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 right ventricle to function better. This research study is designed to compare two methods of how the operation (called pulmonary valve replacement) is done. One is the usual method where a new valve is inserted and only the area of the old valve is operated on (standard pulmonary valve replacement). The second method involves insertion of the new valve in the same way as the usual method but, in addition, areas of the right ventricular wall that are scarred and not functioning well are removed (pulmonary valve replacement plus right ventricular remodeling). The research study compares which method works better based on the size and function of the right ventricle measured by cardiac magnetic resonance imaging six months after surgery, as compared to its size and function before the operation.

Background: Surgical repair of tetralogy of Fallot (TOF) often results in chronic pulmonary regurgitation (PR) with associated right ventricular (RV) dilatation and dysfunction. Mounting evidence indicates that PR leads to significant long-term morbidity and mortality, including arrhythmias, sudden death, and right heart failure. Using cardiac magnetic resonance imaging (CMR), others and we have noted a high prevalence of regional dysfunction and aneurysms in the RV in patients with repaired TOF. Current standard clinical practice in patients with repaired TOF, severe PR, ventricular dysfunction, and/or clinical deterioration is to insert a bioprosthetic pulmonary valve to reduce the volume load on the RV. Although pulmonary valve replacement (PVR) can be achieved with low mortality, data from our group and others have demonstrated persistent or worsening RV dysfunction postoperatively despite a competent pulmonary valve. In patients with left ventricular (LV) aneurysms, surgical remodeling with aneurysm resection has been shown to improve LV mechanics. In view of the potentially deleterious effects of aneurysmal and akinetic wall segments on RV mechanics, we have recently modified our PVR surgical technique in selected patients to include surgical remodeling of the RV with resection of the akinetic wall segments. However, no studies have systematically compared the efficacy of PVR plus surgical RV remodeling to PVR alone.

Research Question: Is there a difference between two surgical strategies—PVR alone (standard treatment: bioprosthetic pulmonary valve insertion and, when present, resection of right ventricular outflow tract [RVOT] aneurysm) versus PVR and surgical RV remodeling (study group: bioprosthetic pulmonary valve insertion and resection of akinetic scarred areas on the anterior RV wall to reduce RV volume)—on RV mechanics and on the incidence of adverse events in patients with repaired TOF and chronic pulmonary regurgitation?

Design: Prospective, randomized, single-center trial.

Ages Eligible for Study:  10 Years and above,  Genders Eligible for Study:  Both

Criteria

Inclusion Criteria:

• Repaired tetralogy of Fallot referred for pulmonary valve replacement at Children''''s Hospital Boston
• Age ≥10 years
• Pulmonary regurgitation fraction ≥25% (measured by MRI) and two or more of the following criteria: i) RV end-diastolic volume index ≥160 ml/m2 (Z score >5); ii) RV end-systolic volume index ≥70 ml/m2; iii) LV end-diastolic volume index ≤65 ml/m2; iv) RV ejection fraction <45%; v) RVOT aneurysm; vi) Clinical criteria: exercise intolerance, symptoms and signs of heart failure, cardiac medications.

Exclusion Criteria:

• Presence of either severe RV outflow tract obstruction (defined as peak-to-peak systolic gradient of ≥60 mmHg by cardiac catheterization) or severe RV hypertension at systemic or higher level
• Additional sources of RV volume overload other than PR and tricuspid valve regurgitation (TR)
• Contraindications to MRI