Atlas of Transesophageal Echocardiography, 2nd Edition (2007)

Chapter 8.3. Transesophageal Echocardiography in Congenital Heart Disease

Jesus Vargas-Barron

Clara Andrea Vazquez-Antona

Angel Romero-Cardenas

Francisco-Javier Roldan

Julio Erdmenger Orellana

Navin C. Nanda

Atrial Septal Defect

The most common type of atrial septal defect is ostium secundum, located in the middle portion of the interatrial septum. The ostium primum type defect is located in the most inferior portion of the septum, near the crux of the heart. The sinus venosus type of defect can be found in the superior portion of the septum and is often associated with partial anomalous connection of the pulmonary veins.

In most patients with atrial septal defect, transthoracic studies provide sufficient information to indicate surgical correction without cardiac catheterization. Indications for a transesophageal echocardiogram, particularly in adult patients, are limited to situations in which conventional transthoracic images do not definitively establish the diagnosis (e.g., obesity, thoracic deformity), when a sinus venosus type defect is suspected (Figs. 8.3.1 and 8.3.2) or when a paradoxic embolism through a patent foramen ovale must be excluded in a patient who has had a stroke (Fig. 8.3.3).

The information obtained from transesophageal two-dimensional recordings should include the following:

1.   The exact location of the defect or the presence of various defects (Fig. 8.3.4);

FIGURE 8.3.1. Atrial septal defect. Transverse plane image at the atrial level demonstrates a sinus venosus type of atrial septal defect (arrow), located near the connection of the superior vena cava (SVC) to the right atrium. AO, aorta; LA, left atrium; RAA, right atrial appendage.

FIGURE 8.3.2. Atrial septal defect. Microbubbles are seen flowing from the superior vena cava (SVC) into the right atrium and from there into the left atrium (LA) through a sinus venosus septal defect. AO, aorta; RAA, right atrial appendage.

2.   The size of the septal defect, with calculation of its area;

3.   Calculation of the shunt flow volume, and the ratio of pulmonary to systemic blood flow;

4.   The site of connection of the four pulmonary veins; and

5.   Any associated defects.

Multiplane images make it possible to determine the exact location of the atrial septal defect. The diameters of the defect can be measured, and the characteristics of the atrial cavity can be examined. Moreover, embryonic structures such as the eustachian valve can be identified (Figs. 8.3.5, 8.3.6 and 8.3.7).

FIGURE 8.3.3. Patent foramen ovale. A contrast study confirms the flow of microbubbles from the right atrium (RA) into the left atrium (LA) (arrows). LV, left ventricle; RV,right ventricle.

FIGURE 8.3.4. Atrial septal defect. Transverse plane image at the level of the atrial septum. The arrows point to two atrial septal defects (ASDs). LA, left atrium; LVO, left ventricular outflow tract; RA, right atrium; RV, right ventricle.

It has been shown that the dimensions of the ostium secundum type defect determined from transverse images correlate well with those obtained in the operating room, as follows:

r = 0.92; P <.001 for horizontal width

r = 0.85; P <.01 for vertical length

The diameter and area of the septal defect can also be calculated from the maximum color flow jet width at the defect site. The defect is assumed to be circular, and comparison with values obtained with those estimated in surgery has shown a fair correlation:

r = 0.73; P = .004

FIGURE 8.3.5. Atrial septal defect. Two-dimensional images with color-coded Doppler at the atrial level. The variations in the shunt through a large septal defect are demonstrated. AV, aortic valve; LA, left atrium; RA, right atrium.

FIGURE 8.3.6. Atrial septal defect. In a patient with a sinus venosus type of atrial septal defect, transverse plane images with color Doppler show a bidirectional shunt through the septal defect (arrow). AV, aortic valve; LA, left atrium; RA, right atrium; SVC, superior vena cava.

The volume of the shunt is calculated as the product of the area of the defect, mean velocity, flow duration, and heart rate.

A good correlation exists between shunt flow volume calculated by transesophageal echocardiography and that obtained by cardiac catheterization, as follows:

r = 0.91; P <.001

FIGURE 8.3.7. Atrial septal defect. Echocardiogram taken with a multiplanar transducer shows a fossa ovalis type atrial septal defect (arrow). EV, eustachian valve; LA, left atrium; RA, right atrium.

FIGURE 8.3.8. Atrial septal aneurysm. M-mode and two-dimensional images in the transverse plane demonstrate the movement of the interatrial septum (IAS) toward the left atrium (LA) in systole and toward the right atrium (RA) in diastole.

The comparison of shunt flow volume calculated by transesophageal echocardiography with the pulmonary to systemic blood flow ratio calculated by cardiac catheterization has also shown good correlation:

r = 0.84; P <.001

Once the diagnosis of atrial septal defect is established, the Qp:Qs ratio can be calculated from the flow that crosses the pulmonary valve in systole (Qp) and the aortic or mitral valve (Qs).

A semiquantitative estimation of mixed shunts is achieved with simultaneous M-mode and color Doppler transesophageal recordings, or by an examination of the positive and negative deflections (spectral analysis) of the flow curve crossing the septum. The planimetry of the positive curve has a certain relationship with the venoarterial shunt, as does the planimetry of the negative curve with the arteriovenous shunt.

Other pathologies of the interatrial septum exist, such as lipomatous hypertrophy or septal aneurysms, which are identified with relative ease using transesophageal imaging. In lipomatous hypertrophy, the transesophageal images show diffuse thickening of the septum. In patients with septal aneurysms the two signs required for diagnosis are (a) bulging of the fossa ovalis region >15 mm beyond the plane of the atrial septum or >15 mm phasic excursion during the cardiorespiratory cycle and (b) the base of the aneurysm measuring >15 mm in diameter (Figs. 8.3.8 and 8.3.9). Shunting has been detected in up to 83% of aneurysms of the interatrial septum studied by transesophageal imaging using echocardiographic contrast imaging in combination with color flow mapping, and in 41% when only transthoracic examination was performed. Moreover, transesophageal recordings have confirmed that the aneurysms are thrombogenic, which explains their frequent association with paradoxic embolism.

FIGURE 8.3.9. Atrial septal aneurysm. Longitudinal plane views demonstrate both atria. The arrows indicate the aneurysmal movement of the interatrial septum. LA, left atrium; RA, right atrium.

Transesophageal studies have also served to evaluate the existence of interatrial shunts secondary to percutaneous mitral valvulotomy with balloon catheter, or as a guide in the closure of atrial septal defects with an umbrella-type patch introduced through a catheter.

Partial Anomalous Pulmonary Venous Connection

The most useful noninvasive technique in the diagnosis of anomalous pulmonary venous connections currently available is transesophageal echocardiography. The pattern of pulmonary venous drainage in relation to the atrial septum is best defined with transverse axis imaging (Figs. 8.3.10 and 8.3.11). Transesophageal echocardiography has a sensitivity and specificity close to 100% in the detection of anomalous pulmonary venous connections.

Partial anomalous connections often accompany sinus venosus type atrial septal defects. The most common form is the connection of the right pulmonary veins with the superior vena cava. Less often these veins are found to be connected to the right atrium or the inferior vena cava (Figs. 8.3.12 and 8.3.13); even less common is the connection of the left pulmonary veins with the innominate vein. Direct visualization of anomalous connections, especially of pulmonary veins, has been facilitated by the advent of multiplane transesophageal probes (Fig. 8.3.14). Contrast studies visualize the clearing of microbubbles in the right atrium by anomalous pulmonary venous flow (Fig. 8.3.15).

FIGURE 8.3.10. Partial anomalous connection of the pulmonary veins. Transverse plane image in a patient with anomalous connection of the pulmonary veins with the right atrium (RA). RLPV, right lower pulmonary vein; RUPV, right upper pulmonary vein.

Total Anomalous Pulmonary Venous Connection

In total anomalous connection of the pulmonary veins, the connection between the four pulmonary veins and the left atrium is absent. The veins drain into the right atrium, either directly or through systems of venous tributaries.

Three types of anomalous connection exist: (a) supracardiac, in which the connection is to the superior vena cava or the innominate vein; (b) cardiac, in which the pulmonary venous return connects to the coronary sinus or directly to the right atrium; and (c) infracardiac, in which the anomalous connection is established with the inferior vena cava or the portal vein. Mixed anomalous connections include at least two of these types.

