Echocardiographic Imaging of Single-Ventricle Lesions

Published on 21/06/2015 by admin

Filed under Cardiovascular

Last modified 22/04/2025

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 5 (1 votes)

This article have been viewed 2833 times

10 Echocardiographic Imaging of Single-Ventricle Lesions

Nadine F. Choueiter, Raylene M. Choy

Key Points

• Echocardiography (echo) is essential in delineating the anatomy, physiology, and postoperative management of single-ventricle (SV) lesions.
• Most common are the lesions that comprise the hypoplastic left heart syndrome (HLHS):

• HLHS is a spectrum of cardiac defects that result in underdevelopment of the left ventricle (LV) and left ventricular-to-aortic outflow axis.
• The aortic valve (AV) and mitral valve (MV) are either hypoplastic or atretic with no flow across the valve by color Doppler.
• The small non-apex-forming LV is best seen from the subcostal apical or parasternal short axis view.
• The atrial septum (AS) is inspected for restrictive flow from subcostal sagittal views.
• The aortic arch is most commonly hypoplastic, and systemic flow is ductal dependent.

SV lesions are complex heart defects that result in one of the ventricles being hypoplastic or absent. The most common of these lesions are those that comprise HLHS. SV lesions are divided into three categories based on the adequacy of pulmonary blood flow (PBF) and systemic blood flow (SBF).

• Lesions with unobstructed PBF and SBF:

• Double-inlet left ventricle (DILV) with Levo (L)-malposition of the great arteries.
• Double-outlet right ventricle (DORV) with normally related great vessels (GVs).
• Unbalanced atrioventricular canal (AVC) with a dominant right ventricle (RV).

• Lesions with obstructed PBF:

• Tricuspid atresia (TA).
• Pulmonary atresia with intact interventricular septum.
• Unbalanced AVC with a dominant LV.
• DILV with D-malposition of the GVs and subpulmonary stenosis or pulmonary stenosis (PS) (Holmes heart).
• Dextro transposition of the great arteries (d-TGA) and PS or subpulmonary stenosis.

• Lesions with obstructed SBF:

• HLHS syndrome.
• Interrupted aortic arch with hypoplastic LV.
• DILV with L-malposition of the GVs and aortic or subaortic stenosis.
• DORV with D-malposed GVs and PS or subpulmonary stenosis.
• d-TGA with aortic or subaortic stenosis.

This chapter discusses in detail the imaging of these three lesions:

• HLHS.
• DILV.
• TA.

Hypoplastic Left Heart Syndrome

Definition and Prevalence

• Underdevelopment of the LV with associated hypoplasia or atresia of both/either of the AV and MV resulting in the inability of the left heart to support systemic circulation.

• 1% to 2% of all congenital heart disease (CHD) and occurs twice as often in boys as in girls.
• Fourth most common congenital cardiac anomaly.
• Most common cause of death from CHD within the first week of life.

The goals of the initial echocardiogram in HLHS are to provide a complete anatomic survey and assess the underlying physiology, which play a critical role in determining the initial management of the patient. In addition to identifying the degree of hypoplasia of the left ventricular (LV) chamber and that of the MV and AV, it is important to assess the function of the RV and tricuspid valve (TV), the size and the direction of flow across the AS, ductal physiology, and associated findings such as ventriculocoronary communications or fistulae and anomalous pulmonary venous return.

Pertinent information is obtained from each of the standard views by two-dimensional (2D) and Doppler.

Parasternal Long Axis View (Fig. 10-1)

• Size discrepancy between the two ventricular chambers: the hypoplastic LV posteriorly and the dilated RV anteriorly.
• Endocardial fibroelastosis echobright areas on the endocardial surface of the LV and the MV papillary muscles.
• Hypoplasia of left atrium (LA). A dilated LA raises the suspicion of an intact AS or a restrictive atrial-level communication.
• Presence of a ventricular septal defect (VSD).
• Patency and mobility of the MV and AV leaflets.

• The MV is usually hypoplastic with thick doming leaflets and abnormal submitral apparatus or a completely atretic MV replaced by a platelike structure. A supravalvar mitral ring might also be present.
• Similarly, AV hypoplasia or atresia may be present and might be associated with subaortic obstruction.
• If patency of the AV or MV is not well defined by 2D imaging, color Doppler with low color scale might help identify antegrade or retrograde valve flow (regurgitation). However, this is best performed from the apical four-chamber (4C) view.

