Tetrology/Truncus arteriosus/Transposition of Great arteries Flashcards
Embryological cause of Tetrology of Fallot
Embryologically, this is thought to be
due to anterior deviation of the conal
septum
Four key features of tetrology of fallot
- Sub pulmonary stenosis
- Ventricular septal defect (VSD)
- Over riding aorta
- Right ventricular hypertrophy (RVH)
Common etiology of tetrology of fallot
DiGeorge syndrome (22q11.2 deletion syndrome) is the most common underlying genetic association for tetralogy of Fallot (TOF), seen in 10%-16%.
• Trisomy 21 (Down syndrome) is the next most common associated syndrome with TOF.
• Mutations in NKX2.5, JAG1 (also seen with Allagile’s syndrome), FOG27, trisomy 13, and CHARGE syndrome may be associated with TOF
key features of DiGeorge
phenotypic facies*
– developmental delay (IQs 70 to 90)/ learning disabilities/ speech delay
– hypocalcemia (due to parathyroid underdevelopment)
– immune deficiency (related to thymic hypoplasia)
routine test for DiGeorge
FISH for 22q11
Newborns with TOF may be_______ or may
have physiology consistent with “pink” TOF,
if the ____________
obstruction is minimal.
cyanotic
right ventricular outflow tract (RVOT)
Most common signs and symptoms of TOF
1) a heart murmur (systolic ejection murmur
@ left upper sternal border)
2) ± cyanosis
3) ± tachypnea (esp. present when only mild
RVOT obstruction exists and resulting
pulmonary over-circulation occurs, from the
left to right shunting across the VSD)
What type of heart murmur do we hear with TOF?
heart murmur (systolic ejection murmur @ left upper sternal border)
Cyanotic CHD classically include the “5 T’s”
- Tetralogy of Fallot – the most common cyanotic CHD
- Truncus arteriosus
- Transposition of the great arteries (TGA)
- Tricuspid atresia
- Total anomalous pulmonary venous return
For a cyonotic newborn, a _______ test should be performed to confirm CHD exsists rather than a pulmonary cause of cyanosis
hyperoxia
For cyanotic or acyanotic newborn suspected of
having CHD work up will likely include:
ECG for chamber info
chest x-ray
Cardiac cath (no longer done)
karyotipic and FISH analysis
On echo of a newborn with suspected TOF… what do we see between the ventricles?
There is a VSD… hole between the right and left ventilces
newborn presents with a heart murmur.. systolic ejection at left upper sternal border, is cyonotic and slightly tachypnic. This is what you see on chest xray.. Diagnosis?
Tetrology of Fallot (boot shaped heart)
For CYONOTIC newborn with TOF, what is the medical manangement before surgery?
Initiate intravenous prostaglandin (PGE) 0.05-0.1 mcg/kg/minute to maintain patency of the ductus arteriosus (PDA) which will augment pulmonary blood flow.
Common side effects of PGE to monitor for include:
Apnea
Fever
Hypotension at higher doses
Increased secretions
Gastric outlet obstruction (chronic use)
Operative intervention for TOF includes
Shunt
Complete repair
Management of “pink” TOF newborn is different then in cyonotic.. what would you tell the parents
Discharge to home with close follow up in clinic.
with the goal to optimize growth with good nutrition.
• Discuss tetralogy of Fallot spells with parents, as
degree of RVOT obstruction may change with
infant’s growth.
• Plan for operative repair at 3 – 6 months of age
You send a ‘pink’ TOF child hold with the parents.. They call a month later and note the baby is tinged blue and rush the baby in. An M3 on totations listens to the heart and doesn’t hear any murmurs and is confused because he knows there is suposed to be a typical ejection systolic murmur. Explain to him what’s going on
During a Tet spell, disappearance of the typical
ejection systolic murmur indicates that RVOT obstruction has become so severe that there is little to no forward blood flow into the branch pulmonary arteries and significant right to left shunting occurs across the ventricular septal defect.
First line therapy to Tet spell
First-line therapy is to calm the infant and provide supplemental oxygen. Placing the infant or child in the knee-to-chest position can increase systemic venous return to the heart and augment blood flow across the RVOT; it also increases systemic vascular resistance (SVR)
*if child doesn’t have an IV.. give intramuscular morphine… if they have an IV, use bolus of saline
Additional meds (besides intramuslcuar morphine or saline bolus) for tet spells
1) IV ketamine
2) IV phenyleprine
3) β blocker therapy (oral propranolol)
What complete operative repair options are there for TOF?
1) Patch closure of the ventricular septal defect (VSD), so that the left ventricular chamber
blood flows into the aorta
2) Relief of right ventricular outflow tract obstruction
To provide relief of right ventricular outflow tract obstruction: what three options are there?
