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13 Adult Congenital Heart Disease and the
Surgical Patient
Matthew Barnard
The Heart Hospital, London, U.K.
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INTRODUCTION
In the future, there will be more adults than children with congenital heart disease—
this already applies to Tetralogy of Fallot which is the commonest of the cyanotic
lesions. Fewer than 20% of patients with congenital heart disease would survive to
adult life without treatment. As a result of modern medical and surgical techniques,
nearly all deaths now occur in adults and not children. As a result, there is an increas-
ing population of patients with adult congenital heart disease who require long-term
follow-up and who may require medical and surgical interventions during the
course of their lives.
The management of adults with congenital heart disease poses clinical, organ-
izational, and logistical challenges including fundamental questions relating to the
For personal use only.
appropriate institutional environment, facilities, staff, training, and educational pro-
grams. There remains a lack of consensus as to whether this type of service should
be organized at the local, regional, or supraregional level. Although many accept
that complex cases benefit from concentration in specialized centers, there remains
uncertainty over care boundaries for the larger number of patients with less com-
plicated lesions (1). The complex medical and psychosocial problems of these patients
requires support from a variety of specialists, and physicians who care for them must
be trained in dealing with adults and acquired disorders, while maintaining invalu-
able input from pediatric cardiologists and surgeons (2).
Completely normal cardiovascular anatomy and physiology is rarely achieved
by corrective surgery during childhood (3). One important principle is that patients
have had their cardiac lesions repaired—not cured (4). Many patients will continue
to manifest residua of their underlying pathology and or sequelae of therapeutic
interventions.
CLASSIFICATION OF CONGENITAL HEART DISEASE
Congenital heart disease embraces a considerable number of complex conditions.
A number of commonly used terms are brought together in Table 1. There are sev-
eral ways of classifying adult congenital heart disease. The number of different
lesions and heterogeneity within each lesion dictate that a reductionist approach is
useful. One distinction is between cyanotic and noncyanotic patients. Cyanotic
patients often have more comorbid medical problems and experience greater num-
bers of serious perioperative complications than noncyanotics (5). Lesions are often
broadly categorized into simple, intermediate, and complex (Table 2). Although sim-
plistic, this facilitates decisions about management, monitoring, and referral to spe-
cialist centers. Patients with simple lesions can be managed in most settings with
minimal alterations to routine care other than antibiotic prophylaxis and anticoagu-
lation. Complex patients should be referred to specialist units if sufficiently stable to
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270 Barnard
TABLE 1 Some Commonly Used Terms in Congenital Heart Disease
ASD Atrial septal defect; commonly classified into ostium primum
(partial AVSD), ostium secundum, sinus venosus
Ostium primum are defects in the inferior septum and comprise the
atrial component of AVSD; secundum defects are absences in
the oval fossa region; sinus venosus defects occur around the
superior atriocaval junction and are associated with pulmonary
veins draining anomalously to the superior vena cava
AVSD Atrioventricular septal defect, often called AV canal defect or
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endocardial cushion defect; defect including primum septal
defect and separate atrioventricular orifices (partial) or primum
septal defect and ventricular septal defect and common
atrioventricular orifice (complete) or intermediate forms
Balanced circulation Relatively equal systemic and pulmonary blood flow
Blalock Taussig shunt Connection of subclavian artery to ipsilateral pulmonary artery;
classical shunt involved transection of subclavian artery and
end-to-side anastomosis to pulmonary artery; modified Blalock
Taussig shunt uses synthetic interposition graft; used to increase
pulmonary blood flow, albeit using inefficient recirculation of
systemic blood
Concordance Connection of two structures the same side morphologically—left
atria to left ventricle or right ventricle to pulmonary artery
For personal use only.
