Coronary artery aneurysms: Comprehensive review and a case report of a left main coronary artery aneurysm

Fluid-structure interaction simulations in patient-specific coronary arteries with aneurysms: Viscoelastic or shear-thinning property of blood

BACKGROUND AND OBJECTIVE

Coronary artery aneurysm is a progressive and often asymptomatic condition with a prevalence ranging from 0.3 % to 5 %. This condition can lead to severe and potentially fatal complications. Given the challenges of conducting experiments on real patients, numerical simulations have emerged as a valuable alternative. This study aims to enhance the accuracy of hemodynamic analysis and fluid-structure interaction assessments by incorporating the viscoelastic properties of blood, which are often overlooked, in simulations of the right coronary artery with various aneurysm morphologies.

METHODS

This research employs numerical simulations to analyse the hemodynamics and assess the one-way coupled fluid-structure interaction within the right coronary artery. The study utilised the simplified Phan-Thien/Tanner model to represent the viscoelastic properties of blood. Different aneurysm morphologies were simulated, and the results were compared with those obtained using the widely recognised Carreau model. The analysis focused on the time-average wall-shear stress, as well as the stress and deformation experienced by the aneurysm wall.

RESULTS

The hemodynamic analysis demonstrated that the simplified Phan-Thien/Tanner model produced similar flow patterns to the Carreau model but resulted in a significant reduction of approximately 50 % in the time-average wall-shear stress. This reduction aligns with previous findings. Additionally, the study revealed substantial differences in the stress and deformation of the aneurysm wall, with the simplified Phan-Thien/Tanner model proving more accuracy. The largest deformations were observed in aneurysms with incipient and fusiform shapes, particularly in the divergent section of the proximal region. In the case of saccular aneurysms, the most compromised area was identified not within the aneurysm sac itself, but in the region of the artery just upstream.

CONCLUSIONS

Incorporating the viscoelastic properties of blood into fluid-structure interaction simulations significantly improves the accuracy of hemodynamic and structural assessments of coronary artery aneurysms. This study underscores the importance of considering these properties when evaluating aneurysm behaviour, which could have important implications for understanding the progression and potential rupture of aneurysms, thereby guiding more effective clinical interventions.

Pathogenetic Significance of Long Non-Coding RNAs in the Development of Thoracic and Abdominal Aortic Aneurysms

Aortic aneurysm (AA) is a life-threatening condition with a high prevalence and risk of severe complications. The aim of this review was to summarize the data on the role of long non-coding RNAs (lncRNAs) in the development of AAs of various location. Within less than a decade of studies on the role of lncRNAs in AA, using experimental and bioinformatic approaches, scientists have obtained the data confirming the involvement of these molecules in metabolic pathways and pathogenetic mechanisms critical for the aneurysm development. Regardless of the location of pathological process (thoracic or abdominal aorta), AA was found to be associated with changes in the expression of various lncRNAs in the tissue of the affected vessels. The consistency of changes in the expression level of lncRNA, mRNA and microRNA in aortic tissues during AA development has been recordedand regulatory networks implicated in the AA pathogenesis in which lncRNAs act as competing endogenous RNAs (ceRNA networks) have been identified. It was found that the same lncRNA can be involved in different ceRNA networks and regulate different biochemical and cellular events; on the other hand, the same pathological process can be controlled by different lncRNAs. Despite some similarities in pathogenesis and overlapping of involved lncRNAs, the ceRNA networks described for abdominal and thoracic AA are different. Interactions between lncRNAs and other molecules, including those participating in epigenetic processes, have also been identified as potentially relevant to the AA pathogenesis. The expression levels of some lncRNAs were found to correlate with clinically significant aortic features and biochemical parameters. Identification of regulatory RNAs functionally significant in the aneurysm development is important for clarification of disease pathogenesis and will provide a basis for early diagnostics and development of new preventive and therapeutic drugs.