- Asymptomatic in childhood; may develop late atrial dysrhythmias.
- Cyanosis may develop with Eisenmenger syndrome.
- Widely split and fixed S2 with 1–3/6 systolic
ejection murmur at lower left sternal border.
- Cardiomegaly on chest radiograph.
- Echocardiogram demonstrates an atrial level shunt.
Cardiac septation occurs between the third and sixth weeks of
fetal development. The septum primum, which arises from the roof
of the common atrium and descends inferiorly, initially divides
the common atrium. The ostium primum is the opening below the inferior
edge of the septum primum, which is obliterated as the septum primum
fuses with the endocardial cushions. The ostium secundum forms in
the midportion of the septum primum prior to closure of the ostium primum.
The septum secundum also arises from the roof of the atrium and descends
along the right side of the septum primum and covers the ostium secundum.
This creates a flap valve whereby blood from the inferior vena cava
may preferentially stream beneath the edge of the septum secundum
and through the ostium secundum into the left atrium. After birth,
the increase in left atrial pressure usually closes this pathway.
An ASD is a hole in the atrial septum (Figure
19–29). ASDs are the third-most
common congenital heart defect, occurring in 1 out of 1000 live births
10% of congenital heart defects. The most common ASD is
the secundum defect, which occurs when the ostium secundum is too
large for complete coverage by the septum secundum. Ostium secundum
defects account for about 80% of ASDs. An ostium primum
ASD, representing 10% of ASDs, occurs as a result of failure
of fusion of the septum primum with the endocardial cushions (ostium
primum defect is discussed later in the section on Atrioventricular
Septal Defects). A third type of ASD is the sinus venosus defect, seen
in about 10% of cases. Sinus venosus ASDs are caused by
abnormal fusion of the venous pathways with the atrium and are characterized
by defects high in the atrial septum near the orifice of the superior
vena cava or, less commonly, low in the atrial septum near the inferior
vena cava. Sinus venosus defects are frequently associated with partial
anomalous pulmonary venous connection, usually with the right upper pulmonary
vein draining into the superior vena cava near the cavoatrial junction. The
rarest type of ASD is the unroofed coronary sinus septal defect.
This occurs when there is loss of the common wall between the coronary
sinus and the left atrium adjacent to the atrial septum. This unroofing
of the coronary sinus leads to a communication between the right
and left atria at the site of the coronary sinus.
Sinus venosus and ostium secundum defects in the atrial
septum as viewed from the opened right atrium.
Failure of postnatal fusion of the septum secundum to the septum
primum results in a persistent slitlike communication known as a
patent foramen ovale (PFO). PFOs are extremely common in the general
population, and autopsy studies have demonstrated a prevalence of
27%. PFOs are generally considered separate from other
ASDs because of the absence of significant shunting, but they remain important
clinically because of the occurrence of paradoxical embolization.
A paradoxical embolus is usually a blood clot arising from a systemic
vein, which would normally pass to the lungs, but in the presence
of a septal defect may instead cross into the systemic circulation.
ASDs lead to increased pulmonary blood flow secondary to left-to-right
shunting. Shunting at the atrial level is determined by the size
of the defect and by the relative ventricular compliance (ie, blood preferentially
fills the more compliant ventricle). At birth, both chambers are equally
compliant, but as PVR falls, the right ventricle remodels and becomes more
compliant. Shunting across the atrial septum causes a volume load
on the right heart. A volume load is created by additional venous
return to a chamber during diastole.
The volume overload from an ASD is usually well tolerated, and
patients are frequently asymptomatic. Symptoms tend to develop when
the ratio of pulmonary to systemic blood flow (Qp/Qs)
exceeds two. The most common symptoms are fatigue, shortness of
breath, exercise intolerance, and recurrent respiratory infections.
Older patients with untreated ASDs tend to develop atrial dysrhythmias,
and adults may develop congestive heart failure and right ventricular
dysfunction. Pulmonary vascular obstructive disease may develop
rarely as a late complication of untreated ASD. Paradoxical embolization
is also an important potential complication of ASD.
The classic physical findings in patients with ASDs include fixed
splitting of the second heart sound and a systolic ejection murmur
at the left upper sternal border due to relative pulmonary stenosis (increased
flow across a normal pulmonary valve). A diastolic flow murmur across
the tricuspid valve is occasionally audible. A prominent right ventricular
lift and increased intensity of the pulmonary component of the second
heart sound may occur with pulmonary hypertension. Chest radiography
shows cardiomegaly, with enlargement of the right atrium, right ventricle,
and pulmonary artery. Electrocardiography frequently demonstrates right
axis deviation and an incomplete right bundle branch block. When
right bundle branch block occurs with a leftward or superior axis,
the diagnosis of AVSD should be considered. Echocardiography confirms
the diagnosis of ASD and defines the anatomy. Cardiac catheterization
is important in selected cases to assess PVR in older patients,
but it is used more frequently with therapeutic intent for device
closure of ASDs.
Because of the long-term complications associated with ASD, repair
is recommended for all patients with symptomatic defects and in
asymptomatic patients in whom the Qp/Qs is
greater than 1.5. Repair is usually performed in children prior
to school age. Closure of ASDs may be performed surgically or using
a device deployed in the cardiac catheterization lab.
Surgical repair is usually recommended for large secundum defects
and for most other types of ASDs. The heart is usually exposed by
median sternotomy. Other surgical approaches have been proposed,
including minimally invasive techniques, but there are technical drawbacks
associated with each of the alternative approaches. In most cases,
a limited midline incision with a partial lower sternal split provides
adequate exposure and a cosmetically acceptable scar. The atrial
septum is exposed through a right atriotomy. Small secundum defects
or PFOs may sometimes be closed primarily by suturing the edge of septum
primum to the edge of septum secundum. More commonly, larger defects
are closed using a patch (polytetrafluoroethylene or autologous
pericardium) and a running polypropylene suture. When anomalous
pulmonary venous drainage is present, a baffle is created to redirect
the flow across the ASD. In all cases, care is taken to deair the
left atrium to avoid the complication of air embolization.
The first transcatheter device closure of an ASD was performed
in 1976. A number of devices are currently available for percutaneous
closure of secundum ASD, and success rates for device deployment are
greater than 90%. Device closure has the advantages of
fewer complications and a shorter hospitalization. Device closure
of small to moderate secundum ASDs and PFOs has now become the standard
of care at most large centers.
Occasionally, adults will present with a newly diagnosed ASD.
Many studies have confirmed that ASD closure in adults over the
age of 40 increases survival and limits the development of heart
failure. When the Qp/Qs is less than
1.5 and the ratio of pulmonary to systemic vascular resistance (Rp/Rs)
is greater than 0.7, significant pulmonary vascular obstructive
disease is usually present. A PVR in excess of 10–12 Woods
units·m2 represents a contraindication to ASD closure.
Operative mortality for ASD repair is close to 0%. Atrial arrhythmias
(1.2%) and postpericardiotomy syndrome (4.7%) are
the most common postoperative complications. The long-term survival
for patients undergoing ASD repair in childhood is normal. The major
long-term complication following surgical closure of ASD is the
development of supraventricular arrhythmias, although the risk is
lowered when the ASD is closed in childhood. The persistence of
this risk despite relief of right-sided volume overload is thought
to be related to incomplete atrial remodeling or due to the presence
of the atriotomy scar. Longer follow-up is required to determine whether
device closure alters the risk of atrial dysrhythmias.
Christensen DD, Vincent RN, Campbell RM: Presentation
of atrial septal defect in the pediatric population. Pediatr Cardiol 2005;
Cowley CG et al: Comparison of results of closure of secundum atrial
septal defect by surgery versus Amplatzer septal occluder. Am J
Hopkins RA et al: Surgical patch closure of atrial septal defects.
Ann Thorac Surg 2004;77:2144.
Krasuski RA: When and how to fix a “hole in the heart”:
approach to ASD and PFO. Cleve Clin J Med 2007;74:137.
Purcell IF, Brecker SJ, Ward DE: Closure of defects of the atrial
septum in adults using the Amplatzer device: 100 consecutive patients
in a single center. Clin Cardiol 2004;27:509.
- Asymptomatic if small.
- Significant congestive heart failure with failure to thrive
develops in the first few months of life if large.
- Most VSDs close spontaneously.
- 2–6/6 pansystolic murmur greatest at the left
sternal border with an active precordium.
- Chest radiograph with cardiomegaly and increased pulmonary
- Echocardiogram demonstrates ventricular level shunting, delineates
anatomic type, and defines the relation to the great vessels.
Ventricular septation is a complex process that requires accurate
development and alignment of a number of structures including the
muscular interventricular septum, the atrioventricular septum (arising
from the endocardial cushions), and the infundibular septum (which
divides the outflow tracts of the right and left ventricles). The
membranous septum is a fibrous portion of the ventricular septum,
which is adjacent to the central fibrous body (where the mitral,
tricuspid, and aortic valve annuli make contact).
VSDs are the most common congenital heart anomalies (with the
exception of bicuspid aortic valve, which occurs in about 1.3% of
the population). VSDs are present in about 4 of 1000 live births
and represent about 40% of congenital heart defects. VSDs
are classified based on their location in the ventricular septum
(Figure 19–30). The most common
defects are perimembranous (80%), which are located in
the area of the membranous septum. Inlet defects (5%) are
located beneath the septal leaflet of the tricuspid valve and are
sometimes called atrioventricular (A-V) canal-type defects. Defects
located high in the ventricular septum are outlet defects (10%).
Outlet VSDs are typically adjacent to both the pulmonary and aortic
valves. Outlet defects are also known by several other names, including supracristal,
infundibular, or doubly committed subarterial. Outlet defects are more
common in the Asian population. Trabecular (or muscular) VSDs (5%)
are completely bordered by muscle. Trabecular VSDs are frequently
multiple and may be associated with perimembranous or outlet defects.
The size of VSDs varies. By definition, a VSD is nonrestrictive
when its size (or the cumulative size of multiple defects) is greater
than or equal to the size of the aortic annulus.
Anatomic locations of various ventricular septal defects.
The wall of the right ventricle has been excised to expose the ventricular
A VSD causes increased pulmonary blood flow due to left-to-right
shunting primarily during systole. This creates a volume load on
the left heart (the left atrium and ventricle receive the increased
venous return during diastole). The right ventricle is not volume
loaded (blood is ejected from the left ventricle through the VSD
and directly into the pulmonary circulation), but it does experience
a pressure load. The volume of shunt flow is determined by the size
of the defect and by the ratio of Rp/Rs.
After birth, the PVR is still high, and shunting across a VSD is
sometimes minimal. Over the first several weeks of life, shunting
tends to increase as the PVR normally falls. Therefore, a patient with
a large VSD may be asymptomatic at birth but eventually develop
severe congestive heart failure.
