MeSH
| Tetralogy of Fallot |
Pulmonary Atresia. |
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Abstract
Tetralogy of Fallot with Pulmonary Atresia is an extreme form of tetralogy
characterized by absence of flow from the right ventricle to the pulmonary
arteries. Pulmonary blood flow is derived from a variety of sources, including
native pulmonary artery branches and aorto-pulmonary collaterals with significant
variability from patient to patient. Management must therefore be individualized
to each patient’s anatomy and physiology. Cardiac catheterization plays
a crucial diagnostic and therapeutic role in this group of patients. This
article is a concise review of the spectrum of anatomic variability seen
in this lesion with an emphasis on diagnostic and therapeutic catheterization
. It also highlights our staged surgical approach to this lesion and provides
data on long-term outcome after complete intracardiac repair.
Background
Tetralogy of Fallot with Pulmonary Atresia (TOF/PA) is a complex lesion
with many different anatomic variants. The intracardiac anatomy is that
of a typical Tetralogy of Fallot with a large subaortic ventricular septal
defect and anterior malalignment of the conal septum resulting in right
ventricular outflow tract obstruction. The pulmonary valve is often absent
with a muscular pouch in its place. Occasionally, it presents as a blind
membrane. The primary source of variability in this lesion is in the anatomy
of the pulmonary arteries, with the spectrum ranging from well-formed,
confluent pulmonary artery branches (Fig. 1A,B) to completely absent native
pulmonary arteries and major aorto-pulmonary collaterals (MAPCA’s) providing
all the pulmonary blood flow (Fig. 2).1
Figure 1. Angiogram in the left BT shunt in anterior/posterior
(A) and lateral (B) projections demonstrates good size right and left pulmonary
arteries. This patient had ductal dependent pulmonary circulation and underwent
placement of the BT shunt shortly after birth. BT = Blalock Taussig.
Figure 2. Descending aortogram showing two large MAPCA’s, one
to each lung, and absent native central pulmonary arteries. The patient
has a right aortic arch.
The majority of cases fall somewhere in between these two
ends of the spectrum, with the total pulmonary blood flow provided by a
combination of diminutive native pulmonary arteries and multiple MAPCA’s
(Fig. 3 A,B). Different segments of the lungs
are fed by either a native pulmonary artery or a MAPCA, and sometimes
by both, referred to as "dual supply".2 Frequently these patients
have underperfused lung segments with little or no flow from the native
pulmonary arteries or the collateral circulation, referred to as arborization
defects (Fig. 4 A,B).
Figure 3A. Descending aortogram in an infant showing multiple
MAPCA’s to both lungs. B. Selective injection into one of the left-sided
MAPCA’s fills the native central pulmonary arteries. Note the very stenotic
intrapulmonary connection between the MAPCA and the native pulmonary arteries.
Click to view angiogram.
Figure 4A. Injection into a reconstructed right pulmonary artery
in a patient who has undergone a right unifocalization. The catheter is
inserted via a right modified Blalock Taussig shunt. Note the lack of perfusion
to segments of the right upper and right lower lobes in the anterior-posterior
projection. B. In the lateral projection the reconstructed right pulmonary
artery is seen to perfuse primarily right middle lobe anterior segments.
Over the last few decades, the management of TOF/PA has evolved from a
conservative approach of no intervention or limited palliation when mandated
by severe cyanosis or unremitting heart failure, to one of early intervention
in the hope of achieving a divided circulation with acceptable right ventricular
pressure in childhood. There are still multiple surgical approaches to
this lesion. Long-term data are needed to determine the optimal form of
management.
It should also be noted that there is a small subset of patients with
true tetralogy of Fallot, i.e. with forward flow from the right ventricle
to the pulmonary arteries, whose pulmonary artery anatomy resembles that
of patients with TOF/PA. These patients have relatively hypoplastic central
pulmonary arteries and their pulmonary blood flow is augmented by MAPCA’s.
Such patients are subjected to a similar management strategy as that for
patients with TOF/PA. However, if they present early on with inadequate
pulmonary blood flow, the initial palliation would be a Blalock-Taussig
shunt rather than a central shunt. The MAPCA’s are dealt with in a similar
fashion as in patients with TOF/PA.
