Transesophageal Echocardiography (TEE) in Congenital Heart Disease with Focus on the Adult

TRANSESOPHAGEAL ECHOCARDIOGRAPHY

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TRANSESOPHAGEAL ECHOCARDIOGRAPHY (TEE) IN CONGENITAL HEART DISEASE WITH FOCUS ON THE ADULT Wanda C. Miller-Hance, MD, and Norman H. Silverman, MD

Approximately 32,000 infants each year in the United States are born with congenital heart disease, translating to 1 out of every 115 to 150 births.60Significant advances in diagnostic techniques and medical and surgical therapies over the past several years allow for survival of a great majority (over 85%) of these patients into adulthood.61This accounts for a flourishing population of adults with congenital malformations of the heart at an increasing rate of about 5% per year.61It has been anticipated that by the year 2000 this population would reach almost a million.60 Nearly 40% of patients with congenital heart disease require surgical intervention to palliate or correct their condition at some point during their life, increasing the need for continuing medical care.74,75 Echocardiography has become the primary diagnostic method for the recognition and assessment of congenital heart disease in the pediatric and adult age groups. The transesophageal approach has permitted the acquisition of anatomic and hemodynamic information not obtainable by transthoracic echocardiography, particularly in the adult patient with substandard echocardiographic precordial windows. Transesophageal echo-

cardiography (TEE) has allowed for the selective use of diagnostic modalities, such as angiography and magnetic resonance imaging, for monitoring of therapeutic catheter procedures and for intraoperative evaluation of congenital heart repairs. This article emphasizes the contribution of TEE to adults with congenital heart disease. Indications for the study, imaging technique, anatomic and hemodynamic assessment of common defects, and the role of TEE during interventional procedures and surgery for congenital heart disease are addressed. Specific cardiac malformations are described with focus on TEE data acquisition and analysis. TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN ADULTS WITH CONGENITAL HEART DISEASE: INDICATIONS, TECHNIQUE, AND ANATOMIC AND HEMODYNAMIC ASSESSMENT A number of publications have addressed practical issues related to TEE in adults, such as insertion of the imaging probe, transducer manipulation, optimization of hardware con-

From the Departments of Anesthesia and Perioperative Care (WCM-H), Pediatrics (WCM-H, NHS) and Radiology (NHS); and the Pediatric Echocardiography Laboratory (NHS, WCM-H), University of California, San Francisco, San Francisco, California

CARDIOLOGY CLINICS VOLUME 18 * NUMBER 4 * NOVEMBER 2000

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trol settings, imaging planes of interest, and interpretation of findings.47,53, 58, 112 These sources should be referred to for a general survey of TEE. The anatomic and hemodynamic evaluation of congenital heart disease in the adult is highly specialized, requiring in depth knowledge of spatial cardiac anatomy, pathology, pathophysiology, differential diagnosis, and alternate diagnostic modalities in the evaluation of the cardiovasto the excular ~ y s t e m . ~49,~ - ~In~addition , tensive cognitive and technical skills essential to performing a TEE examination as proposed by the American Society of Echo~ a r d i o g r a p h ythe , ~ ~procedure necessitates advanced proficiency in the application of various modalities of echocar diography (M-mode, two-dimensional, pulsedand continuous wave Doppler, color flow mapping, contrast echocardiography) to congenital heart disease,", 43, loo a thorough knowledge of the natural history of the defects,75nonsurgical (interventional)techniques, palliative and corrective surgical approaches, long-term sequelae, and potential complications. The following focuses on the indications, imaging technique, and applications of TEE to the anatomic and hernodynamic assessment of the adult with congenital heart disease. Indications and Contraindications

High-quality two-dimensional TEE provides diagnostic-quality images in most congenital cardiac anomalies when the transthoracic examination or other studies have not successfully elucidated the necessary clinically relevant information. By overcoming limitations related to poor windows, suboptimal image quality, or lung interference, this modality is able to facilitate morphologic and functional assessment of congenital cardiac malformations substantially. Indications for TEE in the adult with congenital heart disease are summarized as follows: Indications in inpatient and outpatient settings Define important anatomic and hemodynamic information when the data provided by previous studies are inadequate or suboptimal Establish a complete diagnosis in cases of complex heart disease Confirm or exclude a diagnosis of clinical relevance Indications during interventional cardiac catheterization procedures

Monitoring and guidance of valvuloplasties Monitoring and guidance of angioplasties Monitoring and guidance during closure of intracardiac shunts Monitoring and guidance of transeptal atrial puncture Guidance of electrophysiologic procedures Indications during palliative and corrective surgical procedures Confirmation of preoperative diagnoses Detection of unsuspected findings Exclusion of anticipated pathology Modification of surgical approach and plan Assessment of the adequacy of the surgical repair Guidance of surgical revision Monitoring of ventricular volume Monitoring of intracardiac and intravascular air Monitoring myocardial performance Evaluation of hemodynamic instability Formulation of perioperative anesthetic and critical care plans Transesophageal echocardiography might be superior to routine surface echocardiography in the adult for the evaluation of specific cardiac defects, such as certain types of atrial septa1 defects, anomalous pulmonary venous connections, and complex cardiac malformations. This technology is also key in confirming or excluding diagnoses of major clinical relevance in congenital heart disease, such as atrial baffle pathology (leak or obstruction), Fontan obstruction, or related venous thrombus. Transesophageal echocardiography plays an increasingly important role in the catheterization laboratory in guiding and monitoring of interventional procedures in patients with congenital heart disease and evaluating their successes, failures, and complications. In the perioperative setting during palliative or corrective congenital heart surgery, TEE allows for real-time clinical decision making, hemodynamic monitoring, and immediate assessment of surgical results. Risk benefit considerations should determine when a contraindication for TEE exists. Contraindications in general are similar to those that apply for upper gastrointestinal endoscopy. These include conditions associated with increased risk for complications,

TEE IN THE ADULT WITH CONGENITAL HEART DISEASE

such as airway or esophageal pathology, or severe respiratory decompensation. Potential complications of TEE include trauma to the oropharynx, esophagus, or stomach; esophageal or gastric perforation; laryngospasm; arterial hypoxemia; arrhythmias; hemodynamic alterations; and complications related to the drugs used for the procedure. Technique

The technique for outpatient transesophageal examination in adults with congenital heart disease does not vary significantly from the procedure in other patients. In addition to a careful history, physical examination, and informed consent, the standard safety precautions associated with an endoscopic procedure should be followed. Although serious complications during adult TEE are rare, it should be considered that this is a semi-invasive procedure that may result in some degree of patient discomfort and potential risks. Appropriate measures should be taken to provide adequate local and systemic anesthesia. This usually is accomplished by a combination of oropharyngeal topical anesthesia and intravenous sedation. Standard cardiorespiratory monitoring should include intermittent blood pressure assessments during the procedure, electrocardiographic monitoring, and pulse oximetry. The facilities should be equipped with oxygen and suction capabilities. Drugs and equipment for cardiopulmonary resuscitation should be available. Patients with congenital heart disease may have significant hemodynamic disturbances and be marginally compensated, therefore, the judicious, titrated administration of sedatives is essential. For patients with cyanotic heart disease, additional considerations apply, including: (1)potential for paradoxical air embolism during the administration of intravenous fluids or drugs, (2) detrimental effects of the rapid onset of anxiolytics, ( 3 ) anticholinergics and sedatives, and (4)afterload decreases with exacerbation of right-to-left shunts and systemic arterial desaturation caused by the agents administered during the procedure. Endocarditis after TEE has been reported in the literature but is considered an unlikely event.20Recent guidelines by the American Heart Association have indicated that endocarditis prophylaxis is not recommended for TEE but should be optional for patients considered at high risk.16Selected candidates for

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endocarditis prophylaxis may include those with a prior history of endocarditis, prosthetic heart valves, and postoperative patients with surgically created aortopulmonary shunts or conduits. Image Acquisition

Transesophageal probes can be manipulated in three general directions: (1)advanced or withdrawn, (2) anteflexed or retroflexed, and ( 3 ) rotated clockwise or counterclockwise in relation to the sagittal plane. As the probe is advanced and withdrawn, the basal (superior) and apical (inferior) structures come into view. Transducer anteflexion displays anterior, more cranial cardiac structures; retroflexion reveals posterior, more caudal structures. Clockwise rotation allows for imaging of rightward structures, and counterclockwise rotation of the transducer permits viewing of left-sided structures. Adult transesophageal probes frequently provide an additional control that allows lateral (left and right) motion. The image orientation and nomenclature guidelines proposed by the American Society of Echocardiography for the standard basal short-axis, four-chamber, long-axis, and transgastric short-axis TEE views are ~ u g g e s t e d . ~ ~ Transverse images of the heart and great arteries are obtainable with single, biplane, and multiplane probes. Short-axis views consist of sectional transverse (horizontal) planes, ranging from the base to the apex of the heart (Fig. 1). The most cranial short-axis view is obtained at 0" at the midesophageal level with slight probe anteflexion to display the aorta, main pulmonary artery, and proximal pulmonary artery branches (Fig. 1A). Advancement of the probe demonstrates the aortic valve in short axis, the origin, and proximal course of the coronary arteries. Rotation of the horizontal plane to approximately 40" to 60", if a multiplane probe is available, displays a true aortic valve short axis with visualization of all cusps in one plane (Fig. 1B). Counterclockwise rotation of the probe in this position displays more of the left atrium, left atrial appendage, and left-sided pulmonary veins. Clockwise rotation demonstrates the rightsided pulmonary veins, superior vena cava, atrial septum, and right atrial appendage. Further advancement of the probe at a 0" angle displays the four-chamber view demonstrating the atria; ventricles; sections of the atrial, atrioventricular, and ventricular septae;

