Date of Award
Summer 2021
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biomedical Engineering
First Advisor
LaDisa Jr., John F.
Second Advisor
Cava, Joseph R.
Third Advisor
Gerardin, Jennifer F.
Abstract
Hypoplastic Left Heart Syndrome (HLHS) is a congenital cardiovascular defect where the left side of the heart and related structures cannot support systemic cardiac output. The Norwood procedure, performed in the first days of life, creates a neo-aorta along with arch reconstruction to provide unobstructed systemic output from the well-developed right ventricle. To evaluate the qualities of the patients reconstructed arch geometry, we aim to characterize hemodynamics within the reconstructed arch by including the head and neck arteries, pulmonary arteries, and Blalock-Taussig (BT) shunt. Prior studies have studied reconstructed arch geometry, but the current project adds more complexity to increase realism relative to patient outcomes by adding more vessels within the region that can impact local hemodynamics. It is found that Norwood patients have higher time-averaged wall shear stress (TAWSS) distal to the transverse arch (TA) region where Norwood patients usually develop mild narrowing or coarctation. The reconstructed patient arches also have higher oscillatory shear index (OSI) at the AAo region towards the TA region where most of the surgical reconstruction occurs. Energy loss (EL) was found to highly depend on cardiac output (CO) and is strongly driven by the BT-shunt, if the patient has one, but not arch characteristic measurements studied such as arch width or height. After virtual arch modification, favorable changes in TAWSS and OSI are found in the aortic arch, but the same changes had a negligible impact on EL and cardiac function, implying that the modifications proposed were not drastic enough, or did not target the relevant parameters, such as arch shape, width or height.