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The Adult With Unrepaired Complex Congenital Heart Defects


Most complex congenital heart disease (CHD) present with cyanosis in early childhood and necessitate intervention before adulthood. In contrast, adults with acyanotic complex CHD can escape detection for many decades because they often do not have major associated lesions. The echocardiographic approach should be tailored to the indication: a sequential and segmental approach should be used for an initial diagnostic study. If the study is to be used for preprocedural planning, prior discussion with the interventional cardiologist or surgeon is beneficial to ensure that necessary data are obtained. In a follow-up study when the diagnosis has been well established, a typical adult imaging sequence can be followed. Access to the patient’s clinical record at the time of echocardiography provides the sonographer and interpreting cardiologist with important details regarding the underlying anatomy and the nature of previous interventions. In adults with limited acoustic windows, supplemental data from transesophageal echocardiography (TEE), cardiovascular magnetic resonance imaging (CMRI), and/or cardiac computed tomography (CT) may be required. Adults with neurodevelopmental and neurocognitive deficits and disorders, those who may be anxious, or those with multiple chest incisions may not tolerate prolonged imaging.

In this chapter, we focus on two areas: (1) summary of sequential, segmental analysis for assessment of complex CHD and (2) diagnostic features of cyanotic and acyanotic forms of complex adult CHD. The consensus recommendations of the International Society for Adult Congenital Heart Disease provide a comprehensive and structured approach in echocardiography evaluation of adults with CHD. Recommendations about TEE and three-dimensional (3D) echocardiography in patients with CHD have also been published. ,

Summary of The Sequential, Segmental Approach To Complex Congenital Heart Disease

In the sequential, segmental approach, chambers and vessels are recognized according to their intrinsic morphologic “rightness” and morphologic “leftness” and not determined by their right- or left-sided position in the chest, relative position to other chambers, or by the connection to the systemic or pulmonary circulation. , The heart is considered in three segments (atria, the ventricles, and the great arteries; characteristics are summarized in Table 143.1 ) . The atrioventricular (AV) valves always connect with the corresponding ventricles: the tricuspid valve is more apically positioned than the mitral ( ; arrows ) with the exception of AV septal defect (AVSD) or double-inlet LV.

TABLE 143.1
The Three Segments and Their Morphologic Features
ATRIAL Right Atrium Left Atrium
Appendage Broad based, triangular Narrow, fingerlike, tubular
Terminal crest Present Absent
Pectinate muscles Many; extends toward the atrioventricular valve or Eustachian valve Few; confined to the left atrial appendage
Fossa Ovalis Rim around the fossa ovalis
VENTRICULAR Right Ventricle Left Ventricle
Atrioventricular valve Apical attachment of the tricuspid valve to the septum
Ventricular Crest Present Absent
Semilunar to atrioventricular valve fibrous continuity Absent Present
Trabeculations Coarse apical trabeculations; moderator band, septomarginal trabeculation Fine apical trabeculations
Chordal attachment to the septum Present Absent
ARTERIAL SEGMENT Aorta Pulmonary
Supplies neck vessels or arch Bifurcates to branch pulmonary arteries

Video 143.1. Discordant atrioventricular connection; the tricuspid valve is denoted by the arrow .

  • Abdominal or cardiac situs: Determination of the abdominal situs and atrial arrangement (cardiac situs) from the subcostal view is the first step ( Fig. 143.1 ). Because the features that distinguish between the left atrium (LA) and right atrium (RA) are usually not visualized on transthoracic echocardiography (TTE) (see Table 143.1 ), cardiac situs can be inferred by the following features: (1) the cardiac and abdominal situs are usually concordant, and (2) the RA almost always receives the inferior vena cava (IVC; with the exception of an interrupted IVC). Based on the relationship of the abdominal aorta and IVC, there are three types of cardiac situs: solitus (normal); ( Fig. 143.2A ), situs inversus ( Fig. 143.2B and ), and isomerism (heterotaxy syndrome, when the caval vein and aorta are on the same side of the spine; Fig. 143.3 ).

    Figure 143.1, Sequential segmental analysis.

    Figure 143.2, Subcostal views to identify abdominal situs. A, Situs solitus: the inferior vena cava (IVC) is on the right, and the aorta (Ao) is on the left of the spine. B, Abdominal situs inversus: the IVC is on the left, and the aorta is on the right of the spine.

    Figure 143.3, Left atrial isomerism. A, Subcostal view with the aorta on the right of the spine and absent suprarenal inferior vena cava with azygos continuation. B, Direct connection of the hepatic veins to the right-sided left atrium. C, Apical four-chamber view with bilateral left atrial appendages (arrows) . Ao, Aorta; LA, left atrium.

