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improve the function of the valve and to prevent blood from owing backwards into
the right atrium.
Surgical repair of Ebstein’s anomaly may include mobilizing the anterior leaet
of the tricuspid valve, repositioning the anterior and posterior leaets to cover the
orice area at the normal level, and remodeling and reinforcing the tricuspid annulus using a prosthetic ring, as shown in Fig.4.3d.
Valve repair is preferred over valve replacement, if possible, because it has the
potential to be more durable and avoids potential complications associated with
valve replacement [3].
References
1. Van Son JA, Konstantinov IE, Zimmermann V, etal. Ebstein and Ebstein’s mal-
formation. Eur J Cardiothorac Surg. 2001;20:1082–85.
2. Carpentier A, Chauvaud S, Mace L, etal. A new reconstructive operation for
Ebstein’s anomaly of the tricuspid valve. J Thorac Cardiovasc Surg.
1988;96:92–101.
3. Chen JM, Mosca RS, Altmann K, etal. Early and medium-term results for repair
of Ebstein anomaly. J Thorac Cardiovasc Surg. 2004;127:990–8.
4 Valvular Abnormalities ofAtrioventricular Connections
4.3 Mitral Atresia (MA) withHypoplastic Left Heart
Syndrome (HLHS)
4.3.1 Mitral Atresia [1, 2]
Mitral atresia [1, 2] is a rare congenital heart defect where the mitral valve does not
form correctly, causing a complete blockage of blood ow from the left atrium to
the left ventricle. Mitral atresia often occurs with other congenital heart defects
(atrial septal defect or ventricular septal defect).
Mitral atresia typically involves a univentricular atrioventricular connection to a
dominant right ventricle via a tricuspid valve, with an imperforate or absent mitral
valve and a hypoplastic underdeveloped left ventricle. In cases where there is an
intact ventricular septum, the left ventricular blood inow is obstructed, leading to
a smaller, underdeveloped left ventricle (as seen in Fig.4.4). This can affect surgical
approach and outcome.
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d
Fig. 4.4 Illustrates the different types of morphology associated with underdevelopment of the
mitral valve. In neonates with congenital mitral atresia (MA) and an intact ventricular septum,
blood from the left atrium (LA) is unable to ow to the left ventricle (LV), resulting in varied
degree of underdevelopment of the LV.Mitral atresia is frequently accompanied by other congenital heart defects. Underdevelopment of the mitral valve is characterized by a range of features,
including varying degrees of hypoplasia of the LV and the mitral valve. The TEE images above
mainly depict the different morphologies of mitral valve and the accompanying LV in neonates.
The TEE images of MA depict a univentricular atrioventricular connection with a dominant right
ventricle through a tricuspid valve. This condition is associated with an intact ventricular septum,
and the aorta arises from the rudimentary LV.MA is often part of hypoplastic left heart syndrome
(HLHS), which affects the surgical approach and outcome. The LV can exhibit varying degrees of
hypoplasia (a–c) or may appear as a blind pouch (d, e)
e
c
Types of mitral atresia are based on the anatomy of the heart and include:
• Isolated Mitral Atresia: The mitral valve is completely blocked, and there are no
other signicant structural abnormalities in the heart.
• Mitral Atresia with Hypoplastic Left Heart Syndrome (HLHS): In addition to
mitral atresia, there is also underdevelopment or hypoplasia of the left ventricle,
aortic valve, and ascending aorta (will be discussed in Fig.4.5).
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4 Valvular Abnormalities ofAtrioventricular Connections
a
c
Fig. 4.5 Shows a 1-day-old male neonate who developed respiratory distress and cyanosis a few
hours after birth. He was diagnosed with hypoplastic left heart syndrome (HLHS) and pulmonary
venous hypertension. (a) This schematic drawing shows the typical features of HLHS, including a
small aorta due to hypoplasia, a large main pulmonary artery (PA), mitral atresia with a rudimentary left ventricle (LV), an atrial septal defect (ASD), and a large patent ductus arteriosus (PDA).