Management strategies – initial stage
In order to plan surgical management, the anatomy of the native pulmonary
arteries and MAPCA’s must be clearly defined. The first question to be
answered in a newborn with TOF/PA is whether the pulmonary flow is dependent
on a patent ductus. Often this question can be answered satisfactorily
with echocardiography, but when in doubt, cardiac catheterization is mandatory.
Patients with ductal dependent pulmonary circulation almost always have
good size, confluent pulmonary arteries and no significant MAPCA’s (Fig.
1A,B).
In the majority of cases of TOF with pulmonary atresia, the native pulmonary
arteries are confluent but hypoplastic, sometimes measuring no more than
1-2 mm in diameter. Flow into them is derived from MAPCA’s, typically via
small intrapulmonary communications (Fig. 3B). It is often possible to
see these small pulmonary arteries and multiple MAPCA’s arising from the
descending aorta by echocardiogram. Less frequently, MAPCA’s arise from
the ascending aorta or head and neck vessels. MAPCA’s arising from the
head and neck vessels most commonly arise from the subclavian arteries
and typically perfuse a single lobe (Fig. 5), however, they can arise from
any vessel including the coronary arteries (Fig. 6 A,B).
Figure 5. Selective angiogram of a large MAPCA originating from
the left subclavian artery and supplying the left upper lobe in a patient
with a right aortic arch.
Figure 6A. Selective injection in this patient’s single coronary
artery demonstrating a large MAPCA arising from the proximal left coronary
artery branch and perfusing segments of the right upper and right lower
lobes. B. Lateral projection of the same injection. MAPCA = major aortopulmonary
collateral artery.
If it is clear by echocardiography that there are large collateral
vessels and the pulmonary circulation is not ductal dependent, and the
patient’s oxygenation is adequate with saturations in the high 70’s to
80’s, catheterization can be deferred beyond the immediate newborn period.
In the majority of these cases, the patient will have either adequate or
excessive pulmonary blood flow requiring anti-congestive therapy for the
first several weeks of life. If no intervention is performed, these patients
can remain well oxygenated for a variable period. The natural history of
this lesion, however, is that of eventual progressive cyanosis, either
due to development of stenosis in the aortopulmonary collaterals (Fig.
7), or development of pulmonary vascular disease in segments where unrestricted
flow from large MAPCA’s has been present (Fig. 8).3,4 In patients
with diminutive native pulmonary arteries, we recommend initial intervention
in the first few months of life to optimize the potential for growth of
the native pulmonary arteries.
Figure 7. Descending aortogram in a ten-year-old patient with
TOF/PA who had undergone a central shunt as an infant at an outside institution.
Note the significant stenosis in the MAPCA perfusing the left lower lobe,
as well as in some of the MAPCA’s perfusing the right lung.
Figure 8. Selective angiogram into a large, unrestrictive MAPCA
perfusing multiple segments of the left lung as well as some segments of
the right lung. This patient is at risk of developing early pulmonary vascular
disease if left untreated.
Less commonly, the native central pulmonary arteries are completely absent
and all the pulmonary blood flow is derived from MAPCA’s (Fig. 2). In these
cases, the timing of initial intervention is less crucial, since there
are no native pulmonary arteries to induce growth of. Intervention can
then be based on the patient’s physiologic status. However, if the patient
is well balanced with saturations in the 80’s and intervention in the first
few months of life does not appear necessary, it is important to be vigilant
if any of the MAPCA’s are large without significant stenosis. Any unprotected
lung segment is at risk of developing pulmonary vascular disease by as
early as four to six months of age. In order to defer intervention beyond
this point, cardiac catheterization must be performed to document that
all lung segments are protected. If it is not clear that a MAPCA is pressure
restrictive, a catheter should be inserted distally into the vessel to
record pressure. Not infrequently these patients have large, hypertensive
MAPCA’s arising from the mid thoracic aorta and present early in congestive
heart failure necessitating surgical intervention in the first few weeks
of life.
