Nonlinear Biomechanical Behaviour of Extracranial Carotid Artery Aneurysms in the Framework of Windkessel Effect via FSI Technique

Journal of the mechanical behavior of biomedical materials/Journal of mechanical behavior of biomedical materials, Год журнала: 2024, Номер 160, С. 106760 - 106760

Опубликована: Сен. 30, 2024

Язык: Английский

---

Biomechanics of abdominal aortic aneurysm in the framework of Windkessel effect and fully-developed inflow velocity via two-way non-linear FSI

International Journal of Non-Linear Mechanics, Год журнала: 2023, Номер 157, С. 104517 - 104517

Опубликована: Авг. 11, 2023

Abdominal aortic aneurysm (AAA) is a pathological condition characterised by localised dilation of the infrarenal aorta, which can be fatal if rupture occurs. Current diagnostic criteria for repair are not patient-specific, but computational modelling may help to predict potential growth and risk AAA accurately. This paper highlights how important using Windkessel effect fully-developed inflow velocity framework biomechanical analysis is; in other words, this research investigates different boundary conditions methods affect ability correctly represent biomechanics with complex non-linear parameters two-way fluid–structure interaction (FSI) technique. Time-averaged wall shear stress (TAWSS) highly sensitive conditions, so unrealistic or simplified lead very TAWSS results. study also revealed that use outflow 3-element on pulsatile pressure affects flow pattern increases recirculation period. By accounting preventing backflow numerical studies AAA, maximum displacement found distal branches reduced. Models assuming plug profiles overestimate peak approximately 20% compared models fully developed parabolic inlet profiles. incorporated three-layer anisotropic material model non-Newtonian fluid properties into simulation, providing more realistic representation selection mechanics. The results summarised from parametric could contribute better prediction risk, have implications development improved treatment strategies patients.

Язык: Английский

---

Variation in Layer-Specific Tear Properties of the Human Aorta Along Its Length and Circumference: Implications for Spatial Susceptibility to Dissection Initiation

Journal of Biomechanical Engineering, Год журнала: 2025, Номер 147(4)

Опубликована: Фев. 14, 2025

Hemodynamic variations influence the location of entry tears in aortic dissection. This study investigates whether tear strength across human aorta contribute to these clinical manifestations. Circumferential and axial strips were collected from nine two circumferential sites along each autopsied aorta, yielding 1188 samples (11 aortas × 18 2 directions 3 layers per site). These underwent testing assess energy, constituting resistance propagation. Adventitial parameters significantly higher than those intima media, with no significant differences between latter two, supporting observation that typically occur inner wall. Tear propagation angles approximately 15 75 deg for medial strips, 30 45 adventitia, minimal variation aorta. findings indicate a lesser extent other layers, have tearing compared tearing, aligning circumferentially directed tears. Intimal adventitial increased modestly while varied less, explaining why rarely originate abdominal outer quadrants similar at most locations, except dissimilar adventitia proximal (especially arch), seldom involve entire circumference.

Язык: Английский

---

Impact of mechanical properties of aneurysms and intraluminal thrombus on abdominal aortic aneurysm aoutcomes

Meccanica, Год журнала: 2025, Номер unknown

Опубликована: Фев. 15, 2025

Язык: Английский

---

Impaired Aortic Biomechanical Properties in Patients With Severe Obstructive Sleep Apnea Syndrome

Echocardiography, Год журнала: 2025, Номер 42(4)

Опубликована: Март 28, 2025

ABSTRACT Purpose Evaluating the biomechanical properties of aorta is crucial for assessing cardiovascular risk and preventing disease progression. The aim this study was to evaluate ascending (AA) in severe obstructive sleep apnea syndrome (OSAS) patients with or without hypertension (HT) via velocity vector imaging (VVI). Methods A total 68 OSAS were selected, 35 whom included simple group 33 + HT group, 40 volunteers these two disorders who taken as control group. AA properties, that is, longitudinal strain (ALS), circumferential (ACS), fractional area change (FAC), evaluated VVI. Pulsed Doppler early transmitral peak flow (E), diastolic mitral annular (e’), left ventricular (LV) global (GLS), dimension (AD) also measured. Results ALS (mean ± SD; 32.8% 11.9% 19.7% 7.6% vs. 40.6% 15.6%, p = 0.006), ACS 11.8% 3.5% 8.6% 2.7% 16.5% 5.8%, 0.02), FAC 21.0% 5.3% 12.4% 3.8% 9.7%, 0.004) significantly lower patient groups (OSAS HT, respectively) than LV systolic functions impaired groups. Compared had a greater AD E/e’ ratio GLS ( < 0.01). aortic strongly correlated function parameters. Conclusion are OSAS, especially those HT. Impairments associated diminished abnormal This discovery may help clinicians identify manage potential risks patients. Further large‐scale studies needed confirm predictive value events (e.g., aneurysm dissection) OSAS.