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Figure 1. Various views that can be obtained during the transverse plane examination. Ao = aorta; MPA = main pulmonary artery; RPA = right pulmonary artery; LPA = left pulmonary artery; AoV = aortic valve; RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle; RVOT = right ventricular outflow tract; LVOT = left ventricular outflow tract. (From Muhiudeen Russell IA, Miller-Hance WC, Silverman NH: lntraoperative transesophageal echocardiography for pediatric patients with congenital heart disease. Anesth Analg 87:1058, 1998; with permission.)

and the atrioventricular valves (Fig. 1D). Definition of the atrial situs, venoatrial and atrioventricular relationships, ventricular morphology, and septa1 anatomy is possible from the combination of these views. Anterior angulation of the probe brings the membranous ventricular septum, left ventricular outflow tract, and proximal aorta into view (fivechamber view) (Fig. 1C). Posterior probe angulation displays the coronary sinus. Advancing the probe into the stomach and flexing it maximally generates images of the left ventricle in short-axis, multiple paracoronal cross-sections of the left ventricle, mitral valve, papillary muscles, and oblique sections of the right ventricle (Fig. 1E). Longitudinal views of the heart and great vessels are possible with biplane and

multiplane probes (Fig. 2). With the biplane probe the bicaval view is obtained by clockwise rotation of the transducer to display the interatrial septum, entrance of the superior vena cava, and right-sided pulmonary veins (Fig. 2A). The right pulmonary artery is usually evident in short axis. Advancement of the transducer demonstrates the inferior vena cava to the right atrial junction. Counterclockwise rotation of the probe provides visualization of the left ventricular outflow tract (LVOT) and ascending aorta (Fig. 2B). Further counterclockwise rotation brings into display the right ventricular outflow tract (RVOT) and main pulmonary artery (Fig. 2C). Additional counterclockwise manipulation displays the left atrium and left ventricle in the two-chamber view (Fig. 2 0 ) . Definition of

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ventriculoarterial connections and imaging of outflow tracts is enhanced by the longitudinal plane examination; however, the Doppler angle of interrogation from these views does not allow for accurate assessment of pressure gradients. A multiplane transducer produces intermediate, transitional images between the primary transverse and longitudinal planes. From the level of the base of the heart, bicaval view imaging is obtained at approximately 90" to 1009 long-axis LVOT imaging at 110" to 140", and modified RVOT imaging at 60" to 80" (Fig. 3). The multiplane approach pro-

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vides for acquisition of additional information not conforming to conventional anatomic planes. Patients who may substantially benefit from this technology include those with complex cardiac malformations in which the standard imaging planes may not be adequate for a complete morphologic and hemodynamic assessment. In recent years, the use of transesophageal transducers with multiplane capabilities has been reported to provide further diagnostic information and superior imaging performance in adult patients. The deep transgastric plane examination is feasible with a single, biplane and multiple

Figure 2. Various views that can be obtained during the longitudinal plane examination. SVC = superior vena cava; IVC = inferior vena cava; LA = left atrium; RA = right atrium; RPA = right pulmonary artery; LVOT = left ventricular outflow tract; RVOT = right ventricular outflow tract; Ao = aorta; PA = pulmonary artery; LV = left ventricle. (Modified from Muhiudeen Russell IA, MillerHance WC, Silverman NH: lntraoperative transesophageal echocardiography for pediatric patients with congenital heart disease. Anesth Analg 87:1058, 1998; with permission.)

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Figure 3. Right ventricular outflow tract (RVOT) view. Multiplane transesophageal echocardiography (TEE) allows for transitional imaging between the primary transverse and longitudinal planes. The right ventricular view, which displays the inflow and outflow, can be obtained by rotating the imaging plane to 60" to 80". LA = left atrium; N = tricuspid valve; PV = pulmonary valve; RVOT = right ventricular outflow tract.

probe providing images of the RVOT and LVOT, the systemic and pulmonary veins, the inlet and outlet components of the ventricular septum, and the atria and atrioventricular valves (Fig. 4).36,67 The transgastric location is particularly advantageous for assessment of gradients across ventricular outflow tracts since it optimally aligns the Doppler angle of incidence to the direction of flow. The combination of transverse and longitudinal planes permits examination of the aortic root, transverse arch and vessels, and descending thoracic aorta. Pulsed-, continuous wave, and color flow Doppler examinations should be combined with two-dimensional echocardiography from multiple imaging planes. Specific focus at cardiovascular structures should be dictated by the suspected pathology.

Anatomic and Hemodynamic Assessment The comprehensive echocardiographic assessment of the adult with suspected or known congenital heart disease should include a logical, detailed, and systematic analysis of intracardiac and extracardiac structures. This requires in depth knowledge of the echocardiographic segmental approach to

cardiac diagnosis, the two-dimensional features that determine chamber and great vessel morphology, the imaging techniques used to evaluate cardiac malpositions, and the echocardiographic findings of simple and complex forms of congenital heart disease. There are several recommended resources for exhaustive discussions on the subject of echocardiography and congenital heart disease: Pediatric Eckocardiography by N. H. Silverman (Williams & Wilkins); Eckocardiograpky in Pediatric Heart Disease by A. R. Snider, G. A. Serwer, and S. B. Ritter (Mosby); EckoCardiographic Diagnosis of Congenital Heart Disease: An Embryologic and Anatomic Approach by L. M. Valdes-Cruz and R. 0. Cayre (Lippincott-Raven); and Transesophageal Eckocardiograpky in Congenital Heart Disease by 0. Stumper and G. R. Sutherland (Little, Brown and Company). The segmental morphologic analysis of the heart requires definition of the connections of the various cardiac segments, visceral situs or arrangement, atrial situs, and venoatrial, atrioventricular, and ventriculoarterial connections.%,94 Important determinants in the segmental analysis of congenital heart disease include: Visceral situs Venoatrial connections systemic and pulmonary veins Atrial situs solitus or normal arrangement, inversus, ambiguous Atrioventricular connections concordant, discordant, double inlet, straddling, absent Ventriculoarterial connections concordant, discordant, double outlet, single outlet Atrial, ventricular, atrioventricular septae Atrioventricular and semilunar valves Ventricular outflows Great arteries Atrioventricular and semilunar valves should be examined, septa1 structures delineated, and chamber and great vessel anatomy defined. This information is essential in the assessment of simple cardiac lesions and in the diagnosis of complex forms of congenital heart disease. The combination of pulsed- and continuous wave Doppler and color flow echocardiography allows quantitative analysis of obstructive lesions, regurgitant flows, 51, and intracardiac and extracardiac 8m1 Contrast echocardiography is helpful in demonstrating right to left shunts, and color

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Figure 4. Various views that can be obtained during transgastric plane examination. PA = pulmonary artery; RV = right ventricle; LV = left ventricle; SVC = superior vena cava; RA = right atrium; LA = left atrium; A 0 = aorta; MPA = main pulmonary artery; LAA = left atrial appendage. (From Muhiudeen Russell IA, Miller-Hance WC, Silverman NH: lntraoperative transesophageal echocardiography for pediatric patients with congenital heart disease. Anesth Analg 87:1058, 1998; with permission.)

Doppler echocardiography has high sensitivity in the identification of left to right shunts. TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN THE CATHETERIZATION LABORATORY

Cardiac catheterization currently is used selectively in the anatomic and functional evaluation of congenital heart disease. Over the past 2 decades, interventional procedures have become increasingly important in the

nonsurgical management of congenital cardiac anomalies. TEE allows for safer and more effective application of catheter-based approaches and may reduce fluoroscopic exposure, amount of contrast material administered, and duration of the interventional prolo9Studies addressing the role of this cedure.28, imaging modality confirm major contributions of transesophageal monitoring.1s,lo9,ll7-lzo These include: (1)acquisition of detailed anatomic and hemodynamic data before and during the procedure, (2) real-time evaluation of catheter placement across valves and vessels,

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(3) immediate assessment of the results, and (4) monitoring of complications associated with the interventions. The refinement in interventional cardiac catheterization coupled with advances in TEE currently allows for the high success rate of these procedures and low incidence of complications. INTRAOPERATIVE TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN CONGENITAL HEART DISEASE Intraoperative TEE has been used in adult patients for monitoring of left ventricular preload, detection of myocardial ischemia, and evaluation of native valve repair and prosthetic valve function. Numerous reports in recent years citing the value of TEE in the intraoperative management of congenital heart disease suggest that many patients also may benefit from the diagnostic and functional assessment that this technology provides.@,66, 68, 88, 10G107 Task forces on practice guidelines have proposed the following clinical applications for intraoperative TEE in patients with congenital heart disease: When operations are performed on cardiac defects in which there are significant residual abnormalities, such as outflow tract obstruction, valve regurgitation or stenosis, or intracardiac communications are anticipated or suspected (Society of Pediatric Echocardi~graphy)~~ Monitoring and guidance during cardiothoracic procedures when there is a risk for residual shunting, valvular insufficiency, obstruction, or myocardial dysfunction (American College of Cardiology/ American Heart Association/ American Society of Echo~ardiography)~ Congenital heart surgery for most lesions requiring cardiopulmonary bypass (American Society of Anesthesiologists/ Society of Cardiovascular Anesthesiologist~)~~~ Although these indications for TEE were primarily directed at pediatric patients it would be reasonable to assume that they would also apply to adults undergoing surgery for congenital heart disease. Transesophageal echocardiography has a definitive impact in the perioperative management of patients undergoing congenital

heart surgery.6M6, 68, lo2,Io6, lZ7This modality has been shown to provide additional anatomic information over conventional transthoracic imaging, and the opportunity for confirmation of preoperative diagnoses and modification of the surgical approach if new or different pathology is identified.@,83, 84, *lo Intraoperative TEE assists in the formulation of anesthetic plans by guiding the management of fluids, inotropes, and vasodilators82;allows for continuous monitoring of myocardial function3*lol; and allows detection of intracavitary and intravascular air and myocardial ischemia.30In many congenital surgical tenters TEE has been established as a standard of care for intraoperative assessment of most repairs before removal of bypass cannulas and closure of the sternotomy. This technology allows for immediate detection of suboptimal surgical repairs and significant postoperative residua, improving the efficacy of the surgical intervention. TEE may also help in evaluating potential factors that contribute to difficulties associated with weaning from cardiopulmonary bypass. In several series, reinstitution of cardiopulmonary bypass (CPB) and reoperation is prompted by TEE in as much as 7% of congenital repairs.67,lo4,lo5 In the postoperative setting, TEE provides crucial diagnostic information in the critically ill