(in TOF)
a) sub pulmonary muscle resection
b) RVOT patch placement to increase the diameter
of this area, either via a non-transannular patch or
a transannular patch placement (which increases
the size of a hypoplastic pulmonary valve annulus)
c) placement of a right ventricular to pulmonary
arterial conduit (used for atretic pulmonary valve/
main pulmonary artery or when a coronary artery
crosses the RVOT)
Mortality/ Morbidity of TOF Repair
]
• Mortality following TOF repair:
• Postoperative inpatient hospitalization is:
Mean length of stay for TOF repair:
1.5% - 3.9% (varies depending on method)
~1 to 2 weeks.
o TOF with ventriculotomy & transannular patch ~ 11.7 d (median 7.0 d)
o TOF repair with conduit ~ 12.7 days (median, 7.0 d)
Long term follow up in pts with repaired TOF
have residual pulmonary regurgitation that may become progressively more severe as patients age
–>lead to increasing RV dilation.
• patients with transannular patch repair have significantly more pulmonary regurgitation and larger indexed RV end-diastolic volume than for
those with right ventricular to pulmonary artery conduits.
• RV-PA conduits placed in infancy do not grow
and need to be replaced
When prognosis is good for survival, patients with repaired TOF may require re-operation later in life
• Re-operation needed if
pulmonary regurgitation becomes significant and
leads to right ventricular dilation and dysfunction.
Indications for re-operation for PVR in patients with repaired TOF or similar physiology who have moderate or severe pulmonary regurgitation (regurgitation fraction ≥25%)
IF pt is asymptomatic:
patient is symptomatic:
asymptomatic: need 2+ criteria
symptomatic: pt is showing signs attributable to severe RV volume load, exercise intolerance, signs and symptoms of heart failure and syncope
QOL in children/adolescents with repaired TOF
is not proportional to the severity of residual disease.
• Self-reported QOL appears similar to healthy peers,
while parent/proxy reported lower QOL.
• For both children and parents, QOL positively
correlated with the child’s exercise capacity.
-have normal B-natruitic peptide and reasonable exercise tolerance
Whats going on in Transposition of the great arteries
Atrio-Ventricular concordance
• Ventricular-Arterial discordance
Aorta arises from the morphologic RV
Pulmonary artery from morphologic LV
IN TGA
we see atrio-ventrcular _______
Ventricular arterial _______
- Atrio-Ventricular concordance
- Ventricular-Arterial discordance
Complete TGA, the single discordance….
The single discordance makes the transpotision physiologically complete
Genetics of TGA:
- Represents ____of CHD
- Chromosomal and extracardiac abnormalities rare thus it is likely______
- Male/female ratio _____
- Seen more commonly in infants of ______
5%
sporadic
2:1
diabetic mothers
What are the potential sources of intercirculatory
mixing?
– Atrial Level :
– Ventricular Level:
– Arterial Level :
– Atrial Level (patent foramen ovale, ASD)
– Ventricular Level (VSD – present in 40-45% of all TGA)
– Arterial Level (patent ductus arteriosus)
Your attending has you look at a chest xray of a newborn with a congentital heart defect. The Xray is descirbed as “egg on a string”
Dx?
Transposition of the great arteries
What accounts for the findings of ‘egg on a string’ on chest xray in TGA?
Oval or “egg-shaped” cardiac
silhouette with narrow superior mediastinum. (code
word “egg on a string”)
• Mild cardiomegaly
• Increased pulmonary vascular markings
Diagnostic procedure of choice for TGA?
Echo
A procedure called the Senning procedure is done to correct TGA. Describe the surgery
pulmonary artery switched to original root of aorta and aorta switched to original root of pulmonary artery
coronary arteries attached to neo-aorta
close pda
use a patch to cover where the coronary arteries used to be
What procedure is being done below on pt with TGA?
Arterial switch
The aorta and pulmonary artery are detached from their native roots and reattached to the opposite root; thus, the pulmonary root becomes the neo-aorta, and the aortic root becomes the neo-pulmonary artery.
The coronary arteries are transplanted from the aorta/neo-pulmonary artery to the pulmonary artery/neo-aorta.
Pathology of truncus arteriosus:
Single arterial vessel giving rise to:
Pulmonary arteries
Coronary arteries
Systemic artery (aorta)
Pathology of Truncus arteriorsus associated with:
Single semilunar valve
single arterial vessel giving rise to: pulmonary arteries/coronary arteries/systemic artery (aorta)
Infundibular VSD
short pulmonary trunk originating from truncus gives rise to both pulmonary arteries
Type I and A1 of trunucus arteriosus
Both pulmonary arteries arise from truncus separately but in close proximity
Type II TA
Both pulmonary arteries arise from truncus at some distance from one another
Type III TA
Both pulmonary arteries arise from trunucus seperately either close to or far apart
Type A2 truncus arteriosus
Absence of truncal origin of one pulomonary artery with blood supply to that lung from collateral or PDA
Type A3 TA
Associated with underdevelopment of the aortic arch (interrupted aortic arch)
Type A4 TA