  • Cardiac position: Cardiac position is best assessed in the subcostal view and includes two terms that are not interchangeable: location of the heart within the chest (levoposition, dextroposition, mesoposition) and cardiac orientation. Abnormal location of the heart within the mediastinum may also be a result of other factors, including thoracic abnormalities, mediastinal and thoracic structures, and surgical procedures. Cardiac orientation describes the base-apex long axis of the heart (levocardia, dextrocardia, or mesocardia).

  • Definition of the connection: The AV and ventriculoarterial (VA) connections are defined after successful identification of the three segments (atria, ventricles, and great arteries; see Table 143.1 ). The AV connection can be concordant, discordant, ambiguous, or univentricular. Concordant AV and VA connections are the normal state. Discordant AV and VA connections are features of physiologically or congenitally corrected transposition of the great arteries (cc-TGA), which is a circulation in series (acyanotic) (see Fig. 143.4A ). Concordant AV and discordant VA connections are features of complete transposition of the great arteries (c-TGA) which is a circulation in parallel (cyanotic) (see Fig. 143.4B ). The AV connection is ambiguous, neither concordant nor discordant, when the cardiac situs is isomeric or indeterminate. Univentricular connections can exist with any type of cardiac situs and can be absent right ( Fig. 143.5A and ) or absent left AV valve or double-inlet ventricle ( Fig. 143.5B and ). When there is overriding of the AV valve (malalignment of the annulus of one of the AV valve or atrial septum relative to the ventricular septum), the 50% rule will determine whether the connection is biventricular (overriding <50%, concordant connection with overriding of the AV valve) or a univentricular connection (overriding of one AV valve >50%; see Fig. 143.5B and ). The receiving ventricle can be a morphologic RV, LV (see Fig. 143.5B and ), or indeterminate ventricle. The VA connection (concordant, discordant, double outlet, or common arterial trunk) is best determined by a short-axis sweep that defines the plane of the ventricular septum in relation to the great arteries. The pulmonary artery (PA) is identified by its bifurcation, and the aorta is identified by the origin of neck vessels. The relationship between the ascending aorta and the main PA is described in the parasternal short-axis (PSAX) view. Normally, the RV outflow tract is anterior and loops around the aorta on the PSAX views ( Fig. 143.6B ). When the ascending aorta and pulmonary artery arise in parallel as seen on parasternal long-axis (PLAX) or apical views or seen en face on PSAX views with the aorta anteriorly positioned, transposition of the great arteries (TGA) should be suspected. The position of the ascending aorta should then be described relative to the PA (e.g., anterior to the right, anterior to the left, anteroposterior, or side-by-side arrangement).

    Figure 143.4, Apical four-chamber-views to image atrioventricular (AV) connections and ventricular looping. A, Cardiac situs solitus and discordant AV connection in physiologically “corrected” transposition of the great arteries. The right ventricle (RV) is on the left of the left ventricle (LV), which indicates a ventricular L-loop. B, Cardiac situs solitus and ventricular D-loop in a patient who has an undergone atrial switch (Mustard) procedure. The atria are connected with the corresponding ventricles (concordant AV connections). The arrow indicates the pacemaker lead in the subpulmonic LV. LA, LEFT atrium; PV, pulmonary venous; RA, right atrium.

    Figure 143.5, Univentricular connections: A, Apical four-chamber view of tricuspid atresia, secundum atrial septa defect, and ventricular septal defect (VSD) (asterisk) . Note absence of the right atrioventricular (AV) valve (tricuspid valve). B, Apical four-chamber view of double-inlet left ventricle (LV): both AV valves predominantly connect to the LV because of malalignment of the interatrial and ventricular septum with overriding of the right-sided AV valve (>50% overriding). Note the VSD and straddling of the right-sided AV valve with chords attached to both sides of the interventricular septum (arrow) . The right- and left-sided AV valves are on the same plane. LA, Left atrium; RA, right atrium; RV, hypoplastic right ventricle.

    Figure 143.6, Unrepaired tetralogy of Fallot. A, Parasternal long-axis view showing malalignment of the aortic valve annulus relative to the ventricular septum with malalignment ventricular septal defect (VSD) and overriding of the aorta (asterisk) . Parasternal short-axis view shows anterior and superior deviation of the infundibular septum resulting in malalignment VSD (asterisk) and subpulmonary outflow tract obstruction (+) . The white arrow indicates the muscle bundles in the right ventricular outflow tract. The yellow arrow shows bifurcation of the main pulmonary artery (PA) to the right and left PA. C, Color Doppler flow mapping demonstrates flow acceleration at the level of the subpulmonary outflow tract. D, Continuous-wave Doppler demonstrates severe right ventricular outflow tract obstruction. Ao, Aortic root; AV, aortic valve; LA, left atrium; LV, left ventricle; RV, right ventricle.