The natural history for patients with isolated VSDs is highly
variable. Most VSDs are restrictive and tend to close spontaneously
during the first year of life. Large VSDs are nonrestrictive, resulting
in right ventricular and pulmonary pressures that are systemic or
nearly systemic, and high pulmonary blood flow with Qp/Qs ratios
greater than 2.5–3. Moderate VSDs are restrictive, with
pulmonary pressures that are one-half systemic (or less) and Qp/Qs ratios
of 1.5–2.5. Small VSDs are highly restrictive; right ventricular
pressures remain normal, and the Qp/Qs is
less than 1.5. Patients with large VSDs tend to develop symptoms
of congestive heart failure by 2 months of age. Untreated, excessive
pulmonary blood flow leads to pulmonary vascular obstructive disease
by the second year of life. Patients with smaller VSDs may remain
asymptomatic. In patients with outlet VSDs, prolapse of the aortic
valve may occur, producing aortic insufficiency.
Signs of heart failure in infants with large VSDs include tachypnea,
hepatomegaly, poor feeding, and failure to thrive. On physical examination,
there is a pansystolic murmur at the left sternal border. Usually,
the murmur is louder with smaller defects. The precordium is active.
The pulmonary component of the second heart sound is accentuated
in the presence of pulmonary hypertension. Chest radiography shows
increased pulmonary vascular markings and cardiomegaly. Electrocardiography
is significant for right ventricular hypertrophy.
Patients with small VSDs have little shunting and are usually
asymptomatic, having only a pansystolic murmur. Patients with moderate
VSDs manifest symptoms and signs proportional to the degree of shunting.
In patients who have developed significant pulmonary vascular
obstructive disease, the volume of left-to-right shunting is decreased,
and the murmur may disappear. Eisenmenger physiology results when
the shunt flow reverses to right-to-left, creating cyanosis.
The diagnosis of VSD is confirmed by echocardiography, which
accurately defines the anatomy and excludes the presence of associated
defects. Cardiac catheterization is used selectively in older children
and adults in whom elevated PVR is suspected. PVR is calculated
by the following formula: PVR = (PAmean – LA)/Qp,
where PAmean is the mean pulmonary artery
pressure and LA is the left atrial pressure. The units
of resistance by this formulation (using pressures in millimeters
of mercury and pulmonary flow in liters per minute) are Woods units
(which can be expressed in dynes·sec/cm5 by
multiplying by 80). PVR may be fixed or reactive, and at the time
of cardiac catheterization, response to various pulmonary vasodilators
may be assessed.
The management of a patient with a VSD depends on the size of
the defect, the type of the defect, the shunt volume, and the PVR.
In general, patients with large defects who have intractable congestive heart
failure or failure to thrive should undergo early surgical repair.
If the congestive symptoms can be moderated by medical therapy,
then surgery may be deferred until 6 months of age. Patients with
moderate VSDs may be safely followed. If closure has not occurred
by school age, then surgical closure is indicated. Small VSDs with
Qp/Qs of less than 1.5 do not require
closure. There is a small long-term risk of endocarditis for these
patients, but this can be minimized with the appropriate use of
prophylactic antibiotics. Patients with outlet VSDs have a significant
risk of developing aortic insufficiency due to leaflet prolapse,
and, therefore, all of these patients should undergo surgical closure.
Older children and adults must undergo catheterization to assess
the pulmonary circulation. When there is a fixed PVR greater than
8–10 Woods units·m2, then surgery is
Exposure of the ventricular septum is most often achieved by
making a right atriotomy and retracting the leaflets of the tricuspid
valve. This provides access to perimembranous, inlet, and most trabecular
VSDs. Outlet VSDs are frequently best exposed via a pulmonary arteriotomy
because the defect lies just beneath the valve. Trabecular VSDs
located near the ventricular apex can be very difficult to expose,
and an apical ventriculotomy may be necessary. Once the defect is exposed,
it is closed using a polytetrafluoroethylene patch and a running
polypropylene suture, although some centers may prefer other patch
material or interrupted suture technique. It is important to understand
the anatomy of the conduction tissue when closing VSDs. The AV node
is an atrial structure that lies at the apex of an anatomic triangle (known
as the triangle of Koch) formed by the coronary sinus, the tendon
of Todaro (a prominent band leading from the inferior vena cava
and inserting in the atrial septum), and the septal attachment of
the tricuspid valve. The node then gives rise to the bundle of His,
which penetrates the A-V junction beneath the membranous septum.
The bundle of His then bifurcates into right and left bundle branches,
which pass along either side of the muscular ventricular septum.
In the presence of a perimembranous VSD, the bundle of His passes along
the posterior and inferior rim of the defect, generally on the left
ventricular side. In this critical area, sutures must be placed
superficially on the right ventricular side a few millimeters from
the edge of the defect. The bundle of His tends to run along the
posterior and inferior margin of inlet VSDs as well. The conduction
tissue is usually remote from outlet and trabecular VSDs.
Pulmonary artery banding is a palliative maneuver used to protect
the pulmonary circulation from excessive blood flow. Pulmonary artery
banding is currently performed only in patients who are felt to be
poor candidates for VSD closure because of either associated illness
or anatomic complexity, such as multiple trabecular VSDs (“Swiss
cheese” septum). A band is placed around the main pulmonary
artery and tightened to achieve a distal pulmonary artery pressure
of about one-half systemic. The band is secured to the adventitia
of the pulmonary artery to prevent its migration. Distal migration
may result in narrowing and poor growth of one or both branch pulmonary
arteries, while proximal migration can cause deformity of the pulmonary
valve. Later, when the patient is a candidate for VSD closure, the
band must be removed. Repair of the main pulmonary artery at the
band site is also usually necessary and can typically be accomplished
by scar resection and primary closure or patch repair.
Recently, transcatheter devices have been developed to allow
closure of some VSDs in the cardiac catheterization lab. For specific
VSDs, such as muscular, device closure may be preferable. Complications
with device closure include complete heart block (3.8%),
device embolization (0.01%), and aortic insufficiency (0.03%).
For simple perimembranous VSDs, the risk of device closure is in
excess of traditional surgical closure.
Surgical closure of a VSD is associated with a mortality of less
than 1%. Potential complications include injury to the
conduction tissue and injury to the tricuspid or aortic valves.
Transient heart block may result from tissue swelling or injury from
retraction, but permanent heart block occurs in less than 1% of
cases. When heart block develops after surgery, patients are usually
observed for a period of 7–10 days prior to permanent pacemaker
implantation. Tricuspid insufficiency may be precipitated by annular distortion
or chordal restriction by the VSD patch or sutures. The aortic valve may
also be injured by inaccurate suturing (especially in perimembranous
and outlet defects). A residual VSD is seen in about 5% of
cases, and reoperation is indicated when significant shunting persists
(Qp/Qs > 1.5) or the residual defect
is larger than 2 mm in size. The Qp/Qs ratio
can be calculated by measuring oxygen saturations and using the
following formula derived from the Fick equation: Qp/Qs = (Ao – SVC)/(PV – PA),
where Ao is the aortic (or systemic) saturation, SVC is the
saturation in the superior vena cava, PV is the
saturation in the pulmonary veins (which is usually estimated to
be 95–100%), and PA is the saturation
in the pulmonary arteries. Intraoperative echocardiography is used
routinely to identify residual defects, which can then be repaired before
the patient leaves the operating room.
Anderson H et al: Is complete heart block after
surgical closure of ventricular septal defects still an issue? Ann
Thorac Surg 2006;82:948.
Carminati M et al: Transcatheter closure of congenital ventricular
septal defects: results of the European registry. Eur Heart J 2007;28:2361.
Dodge-Khatami A et al: Spontaneous closure of small residual
ventricular septal defects after surgical repair. Ann Thorac Surg
McDaniel NL: Ventricular and atrial septal defects. Pediatr
Tweddell JS, Pelech AN, Frommelt PC: Ventricular septal defect
and aortic valve regurgitation: pathophysiology and indications
for surgery. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 2006;9:147.
- Common defect in patients with trisomy 21.
- Significant congestive heart failure develops in early infancy.
- Chest radiograph with cardiomegaly and increased pulmonary
- Electrocardiography shows left axis deviation.
- Echocardiogram demonstrates the right and left atrioventricular
valves to be present on the same plane with a common orifice along
with associated atrial and/or ventricular septal defects.
The embryological abnormality in AVSDs is the failure of the proper
development of the endocardial cushions, which results in variable
deficiency of the atrial and ventricular septa and malformation
of the A-V valves. AVSDs represent a group of congenital abnormalities
bound by a variable deficiency of the atrioventricular septum immediately
above and below the A-V valves. Other terms commonly applied to
an AVSD include atrioventricular canal defects, endocardial cushion
defects, and atrioventricular communis. Complete AVSDs have a single
common A-V valve orifice resulting in a single 5-leaflet valve overlying
both the right and left ventricles. Incomplete AVSDs have two separate
A-V valve orifices (tricuspid and mitral) with the mitral valve
invariably having a cleft in the anterior leaflet. While most incomplete
AVSDs have no ventricular level shunting, the classification of
AVSDs as complete and incomplete depends only on the valve anatomy, not
on the presence or absence of a VSD. Incomplete defects without
associated ventricular level shunting have also been termed ostium
primum ASDs, while those with a VSD have been described as intermediate
or transitional AVSDs. AVSDs represent approximately 4% of
congenital cardiac anomalies and are frequently associated with
other cardiac malformations. AVSDs comprise 30–40% of
the cardiac abnormalities seen in patients with Down syndrome.
Complete AVSD is characterized by a common atrioventricular orifice,
rather than separate mitral and tricuspid orifices, and a deficiency
of endocardial cushion tissue, which results in an ASD and an inlet
type of VSD (Figure 19–31). AVSDs
were subclassified by Rastelli into the following three types according to
the morphology of the anterior leaflet of the common A-V valve:
Complete atrioventricular canal. The most common type
has a divided anterior bridging leaflet. Both the left and right valvular
components are attached to the interventricular septum with long,
nonfused chordae. The left and right components of the posterior
bridging leaflet are not separated.
- Type A: The anterior bridging leaflet
is divided and attached to the septum by multiple chordae.
- Type B: The anterior bridging leaflet is
attached to a papillary muscle in the right ventricle.
- Type C: The anterior bridging leaflet is free-floating
with no attachments except to the valve annulus.
When both left and right A-V valves equally share the common
A-V valve orifice, the AVSD is termed balanced. Occasionally, the
orifice may favor the right A-V valve (right dominance) or the left
A-V valve (left dominance). In marked right dominance, the left
A-V valve and left ventricle are hypoplastic and frequently coexist
with other left-sided abnormalities, including aortic stenosis,
hypoplasia of the aorta, and coarctation. Conversely, marked left dominance
results in a deficient right A-V valve with associated hypoplasia
of the right ventricle, pulmonary stenosis or atresia, and TOF.
Patients with severe imbalance require staged single-ventricle reconstruction.