Figure 5. Transesophageal transverse plane view of secundum atrial septa1 defect demonstrating left to right atrial shunting by color flow Doppler in the region of the fossa ovalis. RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle. (See also Color Plate 3, Fig. 19.)

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patient that may define and exclude specific care plans. This imaging approach may obviate the need for postoperative diagnostic studies, prolonged hospitalization, and further surgery, in addition to potentially reducing surgical morbidity and the costs of medical and surgical care. Investigations are currently under way to evaluate the potential influence of this technology on clinical outcomes in patients with congenital heart disease. SPECIFIC CONGENITAL MALFORMATIONS Shunt Lesions Atrial Septa1 Defects

Atrial septal defects are one of the commonest congenital cardiac malformations identified in the adolescent and adult age These lesions account for approximately one quarter to one third of all cases of congenital heart defects in the adult population. Four main morphologic types of interatrial communications are identified: (1)ostium secundum, (2) ostium primum, ( 3 ) sinus venosus, and (4) coronary sinus atrial septal defects. The commonest defect, the secundum type, is centrally located in the atrial septum

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in the region of the fossa ovalis (Fig. 5; see also Color Plate 3, Fig. 19). These defects may be single or of the multiple fenestrated type and may occur in isolation or as part of other complex cardiac malformations. In some cases, this defect is associated with mitral valve prolapse and mitral regurgitation. Sinus venosus defects may be superior or inferior vena caval type. Most defects in this category are located near the entrance of the superior vena cava and right pulmonary veins high in the atrial septum (superior vena caval type) (Fig. 6).lz3Sinus venosus defects are commonly associated with anomalous pulmonary venous connection, particularly of the right sided veins to the superior vena cava or right atrium. TEE has been shown to be superior to transthoracic echocardiography in the diagnosis of this particular type of atrial septal 54, 71 The relatively uncommon defects defe~t.4~. in the inferior vena caval-atrial junction are characterized by a deficiency of the inferior limbic septum. Ostium primum atrial septal defects (partial atrioventricular septal defect, atrioventricular canal, or endocardia1 cushion defect) extend from the lower aspect of the atrial septum to the junction of the atrioventricular valves (Fig. 7; see also Color Plate 3, Fig. 20). These are often associated with a commissure or "cleft" in the anterior mitral leaflet and variable degrees of mitral regurgitation. Visualization of the so-called mitral valve cleft is possible in the transgastric short-

Figure 6. Transesophageal longitudinal plane view of superior-type sinus venosus atrial septal defect demonstrating the deficiency of the atrial septum between the upper portion of the right and left atria near the entrance of the superior vena cava (arrows). RA = right atrium; LA = left atrium; SVC = superior vena cava.

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Figure 7. Transesophageal transverse plane view of primum atrial septal defect showing the extension of the defect from the lower edge of the atrial septum to the level of the atrioventricular (AV) valves and the corresponding shunt by color Doppler echocardiography. RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle. (See also Color Plate 3, Fig. 20.)

axis view at the mitral valve level and can also be recognized in the standard four-chamber and long-axis LVOT views because of the chordal attachments of the anterior mitral valve leaflet to the ventricular septum. Echocardiographically, the atrioventricular valves are seen to insert at the same level because of deficiency in the atrioventricular septum. The least common type of atrial septal defect, the coronary sinus communication, is defined on echocardiography by an enlarged coronary sinus with a deficient roof (unroofed coronary sinus). This frequently is found in association with a persistent left superior vena cava. This systemic venous anomaly can be appreciated in a variety of transesophageal echocardiographic planes. In the transverse axis this is seen as an echo-free space wedge between the left upper pulmonary vein and left atrial appendage. In the longitudinal plane this can be identified as it enters the coronary sinus. Contrast echocardiography with injection of agitated saline into a left arm or neck vein is particularly helpful in identifying the left superior vena cava. The transthoracic echocardiographic evaluation of atrial septal defects in adults may be challenging and in some cases may require the use of the transesophageal window. TEE provides excellent interrogation of the inter-

atrial septum with a sensitivity exceeding that of transthoracic echocardiography for the detection of atrial septal defects.45, 71 The diagnostic evaluation of atrial septal defects is 76 assisted by spectral and color Doppler.56* Echocardiographic findings that support the diagnosis of an interatrial communication in the absence of the definite identification of a defect in.clude right ventricular volume overload, pulmonary artery dilation, and right-toleft shunting by contrast echocardiography. Atrial septal defects are imaged in the transverse and longitudinal planes. These scanning planes allow for detailed characterization of the defect, definition of its location with respect to the atrial septum and size, and the assessment of associated lesions, such as anomalous pulmonary venous drainage, mitral valve prolapse, and regurgitation. Additional goals of the echocardiographic evaluation include assessment of chamber and vessel enlargement, pulmonary artery pressures, and quantification of shunt magnitude. Estimates of pulmonary artery systolic pressures can be derived from the peak velocity of the tricuspid regurgitant jet, if present, using the modified Bernoulli equation. The end diastolic velocity of the pulmonary regurgitation signal provides for an assessment of the pulmonary artery diastolic pressure. The intraoperative evaluation of interatrial communications includes confirmation of the defect location, size and assessment of shunt flow, and evaluation of potentially associated pathology. Additional contributions of TEE to the intraoperative management of these patients include: (1) confirmation of the adequacy of cardiac deairing, (2) assessment of the adequacy of the surgical repair, (3) evaluation of post repair atrioventricular valve competence, and (4) evaluation of ventricular function. Transesophageal echocardiography also plays an important role in the cardiac catheterization laboratory during transcatheter clo57 TEE sure of atrial septal defects (Fig. 8).35, provides confirmation of the diagnosis, and assists in sizing of the defect, determination of optimal occluder dimensions, imaging of atrial septal rims, and evaluation of pulmonary venous return. TEE provides for realtime observation and confirmation of appropriate device placement and effectiveness of occlusion. It also allows for recognition of potential problems such as unusual device arm positions, distortion of systemic or pulmonary venous inflows, and atrioventricular valves.

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Figure 8. A, Transesophageal bicaval view demonstrating detailed features and position of atrial septal defect occluder (closure) device following transcatheter placement. The plane of the interatrial septum is indicated by the large arrows. The central pin that joins the right and left atrial aspects of the device is well seen (small arrow). The smaller closer arrows with asterisk identify the “knuckles” in the left atrial arms of the device. B, Inferior vena cava contrast injection with agitated saline demonstrates no residual right to left atrial shunting following occluder device placement. RA = right atrium; LA = left atrium; SVC = superior vena cava; IVC = inferior vena cava.

Ventricular Septa1 Defects

Ventricular septal defects are the commonest congenital cardiac anomalies identified in infan~y.2~ In adults with adult congenital heart disease, ventricular septal defects account for approximately 10% of all cases.lZ6 A high incidence of spontaneous closure of these defects accounts for the decreased prevalence between pediatric and adult groups. In the adult age group, ventricular septal defects may be found alone or in association with other cardiac anomalies. Morphologically, the ventricular septum is made of the following four components: the (1)membranous, (2) inlet, (3) trabecular, and (4) outlet septa. Ventricular septal defects are classified according to their location as follows: (1)perimembranous, (2) inlet, (3) muscular or (4) doubly committed outlet defects.33 Defects that extend beyond one region of the septum may also be termed for the area they extend into (i.e., perimembranous-inlet, perimembranous-outlet, and perimembranoustrabecular defects). Spontaneous closure of ventricular septal defects occurs most frequently in those located in the perimembranous and muscular regions. Anatomic or functional closure of defects may occur by a variety of mechanisms. Spontaneous closure of most defects, if it occurs, takes place during early childhood al-

though late closure has also been documented in olzer children and young adults. The commonest defect, the perimembranous type, is located near the tricuspid valve just beneath the aortic valve (Fig. 9; see also

Figure 9. Transesophageal transverse plane view of perimembranous ventricular septal defect with color flow Doppler demonstrating the ventricular left to right shunting. Arrows indicate the location of the ventricular septal defect near the septal leaflet of the tricuspid valve. RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle. (See also Color Plate 3, Fig. 21 .)

