Total repair of tetralogy of Fallot
Total repair of tetralogy of Fallot is a corrective surgical procedure that involves closure of the ventricular septal defect (VSD) and relief of right ventricular outflow tract (RVOT) obstruction.
Most patients with tetralogy of Fallot (TOF) undergo elective surgical repair between 3 and 6 months of age 1-5. Some patients may require earlier correction in the setting of severe cyanosis. The VSD is closed using a prosthetic patch graft. Relief of RVOT obstruction can be achieved by means of pulmonary valvotomy, resection of hypertrophied muscle bundles, or placement of a transannular outflow tract patch in those patients with severe pulmonary valve hypoplasia. Occasionally, placement of a tube graft conduit between the right ventricle and the pulmonary artery may be necessary if anomalous coronary artery anatomy obstructs access to the right ventricular infundibulum or complete pulmonary atresia is present. Semilunar pericardial allograft pulmonic valve repair or pulmonary valve sparing approaches may be chosen in some cases. Previous palliative shunts (e.g. Blalock-Taussig shunt, Waterston shunt and Pott shunt) are usually taken down at the time of definitive repair.
Aside from sternotomy wires, lateral chest radiographs may demonstrate calcifications along the anterior right ventricular wall 4.
Echocardiography is the routine imaging tool of choice for TOF repair follow-up. It may demonstrate pulmonary regurgitation of varying degrees and isolated right ventricular restriction 4-6.
This modality may demonstrate the RVOT patch as a high-density material spanning into the pulmonary arteries. The aorta is dextroposed overriding the interventricular septum. A calcified patch at the region of the closed malaligned ventricular septal defect from the muscular septum to the right aspect of the aortic annulus may be seen. May also demonstrate the tube graft from the RVOT patch to the distal main pulmonary artery 4,5.
MRA findings are similar to CTA. Perfusion MRI shows patches as nonenhancing low intensity structures. MRI is the best tool for right ventricular functional assessment (e.g. ejection fraction, end systolic and end diastolic volumes, muscle mass, and regional wall-motion abnormalities) 7-9. Phase contrast cine images can quantify pulmonic regurgitant fraction 4. Delayed enhancement may show abnormal hyperenhancement that indicates ventricular fibrosis, which correlates with markers of adverse clinical outcome and is associated with arrhythmias 9.
Over 85% of patients who undergo early surgical correction will survive into adulthood 2-5.
Long term complications include:
- right heart failure
- pulmonary regurgitation
- pulmonary artery stenosis
- progressive exercise intolerance
- sudden cardiac death
Congenital heart disease
There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorised, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.
congenital heart disease
- normal relationship between chambers and valves
- atrioventricular valves
- outflow tract
- great vessels
- venous inflow
- anomalous valves
- abnormal relationship of chambers and valves
- atrioventricular abnormality
- great vessel connection abnormality
- conotruncal cardiac anomalies
- pentalogy of Cantrell
- Shone syndrome
- congenital heart disease - chest x-ray approach
surgical repairs (mnemonic)
- arterial switch procedure
- Blalock-Taussig shunt
- double switch procedure
- Fontan procedure
- Glenn procedure
- Mustard repair
- Norwood procedure
- Pott shunt
- pulmonary artery banding
- Rastelli procedure
- Sano shunt
- Senning repair
- total repair of tetralogy of Fallot (TOF)
- unifocalisation procedure
- Waterston shunt
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