Early Versus Later Re-valving in Tetralogy of Fallot With Free Pulmonary Regurgitation

Early Versus Later Re-valving in Tetralogy of Fallot With Free Pulmonary Regurgitation - Combined Cross-sectional and Prospective, Multi-centre, Randomized, Parallel-group Clinical Trial

Tetralogy of Fallot (ToF) is a congenital heart defect with four major features including right ventricular outflow tract obstruction. About 25 children are born with this condition in Denmark every year. Corrective surgery is usually performed within the first year. In 50 % of patients, enlargement with a patch is necessary to achieve relief of the outflow tract obstruction. This however results in severe pulmonary regurgitation, which eventually leads to volume overload, right ventricular dysfunction and arrhythmia. To avoid these late complications, pulmonary valve replacement with a prosthesis if performed when patients meet the current guideline criteria. Most patients meet the guideline criteria for revalving when they are between 20 and 30 years of age. The current guidelines however, are based solely on retrospective studies and novel research reveals that in more than 50 % of patients who are treated according to current practice, right ventricular volumes and function as well as exercise capacity and burden of arrhythmia do not normalize or improve. 500 patients with ToF will be enrolled in a multicentre, cross-sectional study, which will yield information about the long-term outcomes after initial repair of ToF, as well as suggestions about the optimal timing for re-valving. Among patients included in the cross-sectional study, 120 patients with free pulmonary regurgitation, will be randomized evenly for early or later re-valving with at least 10-years of follow-up, for evaluation of long-term efficacy and safety of early re-valving.

60 patients who are assigned to early re-valving undergo pulmonary valve replacement within 3 months from randomization.

60 patients who are assigned to later re-valving undergo pulmonary valve replacement when the current European guideline criteria are met.

Surgical implantation of an adult-sized (≥ 18 mm) homograft or Contegra graft as right ventricle-to-pulmonary artery conduit under cardiopulmonary bypass through a sternotomy.

Right ventricular end-diastolic volume (mL) indexed by body surface area (m2) will be assessed in both the early re-valving group and later re-valving group for calculation of the mean in each group and analysis of statistical significance of the difference will be performed. Higher right ventricular end-diastolic volumes are considered a worse outcome.

The rate of deceased patients (irrespective of the cause of death) and total number of patients will be calculated for both the early and later re-valving group and analysis of statistical significance of the difference between the groups will be performed.

Right ventricular end-systolic volume (mL) indexed by body surface area (m2) will be assessed in both the early re-valving group and later re-valving group for calculation of the mean in each group and analysis of statistical significance of the difference will be performed. Higher right ventricular end-systolic volumes are considered a worse outcome.

Right ventricular ejection fraction (%) will be assessed in both the early re-valving group and later re-valving group for calculation of the mean in each group and analysis of statistical significance of the difference will be performed. Lower right ventricular ejection fraction are considered a worse outcome.

Left ventricular end-diastolic volume (mL) indexed by body surface area (m2) will be assessed in both the early re-valving group and later re-valving group for calculation of the mean in each group and analysis of statistical significance of the difference will be performed. Higher left ventricular end-diastolic volumes are considered a worse outcome.

Left ventricular end-diastolic volume (mL) indexed by body surface area (m2) will be assessed in both the early re-valving group and later re-valving group for calculation of the mean in each group and analysis of statistical significance of the difference will be performed. Higher left ventricular end-systolic volumes are considered a worse outcome.

Left ventricular ejection fraction (%) will be assessed in both the early re-valving group and later re-valving group for calculation of the mean in each group and analysis of statistical significance of the difference will be performed. Lower left ventricular ejection fraction are considered a worse outcome.

The rate of patients with bleeding classified as minor, major and life-threatening bleeding (BARC classification) related to the re-valving procedure and the total number of patients will be calculated in both the early and later re-valving group and the difference between the groups will be analyzed for statistical significance.

