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o cyanosis ; clubbing ;
o Arterial pulses …normal in uncomplicated TOF;
o Wide pulse pressure (arterial diastolic runoff)….
aortopulmonary collaterals, palliative surgical shunt or PDA;
o Accentuated precordial RV impulse;
o LV impulse will not be hyperactive (normal cardiac output);
o S2 single& loud (anterior, dextroposed aorta);
o S3/S4 are unusual;
o Aortic ejection click;
o Systolic murmur…crescendo-decrescendo @ LUSB. The
intensity of the murmur inversely parallels the degree of
o Diastolic murmurs are unusual. Rarely AR murmur;
o TOF with PA…..no harsh, obstructive precordial murmurs;
o A harsh diastolic murmur, with a harsh murmur of PS, [harsh
sawing, to-and-fro murmur ] ……TOF and APV syndrome;
o Continuous murmurs….PDA;aortopulmonary collaterals ;may
be best heard in the back.
QRS axis … same as that of a normal newborn
RVH…Tall monophasic R in V1 with an abrupt change to an
rS pattern in V2 (Tall R extends into adj precordial leads in
TOF + APV)
Reduced PBF+ underfilled LVrS in V2-V6
Balanced shunt …qR in V5,V6
L-R shuntQR in V5,V6
LAD with counterclockwise depolarisn TOF+AVSD
Normal sized heart; [may be large in PA]
upturned apex; attenuated & concave left heart border
(infundibular and PA hypoplasia)….boot-shaped heart, or
coeur en sabot…small underfilled LV that lies above
horiz IVS, inferior to which is a concentric hypertrophied
Diminished pulmonary vascularity in proportion to the
degree of cyanosis.
Absent thymic shadow in the newborn may indicate
associated chromosome 22q11.2 microdeletion (DiGeorge
RAA in roughly 25%...accompanied by Rt DA on Rt side
In PA..lacy reticular pattern (d/t the anast b/w lobar/segm
PAs & CAs)
Syst arterial collaterals rarely cause rib notching as they
do not run in intercostal grooves.
VSD; degree of aortic override;
Cranial tilt of the transducer…..infundibulum and the proximal
pulmonary arteries. [location and degree of
infundibular, valvular, and arterial hypoplasia]
RVOT and proximal pulmonary arteries…degree of
VSD [just below the RCC, or at 10 o'clock position].
Tricuspid-aortic continuity confirms the perimembranous
Coronaries…origin and course … echo showed sensitivity of
82%, specificity of 99%, and accuracy of 98.5% in a study by
Need et al
high parasternal and suprasternal views will provide
visualization of the pulmonary arteries and aorta, respectively
3D transthoracic echo (combined with a semiautomatic
border detection algorithm) for measuring right
ventricular volumes and ejection fractions has good
agreement with MRI. 3D echo has reduced accuracy with
larger Right ventricular volumes.
MRI, axial slices offer greater reproducibility for right
and left ventricular end-diastolic volumes and end-
systolic volumes than do short-axis slices.
Subject to significantly less intraobserver variation.
Postoperative PS and PR and also RV volumes better
assessed by MRI than Echo. High quality imaging of
MRI can replace angiography.
64-slice HRCT :
Questions about preoperative pulmonary artery
anatomy, coronary artery anatomy, and systemic or
pulmonary venous anatomy can frequently be resolved
even in newborns with 64-slice high-resolution CT
Computerized Tomography is infrequently used for
evaluation of TOF. Surgical complication like infection
or pseudoaneurysm formation can be detected with CT
scan. Helical CT scanning can be used to identify
airway compression caused by a large ascending aorta
The focus of catheterization has shifted from making the
diagnosis to filling in missing information in the diagnosis such
as the hemodynamic data regarding pulmonary blood supply.
Other specific questions unanswered by echocardiography such
1) coronary anatomy;
2) aorto-pulmonary collateral arteries (number, size,
distribution, any stenosis and blood pressure in each
3) confirmation of presence or absence of native PAs and a
retrograde pulmonary vein wedge injection if needed to
identify their presence if not clear on aortography;
4) number of lung segments connected to native Pas; and
5) lung segments with dual blood supply.
After surgical repair
to evaluate hemodynamically significant residual
lesions, right ventricular outflow tract
residual ventricular septal defects, in patients
who are unstable or otherwise unable to wean
What are the factors that decide treatment?