Discordance Connection of morphologically left structure to morphologically
right structure, e.g., left ventricle to pulmonary artery
Double inlet ventricle Both atrioventricular valves (or greater than 50% of each) connect
to one ventricle; usually left ventricle
Double outlet ventricle Both great vessels (or greater than 50% of each) arise from one
ventricle; usually right ventricle
Fenestration Surgically created hole in atrial or ventricular septum or
intracardiac baffle; diverts proportion of blood from right to left
heart in situations where normal passage through the lungs is
prevented by elevated pulmonary resistance; cardiac output
thereby maintained or increased—at the expense of cyanosis
Fontan Surgeon who described the Fontan procedure; now usually refers
to circulatory arrangement whereby systemic veins are
connected to the pulmonary arteries—without a right ventricle;
the connection may be intracardiac or extracardiac
Glenn Cavopulmonary shunt; connection of the superior vena cava to the
pulmonary artery; bidirectional Glenn refers to connection to
joined right and left pulmonary arteries
Hemitruncus Right or left pulmonary artery from aorta
Konno Enlargement of aortic annulus and left ventricular outflow tract
Left SVC Persistence of connection between left subclavian vein and left
internal jugular vein with coronary sinus; coronary sinus usually
dilated, and if unroofed or fenestrated associated with
intracardiac left to right shunt
Malposition Malposition of the atrial or ventricular septum that results in valve
overriding the septum
(Continued)

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Adult Congenital Heart Disease and the Surgical Patient 271
TABLE 1 Some Commonly Used Terms in Congenital Heart Disease (Continued)
Mustard Intraatrial switch procedure for TGA; intraatrial baffles direct
pulmonary venous blood to the right ventricle and systemic
venous blood to the left ventricle; results in physiological
appropriate but anatomically incorrect circulation
Overriding Valve which is positioned over the ventricular septum
Rastelli VSD closure incorporating baffling mitral inflow to (malpositioned)
aorta; external conduit or homograft to connect right ventricle to
pulmonary artery
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Ross pulmonary autograft Replacement of the aortic valve with native pulmonary valve;
replacement of the pulmonary valve with cadaveric homograft
Senning Similar to Mustard procedure; intra-atrial baffling to redirect venous
blood to the opposite ventricle in TGA
Single outlet Single vessel arising from the heart
Single ventricle One functional ventricle, although there is usually a second
vestigial ventricle
Straddling Valve with attachments on both sides of the ventricular septum;
limits anatomical repair
Transposition great arteries Ventriculoarterial discordance; aorta from right ventricle, pulmonary
artery from left ventricle
For personal use only.
Truncus arteriosus Single arterial vessel arises from the heart; systemic and
pulmonary arteries branch from the single vessel
Univentricular connection Both atria connected to one ventricle; connection is either via two
valves in the absence of one of the atrioventricular valves and
an ASD
Abbreviations: ASD, atrial septal defect; AVSD, atrioventricular septal defect; SVC, superior vena cava; TGA, trans-
position of the great arteries; VSD, ventricular septal defect.
be transferred. At least some patients with intermediate lesions will be managed in
nonspecialist centers and so will pose the biggest challenge to general anesthetists
and intensivists. Some specific and general conditions which suggest transfer to a
specialist unit would be appropriate are listed in Table 3.
PATHOPHYSIOLOGY OF CONGENITAL HEART DISEASE
Congenital cardiac lesions run the gamut from simple septal defects to extremely
complex anatomical rearrangements. All may be considered in terms of the primary
effects of the cardiac lesion and the secondary effects seen as the condition evolves.
Primary and secondary pathophysiological features of patients with congenital
heart disease (CHD) are outlined in Table 4 and the effects of specific lesions are dis-
cussed in more detail later in this chapter. There are a number of important general
considerations however.
Cyanosis and Hyperviscosity
Hypoxemia is caused by either right to left shunting or mixing of pulmonary and sys-
temic venous blood in a common chamber. The main adaptive response to hypox-
emia is secondary erythrocytosis. Blood viscosity increases almost exponentially with

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272 Barnard
TABLE 2 Classification of Congenital Heart Lesions
Complex (best managed in Moderate (can often be managed Simple (can be managed in
specialist unit) in general hospitals; consider most settings using
referral if noncardiac surgery normal management
is major, or recent cardiology principles)
review demonstrates
complications)
Conduits Aorta-LV fistulae Isolated aortic valve
disease
Cyanotic Anomalous pulmonary veins Isolated mitral valve
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disease
Double outlet ventricle AV canal defects Isolated ASD
Eisenmenger Coarctation Small VSD
Fontan Ebsteins anomaly Mild pulmonary stenosis
Mitral atresia Infundibular RVOTO Repaired PDA
Single ventricle Primum ASD Repaired ASD
Pulmonary atresia Unclosed PDA Repaired VSD
Pulmonary vascular disease Pulmonary regurgitation
(moderate/severe)
Transposition great arteries Pulmonary stenosis
(moderate/severe)
Tricuspid atresia Sinus Valsalva fistula/aneurysm
Truncus arteriosus Sinus venosus ASD
Other AV or VA Sub/supravalvar aortic
For personal use only.