The conduction tissue is displaced in an ASVD and is at risk
during the surgical repair. The AV node is located posteriorly and
inferiorly of its normal position toward the coronary sinus in the
triangle of Koch. This triangle is bounded by the coronary sinus,
the posterior attachment of the inferior bridging leaflet, and the
rim of the ASD. The bundle of His courses anteriorly and superiorly
to run along the leftward aspect of the crest of the VSD, giving
off the left bundle branch and continuing as the right bundle branch.
Cardiac anomalies are associated with AVSDs, including PDA (10%)
and TOF (10%). Important abnormalities of the left A-V
valve include single papillary muscle (parachute mitral valve) (2–6%)
and double orifice mitral valve (8–14%). A persistent
left superior vena cava with or without an unroofed coronary sinus
is encountered in 3% of patients with an AVSD. Double-outlet
right ventricle (2%) significantly complicates or may even preclude
complete surgical correction. As mentioned previously, left ventricular outflow
tract obstruction from subaortic stenosis or redundant A-V valve
tissue occurs in 4–7%. Associated transposition of
the great arteries and left ventricular inflow obstruction have
been rarely reported.
The predominant hemodynamic features of an AVSD are the result
of left-to-right shunting at the atrial and ventricular levels.
In the absence of ventricular level shunting, the hemodynamics and
clinical presentation of a patient with an incomplete AVSD resemble
that of a typical secundum ASD with right atrial and right ventricular
volume overload. Patients with a complete AVSD with both atrial-level
and ventricular-level shunting generally present early in infancy
with signs and symptoms of congestive heart failure. In addition,
moderate or severe left A-V valve regurgitation occurs in approximately
10% of patients with an AVSD worsening the clinical picture.
On physical examination, the precordium is hyperactive, often with
a prominent thrill. Auscultatory findings include a systolic murmur
along the left sternal border, a high-pitched murmur at the apex
from left A-V valve regurgitation, and a middiastolic flow murmur
across the common A-V valve. In the presence of elevated PVR, there
may be a split first heart sound. Significant cardiomegaly and pulmonary
overcirculation are found on the chest radiograph. Electrocardiogram reveals
biventricular hypertrophy, atrial enlargement, prolonged PR interval,
leftward axis, and counterclockwise frontal plane loop. Doppler/echocardiography
is diagnostic, defining the atrial and ventricular level shunting,
valvular anatomy, and any associated anomalies. Up to 90% of
untreated individuals with a complete AVSD develop pulmonary vascular disease
by 1 year of age due to the large left-to-right shunt, potentially
exacerbated by the associated A-V valve regurgitation. Patients
with trisomy 21 tend to develop pulmonary vascular obstructive disease
earlier than chromosomally normal infants due to small airway disease, chronic
hypoventilation, and elevated Pco2. Initial
aggressive medical management is undertaken to relieve the symptoms
of congestive heart failure. Elective surgical correction should
be performed by age 3–6 months. Earlier intervention is
indicated for failure of medical management.
Cardiac catheterization should be performed for patients over
the age of 1 year, for patients with signs or symptoms of increased
PVR, or in some cases to further evaluate other associated major cardiac
anomalies. If the PVR is high, it is important to remeasure it while
the child is breathing 100% oxygen with and without nitric
oxide. If the pulmonary resistance falls, it implies that much of the
elevated resistance is dynamic and can be managed in the perioperative period
by ventilatory manipulation, supplemental oxygen, and nitric oxide.
More recently, sildenafil has been shown to decrease elevation in
PVR in children with congenital heart disease. Markedly elevated
PVR (greater than 10 Woods units·m2) that does
not respond to oxygen administration is generally considered a contraindication
Operative treatment is almost always necessary as soon as symptoms
are observed to prevent further clinical deterioration. Even in
the absence of symptoms, operation is best performed before 6 months
of age. Pulmonary artery banding, which permits delaying the repair until
the child is larger, is no longer used today except in select complex
or single-ventricle cases, extremely low birth weight or prematurity,
and very poor clinical condition. This approach exposes the child
to the risks of two operations, and the overall mortality exceeds
that of primary repair in infancy. Patients with incomplete AVSDs
usually require repair within the first few years of life.
Two techniques are widely employed for the repair of complete
AVSDs: a 1-patch technique and a 2-patch technique. Incomplete AVSDs
are repaired with the single-patch technique. Regardless of which
approach is selected, the goals are to close the ASD and VSD and
to separate the common A-V valve into 2 nonstenotic, competent valves.
The cleft in the anterior leaflet of the mitral valve is generally
closed to lessen the risks of long-term mitral regurgitation. For
the 2-patch technique, separate patches are used for the ASD and
VSD. For the 1-patch technique, the superior and inferior bridging
leaflets are divided along a line separating them into right and
left components. A single patch is utilized to close both the ventricular
and ASDs. The cut edges of the leaflets are then resuspended to
the patch. For defects with a small VSD component, a modified single-patch
technique may be employed. For this method, a single patch is sewn directly
to the rim of the VSD, sandwiching the bridging leaflets between
the patch and the crest of the VSD.
The short-term and long-term success of the operation is highly
dependent on the status of the PVR and the surgeon’s ability
to maintain competence of the mitral valve. In developed countries,
it is fortunately relatively uncommon for patients to present late
in the course of an AVSD with refractory PVR elevations. Although earlier
reports recommend that the cleft in the left A-V valve should not
be closed and the valve should be treated as a trileaflet structure,
most authors now believe that closure of the cleft is an important
mechanism in preventing postoperative left A-V valve regurgitation. Significant
A-V valve regurgitation at the conclusion of surgery, severe dysplasia of
the left A-V valve, and failure to close the cleft of the left A-V
valve have been identified as important risk factors for reoperation.
Significant postoperative left A-V valve regurgitation is also a
risk factor for operative and long-term mortality. The cleft should
not be completely closed in the presence of a single papillary muscle
to avoid causing left A-V valve stenosis. In the case of a double-orifice
valve, the bridging tissue should not be divided to create a single
opening in the valve.
Operative mortality is related largely to associated cardiac
anomalies and left A-V valve regurgitation. Mortality for repair of
uncomplicated incomplete AVSDs is 0–0.6%, while
the addition of left A-V valve regurgitation increases mortality
to 4–6%. For complete AVSDs, the mortality without
left A-V valve regurgitation is approximately 5%, compared
with 13% when significant degrees of regurgitation are
present. The difference in operative mortality between patients
with and without regurgitation underscores the importance of careful
management of the left A-V valve.
The majority of reoperations after repair of AVSD are due to
left A-V valve regurgitation or the development of subaortic stenosis.
Significant postoperative A-V valve regurgitation occurs in 10–15% of
patients, necessitating reoperation for valve repair or replacement
in 7–12%. The incidence of permanent complete
heart block is approximately 1%. Heart block encountered
in the immediate postoperative period may be transient due to edema
of or trauma to the AV node or bundle of His. However, right bundle
branch block is common (22%).
Backer CL, Stewart RD, Mavroudis C: What is the
best technique for repair of complete atrioventricular canal? Semin
Thorac Cardiovasc Surg 2007;19:249.
Boening A et al: Long-term results after surgical correction
of atrioventricular septal defects. Eur J Cardiothorac Surg 2002; 22:167.
Dunlop KA et al: A ten year review of atrioventricular septal
defects. Cardiol Young 2004;14:15.
Singh RR et al: Early repair of complete atrioventricular septal
defect is safe and effective. Ann Thorac Surg 2006;82:1598.
Welke KF et al: Population-base perspective of long-term outcomes
after surgical repair of partial atrioventricular septal defect.
Ann Thorac Surg 2007;82:624.
- Widened pulse pressure.
- Continuous “machinery” murmur heard over
the left upper sternal border radiating into the back.
- Very common in premature infants.
- May cause hypoperfusion due to diastolic run off.
- Older patients are asymptomatic with a continuous murmur heard
in the back and radiating into both lung fields.
The ductus arteriosus is a normal fetal vascular structure that
allows blood from the right ventricle to bypass the high resistance
pulmonary vascular bed and pass directly to the systemic circulation. The
ductus communicates between the main pulmonary artery (or proximal
left pulmonary artery) and the proximal descending thoracic aorta.
Histologically, the media of the ductus contains a predominance
of smooth muscle cells, while the media of the aorta and pulmonary
artery contain well-developed elastic fibers. Vasocontrol of the
ductus is mediated by two important mechanisms: oxygen tension and
prostaglandin levels. During fetal development, low oxygen tension
and high levels of circulating prostaglandin maintain ductal patency. During
the final trimester, the ductus becomes less sensitive to prostaglandins and
more sensitive to the effects of oxygen tension. Following birth,
the rise in oxygen tension and a fall in prostaglandins (which were
previously supplied principally by the placenta) lead to ductal closure,
which is usually complete by 12–24 hours. After closure,
the ductus becomes a fibrous cord known as the ligamentum arteriosum.
Failure of closure of the ductus leads to the condition called patent
ductus arteriosus. PDA occurs in about 1 out of 1200 live births and
accounts for 7% of congenital heart defect. The incidence
is much higher in premature infants (greater than 20%). This
elevated incidence is thought to be related to immaturity of the
ductal wall resulting in impaired sensitivity to oxygen tension.
PDA may occur as an isolated defect, or it may occur in association
with a number of other anomalies. Patency of the ductus arteriosus
is desirable in a number of defects in which there is either inadequate
pulmonary blood flow (such as pulmonary atresia) or inadequate systemic blood
flow (as in severe coarctation of the aorta). The discovery that
extrinsic delivery of prostaglandins can maintain ductal patency
has played a critical role in improving the survival of these patients.
The physiologic manifestation of PDA is shunting of blood across
the ductus. The shunt volume is determined by the size of the ductus
and by the ratio of pulmonary to systemic vascular resistance. At birth,
the PVR drops dramatically and continues to decline over the first
several weeks of life. As a result, shunting across a PDA is from
left-to-right. Excessive pulmonary blood flow can lead to congestive
heart failure. In extreme cases, hypotension and systemic malperfusion
may result. Patients with a large PDA who survive infancy tend to
develop pulmonary vascular obstructive disease. Eisenmenger physiology
results when the PVR exceeds the systemic vascular resistance, producing
a reversal of shunting across the ductus to right-to-left. This
leads to cyanosis and, eventually, right ventricular failure. Small
PDAs may persist to adulthood without producing any symptoms or
physiologic derangement. Endocarditis and endarteritis have been
reported as long-term complications of PDA.
In patients with PDA, symptoms are proportional to the shunt
volume and the presence of associated defects. Left-to-right shunting
produces volume overload of the left heart. Infants with congestive
heart failure demonstrate symptoms of tachypnea, tachycardia, and
poor feeding. Older children may present with recurrent respiratory
infections, fatigue, and failure to thrive. Physical findings include
a widened pulse pressure and a continuous “machinery” murmur
heard best along the left upper sternal border. Chest radiography
shows increased pulmonary vascular markings and left heart enlargement.