Types of surgery
TOF is a progressive disorder
most infants require surgery
Timing of complete surgical repair is
dependent on numerous variables
any associated lesions (eg, multiple ventricular
septal defect [VSD], pulmonary atresia)
Current trend is ----- before the age of 1 year
and preferably by the age of 2 years.
Studies have shown that surgery is preferably
done at or about 12 months of age.
The majority of patients born with tetralogy of
Fallot now thrive well into their adult years.
ductal-dependent pulmonary blood flow ?......neonates
with critically restricted antegrade blood flow need to be
started on prostaglandin E1and considered for either total
repair or a systemic-to-pulmonary shunt.
Most newborns with TOF do not have ductal-dependent
pulmonary blood flow and may be followed without
specific early intervention.
Parental education for recognition of cyanotic spells
[even acyanotic TOF are at risk for the development of
spells in the first months of life].
IE Prophylaxis for cyanotic/palliated patients ; patients
for 6 months after patch repair surgery, and those with
TOF WITH PULMONARY STENOSIS
TOF WITH PULMONARY ATRESIA
TOF WITH ABSENT PULMONARY
to increase pulmonary blood flow independent of
ductal patency and to allow pulmonary artery
growth and even total correction.
1. Neonates with TOF & Pulmonary atresia
2. Children with Hypoplastic pulmonary artery
3. Infants with Hypoplastic pulmonary annulus
4. Age less than 3 months who have medically
unmanageable hypoxic spells
5. Infants weighing less than 2.5 kg
6. Abnormal coronary artery anatomy
Ascending aorta with right PA
No longer performed because of high surgical
•Descending aorta with left PA.
•No longer performed
To maintain the patency of the shunt, initial post
op days use heparin followed by aspirin until
The mortality rate - less than 1%
acute shunt thrombosis,
hypoplasia of the arm,
phrenic nerve injury, and
pulmonary artery stenosis.
The longevity of palliation after shunt placement
varies according to the patient's age at the time of
surgery and the type of shunt.
Interventional procedures :
In patients with severe annular hypoplasia…..
palliation of significant cyanosis by balloon
valvuloplasty or RVOT stent placement can be
done… Improvement in antegrade flow is thought to
simultaneously enhance pulmonary arterial growth
by augmenting PBF.
A study by Robinson et al found that intraoperative
balloon valvuloplasty is associated with significant
longitudinal annular growth, with normalization of
annular size over time.
This technique may be most useful in patients with
moderate pulmonary stenosis and moderate pulmonary
Balloon angioplasty of the pulmonary valve
annulus is preferable to a shunt procedure as it is
it avoids a thoracotomy,
reduces the likelihood of distortion of the
However, this must be done with caution if the
outflow obstruction is predominantly at the valve,
dilation can result in an acute ventricular left to
right shunting pulmonary overcirculation.[36–41]
Coil embolization of APCs ….Coiling of vessels that
perfuse pulmonary segments already supplied by
pulmonary arterial flow serves to reduce LV volume
loading as well as to eliminate runoff into the
pulmonary arterial bed during CPB
Definitive Surgery aims @
relieving all possible sources of RVOTO;
If possible, pulmonary valve function is preserved by
avoiding a transannular patch
Closure of VSD (dacron patch)
1. O2 saturation less than 75-80%
2. Cyanotic spells
3. Mildly cyanotic infants who have had previous
shunt surgery mayhave total repair 1-2 yrs after
Today, most centres prefer early repair for PA growth
and preservation of right ventricular function
To relieve RVOTOpulmonary valvotomy, the
insertion of an outflow tract patch or a transannular
patch are often required.
Surgery during early infancy, when the pulmonary
annulus is markedly stenotic, frequently requires the
insertion of a long and wide transannular patch.
Consequently, most patients acquire PR as a result of
the repair. PR may be well tolerated by many in the
early postoperative years, but in the long term chronic
PR is associated with reduced exercise capacity, RV
dilatation, ventricular arrhythmias, and sudden death.
SURGERY in TOF contd…
VSD closure : Done thru’ RA approach whether or not a trans-
annular patch is used, as this approach allows to minimise the
length of the right ventriculotomy (length only necessary to
relieve the RVOT obstruction and not for the VSD exposure).
Efficacy of the RA approach ….