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Color Plate 3, Fig. 21). These defects are best seen in the five-chamber view at the level of the lower esophagus. In the aortic short-axis view, the defect can be seen in close proximity to the tricuspid valve. Associated aneurysms of the membranous septum (ventricular septal aneurysms) or tricuspid tissue tags frequently are observed. The presence of a septal aneurysm has been associated with a high incidence of spontaneous defect closure. Occasionally, perimembranous ventricular septal defects, particularly those that occur in the high membranous septum, are associated with aortic cusp herniation into the defect and progressive aortic valve regurgitation. The development of membranous subaortic stenosis has also been noted in association with perimembranous defects.14,lz8 Muscular defects are entirely surrounded by muscular septum and occur most frequently in the central or apical trabecular region (Fig. 10; see also Color Plate 4, Fig. 22). Color Doppler echocardiography is particularly helpful in the evaluation of multiple defects. Inlet ventricular septal defects, also termed atrioventricular canal-type defects, are located in the posterior or inlet septum and lie in close proximity to the atrioventricular valves. Echocardiographically these defects are recognized by the fact that both atrioven-

tricular valves are found at the same level without the normal offset and inferior tricuspid position. These defects are usually large and rarely close spontaneously. Defects in the outlet septum are referred to as supracristal, infundibular, doubly committed, or subarterial ventricular septal defects. These lie just underneath the aortic and pulmonary valves and frequently coexist in association with aortic regurgitation caused by cusp herniation related to poor aortic valvular support (Fig. 11). The longitudinal plane of the outflow tracts provides adequate visualization of this defect, in addition to anatomic and functional characterization of the aortic valve. Other classifications of interventricular communications consider the presence or absence of restriction and lack of or alignment between the outlet and trabecular septa. Malalignment may be caused by anterior or posterior deviation of the outlet septum with respect to the trabecular portion on the ventricular septum. Full interrogation of the ventricular septum by TEE requires the use of multiple planes because of the complexity of this structure. The combination of two-dimensional echocardiography, spectral, and color Doppler modalities is needed for adequate evaluation. The echocardiographic examination should

Figure 10. Transesophageal transverse plane view of muscular ventricular septal defect with color flow Doppler demonstrating (A) the ventricular level shunt. Arrows indicate location of the defect in the mid muscular septum. 5, Corresponding transgastric shortaxis view. RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle. (See also Color Plate 4, Fig. 22.)

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technique provides exquisite sensitivity to the identification of the tiniest defects, as only a few microbubbles in the left ventricle are required for diagnostic confirmation. Contrast echocardiography is particularly useful for suspected defects unable to be imaged by standard approaches, for small muscular defects in association with pulmonary hypertension, and in the intraoperative evaluation of post repair residual defects. A trioventricular Septa1 Defects (Atrioventricular Canal Defects) Figure 11. Transesophageal longitudinal plane view of subarterial (doubly committed) ventricular septal defect showing herniation of aortic valve cusp (arrow) into the right ventricular outflow tract (RVOT) through the defect. LA = left atrium; LV = left ventricle; A 0 = aorta.

consider the region of the septum involved, the identification of all defects, assessment of the size of the defect and its borders, evaluation of chamber sizes and wall thickness, assessment of shunt size (pulmonary to systemic flow ratio), estimation of right ventricular and pulmonary artery pressures, and identification of additional associated lesions. The peak systolic velocity across the ventricular septal defect allows for estimation of right ventricular systolic pressure (RVSP) and pulmonary artery systolic pressure

RVSP or PASP = SBP - 4 (VSD)* SBP = Systolic blood pressure; VSD = Peak velocity of ventricular septal defect jet.

A large ventricular septal defect has a small pressure gradient, and a smaller, restrictive defect displays a larger pressure difference between the left and right ventricles. In addition to confirming the presence of a defect, color flow mapping of ventricular jets aids in defining the location of the defect and provides optimal alignment of the spectral Doppler beam, assisting in the estimation of interventricular pressure gradients. The authors have used venous contrast echocardiography to detect relatively smalI right-to-left ventricular level shunts.Iz1This

Atrioventricular septal defects, also termed atrioventricular canal or endocardia1 cushion defects, are anomalies that involve aberrant cardiac septation.19This results in defects that typically involve deficiencies on the atrial, atrioventricular, and inlet ventricular septae. Atrioventricular septal defects typically are characterized by a common valve orifice. In the complete form, the common valve contains five leaflets, two of which straddle the atria and ventricular septa, the anterosuperior and posteroinferior bridging leaflets. The classification of these lesions as proposed by Rastelli et a179considers the morphology of the anterosuperior bridging leaflet. The common atrioventricular valve orifice may have an undivided common orifice or can be divided into two orifices by a tongue of tissue that connects the bridging leaflets. The attachment of the atrioventricular valve to the cardiac septae accounts for the level of intracardiac shunting (atrial, ventricular, ventricular to atrial). The echocardiographic examination should focus on the following: (1) defining the type and extent of the intracardiac communications, (2) demonstration of valve morphology, attachment, and function, (3) assessment of commitment of the atrioventricular junction to the underlying ventricular myocardium and ventricular size (balance), and (4)identification of associated defects (tetralogy of Fallot, double outlet right ventricle, total anomalous pulmonary venous connection, pulmonary a t r e ~ i a )TEE . ~ ~ planes, which assist in the evaluation of these defects, involve a combination of esophageal and transgastric transverse, horizontal, and modified planes (Fig. 12; see also Color Plate 4, Fig. 23).67,85 Postoperative assessment of atrioventricular septal defects includes detection of residual

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Figure 12. Transverse plane view of complete atrioventricular septal defect (AV canal defect) in end-diastolic frame (left) demonstrating the anterior bridging leaflet (arrow) and the extent of the interatrial and interventricular communications. Right, Color flow mapping of the defect shows multiple regurgitant jets through the right and left components of the common AV valve (arrows). RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle; ABL = anterior bridging leaflet. (See also Color Plate 4, Fig. 23.)

shunting, for which Doppler color flow mapping is particularly useful, and assessment of left atrioventricular valve regurgitation (the most frequent and significant hemodynamic disturbance), potential atrioventricular valvar stenosis, and LVOT obstruction. OBSTRUCTIONS TO RIGHT VENTRICULAR OUTFLOW TRACT

(7) potentially associated anomalies. The classic echocardiographic features are valve doming during systole and flow disturbance by color flow mapping. The severity of the obstruction can be assessed by Doppler recordings of the peak systolic velocity across the valve. TEE is able to identify residual RVOT obstruction and the presence and degree of pulmonary regurgitation following interventional procedures or surgery.

Pulmonary Stenosis Tetralogy of Fallot

Congenital RVOT obstruction may occur at the subvalvar, valvar, or supravalvar areas, or at the distal pulmonary artery branches.s7In some cases, multiple levels of obstruction can be present. Valvar pulmonary stenosis is the most frequent type of obstruction, found in approximately 10% of adult patients with congenital heart disease.39This lesion frequently occurs in isolation. The origin of the valvar stenosis may be related to commissural fusion or cusp dysplasia. The echocardiographic assessment of valvar pulmonary stenosis includes the following: (1)morphologic examination of the valve, (2) annular size, (3) degree of pulmonary artery dilation, (4) severity of the obstruction, (5) size of the right ventricle, (6) right ventricular thickness, and

The initial description of tetralogy of Fallot in 1888 consisted of an interventricular communication, pulmonary stenosis, rightward deviation or override of the ascending aorta, and concentric right ventricular hypertrophy.' In approximately one third of the cases, an associated atrial septal defect is also found (pentalogy of Fallot). Additional associated lesions include right aortic arch, additional ventricular septal defects, absence of the pulmonary valve, coronary artery anomalies, systemic venous anomalies, aortopulmonary window, and LVOT obstruction. Among the various complex cardiac malformations, tetralogy of Fallot is one of the commonest lesions seen in the adult.

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The clinical findings in patients with tetralogy of Fallot relate mostly to the large perimembranous ventricular septal defect and severity of the RVOT obstruction.129The enlarged, dextroposed aortic root and right ventricular hypertrophy are secondary features of this anomaly. Most patients with this lesion require palliative or corrective surgery early in life because of increasing cyanosis. Those who survive into adulthood with this anomaly either have a mild degree of right ventricular obstruction or demonstrate what some consider to be an extreme form of tetralogy, namely, pulmonary atresia with ventricular septal defect. In this instance the source of pulmonary blood flow is through multiple aortopulmonary collaterals. These collateral vessels may originate anywhere in the arterial system, including the ascending and descending aorta, transverse arch, arch branches, and coronary circulation. The severer forms of tetralogy usually occur in association with pulmonary artery anomalies, such as distal branch pulmonary artery stenosis, hypoplasia, or atresia. At the end of this spectrum, pulmonary artery discontinuity or nonconfluence of the central pulmonary arteries may be observed. In anticipation of surgery, the goals of the echocardiographicexamination are to confirm the diagnosis, define and quantitate the level and severity of the RVOT obstruction, esti-

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mate the size of the ventricular septal defect and shunt direction, and exclude associated pathology. Echocardiographically, the large nonrestrictive perimembranous ventricular septal defect frequently is demonstrated as a large subaortic defect located between the right and noncoronary cusps. This is best appreciated in the aortic short- and long-axis and five-chamber views. The direction and velocity of the shunt across the defect should be interrogated by spectral and color Doppler. Potential additional shunts at the atrial and ventricular level should be considered. The most useful TEE view for demonstration of aortic override is the aortic long-axis view (Fig. 13). The degree of override can be quite variable and may range from minimal to extreme. The anterior and rightward displacement of the outlet septum responsible for the override can be well seen in this view. The examination should also include assessment of aortic valve competence and identification of the confines of the malaligned interventricular communication. Evaluation of the right ventricular outflow and pulmonary arteries requires a combination of scanning planes, which define the subvalvar, valvar, and supravalvar regions in detail. This usually is accomplished by longitudinal, transverse, and modified scanning of the RVOT. Narrowing of the RVOT in tetralogy of Fallot usually results from anterior and cephalad

Figure 13. Long-axis view of the aorta displaying typical degree of aortic override in tetralogy of Fallot (TOF). The ventricular septal defect is indicated by the arrow. LV = left ventricle; RV = right ventricle; A 0 = aorta.