FIGURE 8.3.11. Partial anomalous connection of the pulmonary veins. Postoperative study after correction of anomalous connection of the right pulmonary veins (PV). Pulmonary venous return has been connected to the left atrium (LA). The arrow points to the intact interatrial septum. RA, right atrium.

FIGURE 8.3.12. Partial anomalous connection of the pulmonary veins. With transgastric images and color-coded Doppler it is possible to identify the site of anomalous pulmonary venous drainage (PV) into the inferior vena cava. HV, hepatic vein.

The sites to which anomalous connections occur are, in decreasing frequency, the innominate vein, by way of a left vertical vein; the coronary sinus; the right superior vena cava; the right atrium; and the inferior vena cava.

In four-chamber transesophageal images, dilatation of the right cavities can be demonstrated and the lack of connection of the pulmonary veins to the left atrium can be confirmed. The use of transverse plane images makes it possible to recognize the characteristics of the obligatory atrial septal defect (Fig. 8.3.16). In addition, the small size of the left ventricle can be detected, a finding that has been considered a prognostic index in those patients who undergo surgical correction. When the two-dimensional images are complemented with color Doppler and spectral analysis, the magnitude of the venoarterial interatrial shunt becomes evident, and when flow is recorded in the anomalous pulmonary venous channel it is seen to be forward both in systole and diastole. The appearance of a color mosaic with increased flow velocity corresponds to venous obstruction, a situation of considerable clinical significance.

FIGURE 8.3.13. Partial anomalous connection of the pulmonary veins. Transverse plane image shows dilatation of the right heart cavities and functional tricuspid regurgitation (TR) secondary to anomalous pulmonary venous drainage. RA, right atrium; RV, right ventricle; TV, tricuspid valve.

FIGURE 8.3.14. Partial anomalous connection of the pulmonary veins. Preoperative transesophageal echocardiogram in a patient with anomalous pulmonary venous connection to the right atrium (RA). PV, pulmonary vein.

FIGURE 8.3.15. Partial anomalous connection of the pulmonary veins. Transesophageal echocardiogram with contrast shows the effect of clearing of microbubbles in the right atrium (RA) by pulmonary venous flow. PV, pulmonary vein.

FIGURE 8.3.16. Total anomalous connection of the pulmonary veins. In a patient with total anomalous pulmonary venous connection, color Doppler demonstrates the obligatory atrial septal defect (arrow). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

In anomalous connections of the supracardiac type, transesophageal studies complement the information obtained with suprasternal imaging. In the latter examination, the most common form of supracardiac anomalous connection is well demonstrated: the vertical vein (persistent left superior vena cava) drains into the innominate vein, and from there the venous flow connects with the superior vena cava and finally reaches the right atrium. In contrast, when the anomalous connection is with the right superior vena cava, transesophageal echocardiography shows that the pulmonary veins form a venous confluence posterior to the left atrium that points toward and connects with the posterior portion of the vena cava.

Pulmonary venous anomalous connection can be demonstrated with the greatest facility at the cardiac level in transesophageal images. When the connection is with the coronary sinus, images in the transverse plane show that the pulmonary veins form a retrocardiac confluence, which drains into the coronary sinus at the level of the atrioventricular sulcus. The coronary sinus is very dilated and has an abnormal vertical position (Fig. 8.3.17).

If the anomalous connection is with the right atrium, transesophageal recordings make it possible to establish whether the connection occurs through a large common pulmonary vein or through two to four pulmonary veins that drain separately into the posterior-inferior portion of the atrium (Figs. 8.3.18 and 8.3.19).

In anomalous infracardiac connections, the four pulmonary veins form a common confluence that descends in front of the esophagus, crosses the diaphragm through the esophageal hiatus, and drains into the inferior vena cava, hepatic or portal vein, or a persistent ductus venosus. Diagnosis of this type of anomaly can be established with subcostal recordings. Low transesophageal and transgastric recordings are very useful, especially when drainage is into the inferior vena cava or hepatic veins.

FIGURE 8.3.17. Total anomalous connection of the pulmonary veins. A. Four-chamber image with posterior angulation. There is dilatation of right heart chambers and the coronary sinus (CS) secondary to the anomalous pulmonary venous connection. B. When saline solution is injected through a peripheral vein, all four chambers become opaque. The arrow indicates the washout effect of the anomalous pulmonary venous flow from the coronary sinus into the right atrium (RA). C. Color Doppler demonstrates increased coronary sinus flow as a consequence of anomalous pulmonary venous connection. AO, aorta; LA, left atrium; LV, left ventricle; RAA, right atrial appendage; RV, right ventricle;SVC, superior vena cava; TV, tricuspid valve.

FIGURE 8.3.18. Total anomalous connection of the pulmonary veins. Transesophageal study demonstrates anomalous pulmonary venous drainage directly into the right atrium (RA). LA, left atrium; LPV, left pulmonary vein; RPV, right pulmonary vein; RV, right ventricle.

Transesophageal echocardiography, when performed in the cardiac catheterization laboratory, can avoid the excessive use of angiocardiographic contrast medium. In the operating room, it can aid in planning the type of corrective surgery and in the identification of mixed anomalous connections.

FIGURE 8.3.19. Total anomalous connection of the pulmonary veins. Transverse plane imaging with color Doppler shows flows from both pulmonary veins moving into the right atrium (RA). LPV, left pulmonary vein; RPV, right pulmonary vein.

Ventricular Septal Defect

The echocardiographic diagnosis of ventricular septal defect in children can be usually established with conventional transthoracic recordings. When technical difficulties exist in obtaining adequate images, especially in adolescents and adults, the transesophageal technique is a good alternative method that, with the advent of biplanar recordings, can confirm the diagnosis and determine the size and location of the defect with precision. The interventricular septum is made up of four principal segments: (a) membranous or perimembranous segment; (b) inlet; (c) outlet; and (d) trabecular segment. Septal defects can exist in one or more of these segments. They produce the features discussed in the following paragraphs in transesophageal echocardiographic studies.

A defect of the membranous septum is the most common. On the right ventricular side it is located beneath and behind the supraventricular crest (infracristal). On the left ventricular side it is located in the subaortic portion, near the commissure of the right and noncoronary leaflets. Diagnosis can be established with transesophageal images in transverse and longitudinal planes (Fig. 8.3.20). In the former, the shunt is seen close to the tricuspid valve and in front of the aorta (at the 8 o'clock position). In longitudinal recordings the defect is located in the basal (superior) third of the septum in a small subaortic portion.

A defect of the posterior or inlet septum may be found behind the tricuspid valve and between the tricuspid and mitral valves. It often forms part of a malformation of the endocardial cushions and is often associated with atrioventricular valve defects. The shunt is located with color Doppler, usually in a four-chamber transesophageal image in the transverse plane.

FIGURE 8.3.20. Ventricular septal defect. Four-chamber view with a large perimembranous-inlet ventricular septal defect (D); LA, left atrium; MV, mitral valve; RA, right atrium; RV, right ventricle; TV, tricuspid valve.

A defect of the infundibular or outlet septum is another possibility. On the right ventricular side it is located below the pulmonary leaflets; on the left side, it is inferior to the aortic leaflets. Transesophageal recordings in the transverse plane are not useful for recognizing the exact characteristics of the defect. In longitudinal images, however, it is possible to see the ventricular outflow tracts and, with color Doppler, to demonstrate the shunt crossing the defect.

A defect of the trabecular septum is located in an anterior and inferior portion of the septum. Occasionally, multiple trabecular defects are present (Fig. 8.3.21). This type of defect is usually small, although it can also be very large. Such a defect can be difficult to demonstrate in the transverse plane when it is small; identification usually requires biplanar recordings.

In patients with ventricular septal defects the flow crossing the defect can affect tricuspid structures, and this valvular trauma can promote the development of infective endocarditis. When this occurs, transesophageal recordings with color Doppler aid in identifying the location and magnitude of the ventricular septal defect, the characteristics of the vegetations adhering to the tricuspid leaflets, the existence and severity of the lesions of the leaflets themselves, and the extension of the infectious process to other cardiovascular structures (Figs. 8.3.22, 8.3.23 and 8.3.24).

One of the principal contributions of transesophageal studies in the evaluation of patients with ventricular septal defects is the visualization of the overriding of the atrioventricular valve rings or the straddling of subvalvular structures that cross the interventricular defect and insert in the contralateral ventricle (Fig. 8.3.25).