Left ventricular hypertrophy and left atrial enlargement may be
evident on the electrocardiogram. Echocardiography is the diagnostic
method of choice. Diagnostic cardiac catheterization is performed
only in older patients with suspected pulmonary hypertension to
evaluate for pulmonary vascular obstructive disease. More frequently, catheterization
is utilized for transcatheter occlusion of the ductus in selected cases.
PDA closure is performed for all symptomatic patients. Closure
is also recommended for asymptomatic patients due to the risk of
heart failure, pulmonary hypertension, and endocarditis. Closure of
the ductus may be accomplished by one of three approaches: pharmacologic, surgical,
and endovascular. Indomethacin, which is a prostaglandin inhibitor, stimulates
PDA closure in premature infants. It is rarely effective in full-term infants.
The dosing regimen is 0.1–0.2 mg/kg intravenously
at 12-hour or 24-hour intervals for a total of three doses. This
is effective in about 80% of premature babies. Due to its
side effects, indomethacin is contraindicated in patients with sepsis,
renal insufficiency, intracranial hemorrhage, or bleeding disorders.
Failure of indomethacin after two complete courses results in referral
for surgical closure.
The surgical approach to PDA is through a left posterolateral
thoracotomy via the third or fourth intercostal space. The pleura
is incised over the proximal descending thoracic aorta, which allows medial
retraction of the vagus nerve. The recurrent laryngeal nerve curves
behind the ductus and should be protected throughout the procedure.
Dissection is then performed to demonstrate the pertinent anatomy.
In many cases, the ductus is the largest vascular structure present, and
it must not be confused with the aorta. Ductal tissue is extremely
friable, so direct manipulation is minimized. In premature infants,
the ductus is controlled with a single surgical clip; this procedure
is commonly performed in the neonatal intensive care unit, thereby avoiding
problems associated with patient transfer. In older patients, occlusion
of the ductus is achieved with simple silk ligature or, preferably,
by division between ligatures to minimize recurrence.
Recently, thoracoscopic techniques have been developed to perform
PDA ligation. This approach has the potential benefits of decreased
pain and quicker recovery. Disadvantages include a substantial learning
curve and increased operating time.
A number of endovascular devices have been developed for the
purpose of transcatheter occlusion of the PDA. This approach is
very successful in older infants, children, and adults with small and
moderate sized PDAs and has become the treatment of choice at many centers.
Surgical therapy is reserved for PDAs having a large diameter or
very short length.
Rarely, an adult will present with a significant PDA. These patients
must be carefully evaluated for the presence of pulmonary vascular
obstructive disease prior to ductal closure. If the patient is not a
candidate for device closure, surgical closure can be problematic.
Calcification of the ductal wall is common in adults, which makes
ligation hazardous. In some cases, cardiopulmonary bypass may be
required with closure of the ductus from within the pulmonary artery.
Closure of the ductus by surgical or transcatheter techniques
is achieved with a mortality that approaches zero. Potential complications
include pneumothorax, recurrent laryngeal nerve injury, and chylothorax
(from injury to the thoracic duct). Long-term survival should be
normal following PDA ligation in most patients. Survival in premature
infants depends primarily on the extent of prematurity with its
Burke RP et al: Video-assisted thoracoscopic surgery
for patent ductus arteriosus in low birth weight neonates and infants. Pediatrics
1999;104(2 Pt 1):227.
Cowley CG, Lloyd TR: Interventional cardiac catheterization
advances in nonsurgical approaches to congenital heart disease.
Curr Opin Pediatr 1999;11:425.
Giroud JM, Jacobs JP: Evolution of strategies for management
of the patent arterial duct. Cardiol Young 2007;17:68.
Malviya M, Ohlsson A, Shah S: Surgical versus medical treatment
with cyclooxygenase inhibitors for symptomatic patent ductus arteriosus
in preterm infants. Cochrane Database Syst Rev 2008;1.
- Mild to moderate lesions are asymptomatic.
- Right heart failure and cyanosis with severe lesions.
- Systolic ejection murmur on the left upper sternal border
with a delayed, soft S2.
- Ejection click is often present.
- Increased right ventricular impulse.
Isolated pulmonary stenosis occurs in 5–8% of
all congenital cardiac anomalies. The pulmonary valve is usually
trileaflet with fusion of the commissures. The valve can appear
thickened and domed on echocardiography. Most patients have an associated
PFO or a secundum ASD. Pulmonary stenosis may be valvar or subvalvar
due to muscular narrowing of the infundibulum (Figure 19–32).
Pulmonary stenosis. A: Valvular pulmonary
stenosis. B: Infundibular pulmonary stenosis.
Young infants with severe pulmonary stenosis present with failure
to thrive, right heart failure, and possible hypoxic spells. Older
children tend to have mild to moderate stenosis that is asymptomatic.
They may, however, complain of shortness of breath with exertion
or arrhythmias. The murmur of pulmonary stenosis tends to be prominent
and therefore is not missed on routine exam. The presence of a systolic
ejection murmur should prompt further workup, including an echocardiogram,
which is diagnostic. Patients may be followed symptomatically with
mild to moderate pulmonary stenosis. Surgical or catheter-based
intervention should be considered for a gradient higher than 50
mm Hg, progressive ventricular hypertrophy, or new tricuspid regurgitation.
Neonates presenting with profound cyanosis from severe pulmonary
stenosis need to be placed on PE1 to maintain ductal patency.
The ductus will maintain adequate pulmonary blood flow so that the
patient can be stabilized. For isolated pulmonary stenosis, balloon valvuloplasty
by the interventional cardiologists is highly successful and has replaced
surgical intervention for the majority of patients. Asymptomatic infants
with systemic right ventricular pressures from pulmonary stenosis
are also excellent candidates for balloon dilation. Surgical valvotomy
or a transannular patch for pulmonary stenosis is reserved for patients
who have failed balloon dilation, who have a severely hypoplastic
valve annulus, or who have other associated anomalies including
muscular infundibular narrowing. Older patients with progressive
isolated pulmonary stenosis are excellent candidates for elective
balloon dilation when they develop elevated right ventricular pressures.
Early mortality for patients with critical pulmonary stenosis
is 3–10%. Restenosis occurs in 10–25% of
patients. Once the outflow obstruction is relieved, the right ventricular
hypertrophy and tricuspid insufficiency regress. Although overall
survival is excellent for isolated pulmonary stenosis, over 50% of
patients will require additional interventions, including repeat
balloon dilation, pulmonary valve replacement, and ASD closure.
Late atrial and ventricular arrhythmias occur in 38% of
Earing MG et al: Long-term follow-up of patients
after surgical treatment for isolated pulmonary stenosis. Mayo Clin Proc
Peterson C et al: Comparative long-term results of surgery versus
balloon valvuloplasty for pulmonary valve stenosis in infants and
children. Ann Thorac Surg 2003;76:1078.
Poon LK, Menahem S: Pulmonary regurgitation after percutaneous
balloon valvoplasty for isolated pulmonary valvar stenosis in childhood.
Cardiol Young 2003;13:444.
- Timing of presentation and degree of symptoms are highly
- Cyanosis and heart failure in infants.
- New-onset atrial arrhythmias and reentrant tachycardia in
- Poorest prognosis in symptomatic infants.
- Chest radiograph with the classic “wall-to-wall” heart
- Electrocardiogram demonstrates a right bundle branch block,
right axis deviation, and ventricular preexcitation.
Ebstein’s malformation was first described by Wilhelm
Ebstein in 1866 as a constellation of clinical findings resulting
from an abnormality of the tricuspid valve. It has become evident
over time that the malformation is a disease of the entire right
ventricle and the development of the tricuspid valve. It involves
a spectrum of anatomical abnormalities of variable severity, which
include apical displacement of the septal and mural leaflets of
the tricuspid valve, which have failed to dilaminate from the underlying myocardium;
thinning or atrialization of the inlet component of the right ventricle, with
variable dilation; and malformation of the anterosuperior leaflet,
with anomalous attachments, redundancy, and fenestrations. Several
other cardiac anomalies are often associated with the right ventricular
changes, such as atrial and ventricular septal defects, obstruction
of the outlet from the right ventricle, and Wolff-Parkinson-White
syndrome. Ebstein malformation can also afflict the left-sided systemic
atrioventricular valve in the setting of congenitally corrected transposition.
The malformation is rare, accounting for no more than 1% of
all congenital cardiac anomalies. Due to the significant anatomic
variability in the abnormalities of the tricuspid valve and right
ventricle, the age at presentation and severity of symptoms can
also be highly variable. Patients who present in infancy have the poorest
prognosis. There is a high rate of fetal death, hydrops, and pulmonary hypoplasia
when the diagnosis is made during fetal life. Cyanosis is the most common
presentation in infancy. These patients have severe tricuspid regurgitation
with a poorly functioning right ventricle in the face of elevated
pulmonary arterial resistance. The result is a state of low cardiac
output dependent upon right-to-left shunting across the oval fossa.
With less severe derangements of the tricuspid valve and preserved
ventricular function, patients tend to present later in adolescence
or early adulthood. Many patients are asymptomatic and present with
a murmur noted on physical examination. In symptomatic patients,
a common presentation involves the new onset of atrial arrhythmias
or reentrant tachycardia. Exercise tolerance may be diminished, with
cyanosis during extreme exertion if an ASD is present. Those patients
with an intact atrial septum will often progress to congestive heart
failure with increasing cardiomegaly.
Echocardiography is usually sufficient for accurate diagnosis
and anatomic evaluation. The degree of displacement, tethering,
and dysplasia of the valvar leaflets, as well as the amount of regurgitation, can
be determined. Ventricular function and the extent of atrialization
of the right ventricle can also be evaluated. Additional abnormalities,
including the presence and direction of a shunt at the atrial level,
can be assessed. Electrocardiographic findings include incomplete
right bundle branch block, right axis deviation, ventricular preexcitation,
and atrial arrhythmias. The chest radiograph can vary from normal,
in patients with mild anatomic abnormalities, to the classic “wall-to-wall” heart.
Cardiac catheterization is rarely necessary.
As noted previously, neonates often present with profound cyanosis
and may require prostaglandins to maintain adequate flow of blood
to the lungs during the early neonatal period when pulmonary resistance
is high. It is important to distinguish functional from anatomic
pulmonary atresia. In patients with functional atresia, it may be
possible to wean them from the infusion of prostaglandins while
maintaining adequate saturations of oxygen as pulmonary resistance
falls. These patients can then be followed for development of further
In neonates who cannot be weaned from prostaglandins due to unacceptable
levels of hypoxemia, or in those with anatomic pulmonary atresia,
it is necessary to construct a systemic-to-pulmonary shunt to maintain
adequate pulmonary blood flow. For neonates who also develop significant
symptoms of congestive heart failure while on prostaglandin, it
is necessary to address the underlying valvar pathology. The options
include closure of the tricuspid valve, with or without fenestration,
along with construction of a modified Blalock-Taussig shunt, repair
of the tricuspid valve if ventricular function is reasonable, or
In the older patient with progressive symptoms, a variety of
surgical options exist to address the malformed tricuspid valve.