Preserves the right ventricular function, …..
Resultant PR after limited transannular patching is less severe
than that which occurs after transventricular repair
Less incidence of ventricular/atrial arrhythmias
Easier to preserve the integrity & function of the tricuspid
Concerns of right ventriculotomy (classical RV approach)
Low cardiac output in the early postoperative period,
a higher incidence of arrhythmias,
Risk of late sudden death
Low birth weight
Pulmonary artery atresia
Major associated anomalies
Multiple previous surgeries
Absent pulmonary valve syndrome
Young or old age
Severe annular hypoplasia
Small pulmonary arteries
High peak RV–to–left ventricular pressure ratio
Coexisting cardiac anomalies
Contraindications to primary repair in tetralogy
of Fallot include the following:
The presence of an anomalous coronary artery
Very low birth weight
Small pulmonary arteries
Multiple coexisting intracardiac malformations
Advantages of early total correction
Prevents cerebral hypoxia, cerebral embolism,
abscess and hematological changes
Decrease RVPprevent persistent myocardial
hypertrophy and probably reduce the risk of ﬁbrosis
of the RV
Providing adequate PBF will optimize the
opportunity for normal growth of the main and
branch PAs…also normal pulmonary circulation may
be important for lung development.
Tendency for progressive hypertrophy of the RV
infundibular region is largely abolished by early
B-T Shunt (±)
VSD closure +
RV – PA
VSD closure (±)
( as early as 3-4 mo;
& by 1-2 yr )
VSD closure +
RVOT + Small
TETRALOGY OF FALLOT
B-T Shunt (±)
SURGERY IN TOF + PA :
1. Depends on PA anatomy and collateralization
(cath study) & presence of MAPCAs
2. Stages : complete repair or staged operation
3. If PA anatomy appears amenable to
reconstruction, procedures leading to complete
repair are indicated.
4. Palliative procedures…PA Anatomy
unfavourable… Central shunt vs reconstruction
of RVOT using a patch/conduit while leaving
open the VSD
5. If there is a connection between RV & PT
correction can be achieved with a patch
The complexity of pulmonary blood supply determines the extent of
surgical exploration necessary to perform unifocalization. Eligibility for
complete repair is dependent on this since the RV-PA conduit needs to be
placed to the vessel which is connected to maximum possible pulmonary
vascular bed. Furthermore, closing the VSD at the time of placement of
RV – PA conduit needs to be determined. Adequacy of the pulmonary
vascular bed and the pulmonary vascular resistance are the determinants
of postoperative RV pressure which in turn has been closely correlated
with surgical outcome. At least 10 – 16 lung segments need to be
connected to the RV-PA conduit in order to have satisfactory
hemodynamic result after complete repair9. If the central native PAs
were not identified on echo, it is prudent to demonstrate them
angiographically. Furthermore, a simultaneous contrast injection into the
proximal stump of the pulmonary artery and the pulmonary vein wedge
injection will help to define the length of discontinuity that need to be
“bridged” surgically during repair10.
Preoperative evaluation of adequacy of pulmonary artery size is
difficult because of under filling of PAs and therefore, the potential size
of these PAs after surgical repair is unpredictable.
PA anatomy assessment
To quantitate the degree of PA hypoplasia
1) McGoon ratio: (Diameter of RPA/DAo + Diameter of
Adequate for VSD closure 1.2
Inadequate <0.8 for VSD closure
2) Nakata Index:(CSA of RPA + CSA of LPA)/BSA
Normal value > 200 mm2/m2
> 150 mm2/m2 is adequate.
(Not usable preoperatively when MAPCAs are the
major source of PBF & one-stage unifocalization + full
repair is planned).
3) Total Neo-Pulmonary Artery Index (TNPAI) = APC
index + Nakata Index
APC index is the sum of CSA of all usable
>250 - suitable for one-stage repair including VSD
closure (These pts. have low RV/LV pressure ratio
Critique of all these indices: These indices consider
only the size of proximal vessel and not consider the
condition of distal parts of the vessels (which may be
Recently the value of all these has been questioned
Classification of PA - VSD according to the status of
native pulmonary arteries (NPAs), aorto-pulmonary
collaterals (APCs) and patent ductus arteriosus (PDA).
Type A: Native pulmonary arteries present, no APCs.
