PhD defence S.C.S. (Savine) Minderhoud

Below is a brief summary about the dissertation:

Congenital heart disease (CHD) affects approximately 9 of every 1000 adults worldwide. The normal heart pumps efficiently blood from the veins to lungs and rest of the body. CHD patients have an abnormal anatomy and, therefore, their circulation is altered and the heart pumps the blood less efficiently. Despite impressive improvements in treatment options and subsequently in survival in the past 6 decades, survival outcomes and morbidity in this patient group are far from optimal. 

With magnetic resonance imaging (MRI), we can visualize the shape and contraction of the heart and the bloodstream in the heart and large vessels connected to the heart, for example the aorta. This thesis first describes how we can measure blood flow accurately and consistently. 

Second, the influence of the blood flow on the blood vessel wall of the aorta in patients with an aortic valve consisting of two-leaflets instead of three-leaflets, bicuspid aortic valve, was researched. Patients with a more angular flow over the vessel wall had more enlargement of their aorta, an aneurysm. Patients remained at risk over the years despite their growing aorta. MRI techniques were combined with Positron Emission Tomography to study the onset of disease. Fast blood flow near the vessel wall protected the vessel wall against calcium depositions in the vessel wall. 

Another common CHD is a narrowing of the aorta, aortic coarctation. Despite surgery removing this narrowing, these patients had an increased mortality and morbidity compared to the general population. The shape of the aorta in patients with a repaired aortic coarctation was different from the aorta of healthy controls and characteristics describing the aortic shape were related to mortality and morbidity, indicating geometric factor might play a role in disease development. 

Finally, patients with four combined heart defects, Tetralogy of Fallot, require surgery early in life, but keep a leakage of the valve between the right heart chamber and the lungs, the pulmonary valve. The leakage results in too much blood volume in the right heart chamber, this results in extra tension of the blood volume on the right heart chamber wall. In a small group of patients, less wall tension was related with better function of the right heart chamber and keeping wall tension low might be important to maintain heart chamber function over the years.