Most are based on techniques designed to mobilize the leading edge
of the anterosuperior leaflet, aiming to create a competent monocusp
valve with or without plication of the atrialized portion of the
right ventricle. There is ongoing debate as to the necessity of
obliterating the atrialized portion of the right ventricle. Historically,
plication of this portion of the ventricle has been an integral
part of most repairs, albeit that no clear physiologic benefit with
regards to improved ventricular function has been demonstrated.
In addition, the potential exists for injury to the right coronary
artery as a result of the plication, which may adversely impact
late outcomes and contribute to ventricular arrhythmias.
Replacement of the tricuspid valve is a final option. The late
survival free from reoperation, however, has been equivalent to
valvar repair. If replacement is required, heterografts are preferred
over mechanical valves due to risks of thrombosis. Other options
using tissue valves include the insertion of pulmonary autografts,
mitral valve homografts, and “top hat” mounted
pulmonary or aortic homografts. When replacing the valve, the sutures
should be brought around the coronary sinus, leaving it to drain
into the right ventricle so as to minimize potential injury to the
Ebstein malformation is a rare but challenging congenital cardiac
defect. The high degree of anatomic variability makes it difficult
to have a standardized approach to these children. The symptomatic
neonate carries a very grave prognosis. The presence of associated cardiac
and other congenital anomalies often make survival impossible. Surgical options
are limited at this age and often still result in a poor outcome.
Medical management, if possible, is the best, as surgical success
improves with age. If surgery is required, conversion to functional
tricuspid atresia often offers the best survival, as the ventricle
in the severely symptomatic neonate functions poorly. Transplantation
remains an option, but the availability of organs limits its utility.
Patients who are not symptomatic in the neonatal period will
often remain free from symptoms well into adolescence. Electrophysiologic
symptoms usually precede symptoms of congestive heart failure. Indications
for repair at these ages include symptoms, cyanosis, and progressive
Boston US et al: Tricuspid valve repair for Ebstein’s
anomaly in young children: a 30-year experience. Ann Thorac Surg
Dearani JA, Danielson GK: Tricuspid valve repair for Ebstein’s
anomaly. Operat Tech Thorac Cardiovasc Surg 2004;8:188.
Jaquiss RD, Imamura M: Management of Ebstein’s anomaly
and pure tricuspid insufficiency in the neonate. Semin Thorac Cardiovasc
Paranon S, Acar P: Ebstein’s anomaly of the tricuspid
valve: from fetus to adult: congenital heart disease. Heart 2008;94:237.
Ullmann MV et al: Ventricularization of the
atrialized chamber: A concept of Ebstein’s anomaly repair.
Ann Thorac Surg 2004;78:918.
- Infants present with significant heart failure and hemodynamic
- Sudden cardiac death is the most common cause of mortality.
- Narrow and delayed pulse pressure.
- Classic crescendo-decrescendo murmur at the upper sternal
border that radiates into the neck with a prominent left ventricular
Aortic stenosis is a form of left ventricular outflow tract obstruction
that may occur at a valvar (70%), subvalvar (25%),
or supravalvar (5%) level. Aortic stenosis occurs in about
4% of patients with congenital heart disease. The severity
of aortic stenosis may be graded as mild (peak pressure gradient
less than 50 mm Hg), moderate (50 to 75 mm Hg), or severe (greater
than 75 mm Hg).
Valvar aortic stenosis occurs secondary to maldevelopment of
the aortic valve. Most commonly, a bicuspid valve is present, although
tricuspid and unicuspid valves are also represented. In valvar aortic
stenosis, the leaflets are thickened and frequently dysmorphic,
and there is a variable degree of leaflet fusion along the commissures.
The aortic annulus may be hypoplastic. In 20% of cases, valvar
aortic stenosis is associated with other cardiac defects, most commonly coarctation
of the aorta, PDA, VSD, or mitral stenosis. Males with valvar aortic stenosis
outnumber females by a ratio of 4:1. There is a wide spectrum of
clinical presentation of valvar aortic stenosis, but patients tend
to present in one of two groups: neonates and infants with severe aortic
stenosis develop symptoms of rapidly progressive congestive heart
failure, while older children generally have less severe obstruction
and a more slowly progressive course.
Subvalvar aortic stenosis occurs below the level of the aortic
valve and may be discrete (80%) or diffuse (20%).
Discrete (or membranous) subaortic stenosis is rarely seen in infants
and tends to progress over time. This lesion consists of a crescentic
or circumferential fibrous or fibromuscular membrane that protrudes
into the left ventricular outflow tract. The pathogenesis of discrete
subaortic stenosis is unknown, but it is thought to be an acquired
lesion that develops secondary to a congenital abnormality of the
left ventricular outflow tract in which abnormal flow patterns lead
to endocardial injury with resultant fibrosis. Although the aortic
valve leaflets are usually normal in discrete subaortic stenosis,
the turbulent flow created by the obstruction can cause leaflet
thickening and progressive aortic insufficiency. Diffuse subaortic
stenosis is a more severe form of stenosis that creates a long,
tunnellike obstruction. Diffuse subaortic stenosis should be distinguished from
hypertrophic cardiomyopathy. Both forms of subaortic stenosis are
associated with a high risk of endocarditis.
Supravalvar aortic stenosis is characterized by thickening of
the wall of the ascending aorta. The lesion may be localized (80%)
to the region of the sinotubular ridge (at the level of the valve
commissures), creating an hourglass deformity, or it may be more
diffuse (20%), extending into the aortic arch and its branches.
In both varieties, the aortic valve leaflets may be abnormal. The
free edges of the aortic valve leaflets may adhere to the aortic
wall in the region of intraluminal thickening, and this may lead
to reduced coronary blood flow during diastole. Aortic wall thickening
may also extend into the coronary ostia and further impair coronary
blood flow. Associated cardiac lesions are common, particularly
branch pulmonary artery stenoses. A genetic basis for supravalvar
aortic stenosis has been established. About 50% of cases
of supravalvar aortic stenosis are associated with Williams syndrome,
in which a partial deletion of chromosome 7 (including the elastin
gene) leads to the triad of supravalvar stenosis, mental retardation,
and a characteristic “elfin” facies. Isolated
mutations in the elastin gene have also been shown to produce familial
supravalvar aortic stenosis with an autosomal dominant pattern of
transmission. There is a significant incidence of endocarditis in
patients with supravalvar aortic stenosis. Sudden death is frequently reported
and is probably related to coronary obstruction.
Severe aortic stenosis is usually well-tolerated during fetal development.
Although left ventricular output and antegrade flow across the aortic
valve are decreased, the right ventricle compensates with increased
output, and systemic perfusion is maintained by flow across the
ductus. After birth, there is increased venous return to the left
heart, and this exacerbates the pressure load created by the stenotic
aortic valve, leading to left ventricular dysfunction. As the ductus
closes during postnatal life, systemic malperfusion may develop
with resulting hypotension, acidosis, and oliguria. Coronary perfusion
is also impaired due to the combination of systemic hypotension
and elevated left ventricular end-diastolic pressures. Patients
with critical aortic stenosis typically exhibit severe left ventricular
dysfunction. These patients usually show signs of distress soon
after birth. On examination, there is impaired distal perfusion
with poor capillary refill and diminished, thready pulses. A systolic
ejection murmur may be absent if the cardiac output is severely
diminished. Differential cyanosis may be observed due to perfusion
of the lower body with desaturated blood shunting through the ductus. The
electrocardiogram shows left ventricular hypertrophy, and the chest
radiograph displays cardiomegaly and pulmonary congestion. Echocardiography
establishes the diagnosis.
In contrast to infants with critical aortic stenosis, older children
with valvar aortic stenosis usually present with less severe stenosis
(mild or moderate), and most are asymptomatic. Symptoms of angina, syncope,
and congestive heart failure are not commonly reported. Congenital valvar
aortic stenosis is a progressive lesion, however, and survival is
dependent on the severity of stenosis and its rate of progression.
Sudden cardiac death is the most common cause of mortality. Endocarditis
occurs in less than 1% of patients. The diagnosis of valvar aortic
stenosis in older children can frequently be made on physical exam. There
is a classic systolic crescendo-decrescendo murmur at the upper
sternal border, which radiates to the neck. An ejection click is
often present. A visible apical impulse is suggestive of significant
left ventricular hypertrophy. In severe cases, the pulse may be
weak and delayed (pulsus tardus et parvus). The electrocardiogram
shows left ventricular hypertrophy. The chest radiograph is usually
normal. Echocardiography accurately defines the level of stenosis
and its severity. Using Doppler techniques, the pressure gradient
across the stenotic valve may be estimated using a simplified form
of the Bernoulli equation P = 4V2,
where P is the pressure gradient and V is
the peak flow velocity. Cardiac catheterization is generally reserved
for therapeutic intervention.
The clinical findings in subvalvar aortic stenosis are similar
to those for valvar stenosis. The signs and symptoms of supravalvar
aortic stenosis are similar to those in other forms of left ventricular outflow
tract obstruction. The diagnosis is made by echocardiography, but
cardiac catheterization (and more recently MRI) is essential to
define the aortic, coronary, and pulmonary arterial anatomy prior
to surgical intervention.
The neonate or infant with critical aortic stenosis represents
a true emergency. Endotracheal intubation and inotropic support
is routine. Ductal patency is maintained with prostaglandins, and
acidosis is corrected. All patients with critical aortic stenosis
require some form of urgent intervention. The approach is determined
by the valve morphology and by the presence of associated defects.
In its most extreme form, critical aortic stenosis may be associated
with underdeveloped left-sided cardiac chambers and therefore may
represent a form of HLHS. In these cases, single-ventricle palliation must
be undertaken. For patients with adequate left-sided chambers, relief
of aortic stenosis may be achieved by one of the following three
approaches: percutaneous balloon valvuloplasty, surgical valvotomy,
or aortic valve replacement. Balloon valvuloplasty is generally
considered the procedure of choice when the aortic valve annulus
is adequate and there are no associated cardiac defects. Alternatively,
surgical valvotomy may be accomplished by closed or open techniques.
The closed approach is performed using cardiopulmonary bypass but
without aortic cross-clamping. Dilators of increasing size are passed
through a ventriculotomy in the left ventricular apex and advanced
across the aortic valve. Some centers prefer open surgical valvotomy,
which allows a precise valvotomy under direct vision, although aortic
cross-clamping with cardioplegia is necessary. In all cases, the
goal of therapy is to relieve stenosis without creating excessive aortic
insufficiency. Dramatic clinical improvement is expected following
balloon or surgical valve valvotomy, and early survivals of greater
than 80% have been reported. The incidence of aortic insufficiency
is slightly higher following balloon valvotomy. In most cases, however,
stenosis will recur and repeat valvotomy or aortic valve replacement
will eventually be required. Aortic valve replacement is problematic
in the neonate due to small patient size. In these cases, many consider
the best valve replacement to be a pulmonary autograft (Ross procedure)
with enlargement of the aortic annulus (Konno aortoventriculoplasty).