• Measure hypoplastic ascending aorta (Ao) and AV (typically <4 mm).
• Right ventricular (RV) and TV function by angling transducer toward the right hip. Color Doppler interrogation will reveal the presence of tricuspid regurgitation (TR). Significant TR is a poor prognostic indicator in HLHS.
• Assess right ventricular outflow tract (RVOT) and dilated main pulmonary artery (MPA) by angling the transducer toward the left shoulder.
image

Figure 10-1 Hypoplastic left heart syndrome (HLHS). Parasternal long axis view. Markedly hypoplastic left ventricle (LV), aortic arch obstruction (AAO), left atrium (LA).

Parasternal Short Axis View

• Size discrepancy between the large anterior RV and hypoplastic posterior LV (Fig. 10-2).
• Ventricular function.
• Assess size of the aortic root and ascending aorta in cross section (Fig. 10-3).
• Ascertain the presence and position or absence of two papillary muscles. The MV is often a “parachute” (a single papillary muscle).
• Normal relationship of the GVs with the hypoplastic aorta posteriorly and to the right of the MPA.
• Evaluate the size and direction of flow across the patent ductus arteriosus (PDA). This is usually obtained from a high left parasternal view moving the transducer superiorly toward the left shoulder and rotating it counterclockwise to about the 1 o’clock position. The branch pulmonary arteries (PAs) are seen from this view (also known as the “three pant leg view” or the trifurcation view).

• Doppler interrogation of the PDA is best done from this view. It shows right-to-left flow across the ductus in systole. The direction of flow in diastole is usually dependent on the resistance in the pulmonary vascular bed. The systolic gradient should be assessed for signs of early ductal restriction.

• Presence of ventriculocoronary fistulous connections in the LV myocardium (commonly seen in HLHS with mitral and aortic atresia). This is best performed with color Doppler interrogation of the LV myocardium scanning from base to apex while lowering the color scale because fistulous flow is of low velocity.
• Presence of a VSD using 2D imaging as well as color Doppler interrogation with low color scale to identify small VSDs with low flow velocity in the presence of high pulmonary pressures.
• Evaluate pulmonary valve anatomy and function for stenosis or regurgitation.
image

Figure 10-2 HLHS. Parasternal short axis view. Note the size discrepancy between the small LV posteriorly and the right ventricle (RV) anteriorly.

image

Figure 10-3 HLHS. Parasternal short axis view. The image was taken at the base of the heart. A tiny aortic valve is seen with the left main coronary arising from the left coronary cusp. A dilated pulmonary valve is seen anteriorly.

Apical Four-Chamber View

• Size discrepancy between the two ventricles: a non-apex forming LV and a hypoplastic LV. The RV is dilated and hypertrophied. Move the transducer into the axilla (i.e., into a far posteroinferior and lateral position) to optimize the visualization of the hypoplastic LV.
• Degree of MV hypoplasia (thick doming stenotic leaflets) or atresia (platelike structure). In the presence of concomitant aortic stenosis or atresia, MV leaflet excursion may be limited secondary to markedly elevated LV end-diastolic pressure.
• MV inflow and regurgitation. If flow by color Doppler is present, pulsed wave (PW) Doppler and continuous wave (CW) Doppler interrogation of the gradient across the MV will assess the degree of stenosis. The transmitral gradient will be underestimated in the presence of a large atrial communication. Degree of AV hypoplasia or atresia in addition to subaortic stenosis.
• Aortic antegrade flow (if flow present) or regurgitation by color Doppler and spectral Doppler interrogation.
• TR by color Doppler interrogation.
• Pulmonary regurgitation by color Doppler interrogation.

Subcostal Four-Chamber or Coronal View

• Dilated RA and RV with slitlike or diminutive LV prompting the evaluation of left-sided structures (MV, AV, and aortic arch).
• Size discrepancy between the GVs with a dilated MPA and hypoplastic ascending aorta. If ascending aorta is severely hypoplastic, this region may be difficult to visualize.
• Optimal view to evaluate the AS and the number, size, location, and degree of restriction across the atrial communication. Bulging of the AS into the RA or a dilated LA suggests restriction of flow at the atrial level (Figs. 10-4 and 10-5).
• Flow by color Doppler is usually left to right but can be bidirectional in the presence of severe TR or anomalous pulmonary venous connections.
• The spectral Doppler cursor is often parallel to the direction of flow across the AS, allowing accurate measurement of the mean pressure gradient across the AS. Tracing of the gradient over three cardiac cycles is usually done to account for respiratory variation.
• Posterior deviation of the superior aspect of the septum primum.
• Septum primum attaching directly to the posterosuperior left atrial wall far to the left of the septum secundum.
• Assess for anomalous pulmonary venous return.
• TR.
image

Figure 10-4 HLHS. Subxyphoid long axis color compare image profiling a restricted interatrial communication with aliasing of the jet by color Doppler.

image

Figure 10-5 HLHS: atrial septal pulsed wave (PW) Doppler interrogation demonstrates continuous waveform without returning to baseline throughout the cardiac cycle, suggestive of a restricted interatrial communication.

