Pediatric REPlAcement of the PulmonaRy ValvE in Tetralogy of Fallot -

Pediatric REPlAcement of the PulmonaRy ValvE in Tetralogy of Fallot - The PREPARE-TOF Study

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect with the vast majority of survivors of corrective surgery left with some degree of right ventricular (RV) volume overload due to pulmonary regurgitation (PR) which cause RV enlargement with right heart failure, diminished biventricular function, ventricular arrhythmia, sudden death and decreased exercise performance over time. Pulmonary valve replacement (PVR) has been thought to ameliorate these complications but the timing of replacement has yet to be determined with equipoise at the moment in this decision making process. As nearly all studies in this regard are retrospective with much less data in pediatric TOF than adults, this pilot trial sets the stage to create a prospective randomized trial in the teenage years.

The purpose of this research study is to gather information on adolescents and young adults to help understand and improve the lives of patients with TOF.

Some patients diagnosed with TOF will have a procedure called pulmonary valve replacement (PVR) and some will not. PVR is done for valves that are too damaged to be repaired. This requires a surgeon or an expert in a procedure called cardiac catheterization to replace the damaged pulmonary valve with a valve made of tissue or a mechanical valve. Multiple studies in adult TOF patients have suggested that PVR may lessen many clinical symptoms but no one is sure if it truly does. There is little information about PVR in adolescence but it is thought that lessening the amount of leakage of the pulmonary valve at a young age may avoid future complications such as right heart failure or abnormal beats of your heart. There is no agreement among cardiologists, surgeons or other healthcare providers as to whether PVR truly helps avoid complications in the future and if it does, when PVR should be done. Using the information in this study, we hope to find out if PVR in adolescents is helpful in both the short and long term.

The Investigators believe the results of this study will help provide doctors with enough information to support a future large scale research study to further evaluate the outcomes PVR. This study will involve randomization to either the PVR or no PVR cohort, medical records review, exercise test and Cardiac Magnetic Resonance (CMR) , and questionnaires.

Inclusion Criteria:

1. Males or females with repaired Tetralogy of Fallot (TOF), currently between 13 and 21 years of age.
2. On clinical Cardiac Magnetic Resonance (CMR) : Right Ventricular End-Diastolic Volume Index (RVEDVi) between 140 and 180 cc/m2 inclusive with Right Ventricular End-Diastolic Function (RVEF) > 40% and Left Right Ventricular End-Diastolic (LVEF ) > 50%, RV outflow tract peak velocity < 3 meters/second (if not available this will be skipped); there will be no indexed Right Ventricular end-systolic volume (RVESVi) criteria; by defining RVEDVi and RVEF, Investigators will be inherently defining RVESVi
3. On clinical echocardiogram: RV outflow tract peak velocity < 3 meters/second (if not available this will be skipped), at least mild pulmonary insufficiency and tricuspid regurgitation with an RV pressure estimate < 1/2 systemic pressure.
4. On Exercise Stress Test (EST), aerobic capacity > 60% of predicted.
5. No Q-wave, R-wave, S-wave (QRS) duration criteria on ECG.

Exclusion Criteria:

1. Any condition judged by the patient's physician that would cause this trial to be detrimental to the patient.
2. Specific forms of TOF excluded are those with endocardial cushion defects, TOF with absent pulmonary valve and TOF with multiple aorto-pulmonary collaterals requiring unifocalization.
3. Unilateral branch pulmonary artery stenosis (one lung receives < 25% of total flow)
4. Contraindication to non-sedated exercise CMR (e.g. pacemaker/implanted cardioverter defibrillator); need for sedation
5. If data available, moderate or greater tricuspid regurgitation on echocardiogram or CMR or Qp/Qs > 1.5
6. Significant strokes/hemiplegia or inability to exercise
7. Genetic syndrome/developmental delay which would make QOL and EST date uninterpretable
8. Pregnancy
9. Previous pulmonary valve replacement (PVR)