connection abnormalities stenosis
Tetralogy of Fallot
VSD with other lesion
Abbreviations: LV, left ventricular; AV, atrioventricular; VA, ventricular arterial; ASD, atrial septal defect; PDA, patent
ductus arteriosus; RVOTO, right ventricular outflow tract obstruction.
hematocrit. In the presence of iron deficiency, microcytosis results in erythrocyte rigid-
ity. Increased viscosity should be borne in mind when considering optimal hematocrits
for these patients. Venesection is used for the relief of symptoms but preoperative
venesection is no longer practiced in the absence of symptomatic hyperviscosity (a
constellation of hematological and neurological symptoms, including headaches,
visual disturbances, and embolic complications) (1). Hemoglobin concentrations may
be greater than 19 preoperatively, and a postoperative drop to approximately 14 would
be acceptable. Coagulopathies and gallstones are other consequences of polycythemia.
TABLE 3 Abnormalities Best Treated in Specialist Congenital
Heart Unit
Valvular atresia Eisenmenger reaction
Double inlet/outlet ventricle Pulmonary hypertension
Malposition of great arteries Chronic hypoxemia
Fontan circulation QP:QS > 2:1
Single/common ventricles Ventricular outflow gradient
>50 mmHg
Transposition of great arteries ↑PVR
Atrial switch procedure Secondary polycythemia
Rastelli procedure
Abbreviations: QP, pulmonary blood flow; QS, systemic blood flow; PVR, pulmonary
vascular resistance.

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Adult Congenital Heart Disease and the Surgical Patient 273
TABLE 4 Features of Congenital Heart Disease
Primary Secondary
Shunts Arrhythmias
Stenotic lesions Cyanosis
Regurgitant lesions Infective endocarditis
Myocardial ischemia
Paradoxical emboli
Polycythemia
Pulmonary hypertension
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Ventricular dysfunction
Cyanosis in patients with congenital heart disease may be accompanied by con-
genital syndromes, airway and thoracic cage abnormalities, tracheobronchial com-
pression, and kyphoscoliosis. Brain abscesses, impaired cognitive function, and chronic
neurologic impairment are also recognized. Cyanosis may result in aortopulmonary
collateral arteries, hematological abnormalities, renal impairment, and myocardial
scarring (6). Collateral arteries may be acquired (e.g., bronchial) or congenital (e.g.,
complex pulmonary atresia). Cyanosis results in inadequate skin oxygenation, and
acne or skin infections are common. This can be important in the context of surgical
intervention. Cyanotic patients are frequently small or have an abnormal stature.
For personal use only.
Decreased Pulmonary Blood Flow
In patients with diminished pulmonary blood flow, hypoxemia is minimized by ade-
quate hydration, maintaining systemic arterial blood pressure, minimizing elevations
in pulmonary vascular resistance (avoiding hypercarbia and acidosis), and minimiz-
ing total oxygen consumption.
In the presence of a systemic to pulmonary shunt (e.g., modified Blalock Taus-
sig), pulmonary blood flow is dependent on the size of the shunt and the pressure
gradient across the shunt (i.e., systolic arterial and pulmonary artery pressures).
Mixing Lesions and the Balanced Circulation
In the situation of mixing of systemic and pulmonary venous blood, the peripheral
arterial oxygen saturation is dependent on the pulmonary: systemic flow ratio (QP:QS).
This ratio can be estimated from saturation measurements using the equation
QP SaO2 − SSVO2
=
QS SPVO2 − SPAO2
where SaO2 is the arterial saturation, SSVO2 the systemic venous saturation, SPVO2
the pulmonary venous saturation, and SPAO2 the pulmonary artery saturation.
(Note that SPAO2 is the SaO2 in patients with pulmonary blood flow (PBF) supplied
through a Blalock Taussig shunt.)
In these patients when QP is greater than QS, SaO2 will be higher, but systemic
cardiac output will be lower. When QS is greater than QP, systemic saturations will
be lower but cardiac output higher. Thus, the systemic saturation can give a useful
indication of QP:QS. However, these interpretations are subject to the limitation of
knowing or estimating mixed venous oxygen saturations. A low SaO2 might be due
to low pulmonary blood flow or there could be high pulmonary blood flow and a
low systemic cardiac output with low mixed venous saturations. The relationship

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274 Barnard
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FIGURE 1 Arterial oxygen saturation (SaO2) and systemic venous oxygen saturation (SSVO2) as a
function of QP:QS for different values of pulmonary venous oxygen saturation (SPVO2). It is often
assumed that SaO2 ∼ 75% equates to the ideal QP:QS of ~1:1. This will be the case if there is good sys-
temic perfusion (oxygen extraction resulting in SSVO2 ∼ 50%) and normal lung function (SPVO2 ∼ 100%).