The Ross-Konno procedure has been used successfully for neonates
with critical aortic stenosis in whom the aortic annulus is hypoplastic
and for selected patients in whom valvuloplasty was unsuccessful.
Survival following the Ross-Konno procedure in infants has been
shown to be excellent. Growth of the pulmonary autograft has been
documented, thereby making it an ideal valve replacement for children.
Unfortunately, as part of the Ross procedure, the pulmonary valve
must be replaced using a cryopreserved homograft, which does not grow,
and homograft replacement must be anticipated at intervals as the
All patients with severe valvar aortic stenosis should undergo
intervention, as should all symptomatic patients with moderate stenosis.
Asymptomatic patients with mild or moderate stenosis are generally
observed. As described for critical aortic stenosis, the techniques
used to relieve aortic stenosis in older patients include percutaneous
balloon valvuloplasty, surgical valvulotomy, and valve replacement.
Balloon valvuloplasty is usually performed as the primary intervention
and is associated with a success rate of nearly 90% and
a mortality of less than 1%. Open surgical valvotomy is
an alternative approach with similar results. For valves that are
severely dysplastic, develop restenosis after intervention, or become insufficient
as a result of prior intervention, valve replacement may be necessary.
For older children, there are more options for valve replacement.
The choices include mechanical prostheses, bioprosthetic valves,
and tissue substitutes, such as porcine xenografts, cryopreserved
human allografts, and pulmonary autografts (Ross procedure). The
mechanical valves are the most durable but require chronic anticoagulation.
The bioprosthetic and tissue valves do not require long-term anticoagulation
but tend to deteriorate over time (with the exception of the pulmonary
autograft). The pulmonary autograft has the potential advantage
of growth. but the homograft used to replace the pulmonary valve
will require replacement. Selection of the appropriate replacement
valve is a complex decision requiring input from all involved parties.
Intervention for discrete subvalvar stenosis is usually undertaken
when the gradient exceeds 30–50 mm Hg or when aortic insufficiency
is present. In these patients, resection of the membrane is readily
performed by a transaortic approach. In order to reduce the incidence
of restenosis, many centers advocate concurrent performance of a
septal myomectomy to alter the geometry of the left ventricular
When diffuse subaortic stenosis is associated with hypoplasia
of the aortic annulus, repair is best achieved with a Konno aortoventriculoplasty,
whereby an incision is carried across the aortic annulus and subjacent
ventricular septum, the opening patched, and an aortic valve implanted.
Patients with an adequate aortic annulus may undergo a septoplasty
(modified Konno), in which the septal incision is confined to the immediate
subvalvar area and a patch is used to widen the left ventricular
outflow tract without replacing the aortic valve.
Operative intervention is indicated for patients with supravalvar
aortic stenosis in whom the gradient exceeds 50 mm Hg. A number
of operations have been proposed for the treatment of localized
supravalvar stenosis. The classical repair involves a longitudinal
incision across the obstruction in the ascending aorta, which is
extended into the noncoronary sinus. The thickened, hypertrophic
ridge is resected by endarterectomy, and the aortotomy is augmented
with an elliptical patch. A variation of this repair involves creation
of an inverted-Y aortotomy with one limb of the Y extended into the
noncoronary sinus and the other into the right coronary sinus. A Y-shaped
patch is then used to augment the aortotomy. Finally, the Brom repair
is performed by transection of the ascending aorta beyond the supravalvar
ridge. Separate incisions are then made through the supravalvar
ridge into each sinus of Valsalva. Triangular patches are placed
to augment each of these incisions, thereby relieving the supravalvar
obstruction. Reconnection of the aortic root to the ascending aorta
completes the repair. The repair of the diffuse type of supravalvar
stenosis is performed under circulatory arrest with extensive patching
of the ascending aorta, transverse arch, and involved arch arteries.
Branch pulmonary stenoses are best managed using transcatheter techniques.
Operative mortality approaches zero for resection of discrete
subaortic stenosis. The recurrence rate of discrete stenosis following
membrane resection and myomectomy has been reported to be as low as
4%. Despite the technical complexity of repair of diffuse
subaortic stenosis, excellent results have been reported with high
survival and freedom from reoperation. The results of surgery for
localized supravalvar aortic stenosis are generally good with low
operative mortality and excellent long-term survival. The diffuse form
is more difficult to treat, and recurrence is more likely. Overall
results are much worse when severe bilateral pulmonary artery stenoses
are present. The mortality for aortic valve replacement regardless
of valve choice is 2–5%. The need for reoperation
is dependent on valve choice and patient size. Early and late ventricular
arrhythmias may occur commonly in patients with significant left ventricular
Aboulhosn J, Child JS: Left ventricular outflow
obstruction: subaortic stenosis, bicuspid aortic valve, supravalvar
aortic stenosis, and coarctation of the aorta. Circulation 2006;114:2412.
Brown JW et al: The Ross-Konno procedure in children: outcomes,
autograft and allograft function, and reoperations. Ann Thorac Surg
Cowley CG et al: Balloon valvuloplasty versus transventricular
dilation for neonatal critical aortic stenosis. Am J Cardiol 2001;
Ohye RG et al: The Ross/Konno procedure in neonates
and infants: intermediate-term survival and autograft function. Ann
Thorac Surg 2001;72:823.
- Absent or weak femoral pulses.
- Systolic pressure higher in the upper extremities than in the
lower extremities with similar diastolic pressures.
- Neonates present with hemodynamic collapse, while older children
are usually asymptomatic.
- Rib notching on chest radiograph.
- Commonly associated with a bicuspid aortic valve.
- Patients with Turner syndrome have a high incidence of aortic
Coarctation of the aorta is a narrowing of the proximal descending
thoracic aorta distal to the origin of the left subclavian artery,
near the insertion of the ductus arteriosus (or ligamentum arteriosum). The
severity of luminal narrowing and the length of the aorta affected
are variable. Coarctation is thought to occur as a result of ectopic
tissue from the ductus arteriosus that migrates into the wall of the
adjacent aorta. After birth, as the ductus closes, the ectopic tissue
in the aorta also constricts. Frequently, a posterior shelf of tissue
is present at the point of most severe obstruction. The aortic obstruction
caused by coarctation creates a pressure load on the left ventricle.
The incidence of coarctation is about 0.5 per 1000 live births,
and its prevalence is 5% of congenital heart defects. Coarctation
is commonly associated with other heart defects, including bicuspid
aortic valve (in more than 50% of cases), PDA, and VSD.
Other left-sided obstructive lesions may also be present, such as
aortic arch hypoplasia, aortic stenosis, mitral stenosis, and left
ventricular hypoplasia. Coarctation is also recognized to occur
in association with Turner syndrome.
Patients with severe coarctation present in the newborn period.
Aortic obstruction is so significant that perfusion of the lower
body is dependent upon flow from the ductus arteriosus. Spontaneous
ductal closure typically worsens the aortic obstruction and may
lead to malperfusion of tissues distal to the coarctation. The pressure
load on the left ventricle may precipitate congestive heart failure. Patients
may develop shock with severe acidosis, oliguria, and diminished
distal pulses. Infants with severe coarctation will generally not
survive without intervention.
Older children with coarctation are usually asymptomatic. The
diagnosis is commonly made on the basis of hypertension in the upper
extremities with decreased pulses in the lower extremities. Noninvasive
blood pressure measurements in all four extremities help to quantify
the severity of aortic obstruction. These older patients tend to
develop extensive collateral arteries that bypass the obstruction.
Life expectancy for these patients is limited due to the development
of heart failure later in life. Other long-term complications of
coarctation include endocarditis (frequently involving a bicuspid
aortic valve), endarteritis (in the poststenotic area of the aorta
at the site of the jet of turbulent flow), aortic dissection, aortic
aneurysm, and intracranial hemorrhage (from Berry aneurysms, which
occur more commonly in patients with coarctation).
The diagnosis of coarctation can usually be made clinically.
The infant with significant coarctation is frequently asymptomatic
at birth but following closure of the ductus develops signs of heart
failure such as irritability, tachypnea, and poor feeding. Lower
extremity pulses are absent, and upper extremity pulses may be weak.
Chest radiography shows cardiomegaly and pulmonary venous congestion.
There is a left ventricular strain pattern on the electrocardiogram. Echocardiography
is usually diagnostic, demonstrating narrowing of the aorta at the
coarctation site with a loss of pulsatility in the descending aorta.
In older children and adults with coarctation, a pressure gradient
between the arms and legs usually can be demonstrated by measuring
cuff pressures in all four extremities. On chest radiography, rib
notching may be evident, secondary to erosion of the inferior rib
borders from the development of large intercostal collateral vessels.
Echocardiography usually confirms the diagnosis. Anatomic details
may also be clarified with CT and MRI. Cardiac catheterization is
usually not necessary.
Generally, all patients with coarctation should undergo surgical
repair. For neonates, the acute medical management includes initiation
of PE1 for the purpose of reopening the ductus; this maneuver
partially relieves the aortic obstruction and augments perfusion
of the lower body due to improved antegrade flow across the arch
as well as right-to-left flow across the ductus. Prostaglandins
are usually effective for reopening the ductus when initiated within
7–10 days of life but are less successful thereafter.
Surgical repair of coarctation is usually performed through a
left posterolateral thoracotomy via the third or fourth intercostal
space. The descending thoracic aorta, ductus (or ligamentum), transverse
aortic arch, and brachiocephalic vessels are mobilized. Care is
taken to preserve the vagus nerve and its recurrent laryngeal branch.
The coarctation is usually evident externally by narrowing or
posterior indentation; however, the degree of internal narrowing
is usually much more severe. A dose of heparin (100 units/kg)
may be given intravenously for patients younger than 2 years. Proximal
and distal control of the aorta is achieved using clamps. Usually,
the proximal clamp is positioned on the transverse arch between
the innominate and left carotid vessels with concomitant occlusion
of the left carotid and left subclavian. In infants and children,
the preferred surgical approach to coarctation is resection with
extended end-to-end repair. A generous resection of the coarctation
segment is performed. The proximal aorta is then spatulated along
the lesser curvature and the distal aorta along the greater curvature.
An extended end-to-end anastomosis is then performed.
In older children and adults, it may not be possible to perform
a resection with primary repair without creating excessive tension
on the anastomosis, which may lead to hemorrhage or scarring with
recurrent coarctation. An alternative strategy is necessary in these
cases. Patch aortoplasty may be performed in children in whom further
growth is anticipated. The subclavian flap repair augments the narrowed
aorta using native arterial tissue. Blood flow to the left arm is
maintained by collateral vessels, although long-term studies have
demonstrated a slight discrepancy in limb length in some patients.
