Rationale:
In congenital heart disease the right heart is often affected, in contrast to acquired heart disease where the left ventricle and left sided valves are most often affected. In congenital patients, the right heart problem is most common linked to dysfunction of the pulmonary valve. In these congenital patients, with defects such as Tetralogy of Fallot (ToF), Double Outlet Right Ventricle (DORV), Pulmonary Valve Atresia, and Ventricular Septum Defect (VSD), the primary origin of the problem are dysplastic Pulmonary Valves (PV) and Right Ventricle Outflow Tract Obstruction (RVOTO). Often these valves or obstructions are excised to be replaced directly or in a later stage. Until the end '90s common therapy was to cut out the pulmonary valve and leave patients without pulmonary valve for 10 to 20 years. This resulted in a pendular flow between right ventricle and pulmonary arteries. This works because the pulmonary vascular resistance is low and therefore inflow is easy. There is also a congenital group in which the primary problem was left sided, but a right-sided problem is created by therapy. Since 20 years the Ross procedure is used for congenital aortic valve stenosis. The pulmonary valve is used in childhood to replace the aortic valve, and needs to be replaced in adolescence by a homograft (graft with human donor valve).
In both these groups (repeat) pulmonary valve replacement is necessary, at some stage, with an open procedure; Pulmonary Valve Replacement (PVR) or catheter procedure; Percutaneous Pulmonary Valve Insertion (PPVI), a method available since 2000. Because these valves only last for 10 to 20 years, timing of intervention is very important.
The last 10 years efforts have been done to delineate the best moment for pulmonary valve replacement. The aim is to prevent right ventricular failure due to pressure overload (stenosis of homograft), volume overload (absence of PV after excision or insufficiency of homograft) or a combination of pressure- and volume-overload, which is believed to be most malignant. In the past emphasis was paid to onset of symptoms instead of preventing right ventricular damage. Because symptoms in right ventricular failure are linked to the 'point of no return' (when the right ventricle doesn't fully recover after pulmonary valve replacement), most likely a better strategy is to intervene before symptoms arise. To be able to make reliable criteria for valve replacement we need to better understand the anatomical and functional impairments of the right ventricle and link this to histopathological changes. The investigators believe myocardial fibrosis is correlated to this 'point of no return'. In the last decades knowledge concerning RV volumes and function, electrocardiographic and exercise capacity has grown. But, the relation between volumes, function and histopathology is missing.
Objective:
Primary objectives: to investigate functional and histopathological changes of the right ventricle before and after PVR or PPVI. To investigate if non-invasive assessment of RV-remodeling including CMR-T1rho mapping is possible and validate this with the golden standard of histopathology.
Secondary objectives: to investigate changes in parameters, using echocardiography, electrocardiography, biomarkers, exercise capacity and quality of life in patients undergoing PVR or PPVI.
