Computational Hemodynamic Modeling of Arterial Aneurysms: A Mini-Review

Abstract

Arterial aneurysms are pathological dilations of blood vessels, which can be of clinical concern due to thrombosis, dissection, or rupture. Aneurysms can form throughout the arterial system, including intracranial, thoracic, abdominal, visceral, peripheral, or coronary arteries. Currently, aneurysm diameter and expansion rates are the most commonly used metrics to assess rupture risk. Surgical or endovascular interventions are clinical treatment options, but are invasive and associated with risk for the patient. For aneurysms in locations where thrombosis is the primary concern, diameter is also used to determine the level of therapeutic anticoagulation, a treatment that increases the possibility of internal bleeding. Since simple diameter is often insufficient to reliably determine rupture and thrombosis risk, computational hemodynamic simulations are being developed to help assess when an intervention is warranted. Created from subjectspecific data, computational models have the potential to be used to predict growth, dissection, rupture, and thrombus-formation risk based on hemodynamic parameters, including wall shear stress, oscillatory shear index, residence time, and anomalous blood flow patterns. Generally, endothelial damage and flow stagnation within aneurysms can lead to coagulation, inflammation, and the release of proteases, which alter extracellular matrix composition, increasing risk of rupture. In this review, we highlight recent work that investigates aneurysm geometry, model parameter assumptions, and other specific considerations that influence computational aneurysm simulations. By highlighting modeling validation and verification approaches, we hope to inspire future computational efforts aimed at improving our understanding of aneurysm pathology and treatment risk stratification.

Natural history and clinical significance of aortic focal intimal flaps

“…While there were a small number of FIFs ( n = 6) in our cohort which occurred in the absence of any identifiable atherosclerotic plaque by CT, the co-localization of these lesions with the presence of plaque supports the concept that such flap-like intimal abnormalities are related to the inflammatory and erosive processes that lead to plaque ulceration and ultimately a PAU ( 13 ). Additionally, hemodynamic differences between the thoracic and abdominal aorta could play a role the predilection of FIFs for the abdominal aorta ( 11 , 14 ). Finally, supporting the strong association between FIF and atherosclerosis over more acute pathologies (e.g., dissection, intramural hematoma) is the observation that FIFs were found to be indolent lesions, demonstrating little to no change over years of imaging follow-up and resulting in no adverse events.…”

Medical Image-Based Computational Fluid Dynamics and Fluid-Structure Interaction Analysis in Vascular Diseases

“…Simulations of the interactions of these implants with blood vessels are further complicated by the implants and not reviewed here. Our current review can be complemented by other reviews of image-based computational cardiovascular biomechanics ( Thondapu et al, 2017 ; Zhong et al, 2018 ; Liang et al, 2019 ; Cameron et al, 2020 ; Carpenter et al, 2020 ; Lipp et al, 2020 ; Lopes et al, 2020 ; Ong et al, 2020 ; Thiyagarajah et al, 2022 ).…”

On the Potential Self-Amplification of Aneurysms Due to Tissue Degradation and Blood Flow Revealed From FSI Simulations

“…Both microscopic degradation in vascular tissues and hemodynamic (fluid-dynamic) forces play a crucial role in the initiation, growth and focal rupture of aneurysms (Sforza et al, 2009;Salman et al, 2019;Lipp et al, 2020;Wu et al, 2020). Aneurysms are vascular diseases characterized by excessive tissue degradation and chronic inflammation (Frösen, 2014).…”