1. Tetralogy of Fallot & Surgical Repair Techniques
Ted Hodges, MS3
UNC Pediatrics Clerkship
Newborn Nursery Presentation
November 21, 2014

2. Tetralogy of Fallot Classical Characteristics Pulmonic stenosis
Right ventricular hypertrophy
Overriding aorta
Ventricular septal defect
The exact embryologic abnormality that accounts for TOF is unknown. What is recognized is that during development, there is anterior and cephalad deviation of the infundibular septum. This results in a malaligned ventricular septal defect (VSD), with the aortic root overriding the defect and leading to subsequent right ventricular outflow obstruction (figure 1). The ensuing right ventricular hypertrophy is thought to be a response to the large VSD and right ventricular outflow obstruction with resultant systemic right ventricular systolic pressure
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3. TOF Epidemiology
Prevalence in the United States is 3.9 per 10,000 live births
Accounts for 7-10% of congenital heart defects
Most common lesion requiring intervention in first year of life
Males and females equally affected
Genetics remain unclear
85% sporadic
15% present as a portion of syndrome
Down, Alagille, DiGeorge/Velocardiofacial
Down: Trisomy 21
Alagille: JAG1, AD, presents with jaundice, pruritis, xanthomas, bile duct paucity ->biliary atresia
DiGeorge: 22q11 deletion
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4. Clinical Presentation
Tetralogy of Fallot occurs on a spectrum
Pink Tets → MAPCAs
Pink Tets have minimal RVOT obstruction and may present later with pulmonary overcirculation and heart failure
Children with the most severe RVOT obstruction are cyanotic in the immediate neonatal period
Most children are somewhere between the extremes
Tet Spells
MAPCAs: Major aortopulmonary collateral arteries
Failure of pulmonary trunk to develop causes retention of collaterals that grow off aorta and other systemic arteries that usually regress
Treatment is to group these arteries together and convert to blood supply from right heart circulation
Tet Spells: usually asymptomatic, sudden cyanosis and syncope, treat with beta blockers and morphine
Squatting/knees-to-chest: Increases SVR and decreases R to L shunting
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5. Physical Exam Patients usually comfortable and in no acute distress
During Tet Spell
Hyperpnea
Cyanosis of lips and nail beds
Murmur: “crescendo-decrescendo type with harsh systolic ejection quality”
Best heard at left upper sternal border
Single S2 heart sound
Minimal contribution from pulmonic valve
Adults may have clubbing
Murmur is from PS not VSD because VSD is huge so not high flow
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6. ECG Findings
In addition to ECG findings, “boot shaped” heart seen on CXR
Echo is most useful diagnostic tool, also cath
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7. TOF Repair Algorithm
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8. Blalock-Taussig Shunt
Typically used for palliation of severely cyanotic infants until definitive procedure
Functions like a PDA
Developed by Alfred Blalock and Helen Taussig at Johns Hopkins in 1943
Gortex or PDTE tubing connecting right subclavian right pulmonary artery branch
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9. TOF Corrective Repair
Widen the narrowed pulmonary blood vessels. The pulmonary valve is widened or replaced, and the passage from the right ventricle to the pulmonary artery is enlarged. These procedures improve blood flow to the lungs. This allows the blood to get enough oxygen to meet the body's needs.
Close the ventricular septal defect (VSD). A patch is used to cover the hole in the septum. This patch stops oxygen-rich and oxygen-poor blood from mixing between the ventricles.
Generally performed at 6-9 months
Right ventriculotomy: scarring leads to arrhythmias can requiring pacing later in life
Transannular patch: problem of pulmonary insufficiency, more difficult to manage than stenosis, no annular sparing patch preferred
Patch is pericardium
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10. TOF Prognosis Overall, prognosis is excellent
STS data on over 3000 repairs in North America from 2002 to 2007
BT Shunt mortality: 6.2%
TOF correction mortality: 1.9%
5 year survival with correction: 98.5%
Today, more adults than children living with congenital cardiac malformations
Pattern to transition to immediate neonate repair due to mortality associated with BT shunt, data does not support this: 7.8% mortality with neonatal repair
Pulmonary insufficiency could be corrected with Melody valve instead of surgery.
Most patients still receive corrective surgery at 6-9 months
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11. References
Al Habib HF, et al. Contemporary patterns of management of tetralogy of Fallot: data from the Society of Thoracic Surgeons Database. Ann Thoracic Surg 2010 Sep;90(3):813-9
Barron DJ. Tetralogy of Fallot: controversies in early management. World J Pediatric Congent Heart Surg 2013 Apr;4(2):
Images
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