Subcostal Short Axis or Sagittal View

• Ventricular size and GV discrepancy (Fig. 10-6).
• Assessment of the AS (same as subcostal 4C view).
• Visualizing the PDA as a continuation of the dilated MPA by angling the transducer toward the patient’s left for 2D and Doppler imaging.
• The entire arch can be visualized from this view if the transducer is angled further to the left of the patient’s abdomen. This proves to be useful if suprasternal notch (SSN) imaging is not possible.
• Pulsatility of the abdominal aorta by color Doppler and spectral Doppler. A decrease in pulsatility indicates a coarctation. Flow reversal is seen in the presence of a PDA.
image

Figure 10-6 HLHS. Subxyphoid short axis view at the mid-ventricular level demonstrating the size discrepancy between the ventricles.

Suprasternal Long Axis View

• Define aortic arch anatomy (Fig. 10-7).

• Size of the ascending aorta, transverse arch, and the upper descending aorta.
• Presence of a coarctation, and, in the case of severe coarctation, a juxtaductal posterior shelf is seen with an increased distance between the left carotid artery and the left subclavian artery. Doppler interrogation might not be very helpful in detecting the degree of coarctation in the presence of a large PDA.
• Presence of retrograde flow in the transverse arch and ascending aorta by Doppler interrogation in the presence of critical AV stenosis or atresia.
• Presence of a PDA and confirmation of ductal flow can also be performed from this view.
image

Figure 10-7 HLHS. Suprasternal notch long axis view. Markedly hypoplastic ascending aorta.

Suprasternal Short Axis View

• Arch sidedness and branching.
• Anomalous pulmonary venous return, especially to a vertical vein. In the presence of an intact AS and mitral atresia, the only egress of blood from the LA might be a levoatrial cardinal vein that crosses posterior to the left PA and most commonly drains into the left innominate vein. Other forms of anomalous pulmonary venous drainage are also seen in HLHS (6%).

• Any color flow from the venous system toward the transducer from the SSN view should prompt comprehensive investigation of anomalous pulmonary venous drainage.

Double-Inlet Left Ventricle

Key Points

• Both atria connect through separate right and left atrioventricular valves (AVVs) to a ventricle of LV morphology.
• GVs are most commonly L-transposed, as seen from subcostal sagittal or apical sweep with the PA arising from the LV and the aorta arising from a bulboventricular foramen (BVF) located posteroinferiorly to the dominant ventricle seen.
• The BVF tends to restrict with time, leading to either systemic or pulmonary outflow tract obstruction.

Definition and Prevalence

The most common form of univentricular AV connection. It is defined as the presence of two AVVs committed to one ventricular chamber of LV morphology. DILV is associated with a rudimentary outlet chamber, the BVF. The inlet septum is absent, and both AVVs lie in fibrous continuity with a semilunar valve. The ventricles are L-looped, most commonly with the LV being the more posteroinferior and rightward chamber. The bulboventricle is thus located anterosuperiorly.

• Comprises less than 1% of CHD.
• Associated with situs ambiguous, asplenia/polysplenia.
• Associated with:

• TGA (85%) typically L-looped (aorta anterior and leftward in relation to the PA).
• Outflow tract obstruction.

• Aortic arch anomalies (25%) in TGA and a restrictive BVF.
• PS (25%) not associated with a restrictive BVF.
• Holmes heart refers to DILV with:

• BVF located posteroinferior to the dominant ventricle.
• Normally related GVs.

The purpose of the initial echocardiogram is to provide a complete anatomic survey and assess the underlying physiology. The basic anatomy of atrial and visceral situs and location of the cardiac apex must be defined. This information is best obtained from subcostal views. It is important to determine the presence of a straddling, atretic, or stenotic AVV; the relationship of the GVs; the position and degree of restriction of the BVF leading to either systemic or pulmonary outflow tract obstruction; and the physiology of the PDA and other associated anomalies such as abnormal pulmonary or systemic venous connections.

Pertinent information is obtained from the standard views by 2D and Doppler.