However, an SaO2 of 75% may represent a QP:QS 1:1 in certain situations.
For personal use only.
between SaO2 and QP:QS is hyperbolic, whereas that between systemic venous satu-
ration (SSVO2) and QP:QS is parabolic (Fig. 1).
Elevated QP (and low QS) in a mixing type circulation will be suggested by the
clinical picture of high SaO2, systemic hypotension, oliguria, acidosis, and increased
serum lactate. A rapidly increasing metabolic acidosis is the first and sometimes
dominant sign of pulmonary hyperperfusion. Elevated QP can decrease lung com-
pliance, increase airway resistance, and work of breathing, and if left sufficiently
long can, at an extreme, result in characteristic histological changes in the pulmonary
vasculature (pulmonary vascular disease).
Ventricular Function
Systolic and diastolic ventricular dysfunctions are not infrequent. Right ventricle
dysfunction is seen more commonly than in patients with acquired heart disease.
Simple indices of ventricular function (e.g., ejection fraction) can be rendered inad-
equate by complex anatomy and loading conditions (7). Reduced ventricular com-
pliance is a feature of some right-sided lesions such as Tetralogy of Fallot. An extreme
of diastolic dysfunction is known as restrictive ventricular physiology. In this con-
dition, due to the low compliance of the right ventricle, the pulmonary valve opens
during diastole as a result of atrial contraction. Systemic ventricular impairment
may be congenital (systemic right ventricle, hypertrophic cardiomyopathy) or
acquired (previous surgery). The hemodynamic impact of dynamic left ventricular
outflow obstruction may be reduced by a modest depression of ventricular function.
Arrythmias
Patients with diastolic dysfunction or restrictive physiology as well as those who
have lesions which intrinsically limit ventricular filling (atrial switch procedures for

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Adult Congenital Heart Disease and the Surgical Patient 275
transposition of great arteries—Mustard, Senning operations) tolerate loss of sinus
rhythm or arrhythmias poorly (8). The latter can cause hemodynamic compromise
in these patients more rapidly than in patients with acquired heart disease. The phi-
losophy of treating arrhythmias is therefore relatively aggressive. An underlying
hemodynamic cause (substrate) for the arrhythmia must be sought. Active measures
to return sinus rhythm (including early DC cardioversion) are instituted.
PSYCHOSOCIAL CONSIDERATIONS
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Adults with congenital heart disease are a well-informed population who have
undergone previous major surgery and numerous hospital admissions. They may
be faced with deteriorating cardiac function as young adults. Most patients function
psychologically within the normal range, although low self-esteem, insecurity, and
feelings of vulnerability occur. Three categories of morbidity are seen in adults with
congenital heart disease—psychological, psychiatric, and neuropsychological
(abnormalities due to cardiac dysfunction or interventions). Acute illness exacerba-
tions can lead to profound psychological disturbances. The consequences of psy-
chological problems include a lower proportion competing for higher education,
increased unemployment, and many who underachieve due to a lack of self-
confidence. Patients exhibit increased dependence on carers and greater immaturity.
The effects of chronic illness on activity and social interactions can be pronounced.
For personal use only.
These effects are sometimes reinforced by inappropriate parental attitudes and
“overprotection.” Patients face problems with marriage, financial security, and wor-
ries over childbirth. Concern about genetic transmission of congenital defects is an
issue when considering reproduction.
SPECIFIC LESIONS
Tetralogy of Fallot
Tetralogy of Fallot is the commonest cyanotic lesion in older patients. It comprises a
ventricular septal defect (VSD), aortic overriding of the ventricular septum, and
varying right ventricular outflow obstruction. The perimembranous outlet VSD
allows right to left and bidirectional shunting and consequent cyanosis. The outflow
obstruction results in right ventricular hypertrophy and may be subvalvar (infundibu-
lar), valvar, supravalvar (including branch pulmonary artery stenosis), or a combi-
nation. There may be a right aortic arch or atrial septal defect (ASD). The aortic
annulus and aorta frequently dilate progressively with age. Asmall number of patients
have anomalous coronary arteries (e.g., an anomalous left arterior descending (LAD)
coronary artery arising from the right coronary artery).