Prosthetic patch material may also be used. By avoiding circumferential
prosthetic material, growth potential of the native aorta is preserved.
The disadvantage of patch repair is a high risk of aneurysm formation.
In adults, where growth is no longer an issue, resection of the
coarctation may be performed with subsequent placement of a prosthetic
interposition graft (either Dacron or polytetrafluoroethylene).
One of the principal concerns during coarctation repair is interruption
of distal aortic blood flow, especially to the spinal cord. The
anterior spinal artery is fed by major radicular branches from intercostal arteries.
In patients without well-formed collaterals, ischemia of the spinal
cord may be precipitated by aortic cross-clamping, and paraplegia
may result. Protective measures include induction of mild hypothermia,
maintenance of a high proximal aortic pressure, and minimization
of cross-clamp time. In older patients, distal aortic perfusion
may be maintained by the technique of left heart bypass, where oxygenated
blood is taken from the left atrium and delivered to the femoral
artery or distal aorta using a centrifugal pump. Overall, the incidence
of paraplegia following coarctation repair is less than 1%.
Transcatheter therapy has been proposed for the primary therapy
of coarctation, but this approach is controversial due to the incidence
of recurrent coarctation, need for multiple interventions, injury
to the femoral vasculature (for access), and aneurysm formation.
Improved results have been achieved with balloon angioplasty with
concurrent stent placement in older children and adults in whom
further aortic growth is not anticipated. Balloon angioplasty is widely
accepted for the treatment of recurrent coarctation following surgery,
in which the success rate is on the order of 90%.
The early mortality following repair of coarctation in neonates
is 2–10%, while the risk in older children and adults
is about 1%. The incidence of recurrent coarctation following
resection and end-to-end repair is about 5%. The long-term
survival following repair of coarctation is determined by the presence
of associated defects and the persistence of hypertension.
Following repair, patients may develop severe hypertension. This
can be managed using intravenous beta-blockers (eg, as esmolol)
or vasodilators (eg, sodium nitroprusside). Uncontrolled hypertension
can lead to the complication of mesenteric arteritis. Hypertension usually
resolves within days to weeks after repair, although older children
and adults may require lifelong antihypertensive therapy. Repair
of coarctation during infancy is thought to minimize the risk of late
Golden AB, Hellenbrand WE: Coarctation of the
aorta: stenting in children and adults. Catheter Cardiovasc Interv
Ovaert C et al: Balloon angioplasty of native coarctation: clinical outcomes
and predictors of success. J Am Coll Cardiol 2000;35:988.
Thomson JD et al: Outcome after extended arch repair for aortic
coarctation. Heart 2006;92:90.
Wong CH, Watson B, Smith J: The use of left heart bypass in
adult and recurrent coarctation repair. Eur J Cardiothorac Surg
Wright GE et al: Extended resection and end-to-end anastomosis
for aortic coarctation in infants: results of a tailored surgical
approach. Ann Thorac Surg 2005;80:1453.
- Varying degree of tracheoesophageal compression.
- Patients present with frequent respiratory infections and
upper airway symptoms.
- “Seal bark” or brassy cough.
- Often misdiagnosed.
- Pulmonary artery slings are associated with complete tracheal
Vascular rings comprise a spectrum of vascular anomalies of the
aortic arch, pulmonary artery, and brachiocephalic vessels. The
clinically significant manifestation of these lesions is a varying
degree of tracheoesophageal compression. These vascular anomalies
can be divided into complete vascular rings and partial vascular
rings. Complete vascular rings can be divided into double aortic
arch and right aortic arch with left ligamentum arteriosum. These
two categories can be further subdivided on the basis of the specific
anatomy. Incomplete vascular rings include aberrant right subclavian
artery, innominate artery compression, and pulmonary artery sling.
Other rare variations, which have been described, include left aortic arch
with right descending aorta and right ligamentum, and left aortic
arch with aberrant right subclavian artery and right ligamentum.
The incidence of clinically significant vascular rings is 1–2% of
all congenital heart defects.
Vascular rings and pulmonary slings have been described in conjunction
with other cardiac defects, including, TOF, ASD, branch pulmonary
artery stenosis, coarctation, AVSD, VSD, interrupted aortic arch,
and aortopulmonary window. Significant associated cardiac anomalies
occur in 11–20% of patients with a vascular ring.
A right aortic arch is generally associated with a greater incidence of
By the end of the fourth week of embryonic development, the 6
aortic or branchial arches have formed between the dorsal aortae
and ventral roots. Subsequent involution and migration of the arches
results in the anatomically normal or abnormal development of the
aorta and its branches. The majority of the first, second, and fifth
arches regress. The third arch forms the common carotid artery and
proximal internal carotid artery. The right fourth arch forms the
proximal right subclavian artery. The left fourth arch contributes
to the portion of the aortic arch from left carotid to left subclavian
arteries. The proximal portion of the right sixth arch becomes the
proximal portion of the right pulmonary artery, while the distal
segment involutes. Similarly, the proximal left sixth arch contributes
to the proximal left pulmonary artery, and the distal sixth arch
becomes the ductus arteriosus.
The pulmonary artery is formed from 2 vascular precursors as
well as through a combination of angiogenesis, the de novo development
of new blood vessels, and vasculogenesis, the budding and migration
of existing vessels. As stated previously, the proximal pulmonary
arteries are based on the sixth arches, whereas the primitive lung
buds initially derive their blood supply from the splanchnic plexus.
Ultimately, these two segments of the pulmonary artery join to form
the vascular network of the lung parenchyma.
Children with a complete vascular ring generally present within
the first weeks to months of life. Typically, children with a double
aortic arch present earlier in life than those with a right arch
and retroesophageal left ligamentum. In the younger age group, respiratory
symptoms predominate, as liquids are generally well tolerated. Respiratory
symptoms may include stridor, nonproductive cough, apnea, or frequent
respiratory infections. The cough is classically described as “seal
bark,” or brassy.” These symptoms may mimic asthma, respiratory
infection, or reflux, and children with vascular rings are often
initially misdiagnosed. With the transition to solid food, dysphagia
becomes more apparent.
The presentation of a patient with an incomplete vascular ring
is variable. Children with innominate artery compression usually
present within the first 1 to 2 years of life with respiratory symptoms.
Although, aberrant right subclavian artery is the most common arch
abnormality, occurring in approximately 0.5–1% of
the population, it rarely causes symptoms. Classically, when symptoms
do occur, they present in the seventh and eighth decade, as the
aberrant vessel becomes ectatic and calcified, causing dysphagia
lusoria due to impingement of the artery on the posterior esophagus.
An aberrant right subclavian rarely causes symptoms except when it
is of an abnormally large caliber or associated with tracheomalacia.
Children with pulmonary artery slings generally present with
respiratory symptoms within the first few weeks to months of life.
As with complete rings, respiratory symptoms may include stridor,
nonproductive cough, apnea, or frequent respiratory infections and
may mimic other conditions leading to misdiagnosis. Pulmonary artery
slings are associated with complete tracheal rings in 30–40% of patients,
leading to focal or diffuse tracheal stenosis.
The methods for diagnosing a vascular ring are variable because
of the variability in presentation and the spectrum of diagnostic
tests available. A child with a presumptive diagnosis of asthma
or tracheomalacia may be referred to a pulmonologist and a diagnosis
of vascular ring made or suspected initially by chest radiograph
and bronchoscopy. In some situations, the diagnosis is made by echocardiography
during evaluation for concurrent cardiac defects. Regardless, the diagnosis
generally begins with a chest radiograph. Complementary studies
may include barium esophagogram, CT, MRI, and bronchoscopy. CT,
MRI, or bronchoscopy are important modalities to define the tracheal
anatomy in a patient with a pulmonary artery sling. Echocardiography
may be diagnostic and may be used to rule out other cardiac anomalies.
Tracheograms and cardiac catheterizations, which have been used
extensively in the past, are rarely currently indicated.
A double aortic arch occurs when the distal portion of the right
dorsal aorta fails to regress. The two arches form a complete ring,
encircling the trachea and esophagus. The right arch is dominant
in the majority of the cases, followed by left dominant, with codominant
arches being the least common. The left and right carotid and subclavian
arteries generally arise from their respective arches. The ligamentum
arteriosum and descending aorta usually remain on the left.
The approach to repair of a double aortic arch is via a left
posterolateral thoracotomy. The procedure can easily be accomplished
through a limited, muscle-sparing incision through the third or fourth
intercostal space. The pleura is incised, after identifying the
vagus and phrenic nerves. The ligamentum or ductus arteriosum is
divided while preserving the recurrent laryngeal nerve. The nondominant
arch is then divided between two vascular clamps at the point where
brachiocephalic flow is optimally preserved. If there is concern
regarding the location for division, the arches can be temporarily
occluded at various points while monitoring pulse and blood pressure
in each limb. If there is an atretic segment, the division is done
at the point of the atresia. Dissection around the esophagus and
trachea in the regions of the ligamentum/ductus and nondominant arch
allows for retraction of the vascular structures and lysis of any
residual obstructing adhesions.
There are three anatomic variations for a right arch with a left
ligamentum, which cause a complete vascular ring. If the left fourth
arch regresses between the aorta and left subclavian, a right aortic
arch with aberrant left subclavian artery results. The ligamentum
arteriosum is retroesophageal, bridging the left pulmonary artery
and aberrant left subclavian, forming a complete vascular ring.
If the left fourth arch regresses after the origin of the left subclavian
artery but before the arch reaches the dorsal aorta to communicate
with the left sixth arch (which becomes the ductus arteriosum), there
is mirror-image branching. The ligamentum arteriosum arises directly
from the descending aorta, or from a Kommerell diverticulum off
of the descending aorta, forming the complete ring. If communication
is maintained between the left fourth and sixth arches, there is
mirror-image branching with the ligamentum arising from the anterior,
mirror-image left subclavian, and a ring is not formed.
The surgical approach for a right aortic arch with retroesophageal
left ligamentum arteriosum is the same as for a double arch. The
ligamentum is divided, and any adhesions around the esophagus and
trachea are lysed. Rarely, the Kommerell diverticulum has been reported
to cause compression even after division of the ligamentum. As such,
it may be prudent to resect or suspend the diverticulum posteriorly.
In innominate artery compression syndrome, the aortic arch and
ligamentum are in their normal leftward position. However, the innominate
artery arises partially or totally to the left of midline. As the
artery courses from left to right anterior to the trachea, it causes
tracheal compression. The symptoms of innominate artery compression
may be mild to severe. With mild symptoms and minimal tracheal compression
on bronchoscopy, children can be observed expectantly because the
symptoms may resolve with growth. Indications for surgery include
apnea, severe respiratory distress, significant stridor, or recurrent
respiratory tract infection. Several approaches for the correction
of innominate artery compression syndrome have been described. These
include simple division, division with reimplantation into the right
side of the ascending aorta, and suspension to the overlying sternum.