Type B: Native pulmonary arteries and APCs present.
Type C: No native pulmonary arteries, only APCs
maintain pulmonary blood flow
Neonates with adequate-sized confluent pulmonary arteries
may be amenable to primary definitive surgical repair.
A palliative procedure with a systemic–to–pulmonary artery
shunt may be performed while awaiting complete repair at a
The ultimate surgical goals are:
(1) to incorporate as many pulmonary artery segments as possible
into a pulmonary artery confluence,
(2) to place a conduit from the right ventricle to the pulmonary
artery confluence, and
(3) to close the ventricular septal defect (VSD).
While the primary intervention in the majority of patients is
surgical, selected cases may be amenable to transcatheter
perforation of the right ventricular outflow tract followed by
When the pulmonary arteries are hypoplastic, nonconfluent,
and supplied by aortopulmonary collaterals, a multistaged
repair is often required.
Hypoplastic pulmonary arteries generally require palliative
shunting to induce enlargement and growth of these vessels
so they can be successfully incorporated into the complete
The shunts used may be modified Blalock-Taussig or central
shunts and may be unilateral or bilateral.
Another important strategy to maximize the long-term
outcome in this group of patients is the early
unifocalization of as many of the aortopulmonary
collaterals as possible into a central pulmonary artery
confluence.[22, 23, 24, 25] This maximizes the recruitment of
lung segments and increases the likelihood of performing
the definitive repair.
For complete repair to be performed in a child
who has undergone palliation:
(1) The central pulmonary arterial area must be
greater than 50% of normal;
(2) predominantly left-to-right intracardiac
shunting must be present;
(3) the equivalent of an entire lung must be
supplied by the central pulmonary artery
(4) stenotic lesions in the pulmonary artery
outflow must be addressed.
Some centers have shifted toward performing a single-
stage repair, wherein all the multiple aortopulmonary
collaterals (MAPCAs) are ligated at the aorta.[31, 32]These
MAPCAs are then mobilized toward the posterior
mediastinum to construct a pulmonary artery confluence,
followed by insertion of a pulmonary allograft to establish
continuity between these neopulmonary arteries and the
right ventricle. The ventricular septal defect (VSD) is
Infants with postunifocalization pulmonary arteries that,
combined, are only mildly hypoplastic (> 200 mm2/m2)
have a lower mortality rate and acceptable right
require repeat catheterizations for balloon dilation or
stent placements in stenotic pulmonary artery segments to
alleviate elevated right ventricular pressures.
MAPCAs : management : 2 options
1)Obliterate them by Sx ligation/coil embolisation
2)Surgical unifocalisation : if it is the sole supply to
many segments …..connecting all MAPCAs, as well as
the small native pulmonary arteries, to one source of
blood ﬂow from the RV [ie to a central PA confluence
or prosthetic PA confluence]….. If performed early,it
avoids the dvpt of PVOD changes, as well as stenoses
in the MAPCAs.
If the pulmonary vascular morphology and resistance
are such that adequate PBF can be
accommodated…then RVP after correction will be low
enough to close the VSD.
To assess whether this is likely, surgeons at the
University of California in San Francisco perfuse
blood from the perfusion system through the
pulmonary artery at a rate of 2.5 L/min per m. If PA
mean pressure is <25 mmHg, it is considered safe to
close the VSD. If it is not closed, the patient is
followed; the PVR may decrease over time, allowing
later closure. Also, if stenoses in pulmonary vessels
are noted, relief by balloon angioplasty, with stenting
if necessary, may permit RVP to fall and permit
closure of the defect.
Post surgery if the RVP/LVP is >0.75….RVF may
result…avoid closure VSD / fenestrated patch closure
central Shunt RV – PA connection
+ unifocalization +
Single stage repair VSD
closure + RV to unifocalized
VSD closureunifocalizationRV- PA conduit
Pas + MAPCAs
TETRALOGY OF FALLOT WITH
Post Repair for TOF in general
Current surgical survival, even for symptomatic
infants <3 months of age, is excellent.
Hospital and 1-month survival rates of 100% have
Earlier age at repair (<1 year of age) did not
adversely affect the rate of reintervention; so primary
repair should be regarded as the preferred
Twenty-year survival for hospital survivors,
irrespective of management strategy, was 98% for
patients who have TOF with PS and slightly lower for
patients with PA, reflecting the overall excellent long-
term survival of these patients.