Patients who present as adults will usually already have undergone surgery.
Unoperated adults largely comprise those with anatomical features unsuitable for
repair—usually abnormalities of the pulmonary arteries. Some adult patients will
have undergone palliative procedures to improve pulmonary blood flow prior to
definitive repair (Table 5).
Repair of tetralogy of fallot (TOF) has been performed for over 30 years, conse-
quently older patients will be those individuals who underwent the earliest open
heart surgery procedures. Repair involves closure of the VSD and relief of the out-
flow obstruction. The latter may involve resection of hypertrophic muscle as well as
incision and enlargement of the outflow tract with a patch of pericardium or pros-
thetic material. If the patch needs to be extended beyond the outflow tract across the

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TABLE 5 Key Features of the Tetralogy of Fallot
Anatomy Anterior and cephalad deviation of the outlet septum
Large subaortic VSD
Right ventricular outflow obstruction
Right ventricular hypertrophy
±Branch pulmonary artery stenosis, ASD, right aortic arch
Commonest cyanotic condition
Arrhythmias Right bundle branch block
Complete heart block
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Supraventricular and ventricular tachycardias
More frequent in the presence of right ventricular failure
Palliation Blalock Taussig/modified Blalock Taussig shunt (subclavian to
pulmonary artery)
Waterston shunt (ascending aorta to right pulmonary artery)
Potts shunt (descending aorta to left pulmonary artery)
Central or graft shunt (ascending aorta to main pulmonary artery)
Brock procedure (infundibular resection and pulmonary valvotomy)
Right ventricle to pulmonary artery conduit, leaving VSD alone or repairing
with a fenestrated patch
Repair Closure VSD
Relief RVOTO
Infundibular muscle resection
Transannular patch
For personal use only.
Extracardiac conduit
Pulmonary valve replacement
Outcome 30-yr actuarial survival 8.6% (90% expected)
Sudden death 0–6%
Complications Arrhythmias
Right ventricular outflow tract obstruction
Pulmonary and tricuspid regurgitation
Diminished RV function
Prosthetic complications
Residual VSD
Abbreviations: VSD, ventricular septal defect; ASD, atrial septal defect; RV, right ventricular.
pulmonary valve (transannular), then pulmonary regurgitation is more likely, and
homograft replacement of the pulmonary valve may be preferred. Other extracardiac
conduits connecting the right ventricle to pulmonary artery are an alternative (e.g.,
Hancock prosthesis). Transatrial repair of VSDs has diminished myocardial compli-
cations from ventriculotomy. Twenty-year survival is 80% to 90%, whereas survival
without surgical repair is poor.
Postrepair sequelae and residua include rhythm and conduction disorders, recur-
rent right ventricular outflow tract obstruction, right ventricular outflow tract aneurysm,
recurrent VSD, pulmonary regurgitation, impaired right ventricular function, and tri-
cuspid regurgitation. Functional capacity is usually good or normal, and left ventricu-
lar function is better with early operation. Reduced exercise ability is related mainly to
right ventricular dysfunction consequent to pulmonary regurgitation. Arrhythmias are
common. Ventricular ectopics occur in 40% to 50%, and become more frequent with
age. A variety of arrhythmias and conduction abnormalities are described, including
supraventricular tachycardia, ventricular tachycardia, right bundle branch block, and

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Adult Congenital Heart Disease and the Surgical Patient 277
complete heart block; 15% of patients demonstrate inducible ventricular tachycardia
during electrophysiological studies.
The preoperative management of these patients for noncardiac surgery depends
on the nature of the repair or palliative operation that they have undergone, the extent
of any residual disease, and the sequelae of the condition and of surgery. The clinician
should obtain as much information about these as possible.
In assessing the patient with repaired tetralogy for noncardiac surgery, the
key features to assess are the presence and severity of pulmonary regurgitation,
right ventricular function, residual VSD, and arrhythmias. A patient with moder-
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ate or less pulmonary regurgitation and reasonable right ventricular function is
likely to do well and can be managed with standard techniques and monitoring.
A patient with significantly impaired right ventricular function needs careful
attention to volume status and maintaining contractility. Central venous pressure
monitoring is advisable and transesophageal echocardiography is useful for major
surgery. Patients with very poor right ventricular function should be referred to a
specialist unit.
