Comparison of Two Pulmonary Valve Replacement Methods to Treat Tetralogy of Fallot

Repair of tetralogy of Fallot (TOF), the most common form of cyanotic congenital heart disease, usually involves surgery on the outflow of the right ventricle (RV) and the pulmonary valve in order to relieve obstruction to blood flow from the RV to the lungs. This procedure often leads to regurgitation (leakage) of the pulmonary valve, which puts the burden of handling a larger than normal amount of blood flow on the RV. Over the years, that extra burden leads to enlargement of the RV and to a decrease in its function. Treatment often includes surgical insertion or replacement of a new pulmonary valve. Replacement of the damaged pulmonary valve aims to minimize the leakage and help the RV function better. This study is designed to compare two methods of how the operation (called pulmonary valve replacement \[PVR\]) is performed. In the first method, a new valve is inserted and only the area of the old valve is operated on; this is the standard PVR. The second method involves inserting the new valve in the same way as the standard method but, in addition, areas of the right ventricular wall that are scarred and not functioning well are removed (PVR plus right ventricular remodeling). This study will evaluate which method is more effective based on the size and function of the RV measured by cardiac magnetic resonance imaging (CMR) six months following surgery, as compared to its size and function before the operation.