Total repair of tetralogy of Fallot

Total repair of tetralogy of Fallot (TOF) is a corrective surgical procedure that involves closure of the ventricular septal defect (VSD) and repairrelief of the right ventricular outflow tract (RVOT) obstruction.

Procedure

Most patients 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 is repaired withcan be achieved by means of pulmonary valvotomy, resection of hypertrophied muscle bundles, or placement of a transannular outflow tract patch in those patients with or without resection of obstructing muscle bundlessevere pulmonary valve hypoplasia. Occasionally, placement of a tube graft fromconduit between the RVOT patch toright 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 constructedpresent. 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^1-4.

Radiographic features

Plain film

Lateral chest radiographs may demonstrate calcifications along the anterior right ventricular wall ⁴.

Echocardiography

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 ^4-5-6.

CTMDCT/CTA

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. 

MRI

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) ^6-87-9. 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 ⁸⁹.

ComplicationsPrognosis and complications

Over 85% of patients who undergo early surgical correction will survive into adulthood ^2-5. Long term complications include^1-4:

• arrhythmias
• right ventricular function deteriorationheart failure
• pulmonary regurgitation
• pulmonary artery stenosis
• progressive exercise intolerance
• sudden cardiac death