The important aspects of the Tetralogy of Fallot are summarized in Table 5.
Atrial Septal Defect
ASD is the commonest previously undetected congenital heart lesion in adults. It
For personal use only.
comprises 7% of congenital heart disease overall, but 30% of adult congenital heart
disease. Types include ostium secundum, sinus venosus, and coronary sinus defects.
Ostium primum defects are discussed in a later section. They comprise the atrial
component of the spectrum of atrioventricular septal defects (AVSDs) and are also
referred to as partial AVSD.
Ostium secundum accounts for 70% of ASDs and manifests as an absence of
the septum in the region of the oval fossa, usually 1 to 2 cm in diameter. It is distinct
from patent foramen ovale in that the latter comprises a flap like slit, with no true
septal deficiency. Superior sinus venosus defects account for 10% of the total, and
occur around the superior atriocaval junction. They are associated with partial
anomalous pulmonary venous drainage—usually with the right upper pulmonary
veins draining directly into the superior vena cava. Defects occurring near the infe-
rior vena cava junction do occur, but are rare.
The pathophysiology usually involves a predominant left-to-right shunt. Its
magnitude is dependent on the size of the defect, relative ventricular compliances,
and the ratio of systemic and pulmonary vascular resistances. The net effect is vol-
ume and pressure overload of the right heart, and increased pulmonary blood
flow. If untreated, approximately 10% of patients would develop pulmonary vas-
cular disease and eventually the Eisenmenger reaction (reversal of shunting con-
sequent upon elevated pulmonary vascular resistance). Closure would then be
contraindicated.
Many patients will be asymptomatic or have subtle clinical signs. However,
70% of patients will be symptomatic by 40 years, and many patients over the age of
60 years will be symptomatic. Symptoms when present consist of palpitations,
fatigue, dyspnea, cough, and infection. Chest pain may reflect right ventricular
ischemia. There is a preferential streaming of inferior vena caval blood to a secun-
dum ASD, which places unoperated patients at risk of paradoxical emboli at any
time, even if the shunt is almost entirely left to right. The decline in well being with

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age may reflect the onset of hypertension and coronary artery disease, which decrease
left ventricular compliance and increase left-to-right shunting. Other causes of
decreased left ventricular compliance such as mitral stenosis and mitral regurgita-
tion will also increase shunt flow.
Physical examination demonstrates a prominent right ventricular impulse,
loud S1, fixed and widely split S2. An ejection systolic murmur in the pulmonary
area and a middiastolic tricuspid murmur are the result of increased (right heart)
blood flow. Electrocardiography may show partial or complete right bundle branch
block, right axis deviation, and an increased P–R interval. Echocardiography con-
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firms the presence of a defect, and will often show dilated right atrium and ventricle,
and paradoxical atrial septal motion.
The incidence of arrhythmias, ventricular dysfunction, and pulmonary vascu-
lar disease are related to the age at closure. If there are no arrhythmias prior to clo-
sure, there is a 5% to 10% late incidence of arrhythmias, whereas patients with a
significant defect who exhibit arrhythmias preclosure virtually all have recurrent
arrhythmias by 25 years. Thirty percent of patients with preoperative atrial fibrilla-
tion will retain sinus rhythm at late follow-up. Tachyarrhythmias become increas-
ingly common after the fourth decade.
If surgical repair is delayed (e.g., beyond 40 years), elevation in pulmonary
artery pressures may be observed. Owing to left ventricular volume and geometry
changes, there is a small incidence of mitral regurgitation in adults with secundum
For personal use only.
ASD. If operation is carried out prior to 20 years of age in the presence of normal
pulmonary vascular resistance, survival is the same as controls. These patients can
effectively be treated as if they did not have congenital heart disease. Age at opera-
tion can affect (right) ventricular function. Similarly, ventricular end diastolic pres-
sure increases in a minority of patients who undergo repair as adults, but those
operated on when children do not exhibit left ventricular dysfunction.
Interestingly, the indications for repair continue to be debated. Traditionally
intervention is advised if there is a significant left-to-right shunt (QP:QS more than
1.5:1) in order to avoid arrhythmias, infective endocarditis, pulmonary hyperten-
sion, and increased mortality. Modern echocardiographic techniques have improved
detection of smaller defects in asymptomatic patients. Previous outcome data may
not apply to this group, and at least one long-term follow-up of asymptomatic patients
compared well with surgical treatment. In general, closure is advised for a “signifi-
cant” defect which is defined as volume or pressure overload, exercise limitation,
atrial arrhythmias, late right heart failure, or paradoxical embolism.