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Figure 14. Tetralogy of Fallot. A, Color flow interrogation of the right ventricular outflow tract (RVOT) demonstrates the infundibular muscular obstruction and flow disturbance by color flow Doppler. B, Continuous wave Doppler across the RVOT displays a peak velocity reaching 3.0 m/sec, corresponding to a gradient of 36 mrn Hg. LA = left atrium; A 0 = aorta; PA = pulmonary artery. (See also Color Plate 4, Fig. 24.)

deviation of the outlet septum (Fig. 14; see also Color Plate 4, Fig. 24). The pulmonary valve is frequently bicuspid, stenotic, and domes in systole. The structures in the RVOT may display various degrees of hypoplasia, and size assessment of the various structures is relevant. The severity of the pulmonary obstruction can be evaluated by Doppler interrogation of the main pulmonary artery in the transverse plane or by using the transgastric approach, which visualizes the RVOT. Right ventricular hypertrophy frequently is seen as a response to the RVOT obstruction. The evaluation of the distal pulmonary bed and aortopulmonary collaterals if suspected or present is suboptimal at best by TEE. Most adult patients require additional diagnostic modalities, such as elective angiography or MR imaging for detailed characterization of distal pulmonary artery anatomy. The surgical management of this lesion consists of patch closure of the interventricular communication and relief of the outflow obstruction. Patients who undergo surgical intervention for this anomaly may be at risk for residual right ventricular obstruction at the level of either the infundibulum, pulmonary valve, or pulmonary artery branches. Residual intracardiac shunts may also be observed. Those who require placement of a

right ventricular to pulmonary artery conduit for management of the right ventricular obstruction may eventually develop conduit stenosis and regurgitation. Postoperative issues focus on the right ventricle and outflow tract, the presence of residual outflow tract obstmction and regurgitation, the main and branched pulmonary arteries, the aortic valve, and the left ventricle. Important information to be obtained includes assessment of tricuspid and pulmonary regurgitation; estimates of right ventricular systolic pressure; right ventricular size, thickness, and function; evaluation of aortic regurgitation; and left ventricular function. OBSTRUCTIONS TO LEFT VENTRICULAR OUTFLOW TRACT Bicuspid Aortic Valve

Among the various anatomic types of congenitally malformed aortic valves, the bicuspid aortic valve is the commonest anomaly and the most frequent of all congenital cardiac rnalformation~.~~ This lesion occurs in approximately 2% to 3% of the general popul a t i ~ n . *Initially, ~ bicuspid aortic valves are functionally normal without stenosis and

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with absent to minimal regurgitation. The natural history of this lesion in adult life typically is characterized by the development of fibrocalcific changes and progression of stenosis and regurgitation." Defects commonly associated with a bicuspid aortic valve include perimembranous ventricular septa1 defects and abnormalities of the aorta, such as aortic coarctation. A predisposition for aortic wall changes that mimic cystic medial necrosis and proximal aortic root dissection has been noted in some patients. A bicuspid aortic valve may exist in the context of multiple left-sided obstructed lesions, namely, the Shone complex.92Classic features of this malformation include the following: (1)a supravalvar mitral ring, (2) discrete subaortic membrane, (3) bicuspid aortic valve, and (4)coarctation of the aorta. A bicuspid aortic valve and aortic coarctation are the commonest cardiovascular anomalies in Turner When examined in cross section in the closed position, the morphology of the bicuspid aortic valve is characterized in most cases by two equal or nearly equal cusps (Fig. 15). Less frequently, the cups may be of unequal size with an eccentric commissure. The larger cusp may display a raphe as a remnant of the embryonic fusion between two cusps. The

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disparity in cusp size may lead to redundancy and inappropriate valve coaptation, resulting in regurgitation. Typically, the congenital bicuspid aortic valve displays a single commissural closure line in diastole. In cases when a raphe is present, the identification of a bicuspid valve may be complicated by a tricuspid appearance in diastole created by the true and nonfunctional commissures. In systole the valve opens along only two of the closure lines and will not separate at the echolucent site of the raphe. The echocardiographic assessment of the bicuspid aortic valve should be performed in several planes. The aortic short- and long-axis views are particularly useful in this evaluation. Features of importance are the determination of valve morphology (commissures and position of a raphe), lateral cusp mobility and separation, and the assessment of annular size. The abnormal valve frequently displays thickening, fibrosis, calcification, and limited cusp motion. Additional features include systolic doming and failure of the cusps to clear the examining plane in systole to occupy a position near the aortic wall. Color flow Doppler readily identifies valvular regurgitation and assists in the evaluation of its severity. There may be associated concentric left ventricular hypertrophy, poststenotic dila-

Figure 15. Transesophageal short-axis view of bicuspid aortic valve. A, Demonstrating a single diastolic closure line (arrow) eccentrically located in the aortic root and cusps of slightly unequal Showing , the fish-mouth appearance of the abnormal valve during systole. A prominent size. €I raphe is noted between the two cusps, representing the area of partial commissural fusion (arrow). LA = left atrium; RA = right atrium; RV = right ventricle; A 0 = aorta.

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tation of the ascending aorta, and aortic regurgitation. The mitral valve, LVOT, aorta, and aortic arch should be inspected carefully for associated anomalies. The assessment of the severity of aortic stenosis includes measurements of the aortic valve area by either direct planimetry, continuity equation, or proximal isovelocity surface area method from color Doppler. It should be pointed out, however, that in the presence of an eccentric-, ovoid-, or slit-like shaped orifice, the determination of valve area by planimetry may be inadequate. A quantitative evaluation of the degree of outflow obstruction can be obtained by Doppler echocardiography. The transgastric approach offers optimal axial alignment for Doppler recording of aortic valve flow velocity. The location of poststenotic dilatation may be helpful in optimizing the Doppler interrogation. Using the modified Bernoulli equation, estimates of the peak instantaneous pressure gradient across the stenotic aortic valve can be obtained from Doppler recordings. It is well understood that Doppler echocardiography provides an estimate of the peak instantaneous pressure difference, while cardiac catheterization measurements record the peak-to-peak pressure gradients. Despite the adequate correlation of transthoracic Doppler-derived peak instantaneous pressure gradients with catheter recordings, these estimates frequently exceed those made in the cardiac catheterization laboratory because of differences in activity and anxiety levels and corresponding differences in cardiac In this regard, Doppler mean pressure gradients have been shown to compare well with the mean pressure gradients measured at ~atheterization.~ In the presence of severe left ventricular dysfunction and low cardiac output, Doppler echocardiography may not provide a reliable pressure gradient estimate of aortic stenosis. In patients considered candidates for aortic valve repair using a pulmonary autograft (Ross procedure), the transesophageal exam should include detailed measurements of the aortic and pulmonary annulus to ensure an adequate match. The study should address the functional evaluation of the pulmonary valve and adequacy of the pulmonary cusps, particularly to exclude more than mild regurgitation. Because this surgical procedure involves reimplantation of the coronary arteries, the pre- and postoperative assessment of segmental and global left ventricular function is imperative.2, 89

Discrete Subvalvar Aortic Stenosis

Fixed subaortic obstructions are classified into three categories: (1) membranous, (2) fibromuscular, and (3) tunnel types.23This lesion has been well described in the presence of an intact ventricular septum or a ventricular septal defect. The following focuses on the type of obstruction created by a membranous fibrous membrane or by a fibromuscular ridge because it may be difficult to distinguish between them by echocardiography. A detailed pathologic study of the nature of the fibrous obstruction within the LVOT associated with ventricular septal defects identified three distinct morphologic patt e r n ~ ?The ~ first was a fold of endocardia1 tissue related to the membranous septum; the second was a defect of a fibrous nature, either discrete or diffuse (termed keloidal); and the third was a lesion with circumferential thickening around the ventricular septal defect. In some cases of subaortic stenosis resulting from a ridge or diaphragm of fibroelastic or fibromuscular tissue located underneath the aortic valve, the obstructing tissue may extend from the interventricular septum to the anterior leaflet of the mitral valve (Fig. 16). The ridge may be found in close proximity to the aortic valve or may be located several millimeters below the valve level. The abnormal tissue can be directly attached to one of the valve cusps. Damage to the aortic valve in this lesion is caused by trauma of the high velocity jet against the valve cusps and results in the finding of valvar regurgitation. The echocardiographic evaluation of subvalvar aortic stenosis should consider the anatomy and morphology of the aortic valve and subvalvar obstruction, assessment of aortic valve competency, and evaluation of associated anomalies, Obstruction in the moderate-to-severe range frequently results in left ventricular hypertrophy. The transverse and longitudinal views of the aortic valve and LVOT provide comprehensive definition of discrete membranes and evaluation of aortic valve competence. The five-chamber transesophageal and left ventricular outflow views from the transgastric location allow for color flow demonstration of the level of obstruction and the estimation of pressure gradients by spectral Doppler. The role of TEE has been well documented for assessing the adequacy of the resection, excluding aortic and mitral valve injury during the repair and the presence of iatrogenic