Parasternal Long Axis View

• In the majority of cases, the LV will be the posterior chamber. In a Holmes heart, the LV is the more anterior chamber.
• With rightward or leftward angulation of the transducer, both AVVs are seen entering the LV. Note the presence of AV atresia or straddling of chordal attachments. It is important not to mistake this lesion for a large VSD and a dilated LV. In this case, the atrioventricular connection can be further elucidated by rotating to a parasternal short axis view.
• One great artery is seen arising from the LV and the other from the BVF. The latter might be difficult to visualize if it is severely hyoplastic. If the GVs are transposed, many of the echocardiographic findings of TGA can be seen. The GVs are in parallel with the PA posterior.
• The size of and degree of restriction across the BVF should be evaluated by 2D imaging and Doppler interrogation.

Parasternal Short Axis View

Assess relationship between the dominant LV and the BVF. As mentioned, in the majority of cases of DILV, the BVF is the more anterosuperior and leftward chamber. This is best seen as the transducer is angled toward the base of the heart.

• Commitment of both AVVs to the dominant ventricular chamber, architecture of the papillary muscles and the chordae tendineae.
• Relationship of the GVs. Usually seen as two circles as the transducer is angled toward the base if they are transposed. If the GVs are normally related as in a Holmes heart, then the aorta is seen in cross section, and the PA is seen to the right of the aorta in a longitudinal plane.
• Presence of size discrepancy between the AV and pulmonary valve.
• Presence of aortic/pulmonary atresia.
• Confluence of the PAs.
• Presence and physiology of the PDA from a high left parasternal view.
• Size and degree of restriction of the BVF. It is important to measure the BVF in two orthogonal views to calculate cross-sectional area (major diameter × minor diameter × Π/4) because it is usually elliptical in shape. Patients with a BVF cross-sectional area of less than 2 cm2/m2 are at a higher risk of late obstruction.
• Ventricular systolic function.

Apical Four-Chamber Views (Fig. 10-8)

• This is the best view with which to evaluate the crux of the heart and to visualize the salient features of DILV: the two AVVs are connected to the LV without any intervening septum. Presence of a straddling, atretic, or stenotic AVV. The characteristic features of the LV are seen with fine apical trabeculations, smooth basal septal surface, and no septal chordal attachments.
• Right/left and anterior/posterior relationships between the LV and BVF.
• Relationship of the great arteries.
• Evaluate for systemic and pulmonary outflow tract obstruction.
• Degree of restriction across the BVF if the angle of interrogation can be aligned parallel to the flow.
• Stenosis of the AVVs. It is important to note that the degree of stenosis by spectral Doppler across the AVV is underestimated in the presence of an atrial-level communication. In this situation, stenosis can best be assessed by 2D imaging and the degree of mobility of the AVV leaflets.
image

Figure 10-8 Double-inlet LV apical four chamber (4C) view. Both the RA and LA connect to the dominant LV through two separate AVVs. No inlet septum is seen between the two AVVs.

Subcostal Four-Chamber Coronal View

• Situs, position of apex, atrioventricular connections.
• Ventricular morphology and the characteristic features of the dominant ventricle.
• Position and size of the BVF.
• Relationship of the GVs.
• Commitment of the AVVs.
• Presence and size of atrial-level communication, which is only important in the presence of an atretic or stenotic AVV.
• Evaluate systemic venous return (presence of interrupted inferior vena cava [IVC]).
• Evaluate pulmonary venous return and document the normal connections of four pulmonary veins (PVs) to the LA.

Subcostal Short Axis Sagittal View

• Information obtained from this view is similar to that obtained from the orthogonal coronal views. In addition, the short axis allows the evaluation of the AVVs in a short axis view.

Suprasternal Notch View

• The aortic arch is assessed for obstruction or hypoplasia, especially when the aorta arises from the BVF and there is significant BVF obstruction.
• Aortic arch branching.
• Pulmonary venous return from the “crab” view.

Tricuspid Atresia

Key Points

• Apical views show fibrous tissue replacing TV.
• Atrial septal defect (ASD)/patent foramen ovale (PFO) with right-to-left flow is necessary for survival.
• Varying degrees of RV hypoplasia seen from apical or short axis view.
• Most commonly the GVs are normally related and a perimembranous VSD is present.
• The physiology depends on the relationship of the GVs, the size of the VSD, and the degree of RVOT obstruction (RVOTO).
• Associated cardiac findings are coarctation of the aorta and left juxtaposition of the right atrial appendage (RAA).