Ductal dependent circulation of one or both pulmonary artery branches
Our approach in patients with ductal dependent pulmonary circulation
is to place a Blalock-Taussig (BT) shunt via a lateral thoracotomy from
either the right subclavian artery in the case of a left aortic arch, or
the left subclavian artery if a right aortic arch is present. In the absence
of significant MAPCA’s, complete intracardiac repair can then be performed
at around one year of age, or sooner if the patient’s oxygenation becomes
inadequate with saturations below mid to high 70’s. In a small percentage
of cases with non-confluent native pulmonary arteries, one of the pulmonary
artery branches is "ductal dependant" (Fig. 9A,B), while the other lung
is supplied by MAPCA’s. In these cases, although there may be enough pulmonary
flow from the MAPCA’s for the patient to have adequate oxygenation, it
is necessary to intervene early to prevent interruption of flow to the
ductal dependant branch and assure that it will continue to grow normally.
The PDA is ligated and a BT shunt is inserted into that branch as the first
procedure.
Figure 9A. Selective angiogram in the patent ductus of a three
week old patient who presented with severe cyanosis. The ductus arises
from an anomalous left subclavian artery in this patient with a right aortic
arch. It supplies the entire left pulmonary artery. At presentation at
three weeks of age the ductus was nearly closed and did not respond to
prostaglandin. The patient had a stenotic MAPCA to the right lung and saturations
in the 40’s. B. Following emergent balloon dilation of the ductus,
saturations increased into the 70’s. A left modified BT shunt was placed
ten days later and the ductus was ligated. Click to
view angiogram.
Diminutive, confluent pulmonary arteries and MAPCA’s
At our institution, the majority of patients with tetralogy of Fallot
and pulmonary atresia who have diminutive, confluent pulmonary arteries
and MAPCA’s undergo a staged reconstruction leading to complete repair
by one to two years of age.5 Timing of the initial surgical
intervention is determined by the physiologic status of the patient, but
typically occurs sometime between three and six months of age.6
The initial procedure consists of a direct anastomosis between the diminutive
native pulmonary arteries and ascending aorta, referred to as a Melbourne
shunt. The objective is to promote growth of the hypoplastic native pulmonary
arteries by providing uniform blood flow through both central pulmonary
arteries at substantial enough pressure to encourage growth (Fig. 10A-F).
As the native pulmonary arteries grow, pulmonary blood flow increases and
patients may develop congestive heart failure. However, the orifice of
the shunt typically remains small in comparison to the size of the pulmonary
arteries and therefore pressure restrictive. Whether cardiac catheterization
is performed prior to this initial operation depends on how well the native
pulmonary arteries can be imaged by echocardiography. If there is no question
that they are present and confluent, catheterization can be obviated. If
there is any question about the presence or confluency of the native pulmonary
arteries, cardiac catheterization must be performed before surgical intervention.
Angiography in the ascending and descending aorta is performed to identify
all the MAPCA’s. Often from these injections, it is possible to identify
the diminutive native pulmonary arteries as they are filled by collateral
flow. These have the typical appearance of a "seagull" in the anterior-posterior
projection and are best seen with cranial angulation (Fig. 10A). On the
lateral projection, the central pulmonary confluency extends anterior to
the airway with a beak-like appearance that moves in conjunction with the
heart. Selective injection into each of the MAPCA’s is performed to define
their anatomy and determine how many of the bronchopulmonary segments are
perfused. The selective injections also demonstrate intrapulmonary connections
between the MAPCA’s and native pulmonary arteries, and often allow optimal
definition of the native pulmonary artery anatomy (Fig. 3B, 10A,B). If
the native pulmonary arteries are not opacified by any of these injections,
they are most likely absent (Fig. 2). To know this with certainty, pulmonary
vein wedge angiography should be performed in both right and left pulmonary
veins (Fig.11).
10A: Selective angiogram in a MAPCA in a three month old shows
the severely hypoplastic native pulmonary arteries, which measure at most
1 mm in diameter. 10B: Lateral projection of the same angiogram showing
the tiny central pulmonary arteries extending anteriorly. 10C: Pulmonary
artery angiogram in the same patient at 18 months of age after a Melbourne
shunt at three months of age and left unifocalization with placement of
a 4 mm left BT shunt at 11 months of age. 10D: Lateral projection of the
same angiogram performed via the left BT shunt. Note the dramatic increase
in size of the central pulmonary arteries. The catheter course is from
the left BT shunt into the central pulmonary arteries, and then through
the Melbourne shunt into the ascending aorta. The catheter is pulled back
towards the pulmonary arteries during the injection. The patient underwent
complete repair at 2 ½ years of age. 10E, F. Pulmonary angiogram
in the same patient at 3 ½ years of age, one year after complete
repair. She underwent dilation of left middle and left lower lobe branches
with RV pressure decreasing from ¾ systemic to 2/3 systemic. Click
to view angiogram. BT = Blalock-Taussig, MAPCA = major aortopulmonary
collateral artery, RV = right ventricle.