Transesophageal echocardiography has also been used in the intraoperative evaluation of surgical closure of ventricular septal defects. It is more useful than epicardial recordings. However, when a patch of synthetic material is used to cover the defect, the patch can produce ultrasonic shadowing in the right ventricle that makes color Doppler evaluation difficult and the demonstration of residual shunts impossible. This interference can be avoided by using “high” (i.e., at the level of the right ventricular outflow tract and the aorta) transesophageal recordings complemented with contrast echocardiography.

FIGURE 8.3.21. Ventricular septal defect. Transgastric imaging with color Doppler demonstrates multiple ventricular septal defects (arrows). LV, left ventricle; RV, right ventricle.

FIGURE 8.3.22. Ventricular septal defect. Transverse plane image shows a trabecular ventricular septal defect (arrow). The insertion of the tricuspid subvalvular apparatus in the ventricular septum (VS) also is observed. LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle; TV, tricuspid valve.

FIGURE 8.3.23. Ventricular septal defect. Infective vegetations involving the tricuspid valve (TV) (arrows) are seen in a patient with a ventricular septal defect. LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle.

FIGURE 8.3.24. Ventricular septal defect. Color Doppler shows a ventricular septal defect (D) and also documents aortic regurgitation (AR). LA, left atrium; LV, left ventricle;RA, right atrium; RV, right ventricle.

Common Atrioventricular Canal

The common atrioventricular canal is the extreme form of endocardial cushion defects, also called atrioventricular septal defects. In this malformation there is a common AV valve, a defect of the lower portion of the interatrial septum (ostium primum), and a defect of the high, posterior portion of the interventricular septum (inlet).

The AV valve is formed by five leaflets, three of which correspond to the left ventricle—lateral, anterior, and posterior and two correspond to the right ventricle—one anterior and the other lateral.

FIGURE 8.3.25. Ventricular septal defect. Systolic frame shows insertion of the tricuspid valve (TV) into the interventricular septum. In systole the tricuspid tissue protrudes toward the left ventricular outlet (arrow). D, defect. LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle.

FIGURE 8.3.26. Common atrioventricular canal defect. Diagram of transesophageal recordings in a patient with Rastelli type A common atrioventricular canal, in which the left anterior leaflet crosses the ventricular septum and inserts in a medial papillary muscle of the right ventricle (RV). APM, anterior papillary muscle; LV, left ventricle; PPM, posterior papillary muscle; *, variable morphology.

The left anterior and posterior leaflets cross the crest of the interventricular septum toward the right ventricle. These have been called “bridging leaflets” and have variable degrees of tethering to both ventricles (Fig. 8.3.26).

In addition, the characteristics of these bridging leaflets determine whether one or two atrioventricular orifices exist. If the bridging leaflets are separate, there is only one AV orifice, whereas if the leaflets are joined by fibrous tissue, there are two AV orifices.

In infants and children, transthoracic and subcostal echocardiograms are of sufficient quality to clarify the characteristics of the malformation. Transesophageal studies should be limited to those situations in which it is not possible to obtain satisfactory transthoracic recordings, particularly in adults or during the intraoperative evaluation of surgical correction of the defect.

The transesophageal echocardiographic study should demonstrate the morphology of the atrioventricular valve. With transesophageal four-chamber images and transgastric transverse plane images it is possible to determine whether there is a single AV orifice or two orifices (Fig. 8.3.27). When two-dimensional recordings are complemented with color-coded Doppler, existing shunts can be seen. Patients with two AV orifices usually have a single shunt at the atrial level. Patients with a single AV orifice present with both interatrial and interventricular shunts. The Doppler study also aids in determining the existence and degree of regurgitation of the mitral and tricuspid components of the common AV valve (Fig. 8.3.28).

In four-chamber and longitudinal plane images, it is important to identify the atrial and ventricular components of the AV septum, the size of both ventricles, and, particularly, the characteristics of the left anterior bridging leaflet, which defines the most common variants of this malformation according to Rastelli classification. In type A the left anterior bridging leaflet crosses the interventricular septum and inserts in the medial papillary muscle of the right ventricle. Valvular mobility is limited by the insertions in the crest of the interventricular septum. In types B and C, “crossing” of the left anterior leaflet is greater. In type B, after crossing the septum, the leaflet reaches the medial papillary muscle, which is located in an abnormally apical position. In type C, the leaflet crosses and inserts in the anterior papillary muscle of the right ventricle.

FIGURE 8.3.27. Common atrioventricular canal defect. Four-chamber images in a complete atrioventricular canal or septal defect. The anterior mitral component of the common AV valve can be seen to insert into the free edge of the ventricular septum. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

FIGURE 8.3.28. Common atrioventricular canal defect. When a common atrioventricular valve exists, a color Doppler study aids in recognizing the degree of valvular regurgitation (arrow). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

In patients with separate AV valve orifices, transesophageal study helps demonstrate that the left anterior and left posterior bridging leaflets are joined by a band of fibrous tissue that divides the common orifice.

A “goose-neck” image can be observed in recordings in the longitudinal plane at the level of the left ventricular outlet. This results from the outlet being longer and abnormally far from the interventricular septum because of the more vertical orientation of the AV valve annulus. Obstructions of the left ventricular outlet can be recognized and quantified with the various Doppler techniques.

Transesophageal echocardiography is particularly useful in the operating room because the information it provides allows better planning of the type of corrective surgery, and in the immediate postoperative period it helps identify residual shunts and valvular regurgitation.

Patent Ductus Arteriosus

Patent ductus arteriosus (PDA) involves abnormal communication between the descending aorta and the proximal portion of the left branch of the pulmonary artery. In premature and term infants it can be diagnosed with relative ease using conventional transthoracic recordings. In older children and adults it presents a broad spectrum of clinical manifestations, which vary from the asymptomatic patient with a continuous precordial murmur to a patient with signs of severe pulmonary hypertension.

Transesophageal echocardiography is an alternative when satisfactory transthoracic recordings cannot be obtained. It is difficult to visualize the ductus directly in the transverse plane; it may be suspected when there is retrograde systolic and diastolic flow in the pulmonary artery (Figs. 8.3.29 and 8.3.30). The diagnosis is established with biplanar or multiplanar transducers using recordings in the longitudinal plane. In this plane, the descending thoracic aorta should be recorded at the postductal level. The transducer is then withdrawn slowly to obtain sections progressively superior with slight rotation to the right (Fig. 8.3.31). Doppler shows the shunt as a mosaic of colors connecting the aorta to the pulmonary artery (Fig. 8.3.32). A flow with increased velocity in both systole and diastole is recorded on spectral analysis (Fig. 8.3.33).

FIGURE 8.3.29. Patent ductus arteriosus. In a high transverse section, color Doppler demonstrates flow through the patent ductus arteriosus (PDA). AO, aorta; PA, pulmonary artery.

FIGURE 8.3.30. Patent ductus arteriosus. Simultaneous two-dimensional and color M-mode images show increased velocity of systolic and diastolic flows at the level of the pulmonary artery secondary to a patent ductus arteriosus (PDA)

FIGURE 8.3.31. Patent ductus arteriosus. Longitudinal plane imaging at the level of the great arteries directly visualizes the patent ductus arteriosus (PDA). AO, aorta; PA, pulmonary artery.

FIGURE 8.3.32. Patent ductus arteriosus. The shunt between the aorta (AO) and the pulmonary artery (PA) is corroborated by color Doppler in longitudinal plane imaging. PDA, patent ductus arteriosus.

Another application of transesophageal echocardiography in patients with PDA is for the evaluation of the effectiveness of surgical ligation of the ductus. Likewise, in patients with calcification or hypertrophy of the walls of the ductus, residual shunts can exist and can be detected with color Doppler during surgery.

The transesophageal technique has also been used as an aid during interventional procedures. During percutaneous occlusion of PDA with the double umbrella device, transesophageal echocardiography shows the precise position of the device, and, before the device is released, the completeness of occlusion assessed by color Doppler.

FIGURE 8.3.33. Patent ductus arteriosus. Longitudinal plane images with color Doppler and spectral analysis demonstrate continuous flow from the ductus arteriosus. AO, aorta; PA, pulmonary artery; PDA, patent ductus arteriosus.

In some of the various complications that can occur with PDA, transesophageal studies provide information useful for therapeutic management of the patient. These include pulmonary hypertension and infective endarteritis of the pulmonary artery.