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Figure 16. Subaortic membrane. Longitudinal plane view of left ventricular outflow tract (LVOT) displaying the usual form of subaortic fibrous ridge (S) in diastole. Arrows indicate extension of membrane from septal aspect of ventricular septum to the anterior mitral leaflet. RV = right ventricle; LV = left ventricle; A 0 = aorta; LA = left atrium.

interventricular communications that can occur as a result of the required myomectomy. Coarctation of the Aorta

Coarctation of the aorta is characterized by a ridge of dense tissue that narrows the lumen of the descending aorta posteriorly opposite to the ductus or ligamentum arteriosus. In the pediatric age group it is a common cause of LVOT Obstruction? In the adolescent and adult, is most often diagnosed following the identification of incidental hypertension during a routine physical examination or after the detection of diminished or absent pulses in the lower extremities. Structural lesions associated with coarctation include a bicuspid aortic valve, left heart inflow and outflow anomalies, ventricular septal defects, and patency of the ductus arteriosus. The usual location of the obstructive shelf is just distal to the origin of the left subclavian artery within the juxtaductal region (Fig. 17). The transthoracic suprasternal notch window provides for two-dimensional imaging of the obstruction and for acquisition of the Doppler-derived pressure gradient across the area of narrowing. High parasternal scanning allows adequate imaging of the coarctation site by displaying the aorta in the sagittal plane. Poststenotic dilatation of the descending aorta may be observed. Severe coarctation is suggested by high velocity flow that continues beyond systole extending into diastole

and by decreased pulsations in the descending abdominal aorta. Color flow mapping is key in the detection of the flow disturbance and acceleration at the site of obstruction. Predictors of angiographic severity include the diameter of the color flow image at the coarctation site and the rate of narrowing of the cone of acceleration in the descending aorta proximal to the zone of ob~truction.~~ In all cases, a complete assessment of the entire aortic arch is imperative because coarctation may be found in association with transverse arch and isthmic hypoplasia, and atypical or multiple coarctation sites may occur. Imaging of the entire aortic arch to exclude an obstruction in the older adolescent or adult, and accurate Doppler interrogation may be suboptimal or not feasible by transthoracic echocardiography. Biplane and multiplane TEE can provide helpful two-dimensional information of the site of obstruction, but determination of Doppler gradients is inaccurate because of inadequate alignment of the interrogating Doppler beam. Adult patients may require additional studies for adequate diagnostic evaluation, such as MR imaging 69 and angi~graphy.~~. Postsurgical echocardiographic evaluation should include determination of residual narrowing or recurrent obstruction and assessment of the arch for aneurysmal formation. A Doppler peak velocity above 2.5 meters per second is strongly suggestive of a narrowing of more than 25%.

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Figure 17. Coarctation of the aorta. A, Suprasternal long-axis view of the descending aorta demonstrating prominent posterior ledge in area of coarctation (COA). B,Continuous wave Doppler interrogation from suprasternal transducer position in area distal to the coarctation demonstrates systolic flow, which continues throughout diastole in the descending aorta. The peak flow velocity is 4 m/sec. The high-amplitude, low-velocity signals superimposed in the Doppler tracing (darker signals below baseline) represent the velocity proximal to the coarctation. AAO = ascending aorta; DAO = descending aorta; LSA = left subclavian artery.

EBSTEIN’S MALFORMATION OF THE TRlCUSPlD VALVE The classic findings in Ebstein’s malformation of the tricuspid valve include a large sail-like anterior leaflet and apically displaced septal and inferior (mural) leaflets. This defect represents approximately 40% of all congenital malformations of the tricuspid valve.I7The severity of this lesion varies widely in spectmm.8,86 Frequent presenting symptoms in older patients are arrhythmias, cyanosis, dyspnea, and exercise intolerance. Echocardiographically, the basal attachment of the large, redundant anterior leaflet to the tricuspid annulus is almost always normal. The septal and posterior leaflets are progressively displaced from the atrioventricular junction and frequently display impaired mobility because of short chordae, tethering, thickening, or fibrosis. There is right atrial and ventricular dilation. The right ventricle may demonstrate proximal and distal divisions created by the abnormal tricuspid valve tissue. Tricuspid regurgitation of various degrees usually is seen by Doppler color flow mapping. The origin of the regurgitant jet can be traced to the coaptation point in the distal right ventricular chamber. The ventricular region between the atrioventricular junction and the displaced tricuspid leaflets functionally becomes part of the

right atrium and is known as the atrialized portion of the right ventricle. The functional region of the right ventricle is composed of the remainder of the trabecular and outlet septae. Associated cardiac findings include interatrial communications (patent foramen ovale or secundum atrial septal defect), RVOT abnormalities, and mitral valve prolapse. All of these can be evaluated appropriately by TEE. Transesophageal echocardiography is useful in the intraoperative management of Ebstein’s malformation for baseline evaluation of anatomy and assessment of functional results.21,78 TEE documents the severity of pre- and postoperative tricuspid regurgitation and the adequacy of the repair of associated defects. The anatomy of the tricuspid valve apparatus and right-sided cardiac structures can be assessed in detail.55,lz4 Information with potential implications for surgical repair includes leaflet size, valve mobility and excursion, presence or absence of restriction or tethering, size of the right ventricle, and associated defects.

COMPLEX CONGENITAL MALFORMATIONS Transposition of the Great Arteries In simple transposition of the great arteries (&transposition) there is atrioventricular con-

TEE IN THE ADULT WITH CONGENITAL HEART DISEASE

cordance and ventriculoarterial discordance. The aorta usually originates in a rightwards and anterior position from the right ventricle, whereas the pulmonary artery arises leftwards and posteriorly from the anatomic left ventricle.” This defect is the result of abnormal conotruncal septation. In this condition, the morphologic right atrium is connected to the morphologic right ventricle which empties into the aorta and the morphologic left atrium drains into the morphologic left ventricle which gives rise to the pulmonary artery. The lack of the usual spiralling pattern of the great arteries in this malformation results in their parallel arrangement as they exit the base of heart rather than their normal crisscross relationship. Associated lesions include atrial and ventricular septal defects, patent ductus arteriosus, obstruction to pulmonary outflow, atrioventricular valve abnormalities, variation in the origin and course of the coronary arteries, and aortic arch anomalies. The surgical approach to this lesion has changed dramatically over the past several years from functional or atrial redirection procedures, such as Mustard and Senning operations, to anatomic correction establishing continuity between the ventricles and their respective great arteries. At the present time the preferred surgical approach for neonates with simple transposition is the anatomic correction or Jatene operation.38,91 In this procedure the great arteries are transected and anastomosed to their appropriate ventricular outflows and the coronary arteries are translocated to the systemic outflow. This approach requires a left ventricle prepared or conditioned to sustain systemic pressures and, therefore, is reserved for infants and those patients with anatomic substrates associated with systemic or near systemic left ventricular pressures. The adult population with transposition of the great arteries has most likely undergone palliation, atrial baffle, or switch procedures. In patients with transposition of the great arteries, ventricular septal defect, and pulmonary stenosis, the Rastelli procedure achieves anatomic correction. The repair in this case consists of an intracardiac baffle to close the ventricular septal defect to allow for left ventricular output into the aorta and interposition of a conduit between the right ventricle and main pulmonary artery. Although a comprehensive echocardiographic examination by way of the transthoracic approach is possible in the investigation of potential postoperative issues in these pa-

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tients, in circumstances of inadequate windows or incomplete assessments, TEE frequently is able to provide most of the important diagnostic information. The echocardiographic evaluation following atrial switch procedures should include pulsedwave Doppler, color flow mapping, and contrast echocardiography to assess potential baffle leaks (Fig. 18; see also Color Plate 4, Fig. 25) or obstruction to systemic or pulmonary venous return. Transthoracic imaging may suggest intra-atrial shunting or venous obstruction; however, it might be difficult to visualize the systemic or pulmonary venous pathways in their entirety. In these cases TEE may be of significant benefit.40,41 The combination of the transverse, longitudinal, and modified planes allows for visualization of the caval junctions, the entrance of the pulmonary veins, and the midaspect of the baffle. The atrial reconstruction procedures result in divided atrial cavities, with the systemic venous atrium occupying an anterior and medial position with respect to the pulmonary venous atrium, which is posterior and lateral (Fig. 19). The administration of contrast by way of peripheral or central vein may assist in the identification of baffle leaks and systemic venous ob~truction.~~ In these patients, the right ventricle functions as the systemic pump and late dysfunction is not an uncommon occurrence. The tricuspid valve, which remains as the systemic atrioventricular valve, should be evaluated for the presence of regurgitation because the severity of ventricular dysfunction and the extent of tricuspid regurgitation may have prognostic implications short and long term. Classic echocardiographic findings following atrial switch procedures include right ventricular hypertrophy and a convex appearance of the interventricular septum towards the left ventricle as right ventricular pressure exceeds left ventricular pressure. This can be seen from a variety of transesophageal planes including long- and short-axis views. The aortic longaxis view demonstrates the parallel relationship of the outflow tracts and great vessels with a posterior course of the pulmonary artery. The pulmonary or LVOT should be studied carefully for the presence of obstruction or semilunar valve regurgitation in the longaxis, apical, and transgastric views. As the plane is displaced in the anteroposterior direction, the transgastric views demonstrate the discordant ventriculoarterial connections (Fig. 20). The late postoperative evaluation of

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Figure 18. Intra-atrial baffle leak. Transverse (A) and longitudinal (B) plane views of baffle leak following Senning atrial switch procedure for &transposition of the great arteries. Shunting can be seen across the intra-atrial baffle between the pulmonary and systemic venous atria near the level of the mitral valve. PVA = pulmonary venous atrium; SVA = systemic venous atrium; RV = right ventricle; LV = left ventricle. (See also Color Plate 4, Fig. 25.)