Figure 11: Wedge angiography in the left upper pulmonary vein
reveals absence of a central left pulmonary artery. Note the intraparenchymal
left pulmonary artery branches with no filling of any central vessel.
Although this initial catheterization is almost always diagnostic with
no need for catheter intervention, it requires a significant level of expertise.
It is typically performed in very small and sometimes fragile infants who
may be either very cyanosed or in heart failure. It is not always easy
to selectively engage each and every MAPCA, yet this is often necessary
to accurately define the native pulmonary artery anatomy. In patients with
absent native pulmonary arteries, a transseptal puncture may need to be
performed if the foramen ovale is no longer patent in order to access the
pulmonary veins for wedge angiography.
Caution should be exercised when catheterizing each MAPCA selectively.
These vessels are often tortuous and may be thin walled. Care should be
taken not to apply too much force when advancing the catheter around sharp
bends so as to avoid vessel dissection. In a patient dependant on MAPCA’s
for pulmonary blood flow injuring one of these vessels may lead to life-threatening
cyanosis. Contrast injections should be performed by hand, slowly at the
beginning of the injection while one appreciates the caliber of the vessel
being injected as well as the position of the catheter, then increasing
the rate and power as needed until the vessel is well opacified. If the
tip of the catheter appears to be lodged against the vessel wall its position
should be adjusted, since a forceful injection of contrast could result
in dissection. When measuring pressure in a MAPCA distal to a significant
stenosis or a branch point, it should be realized that the catheter itself
may be large enough to cause obstruction and falsely lower the measured
distal pressure.
Unifocalization
After the initial central (Melbourne) shunt, recruitment of the MAPCA’s
into the pulmonary circulation is achieved via staged unifocalizations
of the right and left lungs. A detailed cardiac catheterization must be
performed before each of these stages to provide the surgeon with an accurate
anatomic roadmap of the collaterals to be unifocalized and their relationship
to the native pulmonary arteries. The Melbourne shunt must be engaged and
each branch pulmonary artery selectively accessed. Biplane angiography
is performed in each branch pulmonary artery (Fig. 12A,B). Selective angiography
in each branch is particularly important in the lateral projection, where
there is too much overlap from the left and right pulmonary artery branches
to define their individual anatomy. If dual blood supply to a lung segment
from the native pulmonary arteries and MAPCA(‘s) is documented, the MAPCA(‘s)
can be occluded in the catheterization laboratory or ligated at the time
of unifocalization. To be certain that there is adequate dual supply it
may be necessary to balloon occlude the MAPCA while performing an angiogram
in the native pulmonary artery.
Figure 12A,B. Selective angiogram in the left pulmonary artery
(A) and right pulmonary artery (B) accessed via the Melbourne shunt. Note
that a wire has been inserted into the distal right pulmonary artery in
order to maintain catheter position in the proximal right pulmonary artery.
Once again, expertise in the catheterization laboratory is necessary
to obtain the necessary information. The Melbourne shunt is short and narrow,
and typically originates from the posterior ascending aorta. It is almost
always necessary to heat shape a catheter in order to successfully engage
the shunt and direct a guidewire into one of the pulmonary artery branches.
Once this is accomplished, it is not always possible to advance the heat-shaped
catheter, which is usually relatively stiff, through the shunt, and it
must be carefully exchanged for a softer catheter. More often than not,
the left pulmonary artery is more easily engaged than the right, and extensive
manipulation may be necessary to make the more acute turn from the shunt
into the right pulmonary artery. To avoid the need for repeat procedures,
it is often preferable to have the catheterization performed in the same
center performing the surgery to make sure all the required information
is obtained, as well as to have the option of reviewing the angiograms
with the surgeon, if there is any doubt, while in the catheterization laboratory.