Because of the left-to-right shunt and the transmission of systemic pressure to the pulmonary circulation, pulmonary vascular disease develops; the shunt diminishes as pulmonary resistance increases. In this situation it has been recommended that transesophageal echocardiography, complemented by provocative maneuvers designed to lower pulmonary vascular resistance, such as the use of 100% inspired oxygen, should be used for the echocardiographic diagnosis of PDA with pulmonary hypertension. We believe that an alternative method in these patients is transesophageal contrast echocardiography. When glucose solution is injected in a peripheral vein, microbubbles can be observed in the descending thoracic aorta as evidence of the venoarterial shunt through the ductus (Fig. 8.3.34). A slight rotation of the transducer shows that there are no microbubbles in the left chambers or in the aortic root, thereby confirming that the shunt is not intracardiac (Figs. 8.3.35 and 8.3.36).

When it is not possible to obtain adequate transthoracic recordings, transesophageal recordings can be an alternative method of diagnosis for detection of vegetations in the pulmonary artery. It is possible to demonstrate the size, shape, and mobility of the vegetations that develop at the site at which the patent ductus flow hits the intima of the pulmonary artery (Figs. 8.3.37 and 8.3.38). The infective process can also involve the pulmonary valve (Fig. 8.3.39).

FIGURE 8.3.34. Patent ductus arteriosus. Contrast study shows microbubbles in both the left pulmonary branch and the descending thoracic aorta, confirming the patency of the ductus arteriosus. AO, aorta; PA, pulmonary artery.

FIGURE 8.3.35. Patent ductus arteriosus. In a patient with severe arterial hypertension, a contrast study shows the presence of microbubbles only in the right heart cavities, ruling out the existence of an intracardiac shunt. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

PDA is the most common cause of continuous murmur detected on the anterior wall of the chest. However, other causes of continuous or systolic–diastolic murmurs, such as aortic insufficiency with ventricular septal defect, aortopulmonary window, rupture of an aneurysm of the sinus of Valsalva into the cardiac cavities, or coronary fistula, are not unusual.

FIGURE 8.3.36. Patent ductus arteriosus. Transverse plane image at the level of the great arteries. With contrast the course of the microbubbles is visualized from the superior vena cava (SVC) to the right atrium (RA), right ventricular outlet, pulmonary artery, and pulmonary branches. No microbubbles appear in the aortic root. AO, aorta;LPA, left pulmonary artery; MPA, main pulmonary artery; RPA, right pulmonary artery; RVO, right ventricular outflow tract.

FIGURE 8.3.37. Patent ductus arteriosus. A vegetation adhering to the anterior wall of the pulmonary branch (V) is observed in a patient with patent ductus arteriosus.

Aortopulmonary Window

The aortopulmonary window is characterized by a communication between the ascending portion of the aorta and the main pulmonary artery with two well-formed semilunar valves. The orifice is usually large and oval and is located on the left lateral wall of the ascending aorta, near the origin of the left coronary artery. The communication occurs less commonly in a more distal position between the ascending aorta and the union of the right branch of the pulmonary artery with the main trunk.

Echocardiographic diagnosis of this malformation requires evidence of volume overload of the left cavities.

It usually is possible to visualize the aortopulmonary defect directly with transthoracic and subcostal two-dimensional images and corroborate the shunt with color Doppler. When transesophageal echocardiography is performed because the diagnosis cannot be demonstrated with transthoracic recordings, the images in both planes show the lack of septation between the aorta and the pulmonary artery above the level of the plane of the valve (Fig. 8.3.40). When two-dimensional images are complemented with color Doppler or contrast studies, the shunt is demonstrated and the size of the defect can be assessed (Fig. 8.3.41).

FIGURE 8.3.38. Patent ductus arteriosus. Infective endarteritis (V) at the level of the bifurcation of the pulmonary artery in a patient with patent ductus arteriosus is evident in this transverse plane image. AO, aorta; LPA, left pulmonary artery; MPA, main pulmonary artery; RPA, right pulmonary artery.

FIGURE 8.3.39. Patent ductus arteriosus. M-mode and two-dimensional images in the longitudinal plane show vegetations at the level of the pulmonary leaflets (V). AO, aorta;LPA, left pulmonary artery; MPA, main pulmonary artery; RPA, right pulmonary artery.

FIGURE 8.3.40. Aortopulmonary window. Transverse plane image of the great arteries demonstrates a large communication between the aorta (AO) and the pulmonary artery.LPA, left pulmonary artery; MPA, main pulmonary artery; RPA, right pulmonary artery.

FIGURE 8.3.41. Aortopulmonary window. Contrast study confirms the flow of microbubbles from the aorta (AO) into the pulmonary circulation. MPA, main pulmonary artery;RPA, right pulmonary artery.

Congenital Aneurysm of Sinus of Valsalva

Congenital aneurysms of the sinus of Valsalva are relatively rare malformations. In the course of their evolution they tend to rupture into cavities of the heart. A few years ago congenital aneurysms without rupture could be diagnosed only by angiography. Now they can be detected using noninvasive ultrasound (Fig. 8.3.42 and Fig. 8.3.43).

FIGURE 8.3.42. Unruptured sinus of Valsalva aneurysm. A shows the aneurysm (asterisk) protruding into the left atrium (LA). The tricuspid aortic valve is in the open position.B demonstrates the size and extension of the aneurysm (asterisk). The arrow points to rupture of the noncoronary cusp of the aortic valve. AO, aorta; LV, left ventricle; RA, right atrium; RV, right ventricle.

FIGURE 8.3.43. Unruptured sinus of Valsalva aneurysm. Longitudinal plane image with color Doppler shows severe aortic valvular regurgitation (arrow). AO, aorta; LA, left atrium; LV, left ventricle; RV, right ventricle.

When the aneurysm ruptures, two-dimensional echocardiography with color Doppler is useful for clarifying its presence, size, and location. When rupture occurs in adult patients, transesophageal echocardiography is superior to conventional transthoracic echocardiography for demonstrating the ruptured aneurysm because of a better acoustic window (Fig. 8.3.44). It is possible to identify deformities of the aortic root with abnormal echoes in the ruptured sinus of Valsalva with biplane or multiplane transducers, using primarily images in the transverse plane.

When the aneurysm ruptures into the right atrium or ventricle, the sinuses of Valsalva usually affected are the noncoronary and the right coronary sinuses, respectively. When the pulsed Doppler sample volume is placed in the cavity connected to the ruptured sinus of Valsalva, turbulent flow with increased velocity is recorded in both phases of the cardiac cycle.

FIGURE 8.3.44. Congenital aneurysm of the sinus of Valsalva. Rupture of an aneurysm of the sinus of Valsalva (arrow) into the right ventricle is demonstrated with transverse plane imaging and color Doppler. AV, aortic valve; LA, left atrium; RA, right atrium; RVO, right ventricular outflow tract.

Transesophageal images make it possible to differentiate sinus of Valsalva aneurysms from aneurysms of the interventricular septum, coronary aneurysms, or coronary fistulas. The association of two-dimensional studies and color Doppler recording is useful for characterizing flow patterns in the heart chambers, detecting the site of an arteriovenous shunt, and discovering associated lesions such as ventricular septal defects and aortic valve regurgitation.

Coronary Artery Fistula

Traditionally, coronary artery fistulas have been diagnosed by coronary angiography. They can be diagnosed with transthoracic echocardiography and color Doppler, although the information provided is limited to the demonstration of a coronary artery dilated in its origin with turbulent flow (mosaic of colors) in the cavity into which the fistula drains. With the advent of transesophageal echocardiography, especially with biplane and multiplane transducers, the diagnosis of these anomalies has been facilitated.

With images in the transverse plane it is possible to identify the origin of the fistula from one of the coronary ostia and the distal portion of the fistula (Fig. 8.3.45). The left-to-right shunt is visualized as a high-velocity mosaic jet arising from the fistula and extending into a cardiac chamber or main pulmonary artery. Pulsed-wave Doppler interrogation of the fistula reveals a continuous systolic–diastolic flow disturbance (Fig. 8.3.46). Images in the longitudinal plane have been described as useful in visualizing the fistula along its entire course (Fig. 8.3.47). Currently, transesophageal echocardiography seems to be the noninvasive diagnostic procedure that provides the most information in patients with coronary fistulas.

FIGURE 8.3.45. Coronary artery fistula. The dilated proximal portion of a fistula between the right coronary artery (RCA) and right ventricle can be seen in transverse (T) and longitudinal (L) plane images. AV, aortic valve; LA, left atrium; PA, pulmonary artery; RA, right atrium.