– Pulmonary regurgitation:
d/t transannular patch repair technique
well tolerated if mild to moderate.
Severe chronic pulmonary regurgitation, however, may lead to
symptomatic RV dilatation and dysfunction.
The severity of pulmonary regurgitation, and its deleterious long-
term effects, are augmented by coexisting proximal or distal
pulmonary artery stenosis, or pulmonary artery hypertension
– Right ventricular (RV) dilatation:
residual longstanding free PR +/– RVOT obstruction or
as a consequence of RV surgical scar (transventricular approach for
repair, now abandoned).
Significant tricuspid regurgitation (TR) may occur as a consequence
of RV dilatation, which begets more RV dilatation.
– Residual right ventricular outflow tract (RVOT)
occur at the infundibulum,
at the level of the pulmonary valve and main pulmonary
distally, beyond the bifurcation and occasionally into the
branches of the left and right pulmonary arteries.
– Aneurysmal dilatation of the RVOT:
relatively common in patients with previous transannular
patch repair and significant pulmonary regurgitation.
Aneurysmal dilatation of the RVOT can be associated
with regional RV hypokinesis.
Swirling of blood can be inferred from color flow
Doppler signals in the aneurysmal right ventricular
outflow tract regions. To date, no episodes ofsudden
rupture of these regions have been reported.
Furthermore, this area can be the focus of sustained
– Residual ventricular septal defect (VSD): residual VSDs can be
encountered from either partial patch dehiscence or failure
of complete closure at the time
– Aortic regurgitation (AR) with or without aortic root
dilatation: AR can be due to damage to the aortic valve
during VSD closure or secondary to an intrinsic aortic root
abnormality (more common in patients with pulmonary
atresia and systemic to pulmonary artery collaterals). The
pathologic substrate for aortic root dilatation seems to be
„cystic medial necrosis‟.
– Left ventricular dysfunction: occasionally, left ventricular
dysfunction can be seen from a variety of factors, including
inadequate myocardial protection during previous
repair(s), chronic LV volume overload due to longstanding
palliative arterial shunts and/or residual VSD, injury to
anomalous coronary artery (uncommon) or longstanding
cyanosis before repair.
– Endocarditis: residual lesions leading to turbulent fl ow
(residual VSD patch leak, RVOT obstruction, PR, TR)
encountered in most patients after initial repair can serve as
substrate for endocarditis.
Supraventricular arrhythmia: atrial fl utter and atrial fibrillation
are relatively common in the current cohort of adults with
previous tetralogy repair. Atrial tachyarrhythmia occurs in about
one-third of adult patients and contributes to late morbidity and
– Ventricular tachycardia (VT):
sustained monomorphic ventricular tachycardia is relatively
The usual arrhythmia focus is in the RVOT in the area of the
previous infundibulectomy or VSD closure during tetralogy repair.
Right ventricular dilatation from impaired hemodynamics is also
contributory to the creation of re-entry circuits within the RV.
The QRS duration from the standard surface EKG has been shown to
correlate well with RV size in these patients.
A maximum QRS duration of 180 ms or more is a highly sensitive
marker for sustained VT and sudden cardiac death in adult
patients with previous repair of tetralogy.
– Sudden cardiac death (SCD): the reported incidence, presumably
arrhythmic, in late follow-up series varies between 0.5–6% over
30 years, accounting for approximately one-third to one-half of
Problems that may develop include
Persistent defects at the patch margin or
Previously unrecognized or underestimated additional defects in the
Partial patch dehiscence
b)Recurrent RVOTO :
Muscle bundles obstruct the os infundibulum in 3%
Nontransannular patches…annulus becomes restrictive as child
Transannular patch…restriction at the distal insertion of the patch
into the branch pulmonary arteries.
Stenosis owing to compression from an aneurysmal RVOT patch ….
should be approached surgically with revision of the patch and
repair of the proximal obstruction.
may develop additional sites of peripheral PS over time.
c)Progressive aortic root dilation &AR :
Intrinsic dvptal abnormalities of aortic valve/root
Palliative shunts or significant APCs left-to-right shunt
volume contribute to aortic dilation.
