IRLM-TOF
Research type
Research Study
Full title
Insights from Right and Left Ventricular Mechanics During Exercise Stress in Relation to Functional Capacity and Recovery Following Surgery in Patients with Tetralogy of Fallot and Pulmonary Regurgitation.
IRAS ID
232328
Contact name
Guy Lloyd
Contact email
Duration of Study in the UK
3 years, 0 months, 1 days
Research summary
Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease (CHD). It is a group of four structural abnormalities within the heart that include narrowing of pulmonary valve (pulmonary stenosis), large hole called a ventricular septal defect (VSD) between the main pumping chambers of the heart (the right and left ventricles (RV/LV)), the aorta sits over the left and right ventricles (overriding aorta) and the right ventricle is enlarged and more muscular (right ventricular hypertrophy).
Adult patients with surgically repaired TOF are an increasing population and the current knowledge about the late clinical outcomes determinants is still evolving. Although the hemodynamic burden associated with post TOF repair is often tolerated well during childhood and adolescence, the incidences of exercise intolerance and heart failure increase in early adulthood. Pulmonary regurgitation (PR)(leaky pulmonary valve), is a frequent adult complication following childhood repair TOF, leading to RV dilatation and dysfunction, exercise intolerance and sudden cardiac death.
Currently literature and guidelines use the combination of symptoms to determine optimum timing of surgical intervention. The optimal timing of pulmonary valve replacement (PVR) with severe PR is contentious. There is limited evidence support the use of stress echocardiography (cardiac ultrasound) to better understand RV function in both adults and children with repaired TOF. The abnormalities of RV and LV function in late survivors of TOF repair remains incompletely understood. In clinical practice, early assessment of RV and LV changes using cardiac imaging and cardio pulmonary exercise test (CPET), as an objective measure of exercise tolerance is feasible.
This study will use the combination of cardiac imaging and cardio pulmonary exercise test (CPET) for more objective evaluation of the RV/LV mechanics before the onset of the symptoms as an objective measure of exercise tolerance in adult patients with TOF.
Lay summary of study results: This research project has evaluated the unique capabilities of combined cardiopulmonary exercise testing (CPET) and echocardiography to describe the right and left ventricle structure, volume, and function in a prospective cohort of 120 adult patients with repaired Tetralogy of Fallot. The study found an overall reduction in exercise capacity which has no relation to the amount of pulmonary regurgitation in this population. The extent of functional limitations in this study was explained by several indices of myocardial function augmentation during exercise, and blood biomarkers. All study findings imply new strategies into the clinical assessment of adult survivors of TOF.
REC name
London - Queen Square Research Ethics Committee
REC reference
18/LO/0092
Date of REC Opinion
16 Feb 2018
REC opinion
Further Information Favourable Opinion