FIGURE 8.3.46. Coronary artery fistula. Longitudinal plane view complemented with a Doppler study of the flow in the coronary fistula. Spectral analysis shows increased flow velocity in both systole and diastole.

Coronary Aneurysms

Although coronary aneurysms are not congenital malformations, we have included the coronary aneurysms seen in patients with Kawasaki disease in this chapter because they occur primarily in children, and their transesophageal echocardiographic evaluation has great relevance. The cardiovascular alterations that can be detected by echocardiography, in addition to the aneurysms themselves, are dilatation of the left ventricle, with deterioration of its systolic function, and pericardial effusion.

Two-dimensional transthoracic and subcostal echocardiography are very useful in the study of children with Kawasaki disease. The use of additional scanning planes has increased the success rate of delineating the anatomy of the coronary artery in these patients.

The feasibility of using transesophageal recordings to explore some coronary segments with greater clarity clearly justifies these studies in the follow-up of children or adults with Kawasaki disease. The transesophageal technique has been particularly useful for visualizing thrombi formed in the aneurysmal coronary arteries. Recordings in the transverse plane show proximal aneurysms, whereas more of the course of a coronary artery can be visualized in longitudinal plane images (Figs. 8.3.48, 8.3.49 and 8.3.50).

FIGURE 8.3.47. Coronary artery fistula. Longitudinal plane image with color Doppler shows the course of the fistula (arrow) between the left coronary artery (LCA) and the pulmonary artery (PA). LA, left atrium; LV, left ventricle; RVO, right ventricular outflow tract.

Transesophageal echocardiography is probably the noninvasive technique of choice in the detection and follow-up of coronary aneurysms in which transthoracic studies are not satisfactory.

Aortic Coarctation

Echocardiographic diagnosis of coarctation of the aorta does not require transesophageal recordings; the vascular obstruction can be identified and quantified with suprasternal images and continuous wave Doppler. In transesophageal echocardiography, the use of transverse scanning probes reveals some overestimation of angiographically calculated diameters, perhaps because of an oblique scanning plane, because the proximal descending aorta is a curved structure rather than a vertical cylinder. Fortunately, it is possible to visualize the coarcted zone with greater clarity using biplane or multiplane transducers (Fig. 8.3.51). Perhaps the principal application of transesophageal echocardiography in patients with aortic coarctation is as a guide in the dilatation of the coarctation with a balloon catheter.

FIGURE 8.3.48. Coronary aneurysm. Transverse plane image shows the normal origin of the left coronary artery (LM). AO, aorta; LA, left atrium.

FIGURE 8.3.49. Coronary aneurysm. Aneurysmal dilatations are seen at the level of the proximal portion of the left anterior descending coronary artery (LAD). LA, left atrium;LV, left ventricle.

Double Aortic Arch

In the double aortic arch malformation, two aortic arches that surround the trachea and esophagus split from the ascending aorta. Later they unite to form the descending aorta.

FIGURE 8.3.50. Coronary aneurysm. Longitudinal plane image shows an aneurysm of the left anterior descending coronary artery (LAD). A thrombus (TH) can be seen inside it.LA, left atrium; LV, left ventricle.

FIGURE 8.3.51. Coarctation of the aorta. Continuous wave Doppler analysis in a patient with coarctation of the aorta (COA) shows characteristic flow distal to the obstruction.

Both arches can be identified with suprasternal and subcostal echocardiography. In most cases the ipsilateral carotid and subclavian arteries originate from them. Transesophageal recordings make it possible to visualize the origin of the two arches from the ascending aorta. The pulmonary artery with its bifurcation should then be shown to be connected to the right ventricle (Figs. 8.3.52 and 8.3.53).

Aortic Stenosis

Transthoracic echocardiography aids in the diagnosis and estimation of the severity of congenital obstruction of the aortic valve. Transesophageal imaging has been used to monitor interventional cardiac catheterization. The routine use of transesophageal monitoring adds additional safety to the procedure and helps reduce both the amount of radiation and the contrast material required.

FIGURE 8.3.52. Double aortic arch. In this echocardiogram taken with a multiplane probe in a patient with a double aortic arch, the normal relationship between aortic valve (AO) and pulmonic valve (PV) can be observed. LA, left atrium; RA, right atrium.

FIGURE 8.3.53. Double aortic arch. Transesophageal study shows the aortic valve (AV) and two aortic arches (AA) splitting off the ascending aorta.

During aortic valvuloplasties, transesophageal imaging allows a more precise measurement of the aortic valve annuli and provides a detailed assessment of the valvular morphology, both before and after dilatation. It also aids in correcting malposition of the guidewire and the balloon catheter and in the rapid detection of aortic regurgitation following each inflation of the balloon. Left ventricular function can be evaluated during inflation of the balloon. The balloon is deflated when ventricular contraction is almost abolished, and the next inflation is performed only when contractility is restored. The images obtained by a transesophageal monoplane transducer are inadequate to determine the spatial position of the balloon catheter. This information is more completely obtained using biplane or multiplane transducers. Likewise, if continuous wave Doppler can be used, the residual transvalvular gradients can be determined.

FIGURE 8.3.54. Aortic stenosis. Transesophageal echocardiogram taken with a multiplanar probe shows a bicuspid aortic valve (AO). LA, left atrium; RA, right atrium; RV, right ventricle.

FIGURE 8.3.55. Ross procedure. M-mode and two-dimensional longitudinal plane images in a patient who underwent a Ross procedure. The pulmonary valve (PV) autograft in the aortic position shows normal motion. AV, aortic valve; LA, left atrium; RVO, right ventricular outflow tract.

Multiplane transducers facilitate recognition of bicuspid valves and provide the exact systolic area of the aortic valves (Fig. 8.3.54).

In our experience, transesophageal echocardiography has been useful in transoperative monitoring of pulmonary valve autograft in the aortic position with placement of a bioprosthesis or homograft in the pulmonary position (Ross procedure) also (Fig. 8.3.55). The principal purpose of this type of surgery is to provide a “permanent” valve replacement in children and adolescents. Placement of a mechanical prosthesis in the aortic position would expose these patients to many years of risk of embolic or hemorrhagic events and the necessity for continuous cardiologic supervision, as well as one or more replacements of the bioprosthesis. Transesophageal echocardiography provides invaluable information in the study of these patients, allowing determination of the diameters of the semilunar valve rings. It is particularly useful in the immediate postoperative evaluation because it permits identification of unsatisfactory results and the necessity for replacing the aortic valve with a prosthesis.

Subvalvular Aortic Stenosis

Subvalvular aortic stenosis can be dynamic or fixed. In the former type, the obstruction is caused by systolic anterior movement of mitral valve structures and is seen in obstructive cardiomyopathy (Fig. 8.3.56). The latter type of obstruction is caused by a subaortic membrane (discrete obstruction) or, less frequently, by a fibromuscular tunnel.

FIGURE 8.3.56. Subvalvular aortic stenosis. Transverse plane image shows significant hypertrophy of the ventricular septum and systolic anterior movement (SAM) of the mitral valve (MV) producing dynamic subvalvular aortic obstruction. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle; TV, tricuspid valve.

Transesophageal study of patients with discrete subaortic stenosis is limited to cases in which an adequate transthoracic study cannot be obtained or as an intraoperative control during surgical resection of the membrane. Visualization of the obstruction with monoplane recordings provides only partial information about the membrane or ring. Images with color Doppler also offer information about the coexistence of aortic valve regurgitation and the not infrequent association of a ventricular septal defect. The information obtained with recordings in the longitudinal plane is more complete, because it is possible to explore all of the left ventricular outlet and reliably quantify the subaortic pressure gradient with continuous wave Doppler (Figs. 8.3.57 and 8.3.58). Other causes of left ventricular outlet obstruction that can be detected with transesophageal imaging include accessory mitral tissue and malalignment of the trabecular septum (Figs. 8.3.59 and 8.3.60).

FIGURE 8.3.57. Subvalvular aortic stenosis. Longitudinal plane image in a patient with a subaortic membrane (arrow). AO, aorta; LA, left atrium; LVO, left ventricular outflow tract; PA, pulmonary artery.