Progressive dilation of aorta correlate with longer time
between palliation & repair ; Pulmonary atresia ; right AA
& male gender.
d) RV dilation;syst/diast dysfunction later RHF
excess volume load from pulmonary regurgitation
pressure load from outflow obstruction,
Hypoxemic coronary perfusion,
surgical incision, patch and scarring, and post–
cardiopulmonary bypass ischemia reperfusion injury—
possibly superimposed on tetralogy associated congenital
abnormalities of the myocardium.
e) LV dysfunction … consequence of adverse
f) Rhythm disturb./SCD : Long-term mortality …. 3%
A review of 125 adult patients with TOF suggested that
a greater degree of PR, a history of sustained VT, QRS
duration >180 ms, or LV dysfunction was a predictor
of sudden death
g) Lower IQ
h) Life time increased risk for IE
i)Membranous subaortic stenosis …..may be seen
years after the initial repair in a few patients…may
require surgical excision.
j)Small coronary-to-RV fistulas, thought to relate to the
excision of muscle in the right ventricular outflow
Post repair TOF + PA :
Need for reoperation/ transcatheter balloon dilation
and stenting of an obstructed conduit in RV to PA
conduit surgery patients.
Ongoing risk for recurrent peripheral PS…serial
catheterizations are indicated for ongoing pulmonary
higher risk for progressive aortic root dilation and
TOF + AVCD :
risk for atrioventricular valve incompetence …. TR right
ventricular dilation, and dysfunction.
Congenital Absence of Pulmonary Valve Syndrome
Chever in 1847
incompletely formed, rudimentary pulmonary valve
that typically is both stenotic and regurgitant ;
aneurysmally dilated PA, and a large malaligned
PDA is always absent….has been postulated as being
responsible for its pathogenesis and PA dysplasia.
Other clinical features fairly typical in this disorder
include the common association of airway
abnormalities that may lead to severe respiratory
The conal septal abnormalities and infundibular
obstruction, however, in distinction to typical
tetralogy, are less severe or absent, and much of the
PS results from annular hypoplasia.
Typically present in the neonatal period, and are
diagnosed based on the presence of their
characteristic murmur and the presence of cyanosis.
A significant proportion of patients will present with
associated respiratory distress or frank respiratory
failure, often requiring mechanical ventilation.
harsh to-and-fro murmur of PS followed by the
diastolic murmur of PR….sound of ’sawing wood’
CXR…Massively dilated Pas ; Infundibular dilation
project leftward as a hump shaped shadow ;
Pulmonary vascularity is normal
Some neonates present with severe bronchial obstruction
and require immediate tracheal intubation and mechanical
ventilation, followed by early surgical repair.
Moderate resp obstruction … lying prone may help … by
relieving the anterior vascular compression of bronchi
Mild or no airway obstruction may require no additional
support in the neonatal period and go on to elective repair
later in infancy.
The surgical repair….. in addition to ventricular septal
defect closure and right ventricular outflow
reconstruction, involves reduction of the aneurysmal
mediastinal pulmonary arteries to relieve bronchial
Outcome of TOF + APV depends largely on the severity of
Even after Sx,some pts continue to have bronchial obstruction
Residual airway hypoplasia and deformity
Abnormally branching segmental pulmonary arteries
compressing the intraparenchymal bronchi
As these patients grow, however, pulmonary function tends
generally to improve as PAP fall and the maturing
tracheobronchial tree develops less compressible walls and
Surgical repair is only definitive treatment.
Palliative surgery is supportive.
Definitive repair to be done as early as
TOF+PA requires indivualization of treatment
dependiing on pulmonary anatomy.
PVR : Early PVR in selected patients results in
beneficial remodelling of the right ventricle
Optimal timing is critical for preserving RV function (not
too late) and avoiding the need for early re-operation
(not too early). Amelioration of RV function following
PVR has to be weighed against the risk of subsequent re-
operation for homograft failure.
Studies…RV end-diastolic volume may become a
helpful indicator for defining both a lower limit
(150 mL/m2) and an upper limit for re-intervention
(200 mL/m2).[normal 60-100]
CMR is the gold standard for evaluation of RV volumes
and quantification of the degree of PR & TR.
Hypoplastic PAs … intervene early …. Encourage
them to grow
Reconstruction of RVOT with a patch or valveless
Placement of a central AP shunt
If MPA,RPA & LPA are present, even though very
small (diameter 3 mm), they are capable of
considerable enlargement if blood ﬂow through them
Creating an AP window early in infancy sufﬁcient
enlargement of the pulmonary arterial tree to later
perform successful repair using the normal pulmonary
arteries and a unifocalization procedure can be avoided.