(b) This chest X-ray shows an oddly shaped silhouette, an enlarged cardiac silhouette, and mild
pulmonary edema. (c) This 3D cardiac CT image shows a very hypoplastic ascending aorta (AAO),
an engorged main pulmonary artery (MPA), and PDA, as well as a rudimentary LV and dilated
right ventricle (RV). (d) This intraoperative photograph shows an enlarged RV, a large MPA, and a
small AAO indicated by the green arrows. (e) This intraoperative TEE, ME AV SAX view demonstrates RV dilatation, a large MPA, and a small AO
de
b
References
1. Anderson RH, Strasburger JF, Jonas RA. Mitral atresia. Circulation.
2007;115(4):442–51.
2. Geva T. Management of patients with mitral atresia. Curr Opin Pediatr.
2018;30(5):609–15.
b
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4.3.2 Mitral Atresia (MA) withHypoplastic Left Heart
Syndrome (HLHS)
Mitral atresia with hypoplastic left heart syndrome (HLHS) is a complex congenital
heart defect that affects the development of the left side of the heart. In addition to
mitral atresia (as discussed in Sect. 4.3), HLHS involves hypoplasia, or underdevelopment, of the left ventricle, aortic valve, and ascending aorta. As a result, the right
ventricle becomes the dominant pumping chamber for the body, and the ductus
arteriosus remains open to allow blood to rescue the underdeveloped left side of the
heart [1, 2].
It is important to note that HLHS is a complex and serious condition, and an
accurate and timely diagnosis is crucial for ensuring the best outcomes. These tests
may include a chest X-ray, echocardiogram, or a computed tomography (CT) scan.
These imaging studies (refer to Fig. 4.5) can provide more detailed information
about the heart and surrounding structures.
The size of the aorta is crucial for the success of the Norwood procedure in treating hypoplastic left heart syndrome. Therefore, careful preoperative evaluation and
planning (as discussed in Fig. 4.6) are necessary to optimize outcomes for each
patient. If the aorta is too small, the surgical complexity, duration, and risk of complications increase.
a
e
Fig. 4.6 Displays hypoplastic left heart syndrome (HLHS) with a hypoplastic aorta, as depicted
in (a), which shows a 3D cardiac CT image with three arrows indicating the hypoplastic ascending
aorta. There is a signicant variation in the aortic morphology of HLHS, which is a crucial factor
in determining the success of surgical intervention. Accurately identifying the morphological features and size of the aorta in the TEE image is of paramount importance in selecting the appropriate surgical option, such as the Norwood procedure. This procedure involves connecting the
bottom part of the pulmonary artery to the hypoplastic ascending aorta and reconstructing it to
create a larger neo-aorta, as shown in (g), which shows a 3D cardiac CT image of the Norwood
operation with a neo-AO reconstruction. In neonates with HLHS, there are varying degrees of
hypoplasia of the ascending aorta, indicated by the green arrow. Intraoperative TEE images, specically the ME AV SAX view, in cases (b), (c), and (d) show a small ascending aorta with a
diameter of less than 3mm. In contrast, case (e) exhibits a larger aorta with a diameter of 5mm,
while case (f) shows an even larger diameter of 6mm
f
c
d
g
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4 Valvular Abnormalities ofAtrioventricular Connections
Balloon septostomy is an initial treatment option for newborns with hypoplastic
left heart syndrome (HLHS). During this procedure, as described in Fig.4.7, a balloon catheter is used to create or enlarge an opening in the interatrial septum, allowing oxygenated blood from the lungs to mix with deoxygenated blood from the body.