Congenital Malformations of the Mitral Valve

Parachute Mitral Valve

The parachute mitral valve is a congenital heart defect that represents between 1% and 2% of malformations of the heart. It can be associated with diverse types of obstruction to left ventricular emptying. Parachute mitral valve is the most common variety of congenital obstructive mitral lesion. The existence of a single papillary muscle in the left ventricle into which the chordae tendineae insert can be demonstrated in transgastric echocardiographic studies in transverse and longitudinal planes. Because of this, the mitral valve has limited diastolic displacement. In four-chamber and left ventricular long-axis transesophageal images, the dome-shaped valvular opening can be seen (Fig. 8.3.61). These recordings and color Doppler demonstrate that obstruction is more significant at the subvalvular level than at the level of the ring (Fig. 8.3.62). In some cases two papillary muscles can exist, but because of their extreme closeness they function as a single muscle.

FIGURE 8.3.58. Subvalvular aortic stenosis. In this longitudinal plane imaged with color Doppler, the arrow points to accelerated flow in the left ventricular outlet, which appears as a mosaic of colors and is secondary to subvalvular aortic obstruction. AO, aorta; LA, left atrium; LVO, left ventricular outflow tract; PA, pulmonary artery.

FIGURE 8.3.59. Subvalvular aortic stenosis. Transverse plane image of the left ventricular outlet. A malalignment exists between the trabecular and infundibular portions of the ventricular septum, which produces subvalvular aortic obstruction (arrow). AV, aortic valve; LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle.

Duplication of the Mitral Orifice

Two mitral valve openings can be identified with transesophageal echocardiography, especially with multiplanar probes. The characteristics of the subvalvular apparatus, including accessory papillary muscles, can be defined, and associated defects identified. When the examination is complemented with color Doppler, stenosis or regurgitation of one of the valvular components can be demonstrated (Figs. 8.3.63, 8.3.64, 8.3.65, 8.3.66, and 8.3.67).

FIGURE 8.3.60. Subvalvular aortic stenosis. Four-chamber image shows severe subvalvular aortic obstruction secondary to posterior deviation of the trabecular portion of the ventricular septum (lower arrow). With color Doppler, accelerated flow in the left ventricular outlet (upper arrow) can be seen. There is a coexisting ventricular septal defect.AV, aortic valve; LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle.

FIGURE 8.3.61. Parachute mitral valve. Four-chamber image shows a congenital stenosis of the mitral valve (dome-shaped opening) and tricuspid subvalvular structures crossing a ventricular septal defect (D). LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle; TV, tricuspid valve.

Functionally Unicuspid Mitral Valve

The left lateral endocardial cushion forms the embryonic origin of the anterior mitral leaflet. The greater component of the posterior leaflet derives from the muscle of the ventricular wall. In the functional unicuspid mitral valve the posterior leaflet is hypoplastic with very short chordae tendineae. The anterior leaflet has irregular thickness, opens in a dome shaped manner and prolapses in systole (Figs. 8.3.66 and 8.3.67).

FIGURE 8.3.62. Parachute mitral valve. Congenital mitral stenosis. The dome-shaped opening of the leaflets (MV) can be seen, and color Doppler demonstrates turbulent flow (arrows). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle; TV, tricuspid valve.

FIGURE 8.3.63. Duplication of the mitral orifice. Transgastric study with multiplanar transducer in a patient with mitral valve with double opening (arrows). RV, right ventricle.

Accessory Mitral Tissue

The presence of accessory mitral tissue in the aortic subvalvular region can create hemodynamically significant obstruction to left ventricular outflow (Fig. 8.3.68). This anomaly may go unnoticed in angiographic studies and even during cardiac surgery. In these patients transesophageal studies, especially with biplane transducers, are very useful because they provide information about the state of the mitral leaflets, aid in clarifying the site of implantation of accessory mitral tissue, and demonstrate anomalies of the chordae tendineae or papillary muscles. They also allow identification of associated malformations. This information is a great help to the surgeon for planning adequate corrective surgery.

FIGURE 8.3.64. Duplication of the mitral orifice. Multiplane transesophageal study shows the mitral valve with two orifices. There is a large ventricular septal defect. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

FIGURE 8.3.65. Duplication of the mitral orifice. Transesophageal echocardiogram with color Doppler shows the left ventricular inflow through both orifices. LA, left atrium;LV, left ventricle; RV, right ventricle.

FIGURE 8.3.66. Transesophageal four-chamber view. Diastolic frame. The anterior mitral leaflet is dome shaped, whereas the posterior leaflet is a small remnant. The myocardium of the posterior and lateral walls of the left ventricle extends to form a ring to support the valve. LA, left atrium; RV, right ventricle.

FIGURE 8.3.67. Transesophageal four-chamber view. Systolic frame. The anterior mitral leaflet prolapses into the left atrium (LA). The posterior leaflet cannot be distinguished from the left ventricular wall. LV, left ventricle, RV, right ventricle.

Anomalous Insertion of Mitral Chordae Tendineae in the Interventricular Septum

Anomalous insertion of the mitral chordae tendineae in the interventricular septum can create obstruction of the left ventricular outflow tract and should be differentiated from subaortic stenosis caused by a subvalvular membrane because the surgical management is different. Transverse plane images make it possible to identify the left ventricular outflow tract obstruction, and longitudinal sections with multiplane transducers help determine the mechanism (Fig. 8.3.69).

FIGURE 8.3.68. Accessory mitral tissue. Accessory mitral tissue (arrow) produces obstruction in the left ventricular outlet. AO, aorta; LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle.

FIGURE 8.3.69. Anomalous insertion of the mitral chordae tendinae. Transesophageal echocardiographic image at 132° demonstrates the abnormal insertion of mitral chordae tendinae (arrows) in the anterosuperior portion of the left ventricle (LV). AO, aorta; LA, left atrium; RV, right ventricle.

Mitral Arcade or Hammock Valve

In this abnormality, the papillary muscles extend directly to the edges of the leaflets. In the most severe form, the muscles fuse on the leading edge of the aortic leaflet, forming the muscular arcade. The view from the left ventricle shows a fibrous tissue bridge in the shape of an arcade below the anterior mitral leaflet that extends from the anterolateral to posteromedial papillary muscles. Echocardiographically, the direct insertion of the leaflets into the papillary muscles or through short and thick chords can be best demonstrated using the transgastric approach and mid retrocardiac transverse planes (Figs. 8.3.70 and 8.3.71).

FIGURE 8.3.70. Four-chamber view showing a mitral hammock valve. Note the direct insertion of the leaflets into the papillary muscles (arrow) and the dome-shaped opening. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

FIGURE 8.3.71. Mitral hammock valve. Transgastric transverse plane image shows the edges of the leaflets inserting directly into papillary muscles with very short and thick chords. LV, left ventricle; RV, right ventricle.

Cor Triatriatum

Cor triatriatum, or subdivided left atrium, is a cardiac malformation produced by a defect in the incorporation of the common pulmonary vein in the left atrium. The defect consists of a fibromuscular membrane, which divides the left atrium into two chambers: a superior chamber that receives the pulmonary veins, and an inferior chamber, or true atrium, that includes the atrial appendage and the mitral valve, a finding which permits differentiation from a supravalvular mitral ring. The membrane usually inserts in the interatrial septum near the fossa ovalis and extends to the lateral wall of the left atrium.

Although the malformation may be diagnosed in newborns and infants with transthoracic recordings, in older patients, transesophageal echocardiography is the noninvasive diagnostic technique that offers the most information. The features discussed in the following paragraphs are demonstrated with transverse and longitudinal plane recordings complemented with continuous wave and color Doppler.

A membrane that divides the left atrium into two cavities is seen. The pulmonary veins drain into the posterosuperior atrial cavity; the atrial appendage and mitral valve are included in the anteroinferior cavity (Figs. 8.3.72 and 8.3.73). In about half of the cases, an atrial septal defect is observed and can coexist with a patent foramen ovale.

FIGURE 8.3.72. Cor triatriatum. The left atrium (LA) is divided by a membrane (arrows), the superior chamber receives pulmonary veins, and the inferior chamber includes the implantation of the left atrial appendage. LV, left ventricle.

The site of communication between the two atrial portions can be recognized with color Doppler, and spectral analysis of the flow shows whether the atrial membrane is obstructive (Fig. 8.3.73). The right cardiac cavities are dilated, and there is tricuspid regurgitation. Pulmonary hypertension can be quantified with Doppler.

The information provided by transesophageal echocardiography is complete enough that patients with cor triatriatum can undergo corrective surgery without requiring cardiac catheterization.