Notas del editor
I will just briefly describe the diagnosis part and important investigations
Al Habib HF, Jacobs JP, Mavroudis C, Tchervenkov CI, O'Brien SM, Mohammadi S, et al. Contemporary patterns of management of tetralogy of Fallot: data from the Society of Thoracic Surgeons Database. Ann Thorac Surg. Sep 2010;90(3):813-9; discussion 819-20. [Medline].
Why I have ended into medical management while I am asked to discuss surgical mangement? ans: basic rule is first to keep the patient alive then treat his disorderInfants with cyanosis are stabilized by administering prostaglandins (to maintain the ductus in an open state). The use of prostaglandins has significantly decreased the need to perform urgent surgery. Instead of performing systemic-to-pulmonary artery shunts on critically ill cyanotic-hypoxic infants, surgeons now have the luxury of having extra time to assess the patient's anatomy and to perform the primary procedure on an elective basis.
There may be an important coronary artery crossing the infundibulum, precluding infundibulotomy and outflow patch placement. In these cases, a right ventricle-to-pulmonary artery homograft conduit is usually required instead to provide an unobstructed outflow. Because such a fixed conduit will need to be replaced one or more times as the child grows, it may be advantageous to place a palliative shunt and delay definitive repair for 1 year or longer to allow for insertion of the largest possible initial homograft.an anomalous left anterior descending (LAD) coronary artery that crosses the right ventricular (RV) outflow tract (RVOT)
Most popular shunt for any age Can be performed in younger infantsLeft sided aortic arch pts have left sided shuntAdvantages of the modified Blalock-Taussig shunt include: preservation of the subclavian artery, suitability for use on either side, good relief of cyanosis,easier control and closure at time of primary repair, excellent patency rate, and (6) decreased incidence of iatrogenic pulmonary/systemic artery trauma.
Performed in infants older than 3 months because the shunt is often thrombosed in in younger infants with smaller arteries.Right sided shunt is performed in patients with left aortic archAnd vice versa.Subclavian artery with ipsilateral pulmonary artery
Increased pulmonary blood flow Interfere with corrective surgery
Robinson JD, Rathod RH, Brown DW, et al. The evolving role of intraoperative balloon pulmonary valvuloplasty in valve-sparing repair of tetralogy of Fallot. J ThoracCardiovasc Surg. Dec 2011;142(6):1367-73.
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HOW IT IS DIFFERENT FROM TOF?IT IS BECAUSE OF VARIABLE PULMONARY ARTERY ANATOMY AND PRESENCE OF MAPCAs If there are excessive aortopulmonary collaterals that deliver competing flow, and the arterial oxygen saturation is relatively high, coil embolization of some of these vessels and potentially the patent ductusarteriosus may be undertaken. This is particularly useful for those collaterals that may be relatively inaccessible at surgery.
MaGoon ratio and Nakata index are used to quantitate the degree Pulmonary hypoplasia.These Pulmonary arterial measurements for the calculation are critical to surgical planning. These are measured using echocardiography, Angiography and MRIMaGoon ratio1. This is sum of diameters of immediately prebranching left and right pulmonary arteries to descending aorta just above level of diaphragm2. MaGoon ratio is measured by echocardiography, angiography and MRI3. Normal value more than 2 to 2.54. TOF survivor with Pulmonary artesia have MaGoon ratio more than 15. Good Fontan candidate should have MaGoon ratio more than 1.8Nakata index1. Nakata index is Cross sectional area of left and right pulmonary artery in mm2divided by total body surface area (BSA)2. Measured in AP view in cath lab and by MRI3. Left and right pulmonary arteries are measured just before first lobar branching.4. Cross sectional area is measured by ( π X 2/diameter x magnification coefficient expressed for body surface area)5. Normal Nakata value is 330 +/- 30 mm2/BSA6. TOF with PS should have value more than 100 mm2/BSA for survival7. Good Fontan Candidate should have index more than 250 mm2/BSA8. FMorRastelli surgery Nakata index more than 200 mm2/BSA (if less than 200 mm2/BSA than shunt is done instead of Rastelli)