In postoperative SV management, the echocardiogram is an important diagnostic tool in evaluating the adequacy of PBF and SBF (PA band gradient, aortic arch flow), ventricular function, atrioventricular regurgitation, restriction across the atrial-level communication, Glenn, Fontan pressures, and branch PA stenosis.

Definition and Prevalence

Absence of a direct connection between the RA and the RV. The atretic valve is usually muscular and rarely fibrous. An atrial-level communication, either a secundum ASD or a PFO, is necessary for survival.

• TA is classified based on the relationship of the GVs and the degree of obstruction across the VSD.

• I: normally related GVs (69%).
• Ia: pulmonary atresia/intact ventricular septum.
• Ib: PS/small VSD.
• Ic: no PS/large VSD.
• II: d-TGA.
• IIa: pulmonary atresia/VSD.
• IIb: PS/VSD.
• IIc: no PS/VSD
• III: L-TGA.

• Third most common form of cyanotic CHD (0.3%–0.7%).

The goal of the initial echocardiogram in TA is to provide a comprehensive evaluation of the anatomy and physiology, paying special attention to the absence of a direct communication between the RA and RV, the size of the VSD, relationship of the GVs, the size of the atrial-level communication, and the physiology of the PDA. In addition, associated anomalies should be ruled out such as left superior vena cava (LSVC), left juxtaposition of the RAA, and coarctation of the aorta. Associated findings are more common with transposed great arteries.

Pertinent information is obtained from the standard views.

Parasternal Long Axis View

• Size discrepancy between the two ventricles with a hypoplastic anterior RV and large posterior LV (Fig. 10-9).
• The TV is seen as a bright shelf or a plate in the floor of the right-sided atrium in D-ventricular loop or the left-sided atrium in L-ventricular loop.
• Absence of antegrade flow across the TV can be documented using color Doppler with a low color scale.
• Size and position of the VSD.
• If the VSD is conoventricular, then deviation of the conal septum can best be seen from this view. Anterior deviation is usually seen with normally related GVs, whereas posterior deviation is seen with transposed GVs. In both cases, this may produce subpulmonary obstruction.
• Features of transposition are seen if TGA is present with the GVs in parallel. In d-TGA, the PA sweeps or dives posteriorly.
• In the case of left juxtaposition of the RAA, the AS is perpendicular to the posterior great artery.
• A dilated coronary sinus should raise the suspicion of a persistent LSVC.
image

Figure 10-9 Tricuspid atresia (TA). Standard parasternal long axis view. Severely hypoplastic RV. Dilated coronary sinus (CS) suggestive of a persistent left superior vena cava.

Parasternal Short Axis View

• Further characterization of the hypoplastic RV. The RV is located superior to the LV and best seen at the papillary level.
• Size and degree of restriction across the VSD.
• Scan the ventricular septum (VS) from base to apex to assess for the presence of additional VSDs by 2D imaging and color Doppler. If additional VSDs are present, flow will be of low velocity because of the equal pressures in both ventricles. In this case, use a low Nyquist setting.
• Determine the presence of subpulmonary obstruction (in normally related GVs or L-TGA) or subaortic obstruction (in d-TGA).
• In the case of transposed GVs, the aorta and MPA can be seen in cross section with the aorta anterior and to the right of the MPA (d-TGA) or anterior and to the left of the MPA (L-TGA).
• Assess for hypoplasia of the PA and confluence of the branch PAs.
• Presence and physiology of the PDA from a high left parasternal view.
• Ventricular function.

Apical Four-Chamber View (Fig. 10-10)

• Appreciate the lack of direct connection between the RA and the RV and, by angling the transducer posteriorly, demonstrate the type of TA, i.e., muscular, echodense plate of tissue in the floor of the RA, or a fibrous fat-filled sulcus across the TV position.
• Evaluate the degree of RV hypoplasia and the size of the VSD.
• Assess the relationship of the GVs by sweeping posterior to anterior at the level of the AVVs into the RVOT. A posterior GV that branches should raise the suspicion for TGA.
• Determine the presence of subpulmonary obstruction (in normally related GVs or L-TGA) or subaortic obstruction (in d-TGA) by sweeping anteriorly into the outflow tracts.
• Presence of abnormal septal configuration in the case of left juxtaposition of the RAA.
image

Figure 10-10 TA. Apical 4C view. Size discrepancy between the RV and LV. Severely hypoplastic RV. The tricuspid valve is replaced by fibrofatty tissue in the right atrioventricular sulcus seen as a thick plate of echoes (arrow).