Figure 19. Intra-atrial baffle procedure (Senning). Four-chamber transesophageal view demonstrating the appearance of the divided atrial cavities following an atrial reconstruction procedure for d-transposition of the great arteries. The systemic venous atrium typically occupies an anterior and medial position with respect to the pulmonary venous atrium, which is posterior and lateral. PVA = pulmonary venous atrium; SVA = systemic venous atrium; RV = right ventricle; LV = left ventricle.

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Figure 20. Transpositionof the great arteries. A, Transgastric echocardiogram (TGE) of dtransposition of the great arteries demonstrating the discordant ventriculoarterial connection with the aorta arising from the morphologic right ventricle on anterior Posterior angulation of the transducer from the transgastric transducer angulation. 13, position identifies the main pulmonary origin from the posterior left-sided chamber of left ventricular morphology. A coexisting ventricular septal defect is present (arrow). A 0 = aorta; RV = right ventricle; LV = left ventricle; MPA = main pulmonary artery; RPA = right pulmonaty artery; LPA = left pulmonary artery.

patients following an arterial switch includes the presence and severity of RVOT and LVOT obstruction, atrioventricular and semilunar valve competence, residual intracardiac shunts, and global and segmental ventricular dysfunction. Congenitally Corrected Transposition (/-Transposition of the Great Arteries)

Congenitally corrected transposition is also known as 2-transposition of the great arteries.22The term Z-transposition refers to the looping pattern of the primitive heart tube during cardiac development resulting in discordance between the atrioventricular and ventriculoarterial connections. The systemic veins drain into the anatomic right atrium, which is connected to the morphologic left ventricle and pulmonary artery. The pulmonary venous return is into the morphologic right ventricle, which contracts into the aorta. The circulations are in series and the physiology is normal. The morphologic left ventricle lies to the right, the morphologic right ventricle to the left, in a side-by-side fashion, and a subaortic infundibulum is present.

Corrected transposition is associated almost invariably with other cardiac anomalies.lZ2Ventricular septal defects, obstruction to pulmonary blood flow at the subvalvar and valvar levels, and left atrioventricular valve (tricuspid valve) anomalies frequently coexist in a high proportion of patients with this lesion.37Ebstein’s malformation of the left-sided atrioventricular (tricuspid) valve is also a common finding.96The origin of the coronary arteries in this lesion is from the sinuses of Valsalva facing the pulmonary artery; however, the branching pattern in most of the cases is inverted. The course of the coronary vessels follows the anatomy of their respective ventricles so that in this anomaly the distribution of the coronary arteries is a mirror image of that seen in the normal heart. This is appreciated better in the aortic shortaxis plane. An abnormal atrioventricular conduction system in patients with congenitally corrected transposition accounts for the high incidence of complete heart block. Definition of the atrioventricular connection by echocardiography requires identification of the characteristic features that establish ventricular morphology. The distinction between the anatomic ventricles is possible from a combination of multiple views.

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Among the various echocardiographic signs to assess ventricular morphology the finding of septal attachment of the tricuspid valve and the lack of ventricular septal attachments of the mitral valve are considered the most reliable. Atrioventricular valves are associated with their respective ventricles, and a morphologic tricuspid valve will identify a right ventricle and a mitral valve a left ventricle. The morphologic right ventricle is defined by inferior insertion of the septal tricuspid valvar leaflet to the atrioventricular septum and by the moderator band (Fig. 21). The morphologic left ventricle is characterized by two distinct papillary muscles. The transverse and longitudinal transesophageal planes and the transgastric views identify the abnormal spatial relationship of the arterial trunks in corrected transposition. Typically, an anterior and leftward aorta with respect to the pulmonary artery is present. In addition to the evaluation of the specific cardiac pathology, long-term issues of concern routinely are assessed echocardiographically during follow up and include the progressive deterioration of systemic (right ventricular function) and left atrioventricular valve competence.

Double-Outlet Right Ventricle

Double-outlet right ventricle is a cardiac anomaly characterized by marked anatomic ~ariability.~~ In this condition, the ventriculoarterial connection is defined by both great arteries arising completely or predominantly for the anatomic right ventricle. The great artery relationship is often side-by-side and the aorta is usually on the right. The great arteries are separated from the ventricular mass by bilateral subarterial conus, and, in the commonest arrangement, the great vessels are parallel and semilunar valves are at the same level. A ventricular septal defect almost always is present, and its location greatly influences the physiologic manifestation of this condition. The ventricular septal defect can be subaortic, subpulmonary, doubly committed (subpulmonary and subaortic), or remote. The physiology may resemble that of a simple ventricular septal defect, transposition of the great vessels, tetralogy of Fallot, single ventricle, or atrioventricular valve atresia. The Taussig-Bing anomaly is characterized by a double-outlet right ventricle with a subpulmonary nonrestrictive ventricular septal defect mimicking transposition with ventricu-

Figure 21. Corrected transposition. A, TEE from patient with corrected transposition of the great arteries (ktransposition) and Ebstein-type deformity of the tricuspid valve. Note marked inferior insertion of the septal leaflet of the tricuspid valve (arrow with asterisk) into the morphologic right ventricle (MRV) well below the level of insertion of the mitral valve (arrow). B, TGE demonstrates morphologic left ventricle (MLV) with its two papillary muscles and MRV in short axis. RA = right atrium; LA = left atrium.

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lar septal defect physiology. A variety of associated lesions have been identified in this anomaly and include outflow tract obstruction (pulmonary or systemic) at valvar and subvalvar levels and atrioventricular valve abnormalities (i.e., atrioventricular septal defect, atrioventricular valve stenosis, or straddling). Coarctation of the aorta is often seen in the presence of aortic hypoplasia or valvar aortic stenosis. The anatomy and physiology of the specific type of double-outlet right ventricle are key determinants in surgical decision making. The approach to the double-outlet right ventricle with a subaortic ventricular septal defect is that of patch closure of the interventricular communication. The double-outlet right ventricle with pulmonary stenosis and a subaortic ventricular septal defect likely requires a Rastelli procedure with the ventricular septal patch placed to allow for left ventricular output into the aorta and a conduit providing for right ventricular output into the pulmonary artery. In the case of the Taussig-Bing anomaly, an arterial switch procedure (Jatene repair) and ventricular septal defect closure is usually the procedure of choice. The echocardiographic assessment of this malformation should address the relationship of the great arteries to each other and to the ventricular mass; the presence, size and location of the ventricular septal defect in addition to its relationship to the great arteries; and potential ventricular outflow and aortic arch obstruction. The spatial relationship of the great vessels can be ascertained by a combination of esophageal transesophageal and transgastric views. The anatomic characterization of the ventricular septal defect requires a combination of multiple imaging planes. Color mapping of flow patterns is essential to define the commitment of the defect to a particular outflow. The lack of fibrous continuity between the mitral valve and aorta is a frequently seen echocardiographic feature in this condition. In the intraoperative setting, TEE is particularly helpful in the primary repair or revision of this lesion because it identifies levels of intracardiac shunting, presence and magnitude of outflow obstructions, and provides a monitor of cardiac function.

Truncus Arteriosus Persistent truncus arteriosus is an anomaly that consists of an outlet ventricular septal

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defect and a common arterial trunk that overrides both ventricles. This anomaly is caused by failure of septation of the distal conus, truncus arteriosus, and aortic sac. The single arterial root gives rise to the coronary, pulmonary, and systemic circulations. This defect accounts for 1%to 2% of cases with congenital heart disease.48In 1949, Collett and Edw a r d ~proposed ~~ a classification of truncus arteriosus based on the degree of development of the aortopulmonary septum and the anatomic origin of the pulmonary arteries from the single trunk. In 1976, Calder et a17 introduced a classification based on the presence or absence of a ventricular septal defect, and the morphology of the pulmonary arteries and the aortic arch. This classification can be summarized as follows: in type I (similar to the Collett and Edwards classification), an aortopulmonary septum is identified and is characterized by a pulmonary trunk, which arises separately from the common trunk close to the truncal valve; in type II, the aortopulmonary septum is absent and the pulmonary branches arise directly from the truncus from separate ostia, usually posteriorly; type I I I has only one pulmonary artery arising from the truncus and the source of blood supply to the other lung is from either the base of the aortic arch or the systemic arteries; and type IV is associated with aortic arch underdevelopment (interruption, atresia, preductal coarctation, or severe hypoplasia). Regardless of the classification scheme, the important issue in the description of truncus arteriosus is whether a right ventricular to pulmonary artery conduit can be performed as a primary repair or if the conduit operation cannot be performed. Associated lesions may include a patent foramen ovale, right aortic arch, truncal valve pathology, coronary artery anomalies, and additional ventricular septal defects. The echocardiographic recognition of this lesion in the neonate is suggested by the identification of a truncal root, which overrides a ventricular septal defect, and by deficiency of the infundibular septum (Fig. 22). The surgical management of this condition requires removal of the pulmonary arteries from the truncal root, closure of the root defect, patch closure of the ventricular septal defect, and reconstruction of the right ventricular outflow. The complete repair usually takes place at an early age, and, beyond the immediate perioperative period, most patients do relatively well. Postoperative problems relate pri-