FIGURE 8.3.73. Cor triatriatum. Shows the communication between the two chambers and turbulent color Doppler flow signals produced by the obstruction. LA, left atrium;LV, left ventricle.

FIGURE 8.3.74. Ebstein anomaly. Four-chamber image shows tethering (arrows) of the tricuspid septal leaflet (S). The movement of the anterior leaflet (A) is large, and the diameter of the tricuspid ring is increased (37 mm). LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle.

Ebstein Anomaly

Ebstein malformation is characterized by the abnormal insertion of the tricuspid valve, which is tethered from the atrioventricular ring along the endocardium of the right ventricle. This creates an atrialized portion of the right ventricle located between the true valve ring and the area corresponding to the abnormal attachment of the tricuspid leaflets. The degree of attachment is variable. In the mild form, only the proximal portions of the septal and posterior leaflets are tethered, to the interventricular septum and ventricular wall, respectively. Usually the anterior leaflet is elongated, with an abnormally posterior insertion into the edge of the junction of the right ventricular inlet and trabecular portion. The tricuspid valve is often insufficient and occasionally stenotic.

FIGURE 8.3.75. Ebstein anomaly. Transverse plane image in a patient with Ebstein malformation. There is tethering of both the anterior (A) and septal (S) leaflets of the tricuspid valve. The functional right ventricle (RV) is moderately reduced in size. LA, left atrium; LV, left ventricle; RA, right atrium.

Two-dimensional echocardiography has replaced angiography as the procedure of choice for the diagnosis of Ebstein anomaly. Patients with this anomaly have been studied by transthoracic two-dimensional echocardiography using parasternal, apical, and subcostal imaging. The four-chamber apical view is particularly valuable for determining the dimensions of the tricuspid valve ring, the atrialized portion of the right ventricle, and the functional right ventricle. On the basis of these findings, the indices of anatomic severity of the lesion have been described. It is also possible to observe the elongation of the anterior leaflet and its exaggerated movement, as well as the ventricular attachment of the septal leaflet. With this information, the most appropriate type of surgery can be chosen.

In adult patients with Ebstein malformation, transesophageal echocardiography is the most useful diagnostic technique available. Using monoplanar transesophageal recordings, it is possible to determine the characteristics of the septal and anterior tricuspid leaflets and visualize the atrialized portion of the right ventricle in a four-chamber image (Figs. 8.3.74and 8.3.75). The degree of tricuspid regurgitation and associated atrial septal defects can be evaluated with color Doppler (Fig. 8.3.76). In transgastric images the three tricuspid leaflets can be visualized and the attachment of the posterior leaflet to the ventricular wall evaluated from the apex to the tricuspid ring.

FIGURE 8.3.76. Ebstein anomaly. Color Doppler aids in evaluating the degree of tricuspid regurgitation (TR) as well as the coexistence of an atrial septal defect (D). LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

With biplanar transesophageal recordings, particularly with right ventricular longitudinal images, multiple data can be obtained, including partial attachment of the leaflet to the infundibulum or the trabecular portion of the right ventricle and adequate imaging of the right ventricular outflow tract and pulmonary arterial tree. In addition, the dimensions of the atrialized and functional portions of the right ventricle can be determined. Likewise, with recordings in two planes with color Doppler, more information on the degree of tricuspid regurgitation is available, and the interatrial septum can be explored completely and the type of septal defect identified with precision (Figs. 8.3.77 and 8.3.78).

With the development of new corrective surgical techniques for Ebstein malformation, echocardiographic studies have served to guide reconstructive surgical management (valvuloplasty) or tricuspid replacement. Transesophageal biplanar or multiplanar imaging is the optimum type of study for evaluating the anatomic and functional status of each of the tricuspid leaflets and their subvalvular apparatus, and the size of the atrialized and functional portions of the right ventricle.

Pulmonary Valvular Stenosis

Pulmonary valvular stenosis may be isolated or may form one part of complex congenital heart disease. When it is isolated, the diagnosis and severity of the obstruction can be established with transthoracic recordings. Transesophageal images have been used during interventional procedures in the hemodynamic laboratory to reduce the length of exposure to x-rays and the quantity of contrast material required.

FIGURE 8.3.77. Ebstein anomaly. Longitudinal plane image with color Doppler shows tethering of the posterior tricuspid leaflet (P). Large movement of the anterior leaflet (A) can be seen. Color Doppler demonstrates mild tricuspid regurgitation (TR). AO, aorta; LA, left atrium; RA, right atrium.

FIGURE 8.3.78. Ebstein anomaly. Longitudinal plane examination complemented with color Doppler demonstrates regurgitation as well as an atrial septal defect (D). AO, aorta; LA, left atrium; RA, right atrium.

The use of transesophageal recordings only in the transverse plane has limitations because it does not offer adequate visualization of the right ventricular outflow tract, and even analysis of the leaflets themselves is incomplete. With biplane or multiplane transducers, the monitoring of balloon pulmonary valvuloplasties provides an assessment of the morphology both before and after dilatation. It is particularly useful for avoiding a malposition of the balloon or guidewire, which can provoke a tricuspid valve lesion. Doppler evaluation of the postdilatation transvalvular pressure gradient has limitations, however, because of the difficulty of aligning the Doppler beam to the direction of blood flow. With color Doppler an immediate estimation of the presence and magnitude of valvular regurgitations is available (Fig. 8.3.79).

Transesophageal study with biplanar images is also useful for recognizing the three pulmonary leaflets (right, left, and anterior). It helps identify bicuspid valves and, most importantly, allows differentiation of valvular and infundibular obstructions or identification of their coexistence (Figs. 8.3.80 and 8.3.81).

Tetralogy of Fallot

Tetralogy of Fallot is caused by an alteration in the development of the embryonic conus. The anterior displacement of the ventricular infundibulum produces pulmonary subvalvular stenosis (in two thirds of patients, stenosis is also valvular). There is a large ventricular septal defect, which is usually below the aortic valve and anterior to the membranous portion of the interventricular septum, although it can extend to other portions of the interventricular septum. The aorta is biventricular, because it overrides the interventricular septum. Approximately 10% of patients with tetralogy of Fallot have anomalies of the coronary arteries.

FIGURE 8.3.79. Pulmonary valve stenosis. Color Doppler–guided continuous wave Doppler demonstrates a peak transvalvular gradient of 90 mm Hg.

In infants and children, conventional transthoracic echocardiography allows the diagnosis of tetralogy of Fallot, and, in most cases, the indication for cardiac surgery, without requiring cardiac catheterization. Transesophageal echocardiography is the noninvasive technique of choice in adolescents and adults for recognizing the diverse abnormalities found in these patients. Recordings in transverse and longitudinal planes are indispensable for evaluating these abnormalities (Figs. 8.3.82 and 8.3.83).

FIGURE 8.3.80. Pulmonary valve stenosis. It is possible to recognize subvalvular pulmonary obstruction (arrow) in the longitudinal plane image. Pulmonary valve leaflets are thickened as well. AO, aorta; LA, left atrium; PA, pulmonary artery; RVO, right ventricular outflow tract; SVC, superior vena cava.

FIGURE 8.3.81. Pulmonary valve stenosis. Significant stenosis of the right ventricular infundibulum (arrow) is demonstrated by color Doppler in longitudinal plane imaging. AV, aortic valve; LA, left atrium; PA, pulmonary artery; RA, right atrium; RVO, right ventricular outflow tract.

With transgastric images in the transverse plane or transesophageal images in the longitudinal plane, dextroposition of the aorta overriding the interventricular septum is recognized. When these images are complemented with color Doppler, the characteristics of the interventricular shunt and the degree of obstruction to right ventricular outflow can be appreciated.

Subvalvular or mixed pulmonary stenosis requires images in the longitudinal plane. With these, the ventricular infundibulum can be explored, the characteristics of the pulmonary valves clarified, and the diameters of the principal pulmonary arterial branches determined, information of great utility for selecting palliative or corrective surgery. With biplane or multiplane transducers, the degree of right ventricular hypertrophy can also be defined, as can the courses of the coronary arteries. Continuous wave and color Doppler study offers information about the degree of obstruction to right ventricular outflow. Moreover, it allows differentiation of tetralogy of Fallot with very severe pulmonary stenosis from pulmonary atresia with ventricular septal defect. In the former, flow in the pulmonary artery is turbulent and systolic, whereas in pulmonary atresia the flow that reaches the pulmonary artery comes from the aorta through a PDA and appears in both phases of the cardiac cycle, predominantly in diastole.