Unifocalization is performed via a lateral thoracotomy. Each MAPCA is
detached from the aorta and joined to the native pulmonary arteries. Although
some MAPCA’s have intrapulmonary connections to the native pulmonary arteries,
these are often small and restrictive. The objective of the unifocalization
is to recruit as many of the perfused lung segments as possible and maximize
the cross-sectional area of the pulmonary vascular bed. At the same time,
by unifocalizing unobstructed MAPCA’s, those lung segments are protected
from the development of pulmonary vascular disease. Conversely, stenoses
within the MAPCA’s are surgically relieved as much as possible, at the
same time that these vessels are anastomosed to the native pulmonary arteries
(Fig. 13A,B,C,D). The use of synthetic material is avoided, and it is almost
always possible to join the MAPCA’s directly to the native pulmonary arteries
or to each other. When an interposition graft is required due to excessive
distance from a MAPCA, the patient’s azygos vein is used to create the
anastomosis.7 The timing is again dictated by the patient’s
physiology, but can typically be performed approximately six months after
the Melbourne shunt. If the patient is in congestive heart failure at the
time of unifocalization, the side with the most unobstructed MAPCA’s is
attacked first. On the other hand, if the physiology is that of significant
cyanosis, the side with the most stenotic collaterals is unifocalized first.
At the time of unifocalization, a modified Blalock Taussig shunt may be
placed if pulmonary blood flow needs to be enhanced. The timing between
right and left unifocalizations is also typically around six months.
Figure 13A-D. Right unifocalization. A. Selective injection
in the right pulmonary artery via a left BT shunt demonstrates a good size
branch to the right lower lobe and very small branch to the right upper
lobe. B. Selective injection in a MAPCA to the right lower lobe in
the same patient. Note the presence of severe mid segment stenosis.
C. Additional MAPCA from the underside of the aortic arch to the right
upper lobe with evidence of proximal stenosis. D. Selective injection in
the right pulmonary artery following unifocalization of the two right-sided
MAPCA’s showing significantly improved flow to the right upper lobe, as
well as increased perfusion to segments of the right lower lobe. There
are no significant peripheral stenoses visible. Click
to view angiogram. BT = Blalock-Taussig, MAPCA = major aortopulmonary
collateral artery.
Absent native central pulmonary arteries
If the native central pulmonary arteries are absent, sequential unifocalizations
are performed by detaching the MAPCA’s from the aorta and surgically constructing
a central pulmonary artery using a roll of autologous pericardium or pulmonary
homograft to anastomose with MAPCA’s. The reconstructed neo-pulmonary artery
is brought into the mediastinum via a pericardial window and tacked to
the ascending aorta (Fig. 14 A-D), and a Blalock Taussig shunt is inserted
from the ipsilateral subclavian artery to the neo-pulmonary artery.
Figure 14. Angiography in the right pulmonary artery in anterior/posterior
(A) and lateral (B) projections in a patient with absent native central
pulmonary arteries following bilateral unifocalizations. A neo right pulmonary
artery has been constructed into which the BT shunt is inserted. Note extension
of the neo right pulmonary artery anteriorly in front of the airway in
the lateral projection. The reconstructed right pulmonary artery has been
brought into the mediastinum and tacked to the ascending aorta. (C), (D).
Angiography in the left pulmonary artery in the same patient. A left BT
shunt was inserted into the unifocalized LPA after anastomosing a large
MAPCA to the LPA remnant within the lung. The patient underwent complete
repair at 16 months of age using a pericardial roll to join the reconstructed
right and left pulmonary arteries and a Hancock conduit was placed from
the right ventricle to the pericardial roll. 14E,F. Angiogram in AP/cranial
(E) and lateral projections (F) in the RV outflow tract 1 ½
years after complete repair. RV pressure was 2/3 systemic. 14G 14H
14I 14J . Peripheral stenoses in the right upper lobe branch and
in the distal main RPA (G – anterior/posterior, H – lateral) were dilated
with RV pressure decreasing to 55% systemic post dilation (I – anterior/posterior,
J – lateral). AP = anterior/posterior, BT = Blalock-Taussig, LPA = left
pulmonary artery, MAPCA = major aortopulmonary collateral artery, RPA =
right pulmonary artery, RV = right ventricle. Click
to view angiogram.