Subcostal Four-Chamber Coronal View

• Excellent view to determine abdominal viscera, atrial situs, ventricular looping, and relationship of the GVs. A posterior GV that branches should raise the suspicion for TGA.
• The AS is usually perpendicular to the transducer, allowing adequate visualization of the ASD; color Doppler will show right-to-left flow across the ASD. It is unusual for the ASD to be restrictive.
• Visualize the TV as a platelike structure with a hypoplastic RV (Fig. 10-11).
• Determine the size and presence of the VSD.
• Findings consistent with left juxtaposition of the RAA (if present).

• Convexity of the RA to the left.
• Superiorly, the AS wraps around the RA.
• Small RA.
• RAA courses from right to left posterior to the great arteries and anterior to the LA.

image

Figure 10-11 TA. Subxyphoid 4C view. Moderate-sized interatrial communication (arrow), platelike right atrioventricular junction, and a diminutive RV.

Subcostal Short Axis Sagittal View

• Careful sweeping from right to left allows assessment of the ASD, size of the RV, the VSD, and the degree of RVOTO (if present, secondary to anterior deviation of the outlet septum, muscular hypertrophy, or anomalous muscle bundles).
• Assess the degree of RVOTO by color Doppler and spectral Doppler; the Doppler beam will be parallel to RVOT flow.
• Evaluate ventricular function.

Suprasternal Long Axis View

• Evaluate the aortic arch by 2D imaging: ascending aorta and transverse arch dimensions, especially when there is associated TGA.
• Color Doppler interrogation of the arch may show retrograde filling of the arch with severe arch hypoplasia. Spectral Doppler interrogation will underestimate the gradient across a coarctation due to ductal filling distal to the coarctation.
• A large ductus is seen in the presence of a coarctation with mainly right-to-left flow from the MPA into the arch in systole and left-to-right flow in diastole.

• In cases of pulmonary obstruction or atresia, the ductus is long and narrow, directed superior and posterior from the MPA to the aorta rather than its usual inferior and posterior direction.

• Pulmonary atresia with severe RV hypoplasia; there is loss of the typical isthmic narrowing.

Suprasternal Short Axis View

• Arch sidedness.
• Confluence and size of the branch PAs.
• Assess pulmonary venous drainage.
• Evaluate for persistent LSVC.

Postoperative Evaluation

Echocardiographic evaluation following first-stage palliation includes the following:

Post-PA Band Placement

Evaluation of patients after PA banding involves the following.

• Visualizing and documenting appropriate placement of the band: echobright density across the MPA (Fig. 10-12).
• Assessing for migration of the band.

• Most commonly toward the right PA, causing distortion of this branch.
• Toward the pulmV encroaching on the valve leaflets.

• Assessing the tightness of the band:

• Marked poststenotic dilation of the MPA.
• PulmV leaflets may be echobright and thickened.
• Assess the gradient across the PA band by color Doppler and spectral Doppler (Fig. 10-13).

• Systolic PA pressure (PAP) can be estimated in the case of a large VSD and no systemic outflow tract obstruction. Systolic blood pressure equals RV systolic pressure. Systolic PAP is obtained by subtracting the systolic blood pressure from the PA band gradient.
image

Figure 10-12 Parasternal short axis view of the branch pulmonary arteries (PAs). The narrowing at the main PA indicates the presence of a PA band (arrow).

image

Figure 10-13 PA band. Parasternal short axis view of the branch PAs. Color Doppler shows aliasing of the jet at the site of the PA band.

Post-PA Band Removal Assessment

• Residual narrowing may be seen by 2D imaging.
• Swirling is seen by color Doppler.

Norwood and Damus-Kaye-Stansel Procedures

The goals of the postoperative echocardiogram after a Norwood or Damus-Kaye-Stansel (DKS) procedure and before a bidirectional Glenn/Hemi-Fontan procedure are to evaluate for the following.

• Restriction of the interatrial communication.

• Subcostal views.
• Mean velocity across the atrial communication greater than 1 mm Hg.

• Obstruction across the DKS or the newly created aortic arch (Figure 10-14 shows the DKS procedure).

• 2D images and Doppler of arch from the SSN view.
• Assess pulsatility of the abdominal aorta from subcostal views.
• Obstruction or stenosis of the RV-PA conduit or the modified Blalock-Taussig (m-BT) shunt.

• Proximal aspect of the RV-PA conduit is best seen from the parasternal long axis view angling toward the RVOT or from an apical 4C view.

• Optimal angle of interrogation for Doppler apical 4C view.