FIGURE 8.3.82. Tetralogy of Fallot. Longitudinal plane imaging in tetralogy of Fallot (TOF). The aorta (AO) overrides the ventricular septum (VS). AV, aortic valve; LA, left atrium; LV, left ventricle; RV, right ventricle.

FIGURE 8.3.83. Tetralogy of Fallot. In this longitudinal plane image it is possible to identify stenosis of the right ventricular infundibulum (arrow). The pulmonary valve annulus is small. LA, left atrium; LV, left ventricle; PA, pulmonary artery.

FIGURE 8.3.84. Pulmonary atresia. In a patient with pulmonary atresia, color Doppler and spectral analysis identify systolic and diastolic flow from a systemic-pulmonary fistula.

Transesophageal echocardiography is particularly important for transoperative and late postoperative evaluation of surgical results. Biplane or multiplane imaging provides assessment of the operated subvalvular, valvular, and proximal supravalvular pulmonary anatomy; the ventricular-to-pulmonary conduits; and the adequacy of the ventricular septal patch. In patients with palliative shunts it is possible to recognize the lack of patency of the fistula or diminished flow because of increased pulmonary vascular resistance with Doppler studies (Fig. 8.3.84).

Transesophageal Echocardiography in Interventional Procedures

Transesophageal echocardiography plays an important role in the cardiac catheterization laboratory as a guide before and during interventional procedures. This technique helps in the proper insertion of catheters, provides immediate results, and detects complications. It is used during valvuloplasty, angioplasty, and electrophysiological studies; but its main utility is during the insertion of devices for closure of atrial and ventricular septal defects. It is also useful in postsurgical vascular obstruction that requires the use of a balloon catheter or stent and during atrioseptostomy. Transesophageal echocardiography reduces radiation exposure time and the use of contrast material.

Atrial Septal Defect Closure

Factors in successful percutaneous closure of an atrial septal defect with a device are the size and location of the defect and, most importantly, the characteristics of its rims. Transesophageal echocardiography helps decide if the procedure is technically feasible or not. The ostium secundum type can usually be closed percutaneously (Fig. 8.3.85). Enough tissue must be present adjacent to the anterior rim of the defect for successful placement of the device. The superior rim of the defect is related to the superior vena cava, the posterior rim to the inferior vena cava, the anterosuperior rim to the aorta, and the anteroinferior rim to the AV valves. The relationship of the defect with adjacent structures is particularly important before implanting the device, because the Amplatzer device left atrial disc measures 7 mm more than the central disc, which is related to the size of the atrial septal defect. There must, therefore, be a distance between the defect rim and the mitral valve and right superior pulmonary vein of at least 7 mm. For some interventional cardiologists, an aortic rim <7 mm does not contraindicate the placement of an Amplatzer device because it is flexible and is designed to embrace the aorta.

FIGURE 8.3.85. Transesophageal images showing a secundum atrial septal defect with flow signals moving from the left atrium (LA) into the right atrium (RA). The anterosuperior rim is of adequate size but the aortic rim is small. AO, aorta.

The maximum diameter of the defect is measured using a balloon catheter and this measurement helps choose the size of the device (Fig. 8.3.86). Subsequently, transesophageal echocardiography is used to visualize the position of the device prior to its releasing, confirm its adequate placement, and detect any complications such as obstruction of the right superior pulmonary vein and/or the mitral valve. The technique also helps determine the presence and severity of any residual shunting after defect closure (Figs. 8.3.87, 8.3.88 and8.3.89).

FIGURE 8.3.86. The balloon catheter is inflated till the shunt disappears. Note an increase in the defect diameter. This helps choose an adequate device for defect closure. RA, right atrium.

FIGURE 8.3.87. Transesophageal view showing the measurement of the rims of superior and inferior vena cava and the longitudinal diameter of the defect. In this view, assessment of the correct position of the device overriding the rim of the superior vena cava (SVC) is done. LA, left atrium; RA, right atrium.

Ventricular Septal Defect Closure

Echocardiography has begun to play an important role in the selection of cases and during the procedure for percutaneous ventricular septal defect closure. Transesophageal echocardiography provides anatomic data such as affected septal segments, size of the defect, malalignment of the septal components and the relationship of the defect to the AV valves.

Percutaneous closure is mainly used in the muscular type of defect (Figs. 8.3.90 and 8.3.91). To perform this procedure it is necessary that the defect is at least 3 mm away from the apex, is not related to the cardiac valves, and is congenital in origin. There are isolated case reports of percutaneous perimembranous defect closure.

FIGURE 8.3.88. Transesophageal view taken at 47°, showing the device embracing the aortic rim of the defect. AO, aorta; LA, left atrium; RA, right atrium.

FIGURE 8.3.89. Amplatzer device in correct position. Color Doppler examination detects a small central leak. AO, aorta, LA, left atrium, RA, right atrium.

Intraoperative Transesophageal Echocardiography in Congenital Heart Disease

The utility of intraoperative transesophageal echocardiography is well established in the management of patients with congenital heart disease. This modality supplements transthoracic echocardiography by providing additional anatomic information, the opportunity to confirm the diagnosis, and based on additional findings, to modify surgery or perform a surgical revision before the patient leaves the operating room.

FIGURE 8.3.90. Transgastric transverse plane image showing an Amplatzer device closing a muscular ventricular septal defect. LV, left ventricle; RV, right ventricle.

FIGURE 8.3.91. Transgastric transverse plane image with color Doppler shows a posterior residual shunt. LV, left ventricle; RV, right ventricle.

Intraoperative transesophageal echocardiography is basically useful in:

1.   AV valve repair. The surgical repair of atrioventricular septal defect varies according to the characteristics of the common AV valve (Fig. 8.3.92).

This modality is useful in assessing residual mitral regurgitation, which is not infrequent, and postsurgical shunts. In Ebstein anomaly, the surgical treatment can vary from tricuspid valvuloplasty or replacement to a Fontan-type surgery depending on the severity of valvular tethering and right ventricular function. Transesophageal echocardiography provides immediate information regarding any residual tricuspid insufficiency following valvuloplasty as well as the functional status of a prosthetic valve or Fontan-type surgery. It also helps assess residual atrial and left ventricular function.

FIGURE 8.3.92. Transesophageal images in a patient with complete atrioventricular septal defect and dysplastic left mural leaflet (A). The postoperative study (B) shows a normally functioning prosthetic mitral valve and the absence of residual cardiac shunts. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

FIGURE 8.3.93. Intraoperative transesophageal images in a patient with tetralogy of Fallot. A. The right ventricular outflow tract is not narrowed but the pulmonary valve shows systolic doming of the leaflets (arrow). B. Doppler examination shows a high transvalvular pressure gradient. C, D. The postoperative study demonstrates residual moderate pulmonary valve regurgitation and mild stenosis.

2.   Right ventricular outflow tract obstruction. After surgical repair of tetralogy of Fallot, transesophageal echocardiography is useful in detecting residual obstruction, severe pulmonary insufficiency, or septal defects that may need additional repair (Fig. 8.3.93). Similarly, the technique is also useful in patients undergoing surgery for subaortic stenosis, especially the tunnel type. In addition, aortic valve function can be assessed.

3.   Complex congenital lesions. In patients with transposition of the great arteries and Mustard or Senning surgery, intra-atrial baffles are clearly visualized and any residual obstruction detected, such as in the baffle that directs blood flow from the pulmonary veins to the right atrium. In Jatene anatomic correction, the anastomosis of the great vessels can be evaluated, as well as the functional status of the pulmonary and aortic valves, and the left ventricle. Intraoperative transesophageal echocardiography is especially useful in complex repairs of outflow tracts such as placement of intraventricular conduits in patients with double outlet ventricle (Rastelli surgery).

4.   Assessment of ventricular function. Transesophageal echocardiography is useful in assessing ventricular function during and immediately after surgery. Ventricular dysfunction associated with cardiopulmonary bypass has poor prognosis. Intraoperative transesophageal echocardiography is not without limitations. For example, assessment of residual mitral regurgitation after repair of atrioventricular septal defects should take into account the different hemodynamic factors such as preload, ventricular function, and systolic blood pressure. Otherwise, significant residual regurgitation would be misdiagnosed as mild.

Valvular repairs and complex reconstruction of the outflow tracts benefit the most from the additional information provided by intraoperative transesophageal echocardiography.

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