Transcatheter device closure is now routine. It is suitable for secundum defects
less than approximately 30 mm, with a rim around the defect. Long-term compar-
isons of outcome with surgery are awaited. Endocarditis prophylaxis is not subse-
quently required.
Implications of nonoperated ASD include paradoxical embolism and elevated
work of breathing due to decreased lung compliance. Late atrial arrhythmias may
occur, and right heart failure or pulmonary vascular disease occurs in approxi-
mately 10%.
Patients who have undergone surgical closure should present few problems
when undergoing noncardiac surgery, with arrhythmias being the commonest com-
plication. Patients who have not undergone closure should be managed as normal,
with specific attention paid to endocarditis prophylaxis and prevention of paradoxi-
cal embolism. Volume status should be maintained, to avoid increasing the magnitude
of shunting. Theoretically, changes in pulmonary and systemic vascular resistance can

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Adult Congenital Heart Disease and the Surgical Patient 279
alter the magnitude or even direction of shunting, but in the experience of this author
this is of little clinical significance, because such alterations would have to be enor-
mous to produce noticeable effects.
Transposition of the Great Arteries
Transposition of the great arteries (TGA) is defined as atrioventricular concordance
and ventriculoarterial discordance—put simply, the atria are connected to the appro-
priate ventricle but the ventricles are connected to the “opposite” great artery. The
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aorta arises from the anatomical right ventricle and the pulmonary artery arises from
the anatomical left ventricle. Blood flow, therefore, occurs in two parallel circulations
rather than the normal series arrangement. Maintenance of life depends on a degree
of mixing of oxygenated and deoxygenated blood between the two circulations. This
can occur through an atrial or VSD, patent arterial duct, or atrial septostomy. Pallia-
tive intervention in the newborn to achieve mixing was originally achieved surgically
(Blalock Hanlon septostomy) and subsequently by percutaneous balloon atrial sep-
tostomy (Rashkind). TGA is described as simple in the presence of an intact ventric-
ular septum. Complex TGA involves the combination of TGA with VSD and possibly
other abnormalities. The pulmonary artery overrides the ventricular septum, and if
more than 50% is committed to the left ventricle the abnormality may be described as
TGA with VSD, whereas if more than 50% of the pulmonary artery is committed to
For personal use only.
the right ventricle the correct terminology is double outlet right ventricle. Overall,
75% of TGA lesions are simple, 20% are combined with VSD, and 5% of patients have
TGA with subpulmonary stenosis. Up to 28% demonstrate anomalies of the coronary
arteries, which is important for surgical intervention in childhood.
TGA with VSD may be associated with unobstructed outflow; alternatively,
deviation of the outlet septum causes outflow tract obstruction. Posterior deviation
of the outlet septum restricts pulmonary blood flow, whereas anterior deviation
results in subaortic stenosis. Complex TGA with subpulmonary stenosis presents
early in life with severe cyanosis due to decreased pulmonary blood flow. Complex
TGA with unobstructed aortic flow leads to gradual development of heart failure
and may present later.
Adults with this circulation will usually have previously undergone surgery.
Very occasionally a degree of subpulmonary stenosis can result in balanced flow
which is compatible to survival to adult life without surgery. Surgical interventions
are varied and have altered in response to the development of late complications.
Simple TGA was originally and successfully treated with atrial redirection (atrial
switch) operations, the Senning and Mustard procedures. These procedures redirect
blood within the atria to the opposite ventricle, resulting in physiologically appro-
priate circulation pathways. The Rastelli operation was originally introduced for
TGA, VSD, and left ventricular outflow obstruction (subpulmonary stenosis). It
involves closing the VSD and thereby tunneling left ventricular blood to the aorta.
Right ventricle to pulmonary artery continuity is achieved by placing a valved con-
duit between the two. The arterial switch operation involves transecting the aorta
and pulmonary arteries and reconnecting them to the appropriate ventricle. The
atrial or arterial switch procedures can be combined with VSD closure in the context
of TGA, VSD, and unobstructed aortic flow. Finally, palliative atrial procedures
involve redirection of blood at atrial level, while retaining or creating a VSD. This
has been used in those patients who are unsuitable for physiological repair, usually
because of pulmonary vascular abnormalities.