• Distal aspect of the RV-PA conduit is best seen from a subcostal short axis view (Fig. 10-15), subxyphoid short axis view (Fig. 10-16), or high parasternal long axis view.

• Optimal angle of interrogation for Doppler SSN view.

• The m-BT shunt is well visualized and traced from the SSN short axis view as it usually originates from the right innominate or right subclavian artery and connects distally to the right PA (Fig. 10-17).

• Optimal angle of interrogation: SSN.
• Distortion or stenosis of the branch PAs.

• Optimal visualization and angle of interrogation: parasternal short axis, SSN short axis views.

• AVV regurgitation (AVVR).

• Parasternal short axis, apical 4C views.

• Neo-AV insufficiency.

• Parasternal long axis, apical 4C views.

• Ventricular systolic function.

• Parasternal short axis, subcostal short axis views.

image

Figure 10-14 Damus-Kaye-Stansel (DKS) procedure. Subxyphoid short axis view demonstrating the patency of the DKS procedure into the aortic arch reconstruction.

image

Figure 10-15 Sano shunt. Subxyphoid short axis view at the mid-ventricular level profiling the origin of the Sano shunt from the RV with color Doppler demonstrating aliasing through the proximal shunt.

image

Figure 10-16 Sano shunt. High parasternal long axis view of the right ventricular outflow tract (RVOT) allows visualization of the proximal-to-mid Sano shunt.

image

Figure 10-17 Modified Blalock-Taussig (m-BT) shunt. Suprasternal notch (SSN) cross-sectional view of the aorta. The insertion of the distal end of the m-BT shunt into the right PA is seen.

Hybrid Procedure

Hybrid palliation consists of surgical bilateral PA banding, combined with transcatheter balloon atrial septostomy and ductal stenting. It was recently introduced as a less invasive alternative to the Norwood procedure. It avoids the use of cardiopulmonary bypass, which may be associated with adverse neurologic events in the neonatal period. Experience with the hybrid procedure is limited but encouraging.

Post-Hybrid Procedure Assessment

• PA bands

• As previously mentioned in the Post-PA Band Placement section.

• Ductal stent.

• SSN and high left parasternal views (Fig. 10-18).

image

Figure 10-18 Bidirectional Glenn. Modified suprasternal notch imaging with the indicator at approximately the 12 o’clock position off slightly to the right side of the neck demonstrates color flow in the Glenn-PA anastomosis.

Echocardiographic Evaluation After Bidirectional Glenn/Hemi-Fontan Procedure

The goals of the echocardiogram after a bidirectional Glenn/Hemi-Fontan procedure and before a Fontan procedure completion are to evaluate for the following.

• Superior vena cava (SVC)/cavopulmonary anastomosis obstructions and PA branch distortion or obstruction.

• High parasternal view, SSN.
• Flow in the SVC and branch PAs by color Doppler and spectral Doppler is low velocity and phasic (decrease the Nyquist limit) (Figs. 10-19 and 10-20).

• Residual antegrade flow from the ventricle to the PA if the central PA was oversewn or tightly banded.

• Parasternal views.

• Thrombi in the PA stump, especially if the pulmV leaflets have not been oversewn.

• Parasternal views.

• Venovenous collaterals and aortic-to-pulmonary collaterals.

• Detected by color Doppler mapping in the SSN views (decrease Nyquist limit).
• By spectral Doppler flow is continuous throughout the cardiac cycle.

• Similar to the post-Norwood or DKS palliation echocardiogram, it is important to assess for restriction at the level of the atrial communication, AVVR, aortic arch obstruction (AAO), and ventricular function.
image

Figure 10-19 Bidirectional Glenn. Doppler profile of the bidirectional Glenn demonstrating low-velocity phasic flow.

image

Figure 10-20 Fontan. Subxyphoid long axis image profiling the inferior vena cava connection to the Fontan pathway. The color Doppler interrogation demonstrates low-velocity laminar flow.

Echocardiographic Evaluation After Fontan Procedure Completion

The goals of the echocardiogram after completion of the Fontan procedure are to evaluate for the following.

• Patency of the Fontan conduit (lateral or extracardiac).

• Subcostal view can demonstrate the dilated IVC and the IVC-to-PA pathway (Fig. 10-21).

• Assess for the presence of thrombus in the pathway (echodense material).
• Flow in the conduit is interrogated from subcostal sagittal imaging and is low velocity and phasic.
• Patency and size of the fenestration can be assessed by color Doppler from the apical views.

• Measure the mean gradient across the fenestration by PW Doppler over several cardiac cycles from apical views (estimate of the transpulmonary gradient).