The rate of acute kidney injury categorized as stage one, two and three (KDIGO classification) and the total number of patients will be calculated in both the early and later re-valving group and the difference will be analyzed for statistical significance.

The rate of patients who decease due to cardiovascular causes and patients who suffer from a disabling stroke after the time of randomization will be calculated for both the early and later re-valving group and the difference will be analyzed for statistical significance

The rate of patients who decease due to a cardiovascular cause and the total number of patients will be calculated in both the early and later re-valving group and the difference will be analyzed for statistical significance

The rate of patients who suffer from a disabling stroke og transient ischemic attack after the time of randomization will be calculated in both the early and later re-valving group and the difference will be analyzed for statistical significance

The mean New York Heart Association Class categorized as 1-4 will be assessed in both the early and later re-valving group and the difference will be analyzed for statistical significance. Higher mean values are considered a worse outcome.

The mean health-asssociated quality of life will be assessed in both the early and later revalving group and the difference will be analyzed for statistical significance. EQ-5D-3L will be used for assessment. The questionnaires are available in Danish. Higher values are considered better outcomes.

The mean health-associated quality of life will be assessed in both the early and later re-valving group and the difference will be analyzed for statistical significance. EQ-5D-Y will be used for assessment. The questionnaires are available in Danish. Higher values are considered better outcomes.

Rate of patients with new sustained supraventricular or ventricular arrhythmia and the total number of patients

The rate of patients with new supraventricular or ventricular arrhythmia and the total number of patients will be calculated for both the early and later re-valving group and the difference will be analyzed for statistical significance.

The mean peak oxygen consumption (VO2/min) indexed to body weight (kg) will be assessed for patients in both the early and later re-valving group and the difference in means will be analyzed for statistical significance. Higher mean values are considered a better outcomes.

The median time until structural valve deterioration defined as time until need for valve replacement in patients who are revalved during the study will be calculated.

Rate of patients who are re-valved during the course of the study and suffer from endocarditis and the total number of patients who are revalved during the study

The rate of patients who suffer from endocarditis after re-valving during the course of the study and the total number of patients who are revalved during the study will be calculated

Rate of patients who are re-valved during the course of the study and suffer from prosthetic valve thrombosis and the total number of patients who are revalved during the study

The rate of patients who suffer from prosthetic valve thrombosis after re-valving during the course of the study and the total number of patients who are revalved during the study will be calculated

The mean number of contacts to the health system defined as composite of hospital admissions, outpatient contacts and contacts to the general practitioner will be calculated in both the early and later re-valving group and the difference will be analyzed for statistical significance

The mean number of children will be assessed for female patient in both the early and later re-valving group and the difference will be analyzed for statistical significance

Inclusion Criteria: ToF with pulmonary stenosis repaired with a TAP within the first two years of life. RVOT anatomy is suitable for implantation of an adult sized conduit ( 18 mm homograft or Contegra graft) as assessed by MRI. Exclusion Criteria: ToF with pulmonary atresia, ToF with common atrioventricular canal, ToF with absent pulmonary valve syndrome, major aortopulmonary collateral arteries and other significant associated anomalies. Palliation with a shunt (Blalock-Taussig or central) at any time. The patient is symptomatic. Sustained supraventricular or ventricular arrhythmia. RVEDVi > 140 mL/m2 as assessed by MRI (appendix 1). RVESVi > 60 mL/m2 as assessed by MRI. RVEF < 50 % as assessed by MRI. Moderate or severe tricuspid regurgitation as assessed by echocardiography or MRI. Significant residual lesions requiring intervention (e.g. ventricular septal defect, aortic regurgitation, branch pulmonary artery stenosis). Co-morbidity preventing exercise testing (e.g. genetics, neuro-cognitive dysfunction, physical disability). Contraindication for MRI (e.g. permanent pacemaker, intra-cardiac defibrillator, intracranial ferro-magnetic device). Pregnancy at time of inclusion. Age < 12 or unable to comply with instructions given during MRI or exercise testing.