomy and hemodynamic evaluation than TTE in this setting, and TEE is essential for monitoring during transcatheter closure.

Longitudinal transgastric echocardiographic views utilizing a single-plane probe: anatomic correlations and clinical applications

In order to widen the diagnostic capability of single-plane transesophageal echocardiography, which has been so far confined to transverse imaging planes, we obtained four transgastric longitudinal echocardiographic views which have not been previously described. These views can image structures such as superior and inferior vena cava, the right ventricular inflow and outflow tract, the mitral apparatus and the ascending aorta, which are poorly visualized by transesophageal transverse single-plane echocardiography. Among 400 consecutive patients these scans gave relevant additional diagnostic information in 62 cases (15.5%) and provided the correct diagnosis in 37 (9.2%). There were no complications related to the longer gastric manipulation of the probe and the quality of the images was high. We conclude that longitudinal echotomographic scanning of the heart is not exclusively confined to the use of biplane or omniplane probes, but longitudinal views can be consistently obtained with a single-plane instrument.

Comparison of cardiac dimensions by transesophageal and transthoracic echocardiography

Transesophageal echocardiography (TEE) has advanced rapidly as a valuable cardiovascular diagnostic technique. As the use of TEE increases, so does the importance of well-defined normal cardiac measurements. Presently, few data exist on the accuracy of M-mode TEE-derived measurements. Therefore in 81 adult patients, TEE-derived M-mode measurements were compared with analogous measurements that were made by standard M-mode transthoracic echocardiography (TTE). The TTE and TEE measurements did not differ in aortic root diameter, end-diastolic left ventricular diameter, end-diastolic septal wall versus anterior wall thickness, or end-diastolic posterior wall versus inferior wall thickness. These TEE measurements were within 95% confidence limits of TTE measurements. TEE-derived left atrial diameter (3.5 +/- 0.8 cm) was less than that derived by TTE (3.8 +/- 0.8 cm; p less than 0.001) and fell outside of the 95% confidence interval. TTE left atrial size could be estimated as follows: TTE-derived left atrial diameter = TEE-derived left atrial diameter x 0.6 + 1.5 cm. In conclusion, M-mode measurements of aortic root diameter, left ventricular diameter, and wall thicknesses as derived by TTE and TEE are comparable. TEE-derived left atrial diameter may be used to estimate the left atrial TTE measurement. TEE-derived M-mode measurements are likely to be most useful when results of TTE are technically inadequate.

Clinical usefulness of biplane transesophageal echocardiography

The clinical usefulness of biplane color Doppler transesophageal echocardiography is illustrated by the results obtained in 300 successive examinations. The additional contribution of the newer longitudinal plane was judged significant or major in 64% of the cases. The method was useful mainly for intraoperative examinations, assessment of native valvular disease, prosthetic valve evaluation, search for tumors, and assessment of endocarditis, congenital heart disease, and aortic disease. In contrast, the longitudinal plane option was not contributory in 68% of the cases of thromboembolism. Typically, the technique aided in the evaluation of mitral valve insufficiency and the detection of paraprosthetic leaks. Lesions located at the level of the ascending aorta, the left and right ventricular outflow tracts, and the interatrial septum were also visualized best. The limitations of the method were negligible and the duration of the examination was not significantly increased in comparison to the monoplane method. When available, biplane transesophageal echocardiography seems to be preferred in most clinical settings.

Incidence of bacteremia in transesophageal echocardiography: a prospective study of 140 consecutive patients

The incidence of bacteremia related to transesophageal echocardiography was studied in 140 consecutive patients (71 women and 69 men with a mean age of 53.7 +/- 15 years). Thirty-four patients had one or more prosthetic heart valves. Blood cultures were obtained from each patient through separate venipuncture sites immediately before and after transesophageal echocardiography. An additional late blood culture was obtained in 114 patients 1 h later. The skin was cleaned with povidone-iodine and venipunctures were performed with separate butterfly needles with use of sterile gloves and drapes. Blood samples were drawn into separate syringes, transferred to aerobic and anaerobic culture bottles and processed with use of a semiautomated system. The overall incidence of blood cultures positive for bacteremia was 2% (8 of 394 bottles) and all positive cultures grew in a single blood culture bottle. Positive cultures occurred in 4 (1.4%) of 280 bottles before the procedure, in 2 (0.7%) of 280 bottles immediately after the procedure and in 2 (0.9%) of 228 late (1-h) blood culture bottles. Bacterial isolates were coagulase-negative staphylococci (n = 5), Propionibacterium (n = 2) and Moraxella (n = 1). All were considered contaminants. Mean endoscopic time in these patients was not significantly different from that in the other patients. Follow-up of patients with a blood culture positive for bacteremia revealed no clinical evidence of systemic infection. It is concluded that 1) the incidence of bacteremia related to transesophageal echocardiography is very low, and 2) the incidence of blood cultures positive for bacteremia after transesophageal echocardiography is indistinguishable from the anticipated contamination rate.

Biplane transesophageal echocardiography: clinical applications of the long-axis plane

Tomography of the heart and great vessels is limited during conventional transesophageal echocardiography by the inability to rotate the transducer at the end of the transesophageal echocardiographic endoscope. A biplane transesophageal echocardiographic probe has been developed recently with a second transducer capable of long-axis imaging that yields long-axis views in addition to the familiar short-axis views. We describe our experience with 37 patients with a variety of cardiovascular diseases. In 17 patients new diagnostic information was obtained, although management was not changed. Long-axis scanning was particularly useful in the assessment of diseases of the thoracic aorta, valvular morphology and regurgitation, and congenital heart disease. Important limitations of the biplane imaging system include reduced image quality and a continued inability to rotate the transducer to obtain any desired plane of imaging. Nonetheless, biplane imaging enhances the versatility of transesophageal echocardiography and improves three-dimensional conceptualization of cardiac disease.