Final stage – complete intracardiac repair
The final stage following bilateral unifocalizations is complete intracardiac
repair with closure of the ventricular septal defect and right ventricle
to pulmonary artery conduit (Figs. 10 E,D, 14 E,F). At the time of complete
repair, pulmonary artery reconstruction is also performed as needed, relieving
any stenoses that are surgically accessible. The patient’s candidacy for
complete repair must be carefully assessed by way of a detailed cardiac
catheterization. The anatomy and physiology of the pulmonary vasculature
is examined with careful measurements of pulmonary artery pressure and
resistance. Not infrequently, significant distal pulmonary artery stenoses
are identified in either the native pulmonary arteries and MAPCA’s, or
the surgically created connections between these two structures. Stenoses
that appear surgically inaccessible from a median sternotomy are treated
with balloon angioplasty to optimize the patient for complete repair (Fig.
15A-D). Angiography in the descending aorta should also be performed prior
to complete repair to exclude the presence of any remaining collaterals.
If any collaterals are found, they may need to be occluded in the catheterization
laboratory.
Figure 15A. Right pulmonary artery angiogram demonstrating significant
long segment stenosis. The stenosis extends fairly distally into the hilum,
best appreciated in the lateral projection (B). Initial angiography was
performed with a catheter advanced retrograde through the central shunt.
C, D. Following balloon angioplasty, there is marked improvement in the
stenosis. Note the catheter is now accessing the shunt in a prograde fashion
from the right ventricle to the ascending aorta and through the central
shunt. By accessing the pulmonary artery from a venous approach to perform
balloon angioplasty, it was possible to avoid placement of a large sheath
in the femoral artery.
If the calculation of pulmonary resistance suggests that the postoperative
right ventricular pressure after complete repair will be prohibitively
elevated, one must carefully examine the reasons why. If it is due to surgically
inaccessible pulmonary artery stenoses, balloon angioplasty is performed
- often more than once. Cutting balloons and high pressure balloons need
to be used to achieve optimal results. After sequential ballooning over
a period of 6-18 months, it is often possible to proceed to complete repair,
at which time further pulmonary artery reconstruction can be performed
as needed. If the reason for the elevated resistance is primarily arborization
defects with large underperfused lung segments, complete repair may not
be possible, or it may be necessary to fenestrate the VSD patch postoperatively
to maintain adequate cardiac output.
The information obtained at catheterization prior to this final stage
is crucial, as it will determine whether a complete repair can be safely
performed. At times, it may be difficult for the physician doing the catheterization
to know whether the surgeon can reach a specific area of peripheral stenosis
or whether balloon angioplasty should be undertaken. When balloon angioplasty
is necessary, access to the peripheral stenosis must be through an aorto-pulmonary
shunt, with its inherent technical difficulties. It may also be challenging
to decide whether a remaining MAPCA that failed to be unifocalized via
a previous lateral thoracotomy should be occluded, or could be unifocalized
via a median sternotomy at the time of complete repair. For these reasons,
we often recommend that patients undergo catheterization at the institution
where complete repair is to be performed, so that the information can be
shared with the surgeon as it is obtained, and interventional decisions
made jointly in the patient’s best interest.
These patients are of course facing further surgical procedures typically
some years after "complete repair," most commonly replacement of the right
ventricle to pulmonary artery conduit because of stenosis, insufficiency
or a combination of the two. It will again be important to evaluate the
pulmonary artery anatomy carefully before surgical intervention, in order
to alert the surgeon to any further pulmonary artery reconstruction that
may be necessary at that time. These patients are typically older, and
therefore can cooperate with such non-invasive imaging modalities as magnetic
resonance imaging (MRI). MRI may offer excellent anatomic detail of the
pulmonary arteries at this stage, when the vessels are typically larger
and therefore well within the margin of resolution of this technique. However,
when physiologic data is needed, such as in patients with persistent elevation
of the pulmonary artery pressure, cardiac catheterization should be performed.
Catheterization is of particular importance in patients with distal pulmonary
artery stenoses inaccessible to the surgeon, where balloon pulmonary angioplasty
or stenting may be indicated. MRI can still be a very useful adjunct to
the patient’s evaluation by demonstrating the anatomy prior to catheterization.