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Figure 22. Truncus arteriosus. A, Transgastric view of truncus arteriosus displaying the biventricular origin of the large central vessel arising above the ventricular septa1 defect. The origin of the aorta is seen from the distal superior aspect of the common truncal root. B, TGE showing the origin of right and left pulmonary arteries from a large common root. A 0 = aorta; RV = right ventricle; LV = left ventricle; TR = truncal root; RPA = right pulmonary artery; LPA = left pulmonary artery. (From Muhiudeen IA, Silverman NH, Anderson RH: Transesophageal transgastric echocardiography in infants and children: The subcostal equivalent. J Am SOC Echocardiogr 8:231,1995; with permission.)

marily to residual intracardiac shunts, truncal stenosis and regurgitation, distal pulmonary bed abnormalities, need for right ventricular to pulmonary artery conduit replacement for stenosis and regurgitation, and ventricular dilation and dysfunction. The goals of the echocardiographic examination in the adult with a history of truncus arteriosus repair should address carefully the potential for each of these postoperative issues. SYSTEMIC ARTERIAL TO PULMONARY ARTERY CONNECTIONS Patent Ductus Arteriosus

Patency of the ductus arteriosus is a common congenital anomaly, which may be found as an isolated defect or in association with other cardiac malformations accounting for approximately 10% of all cases of congenital heart disease.6In most cases in the adult, the vascular channel that connects the aorta to the posterior aspect of the pulmonary trunk is restrictive in nature with a clinically

insignificant shunt (left-to-right flow); however, a nonrestrictive ductus may be present with increased pulmonary vascular resistance and reversal of shunt flow (right-to-left shunt). Echocardiographic goals in the evaluation of this anomaly include: (1) morphologic characterization of the ductus and surrounding structures, (2) assessment of the shunt magnitude, (3) estimation of pulmonary artery pressures, and (4) exclusion of associated anomalies. Doppler and, in particular, color flow mapping increases the diagnostic accuracy of echocardiography for this lesion. Reliable estimates of systolic pulmonary artery pressures are possible by Doppler echocardiography in patients with patent ductus arteriosus or any other type of aortopulmonary Imaging of the ductus arteriosus is feasible by color Doppler flow mapping during TEE.63* 114 A study evaluating the diagnosis of patent ductus arteriosus by TEE in a small group of adult patients suggested a higher diagnostic rate for TEE over transthoracic echocardiography1° and superiority of the longitudinal over the transverse ~1ane.l~~

TEE IN THE ADULT WITH CONGENITAL HEART DISEASE

Transesophageal echocardiography is useful for documentation of adequate ductal occlusion during transcatheter procedures and in the intraoperative setting during surgical closure of the ductus arteriosus in adults, particularly in those with evidence of calcification.lz5 Aortopulmonary Shunts Surgically created aortopulmonary connections usually are performed as palliative procedures to provide or augment pulmonary blood flow in selected patients with cyanotic congenital heart disease. The experience with TEE has been somewhat limited in the evaluation of these procedures to this date. It is reasonable to anticipate that spectral and color Doppler echocardiography may improve the diagnostic accuracy in the identification and assessment of these shunts. SYSTEMIC VENOUS TO PULMONARY ARTERY CONNECTIONS

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left ventricular variety (i.e., tricuspid atresia, hypoplastic left heart syndrome, double-inlet left ~ e n t r i c l e )In . ~cases ~ of marginal right ventricular size, a Glenn anastomosis may be considered as a mechanism to divert right ventricular preload directly into the pulmonary circulation (one-and-a-half ventricle repairs). This approach may also be effective in decreasing large right ventricular volumes in the presence of severe tricuspid valve regurgitation (i.e., Ebstein’s anomaly).50Imaging of the Glenn connection is not always possible by TEE but is enhanced by longitudinal plane imaging, requiring a biplane or multiplane probe. The interposition of the bronchus between the esophagus and pulmonary artery frequently limits the comprehensive assessment of the pulmonary vascular tree, in which case additional diagnostic modalities may be required. It is important to evaluate the anastomotic site and the caliber of the right and left pulmonary arteries. Unobstructed systemic venous to pulmonary artery flow typically demonstrates low velocity biphasic flow with respiratory variation upon spectral Doppler interrogation.

Glenn Anastomosis

Fontan Procedure

Although the Glenn anastomosis has evolved somewhat over the years, the main goal of the procedure is the creation of a connection between the superior vena cava and pulmonary artery.116The current approach favors flow from the superior vena cava into both branched pulmonary arteries (bidirectional Glenn). The surgical procedure involves an end-to-side anastomosis between the superior caval vein and the pulmonary artery, in contrast to the classic Glenn anastomosis in which the pulmonary artery is divided and the superior vena caval flow is diverted exclusively into the right pulmonary artery by means of an end-to-end anastomosis. Classic Glenn anastomosis provides adequate palliation in a large number of patients; however, it frequently results in the development of arteriovenous malformations, thus fell into disfavor. The Glenn anastomosis usually is performed in the context of complex congenital heart disease in anticipation of a Fontan procedure. The indications for a Glenn connection typically include single ventricle physiology or “one-and-a-half” ventricle repairs. The univentricular heart may be of the right or

The eventual separation of the pulmonary and systemic circulations in the patient with a single ventricle or univentricular heart typically requires a Fontan procedure.32Although this operation has evolved dramatically over the past, the common goal of the surgical variations of this procedure is to direct inferior vena caval flow into the pulmonary arteries, bypassing a ventricular chamber. The Fontan procedure frequently implies either a direct right atriopulmonary connection or a total cavopulmonary connection with a Glenn anastomosis (between superior vena cava and pulmonary artery) and inferior vena cava to pulmonary artery connection by way of an intracardiac lateral tunnel technique or extracardiac pathway. A number of anatomic and hemodynamic variables are considered carefully in anticipation of performing this operation. Critical issues include the status of the pulmonary bed (anatomy, pulmonary artery pressures and resistance), systemic atrioventricular valve competency, and systemic ventricular function. In addition to defining and confirming the morphologic features of the primary cardiac malformations, TEE contributes to the assessment of shunts, venous

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obstruction, and thrombi within the systemic venous pathways.25.26, Io8 Echocardiography is essential in the intraoperative and postoperative evaluation of valvular and ventricular function.

These issues imply that optimal circumstances for hemodynamic assessment require conditions that reflect the patient's baseline steady-state.

LIMITATIONS OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN CONGENITAL HEART DISEASE

SUMMARY

The literature extensively documents contributions of TEE in the immediate evaluation of the adequacy of the repair in congenital heart surgery and detection of residual abnormalities that may require 106,113 Decisions regarding return to bypass to address significant residual lesions, however, should consider that a variety of perioperative factors may influence the echocardiographic findings and may under- or overestimate the hemodynamic severity of the condition in question. Although the presence of a significant residual outflow tract gradient by echocardiography has been considered a strong indication for reinstitution of cardiopulmonary bypass, several recent studies suggest potential pitfalls in the application of pressure data alone to intraoperative decision making." Factors that may exaggerate the severity of the obstruction when compared with intraoperative and postoperative gradients include the effects of long-standing ventricular hypertrophy, the level of inotropic support, and the high catecholamine state during the immediate bypass period. These factors are more likely to influence the RVOT than the LVOT. In addition to pressure gradients and flow turbulence, other criteria of relevance in the assessment of outflow tract repairs should include the nature of the obstruction, whether dynamic or fixed, and the likelihood that the obstruction may improve over time. Left atrioventricular valve regurgitation is a significant issue of concern following surgery for certain congenital heart defects (i.e., atrioventricular septa1 defects). Various investigators have addressed the utility of TEE in rendering information on the mechanisms of left atrioventricular valve regurgitation in the intraoperative settings5 Factors such as the functional state of the myocardium and loading conditions, however, may significantly influence the echocardiographic findings and suggest caution in the data interpretation.

Remarkable innovations in medical and surgical approaches over the past several decades now allow for correction of major cardiac defects in children, even in early mfancy. These advances have provided for survival of many pediatric patients with congenital heart disease into adulthood. Although transthoracic echocardiography remains the primary imaging technique for the characterization of simple and complex congenital cardiovascular malformations in the pediatric and adult age groups, high-resolution transesophageal imaging has markedly expanded the anatomic and hemodynamic assessment in these patients. The benefits of this imaging approach apply particularly to those with challenging or limited transthoracic examinations or poorly characterized congenital cardiovascular malformations. The utility of TEE in defining the anatomy of the usual spectrum of congenital cardiac malformations is well established. The transesophageal approach has been shown to provide additional diagnostic information over conventional transthoracic imaging for specific structural cardiac anomalies and in the perioperative setting, the opportunity for confirmation of preoperative diagnoses, and modification of the surgical plan if new or different pathology is identified. This imaging modality also may reliably provide for immediate detection of suboptimal surgical repairs and significant postoperative residua, potentially improving the efficacy of the surgical intervention. This accounts for the vital role of this technology in perioperative management and integration into the standard of care in many congenital heart centers. The usefulness of TEE also has been documented during diagnostic and therapeutic cardiac catheterizations of patients with structural cardiac anomalies, allowing for safer and more effective application of these technologies. The experience supports the use of TEE as a useful approach in the surveillance of the adult with operated and unoperated congenital heart disease.

TEE IN THE ADULT WITH CONGENITAL HEART DISEASE

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Address reprint requests to Wanda C. Miller-Hance, MD Department of Anesthesia and Perioperative Care University of California, San Francisco 521 Parnassus Avenue M-480, BOX 0648 San Francisco, CA 94143 e-mail: wmhQanesthesia.ucsf.edu