Computational analysis of flow and transport suggests reduced oxygen levels within intracranial aneurysms, especially in individuals with sickle-cell disease.

Abstract

Sickle cell disease (SCD) is a genetic condition characterized by an abundance of sickle hemoglobin in red blood cells. SCD patients are more prone to intracranial aneurysms (ICA) compared to the general population, with distinctive features such as multiple intracranial aneurysms: 66% of SCD patients with ICAs have multiples ICAs, compared to 20% in non-sickle patients. The exact mechanism behind these associations is not fully understood, but there is a hypothesized link between hypoxia and impaired synthesis of extracellular matrix, which may weaken the vessel walls, favoring aneurysm formation and rupture. SCD patients experience reduced blood oxygen levels, potentially exacerbating hypoxia in ICAs, and potentially contributing to aneurysm development and early onset in these patients. In this work, we performed a series of computational studies (Fluent) using idealized geometries to investigate the key differences in the oxygen transport and blood flow dynamics inside an aneurysm formation for sickle and non-sickle cases. We found that using SCD parameters resulted in a 14% to 68% reduction in blood flow and a 37% to 70% reduction in oxygen availability within the aneurysm, depending on the vessel curvature and the aneurysm throat diameter, due to factors including oxygen-dependent viscosity and alteration in the oxygen transport. The results indicate that depending on geometry and flow characteristics, some degree of hypoxia maybe present in aneurysm bulb and would be more severe in SCD patients. This study hopes to bring into attention the potential presence of hypoxic environment in the aneurysm bulb.