  • Ventricular looping: Ventricular looping determines the distribution of the coronary artery pattern and conduction system. The apical four-chamber view differentiates D-(dextro) loop (normal; morphologic RV right of morphologic LV) (see Fig. 143.4B and ) versus L-(levo) loop (morphologic RV left of morphologic LV) (see Fig. 143.4A and ). Importantly, the transducer has to be positioned according to the standard orientation and should not be reversed in an attempt to familiarize image display.

  • Associated malformations: Description of associated cardiac malformation is the last step and includes but is not restricted to cardiac shunts (at any level), valvular function, LV or RV outflow tract obstruction, anomalous systemic or pulmonary venous connection(s), aortic coarctation, aortopulmonary vessels, and iatrogenic (palliative) shunts. Coronary anomalies are very difficult to ascertain by TTE in adults, although variations in coronary artery patterns are commonly seen in cyanotic CHD and should be sought before intervention using complementary imaging modalities as necessary.

Video 143.2. Situs inversus and discordant atrioventricular connection.

Video 143.3. Situs solitus with absent right atrioventrcular connection (tricuspid atresia).

Video 143.4. Double-inlet left ventricle. The arrow indicates ventricular septal defect.

Cyanotic Complex Congenital Heart Disease

Central cyanosis in an adult with unrepaired CHD is a result of one of three major mechanisms, which need not be mutually exclusive: central mixing of pulmonary and systemic blood flow, reduction of pulmonary blood flow, or Eisenmenger physiology resulting in reversal of an intracardiac shunt. We will review some of the more common cyanotic lesions, the most complex forms of CHD (single-ventricle physiology), and palliative shunts.

Tetralogy of Fallot

Tetralogy of Fallot (ToF) is the most common form of cyanotic CHD with survival to adulthood and is defined by the presence of pulmonary outflow tract stenosis (at multiple levels), malalignment ventricular septal defect (VSD), dextroposition of the aorta with override of the ventricular septum, and RV hypertrophy (see Fig. 143.6 and ). Anterosuperior deviation of the infundibular (outlet) septum is the intrinsic anatomic defect that results in a malalignment-type VSD, partial commitment of the aorta to the RV, and subpulmonary outflow obstruction ( Fig. 143.6B ). Hypertrophy of the septoparietal trabeculation may be an additional diagnostic feature. The PLAX view typically demonstrates the malalignment outlet VSD and the override of the aorta (see Fig. 143.6A and ). If override of the aorta is greater than 50%, it would be described as “double-outlet RV” rather than ToF.

Video 143.5. Tetralogy of Fallot showing malalignment ventricular septal defect (asterisk) and override of the aorta (arrow).

The deviation of the infundibular septum anteriorly and superiorly is best seen in the PSAX view, and subvalvar pulmonary stenosis often begins at this level with usual extension to include valvar and supravalvular levels ( Fig. 143.6C ). The parasternal and subcostal short-axis views are useful to delineate the level of RV outflow tract obstruction and provides suitable alignment for Doppler interrogation of the level of obstruction ( Fig. 143.6C and D ). Valvular and supravalvular pulmonary obstruction can be well-depicted on the PSAX view. Delineation of branch pulmonary artery stenosis usually require CMRI or CT. Importantly, the severity of pulmonary obstructive gradient may be underestimated in the presence of right-to-left shunting at the VSD level. Associated defects that should be assessed include atrial septal defect (ASDs; pentalogy of Fallot), additional VSDs, AVSD, right-sided aortic arch (with mirror-image branching or aberrant left subclavian artery contributing to a vascular ring), and anomalous origins of the coronary arteries. Enlargement of the aortic root and ascending aorta are common and generally benign associated findings. , Surgical repair should be considered, even with a late diagnosis, to improve long-term outcome and typically includes relief of subvalvar and supravalvar pulmonary stenoses, pulmonary valvotomy, and VSD patch closure. Although echocardiography can typically establish the diagnosis of ToF in adults, multimodality imaging should be used for characterization of the vascular anatomy (PAs, aortic arch ± aortopulmonary collaterals) and the coronary artery pattern and patency. ,

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