The Norwood procedure is a complex staged surgery used to treat hypoplastic
left heart syndrome (HLHS) in newborn. It involves three stages: (as shown in
Figs.4.8, 4.9, 4.10, and 4.11).
c
d
Fig. 4.7 Shows the initial stage of treatment for hypoplastic left heart syndrome (HLHS), which
involves the early introduction of prostaglandin E1 to maintain ductal patency and performing balloon atrial septostomy (BAS). However, this procedure can be challenging in infants with HLHS
and a small atrial septal defect (ASD). (a) This is an intraoperative TEE image showing a fourchamber view, which demonstrates mitral atresia with a hypoplastic left ventricle and a large right
ventricle. (b) A color Doppler TEE image reveals a small and underdeveloped ascending aorta
(AO), as well as a large pulmonary artery (PA). (c) The color Doppler TEE image from the UE left
pulmonary artery view conrms the patency of a PDA ow with the use of prostaglandin E1 infusion. (d) Following the BAS procedure, the ME four-chamber view shows a blood ow across the
interatrial septum from the LA to the RA, allowing for unobstructed mixing of blood between the
two chambers
c
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a
d
g
Fig. 4.8 Shows the staged Norwood procedure being performed on a neonate with hypoplastic left
heart syndrome (HLHS). (a) This 3D cardiac CT image of a neonate with HLHS shows a large main
pulmonary artery (MPA) and patent ductus arteriosus (PDA) originating from the RV and directly
connecting to the descending aorta, along with severe hypoplasia of the ascending aorta and (AAO,
white arrow) connecting to the aortic arch. (b) This illustration shows the anatomic changes made
during the modied Norwood procedure for HLHS, which include joining the bottom part of the
pulmonary artery with the ascending aorta to create a larger neo-aorta (neo-AO) (also known as the
Damus-Kaye-Stansel procedure) divided distal MPA, creating a shunt graft between the innominate
and pulmonary arteries (known as the modied Blalock-Taussig shunt), and excising the atrial septum. Red arrows indicate the direction of blood ow. (c) Intraoperative photograph illustrates the
transection of the distal MPA, a diminutive ascending aorta (AO), the aortic arch, and the vascular
allograft used to reconstruct a neo-aorta (neo-AO). (d) During the intraoperative TEE, a UE AAO
view demonstrated a small aorta and a large pulmonary artery (PA) arising from a functional single
right ventricle (RV). The large PA and small AO will fuse side by side to create a neo-aorta (red
arrows). (e) Postoperative TEE after Norwood procedure showing neo-aorta (neo-AO) connecting to
the aortic arch. (Asterisk indicates original PA; white small arrow indicates the original small AO).
(f) Color Doppler TEE showing blood ow directly from functional RV to neo-AO without obstruction and the blood owing very clearly to left coronary artery (LCA). Right coronary artery is not
shown in this view. (Asterisk indicates original PA; white small arrow indicates the original small
AO). (g) The color Doppler TEE of the UE AV SAX view revealed a turbulent blood ow in the
modied Blalock-Taussig shunt, which connects the subclavian artery to the RPA. (h) This postop-
erative 3D volume-rendered CT image shows the neo-AO formed by the jointing of the MPA trunk
to the side of the original AAo (yellow arrowhead) after the Norwood procedure (DKS procedure).
This new connection allows blood from the RV to communicate directly into the AAo, with the left
coronary artery (LCA) and right coronary artery (RCA) are clearly visible. The asterisk indicates the
original MPA arising site. The common atrium (CA) is also visible
b
e
f
h
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4 Valvular Abnormalities ofAtrioventricular Connections
ab
c
Fig. 4.9 Shows a delayed closure of sternotomy in a patient who underwent the Norwood procedure, as seen in Fig. 4.8. This complication may result from a variety of factors and can have
implications for the patient’s recovery and overall outcome. (a) This postoperative TEE image
shows the neo-aorta (neo-AO) after the Norwood procedure, as viewed from the UE with a focus
on the ascending aorta (AAo). Mild arch obstruction was noted during sternotomy closure, which
may have implications for the patient’s recovery. (b) This color Doppler TEE image, taken after the
Norwood procedure, shows turbulence at the junction of this neo-AO to the aortic arch (indicated
by the arrow). This stenosis is caused by extrinsic compression from the sternal closure resulting