• Obstruction/narrowing in bidirectional Glenn/Hemi-Fontan procedure, as described previously.
• Obstruction in the pulmonary venous pathway because of improper baffle creation in the lateral tunnel or compression of the PVs by the extracardiac conduit.

• Identify drainage and connection of all four PVs by 2D imaging color Doppler and spectral Doppler (SSN short axis, subcostal coronal, parasternal short axis views).

• Similar to post-Norwood and post-BDG echo assessments, it is important to assess AVVR, neo-AV insufficiency, ventricular function, presence of systemic venovenous collaterals, and aortic-to-pulmonary collaterals.
image

Figure 10-21 Hybrid palliation of HLHS. High left parasternal window profiling the struts of the ductal stent. Flow across the stent is noted in systole from the PA to the aorta.

Suggested Reading

1 Bevilacqua M, Sanders SP, Van Praagh S, et al. Double-inlet single left ventricle: echocardiographic anatomy with emphasis on the morphology of the atrioventricular valves and ventricular septal defect. J Am Coll Cardiol. 1991;18:559-568.

It discusses the echocardiographic anatomy of DILV with special attention to the morphology, size, and function of the AVVs and VSD and their relationship to PS, aortic stenosis, and AAO.

2 Orie JD, Anderson C, Ettedgui JA, et al. Echocardiographic morphologic correlations in tricuspid atresia. J Am Coll Cardiol. 1995;26:750-758.

It describes how TA in most cases is secondary to the absence of an RA-RV junction along with the associated findings in TA.

3 Fraisse A, Colan SD, Jonas RA, et al. Accuracy of echocardiography for detection of aortic arch obstruction after Stage I Norwood procedure. Am Heart J. 1998;135(2 Pt 1):230-236.

This study evaluates the accuracy of echo in the diagnosis of AAO after a stage I Norwood procedure, identifies echocardiographic predictors of arch obstruction, and examines the time course of its development. It shows that echo is a highly specific but poorly sensitive modality in detecting AAO after a stage I Norwood procedure. Early cardiac catheterization with possible intervention should be considered in patients with moderate or severe RV dysfunction, moderate or severe TR, or an abnormal abdominal Doppler flow pattern during that period.

4 Jacobs ML, Mayer JEJr. Congenital Heart Surgery Nomenclature and Database Project: single ventricle. Ann Thorac Surg. 2000;69(Suppl 4):S197-S204.

The STS-Congenital Heart Surgery Database Committee and the European Association for Cardiothoracic Surgery have proposed a classification that is relevant to surgical therapy.

5 Cook AC, Anderson RH. The anatomy of hearts with double inlet ventricle. Cardiol Young. 2006;16(Suppl 1):22-26.

6 Munoz-Castellanos L, Espinola-Zavaleta N, Keirns C. Anatomoechocardiographic correlation double inlet left ventricle. J Am Soc Echocardiogr. 2005;18(3):237-243.

Anatomoechocardiographic correlation between the morphologic features of equivalent anatomic specimens and the echocardiographic images of patients to provide a means of interpreting the image correctly and making a more precise diagnosis of the cardiac defect.

7 Cardis BM, Fyfe DA, Ketchum D, et al. Echocardiographic features and complications of the modified Norwood operation using the right ventricle to pulmonary artery conduit. J Am Soc Echocardiogr. 2005;18(6):660-665.

8 Galantowicz M, Cheatham JP. Lessons learned from the development of a new hybrid strategy for the management of hypoplastic left heart syndrome. Pediatr Cardiol. 2005;26:90-99.

9 Jacobs ML, Anderson RH. Nomenclature of the functionally univentricular heart. Cardiol Young. 2006;16(Suppl 1):3-8.

It provides an anatomic distinction between the functionally univentricular heart or the functional SV and the hearts with an SV chamber.

10 Khairy P, Poirier N, Mercier LA. Univentricular heart. Circulation. 2007;115(6):800-812.

An overview of the nomenclature and classification of the univentricular heart, epidemiology and pathological subtypes, genetic factors, physiology, clinical features, diagnostic assessment, therapy, and postoperative sequelae. The focus is on information of interest and relevance to the adult cardiologist and cardiac sonographer.

Related posts:

The Fetal Echocardiogram Echocardiography in the Cardiac Catheterization Laboratory Atrioventricular Septal Defect: Echocardiographic Assessment Echocardiographic Assessment After Heart Transplantation Myocardial Pathology Thromboembolic Phenomena and Vegetations