Multiscale and Multiphysics of Blood Flow and Arterial Mechanics Growth and Remodeling

Abstract

The circulatory system, resembling a complex network of pipes (blood vessels) and a ceaseless pumping system (heart), orchestrates the delivery of oxygen and nutrients to every cell and tissue in the human body. Unlike conventional engineering pipes, vascular tissue exhibits the remarkable ability to adapt its physical and mechanical properties in response to its environment, a phenomenon known as growth and remodeling (G&R). This process aims to maintain a balanced stress level, termed homeostatic stress.In healthy arteries, maintaining mechanical equilibrium involves a clever negative feedback loop that restores the system to its preferred state after any disturbances. However, when this delicate balance is disrupted, it can lead to a phenomenon called pathological G&R, characterized by a positive feedback loop. Aortic and intracranial aneurysms are prominent examples of this disrupted G&R. Characterized by the enlargement of vessels, aneurysms pose significant health risks, contributing to numerous annual fatalities. Moreover, blood disorders such as sickle cell disease can disrupt mechanical equilibrium by altering blood flow dynamics and creating localized hypoxia, especially in small arteries, such as the one found in our brain. Therefore, recognizing the connection between blood disorders and tissue-related diseases underscores the importance of exploring the interplay between fluid dynamics and tissue mechanics. This thesis investigates the interplay between computational fluid dynamics, mathematical modeling, and finite element analysis in the context of cardiovascular diseases. It primarily focuses on ascending thoracic and intracranial aneurysms related to sickle cell disease. We aim to enhance our understanding of the intricate mechanisms underlying vascular diseases. This heightened insight will be central in developing more holistic diagnostic and therapeutic approaches to effectively lessen their significant impact on individuals' health.