in a junctional kinking. (c) To prevent external compression or excessive tension on the neo-AO
following the Norwood procedure, delayed sternal closure can be achieved by using a small piece
of plastic tube (arrow) and sterile dressing to cover the wound temporally opened
4.3 Mitral Atresia (MA) withHypoplastic Left Heart Syndrome (HLHS)
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Fig. 4.10 Shows the staged surgical palliation procedure for a hypoplastic left heart syndrome
(HLHS). Managing HLHS remains one of the greatest challenges in congenital heart surgery. The
three-stage surgical palliation procedure remains the most common treatment for patients with
HLHS.Without surgical intervention, 95% of children with HLHS die within the rst month of life
(ref 2, 3). (1) The upper panel of the diagram shows the three stages of surgical palliation for a
HLHS from left to right. Stage I of the modied Norwood procedure involves aortic arch reconstruction through a side-to-side anastomosis of the main pulmonary artery (MPA) to the ascending
aorta (AAO), an atrial septectomy, and a modied Blalock-Taussig shunt. The Norwood stage I
procedure is best be completed during the neonatal period. Stage II is the Hemi-Fontan procedure
(bidirectional Glenn shunt-superior cavopulmonary anastomosis), which is highly suggested to be
completed when the child is between 4 and 6months of age. Stage III is the Fontan procedure
(TCPC-total cavopulmonary connection), which is better to be completed when the child is
between 2 and 3years of age. (2) The middle panel are photos demonstrating the corresponding
cardiac CT images at different stages of this palliative surgery. (3) The lower panel are diagrams
illustrating the corresponding TEE images at different stages of this surgery
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4 Valvular Abnormalities ofAtrioventricular Connections
c
Fig. 4.11 Shows the staged operation of the Fontan procedure that was scheduled for a 5-year-old
female patient diagnosed with hypoplastic left heart syndrome (HLHS) who had previously undergone the Norwood procedure and bidirectional Glenn shunt. (a) A Fontan procedure with an extracardiac conduit and fenestration (F) is depicted in a schematic drawing. This procedure involves
the use of an extracardiac conduit with a fenestration (F) to divert blood ow from the inferior vena
cava (IVC) combined with the superior vena cava (SVC) to RPA create a blood ow circuit called
total cavopulmonary connection (TCPC). (b) The intraoperative color TEE in the bicaval view
shows an extracardiac conduit connecting the IVC and RPA, with a fenestrated blood ow from the
conduit to the right atrium (RA). (c) The postoperative 3D volume rendering CT image in frontal
view shows a successful TCPC with a fenestration jet ow (F) into the common atrium (CA). The
proximal and distal ends of the RPA are labeled as P and D, respectively, and the arrowhead points
to the original hypoplastic ascending aorta. (d) The postoperative contrast-enhanced CT in obliquecoronal section also shows a patent dark jet ow (indicated by a yellow arrow) into the lumen of
the CA.The major blood from IVC ows upward to RPA through this fully patent conduit, bypassing intracardiac structures, is demonstrated. The abbreviation CA refers to the common atrium;
P-RPA refers to the proximal end of the RPA
d
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1. The rst stage (Norwood procedure) involves reconstructing the aorta to create a
neo-aorta for blood ow to the body and creating a modied BT shunt for blood
to the lung circulation, as shown in Figs.4.8 and 4.9.
2. The second stage, called the bidirectional Glenn shunt, is usually performed
when the child is a few months old (as discussed in Sect. 4.1: Fig.4.2, Sect.
5.1.6: Fig. 5.35).
3. The third stage, known as the Fontan procedure [2, 3], is typically performed
when the child is 2–3years old, as described in Fig.4.10. However, the complete
procedure will be detailed in Fig.4.11.
References
1. Wernovsky G, Ghanayem N, Ohye RG.Hypoplastic left heart syndrome. Lancet.
2016;387:2193–204.
2. Cohen MS. Survival and quality of life for hypoplastic left heart syndrome
patients after the Fontan procedure. J Am Coll Cardiol. 2019;73:3078–87.
3. Khairy E, Poirier N, Mercier LA.Hypoplastic left heart syndrome: current con-
siderations and expectations. J Am Coll Cardiol. 2010;56(10):793–800.
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