A joint review by the interventionalist and the surgeon can then lead to
a plan of action best suited to the specific patient’s anatomy.
The extensive anatomic variability encountered in this lesion makes
each one of these patients virtually unique. It is important to approach
each patient, and each stage of their reconstruction, with extreme attention
to detail. The ultimate goal should be that of preserving perfusion to
as many lung segments as possible and avoiding irreversible changes in
the pulmonary vascular bed. The outcome of these complex patients is dependent
not only on their underlying anatomic and physiologic substrate, but also
largely on the surgical and interventional expertise brought to their care.
It is therefore crucial that each procedure they are subjected to be performed
in an experienced institution by an expert team, optimally with the interventional
cardiologists and surgeons working together.
Outcome
Our institutional experience with this lesion has been recently published.
8 From a total of 46 consecutive patients, there have been no
hospital deaths, and one late death due to bronchopulmonary dysplasia.
Over 90% of patients in our series have either successfully undergone complete
repair or are currently being staged and are considered good candidates
for eventual complete repair. In the operating room, post-operative mean
pulmonary artery pressure to mean systemic arterial pressure ratio had
a median value of 0.36 (range 0.19-0.58). Two patients required VSD fenestration
2 and 3 months after complete repair due to a rise in right ventricular
pressure without the development of new peripheral pulmonary artery stenosis.
This compares favorably to other published series with an early mortality
rate of 10.6% and overall mortality of 18.8%. 9 The surgical
approach in this latter series was an attempt at single stage unifocalization
and full intracardiac repair. We believe a staged surgical reconstruction
optimizes the recruitment of collateral vessels in a fashion that is matched
to the patient’s physiology at each stage. The crucial decision of whether
to proceed to complete intracardiac repair is made at a time when the pulmonary
anatomy and physiology have been optimized and can be well assessed. The
sources of pulmonary blood flow are controlled early to avoid exposure
of unprotected lung segments to high pressure.
During long-term follow-up over a median of 40 months, the right ventricular
to left ventricular pressure ratio has averaged 0.51 + 0.24. Over
60% of these patients have required further interventions, most commonly
balloon angioplasty of distal pulmonary artery stenosis 8 (Figs.
14G-J, 16A,B). Other series have reported similar reintervention rates.
5,9,10 These patients require ongoing close follow-up with particular
attention to non-invasive estimation of right ventricular pressure and
distribution of pulmonary blood flow. Cardiac catheterization should be
performed if a progressive increase in right ventricular pressure is documented
or if there is marked asymmetry of flow to the right and left lungs, and
pulmonary artery angioplasty and/or stenting undertaken if warranted. Longer-term
follow-up should continue so that we can better assess the optimal management
strategies among the various currently advocated algorithms.
Fig. 16. Right pulmonary artery angiogram before (A) and after
(B) balloon angioplasty in a patient two months after complete repair.
The left pulmonary artery was also dilated. Right ventricular pressure
decreased from 80% systemic to 60% systemic. Click
to view angiogram.
Acknowledgments: I would like to acknowledge the leadership of our
surgical team, Drs. Roger Mee and Brian Duncan, and the contribution of
my interventional colleagues, Drs. Larry Latson, Tamar Preminger and Cesar
Igor Mesia, and the catheterization laboratory support staff, in the superb
care of this difficult group of patients. I would also like to acknowledge
the assistance of Shelby Scouten in the preparation of this manuscript.
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Reddy MV, McElhinney DB, Armin Z, Moore P, Perry AJ, Teitel DF, Hanley
FL. Early and intermediate outcomes after repair of pulmonary atresia with
ventricular septal defect and major aortopulmonary collateral arteries.
Circulation 200;101:1826-32.
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Rome JJ, Mayer JE, Castaneda Ar, Lock JE. Tetralogy of Fallot with pulmonary
atresia. Rehabilitation of diminutive pulmonary arteries. Circulation 1993;88:1691-8.
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Contact information
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Dr. Lourdes R. Prieto
Department of Pediatric Cardiology
Division of Pediatrics
9500 Euclid Avenue, M-41
Cleveland Clinic Foundation,
Cleveland, Ohio 44095, USA.
Phone: 216-445-3865
Fax: 216-445-3692
prietol@ccf.org
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www.impaedcard.com
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