An aberrant right subclavian artery occurs when there is regression
of the right fourth arch between the right common carotid and right
subclavian arteries. The right subclavian then arises from the leftward
descending aorta, laying posterior to the esophagus as it crosses from
left to right. Although the artery can compress the esophagus posteriorly,
it is rarely the cause of symptoms in children. Surgical treatment
involves simple division via a left posterolateral thoracotomy. Rarely,
reimplantation or grafting from the right carotid or aortic arch
may be necessary.
Normally, the right and left sixth aortic arches contribute to
the proximal portions of their respective pulmonary arteries. If
the proximal left sixth arch involutes and the bud from the left
lung migrates rightward to meet the right pulmonary artery, a pulmonary
artery sling is formed. Pulmonary artery slings are associated with
complete tracheal rings and tracheal stenosis in 30–40% of patients.
Origin of the right upper lobe bronchus from the trachea has been reported
in frequent association with pulmonary artery sling.
Initial attempts at the repair of a pulmonary artery sling involved
reimplantation after division of the left pulmonary artery and translocation
of the trachea without cardiopulmonary bypass. These early reports
had a high incidence of left pulmonary artery thrombosis. This has
led some authors to advocate division of the trachea and translocation
of the left pulmonary artery. This approach would seem sensible
if the trachea were being divided in the course of tracheal reconstruction.
However, currently most authors advocate the reimplantation of the
left pulmonary artery, which has resulted in excellent results.
The procedure is done via a median sternotomy on cardiopulmonary
bypass to insure optimal visualization of the repair. Aortic cross-clamping
is not necessary. The left pulmonary artery is divided off of the
right pulmonary artery, translocated anterior to the trachea, and
reimplanted into the main pulmonary artery.
Any necessary reconstruction of the trachea is done concurrently
with bronchoscopic assistance. Many techniques for tracheal reconstruction
have been described, the most common of which are resection with
primary reanastomosis and sliding tracheoplasty for short segment
stenosis, and rib cartilage or pericardial patch for long areas
Over 95% of vascular rings without concurrent cardiac defects
can be performed through a left thoracotomy. A right thoracotomy
is indicated for the rare cases where there is a right ligamentum
arteriosum. A right ligamentum occurs in the setting of a left aortic
arch with right descending aorta, where the ligamentum bridges from
the descending aorta to the right pulmonary artery forming a complete
ring. Right ligamentum arteriosum has also been described with a
left aortic arch with aberrant right subclavian artery. In this
case, the ligamentum may arise from the aberrant subclavian artery, from
a diverticulum off of the arch, or directly from the left arch to
the right pulmonary artery. In addition, a double aortic arch with
an atretic segment proximal to the right carotid artery is more
easily divided through a right thoracotomy. The approach to these
anomalies is the same as for a left-sided ring division, with the
caveat that the right recurrent laryngeal nerve will loop around
the right ligamentum.
Repair of vascular rings has been described using video-assisted
thoracoscopic surgery (VATS) both with and without robotic assistance.
Candidates for thoracoscopic division are limited to those patients
requiring only the division of nonpatent vascular structures. In
general, VATS is used for patients weighing more than 15 kg due to
current size limitations of the instruments.
Mortality for the repair of a vascular ring is 0.5–7.6%,
with improved survival occurring in more recent series. The majority
of deaths are related to other cardiac defects or respiratory infection and
failure. Backer and colleagues reported a series of 16 patients
repaired utilizing left pulmonary artery division and reimplantation
for pulmonary artery sling, all of whom also required tracheal reconstruction.
There were no operative mortalities and one late death due to respiratory
complications. The major source of morbidity, as well as mortality, in
this and other series is related to the tracheal reconstruction.
Alsenaidi K et al: Management and outcomes of
double aortic arch in 81 patients. Pediatrics 2006;118:e1336.
Backer CL et al: Pulmonary artery sling: results with median
sternotomy, cardiopulmonary bypass, and reimplantation. Ann Thorac
Backer CL et al: Trends in vascular ring surgery. J Thorac Cardiovasc
Humphrey C, Duncan K, Fletcher S: Decade of experience with
vascular rings at a single institution. Pediatrics 2006;117:e903.
Woods RK et al: Vascular anomalies and tracheoesophageal compression:
a single institution’s 25-year experience. Ann Thorac Surg
- Variable symptoms include congestive heart failure, angina,
and sudden death.
- Electrocardiogram often demonstrates ischemia or prior infarction.
- Mitral regurgitation is commonly present along with significantly
depressed ventricular function; the mitral regurgitation usually
returns to normal following surgical intervention.
- Cardiac catheterization or cardiac MRI is often helpful to
delineate the coronary anatomy.
Coronary artery anomalies occur in between 0.3 and 1.3% of the
population. They can be classified as minor, secondary, or major
on the basis of their clinical significance. Minor defects have
no functional significance and are usually detected as incidental
findings at cardiac catheterization. Secondary defects have no intrinsic
significance but alter surgical management when they are present.
An example of a secondary defect is an anomalous origin of the left
anterior descending from the right coronary artery, which crosses
the hypoplastic infundibulum in a patient with TOF. The presence
of this vessel may prevent the safe performance of a transannular incision
and thereby mandate the use of a conduit. Major defects are the
most important form of coronary anomaly because they exert an intrinsically
adverse effect on the myocardium. Major anomalies can be subdivided
based on anatomy: coronary arteriovenous fistula, anomalous pulmonary origin
of a coronary artery, anomalous aortic origin of a coronary artery,
myocardial bridging, or coronary artery aneurysm.
Coronary arteriovenous fistula is the most common major coronary
anomaly. An abnormal connection exists between a coronary artery
(usually the right) and another vascular structure (usually one
of the right heart chambers). Most fistulas are isolated and solitary.
The fistula leads to left-to-right shunting, which can produce congestive
heart failure. Other symptoms include angina, endocarditis, myocardial
infarction, arrhythmia, and sudden death. The diagnosis is suggested by
echocardiography and confirmed by catheterization.
The second-most common major coronary anomaly is the origin of
a coronary artery from the pulmonary artery. The most common manifestation
is the anomalous left coronary artery arising from the pulmonary
artery (ALCAPA). The right coronary (or both coronaries) may also
arise anomalously from the pulmonary artery but only in very rare
cases. ALCAPA is usually well tolerated during fetal development, but
after birth, the pulmonary systolic pressure usually drops (following
ductal closure and decline in PVR) and the anomalous coronary is
perfused with desaturated blood at low pressure. Collateral vessels
develop between the normal right coronary artery and the abnormal
left coronary, but the benefit is negated due to the development
of coronary steal, whereby the collateral blood shunts left to right
by retrograde flow in the anomalous coronary into the low-pressure
pulmonary artery. Most patients will present between 6 weeks and 3
months of life. Typical symptoms include irritability, difficulty
in feeding, and other signs of congestive heart failure. Untreated,
ALCAPA is nearly always fatal. Rarely, patients will survive to
adulthood and present with symptoms of angina or sudden death. On
examination, patients with ALCAPA frequently have a holosystolic
murmur of ischemic mitral regurgitation. The pulmonary component
of the second heart sound may be pronounced because of pulmonary
hypertension. Chest radiography is significant for cardiomegaly and
pulmonary edema. Electrocardiographic evidence of ischemia and infarction
is usually present. Echocardiography is usually diagnostic and is
useful for assessing the severity of left ventricular dysfunction
and ischemic mitral regurgitation that are commonly present. Catheterization
is occasionally necessary to clarify the anatomy, but this technique
is used less frequently because of the risk of inducing life-threatening
Anomalous aortic origins of the coronary arteries are usually
minor defects, but a potentially dangerous abnormality exists when
the left main coronary artery arises from the right coronary sinus
and passes between the pulmonary artery and aorta. This defect has
been associated with cardiac symptoms and sudden death, as has the
origin of the right coronary artery from the left coronary sinus
(usually when the right coronary is dominant). The etiology of ischemia
in both defects is thought to be related to the acute angle of origin
and slitlike orifice of the anomalous vessel and the extrinsic compression
created by the apposing walls of the aorta and pulmonary artery.
These defects usually present in older patients. Symptomatic patients
are treated surgically by coronary artery bypass.
Myocardial bridging occurs when a segment of an epicardial coronary
artery (usually the left anterior descending) takes an intramyocardial
course over a short segment. Although this is a common incidental
finding at cardiac catheterization, this defect has been associated
in some cases with myocardial ischemia. Treatment involves dividing
the muscle bridge to free the coronary, coronary bypass beyond the bridge,
or transcatheter stenting.
Coronary aneurysms occur rarely, usually in conjunction with
an inflammatory condition such as Kawasaki syndrome, polyarteritis
nodosa, Takayasu arteritis, or syphilis. Coronary aneurysms may thrombose
or lead to distal coronary stenosis or embolization. Rupture occurs uncommonly.
Treatment ranges from antiplatelet therapy to coronary artery bypass
grafting, and possible transplantation.
All symptomatic fistulas should be occluded, either surgically
or by transcatheter techniques. In some cases, coronary bypass grafting
may be necessary when distal flow is compromised by fistula occlusion.
Treatment of asymptomatic fistulas is controversial, but occlusion
should probably be undertaken when significant left-to-right shunting
Surgical repair is indicated for all patients with ALCAPA. Historically,
the initial surgical approach involved ligation of the proximal
left coronary artery. This served to eliminate coronary steal and
allow perfusion of the left coronary system by collaterals from
the right. Despite the ease of simple ligation, most centers have abandoned
this approach in favor of establishment of a 2-coronary system, which
offers better long-term freedom from ischemia. In older patients,
this may be achieved by proximal ligation of the left coronary artery
in conjunction with coronary artery bypass, ideally with a left internal
mammary graft. Coronary bypass is technically difficult in neonates, and
a number of alternative operations have been devised to create a
direct connection between the aorta and the anomalous coronary artery.
Most commonly, this can be achieved by removing the origin of the
left coronary artery (along with a button of adjacent pulmonary
artery) and reimplanting the vessel directly into the side of the
aorta. Another approach involves creation of a side-to-side connection
between the aorta and pulmonary artery with placement of an intrapulmonary
baffle to direct flow from this connection to the anomalous left
Survival following surgical repair of ALCAPA has improved over
the years. Recent reports have suggested an operative mortality
of 6% or less. Ventricular function tends to normalize
after surgery. In most patients, mitral valve function also improves,
but for patients with severe mitral regurgitation, concurrent mitral
valve repair may be indicated.
De Wolf D et al: Major coronary anomalies in childhood.
Eur J Pediatr 2002;161:637.
Friedman AH et al: Identification, imaging, functional assessment and
management of congenital coronary arterial abnormalities in children.
Cardiol Young 2007;17:56.
Lange R et al: Long-term results of repair of anomalous origin
of the left coronary artery from the pulmonary artery. Ann Thorac Surg
Satou GM, Giamelli J, Gewitz MH: Kawasaki disease: diagnosis, management,
and long-term implications. Cardiol Rev 2007; 15:163.