Язык: Английский

---

Modeling Techniques and Boundary Conditions in Abdominal Aortic Aneurysm Analysis: Latest Developments in Simulation and Integration of Machine Learning and Data-Driven Approaches

Bioengineering, Год журнала: 2025, Номер 12(5), С. 437 - 437

Опубликована: Апрель 22, 2025

Research on abdominal aortic aneurysms (AAAs) primarily focuses developing a clear understanding of the initiation, progression, and treatment AAA through improved model accuracy. High-fidelity hemodynamic biomechanical predictions are essential for clinicians to optimize preoperative planning minimize therapeutic risks. Computational fluid dynamics (CFDs), finite element analysis (FEA), fluid-structure interaction (FSI) widely used simulate hemodynamics biomechanics. However, accuracy these simulations depends utilization realistic sophisticated boundary conditions (BCs), which properly integrating with rest cardiovascular system. Recent advances in machine learning (ML) techniques have introduced faster, data-driven surrogates modeling. These approaches can accelerate segmentation, predict biomechanics, assess disease progression. their reliability high-quality training data derived from CFDs FEA simulations, where BC modeling plays crucial role. Accurate BCs enhance ML predictions, increasing clinical applicability. This paper reviews existing models, discussing limitations technical challenges. Additionally, recent advancements explored, current states, future directions, common algorithms, limitations.

Язык: Английский

---

A study on the ultimate mechanical properties of middle-aged and elderly human aorta based on uniaxial tensile test

Frontiers in Bioengineering and Biotechnology, Год журнала: 2024, Номер 12

Опубликована: Март 21, 2024

Background: The mechanical properties of the aorta are particularly important in clinical medicine and forensic science, serving as basic data for further exploration aortic disease or injury mechanisms. Objective: To study influence various factors (age, gender, test direction, anatomical location, pathological characteristics) on thickness aorta. Methods: In this study, a total 24 aortas (age range: 54–88 years old) were collected, one hundred seventy-four dog-bone-shaped samples made, then uniaxial tensile was run, finally, grouping performed through histological staining. Results: Atherosclerotic plaques mainly distributed near openings blood vessel branches. distribution most severe abdominal aorta, followed by arch. Aortic atherosclerosis more trend male group. comparison thickness, there no significant differences age (over 50 years) average greater group than female decreased progressively from ascending to Comparing parameters, parameters negatively correlated with age, especially circumferential (ε p “Y = −0.01402*X + 1.762, R 2 0.6882”, ε t −0.01062*X 1.250, 0.6772”); males healthy larger, while females larger group; has anisotropy, direction those axial direction; largest ultimate stress [σ “1.69 (1.08,2.32)”] elastic modulus [E “8.28 (6.67,10.25)”] significantly “2.2 (1.31,3.98)”, σ “0.13 (0.09,0.31)”] (E “14.10 ± 7.21”) adaptive intimal thickening other groups, strain “0.82 0.17”, “0.53 0.14”) Conclusion: present systematically analyzed sex, site, characteristics biomechanical described atherosclerosis, illustrated changes. At same time, new insights into features presented.

Язык: Английский

---

Layer-Specific Biomechanical and Histological Properties of Normal and Dissected

Heliyon, Год журнала: 2024, Номер 10(14), С. e34646 - e34646

Опубликована: Июль 1, 2024

Recent studies have attempted to characterize the layer-specific mechanical and microstructural properties of aortic tissues in either normal or pathological state understand its structural-mechanical property relationships. However, tissue mechanics compositions dissected ascending aortas not been thoroughly compared with a statistical conclusion obtained. Eighteen specimens were harvested from 13 patients type A dissection 5 donors without diseases, each specimen further excised obtain three samples including an intact wall, intima-media layer adventitia layer. For sample, biaxial tensile testing was performed experimental stress-stretch ratio data, which fed into Fung-type model quantify stiffness, Elastin Van Gieson stain Masson's trichrome employed elastic collagen fiber densities. Statistical analyses determine whether any significant differences exist between diseased tissues. The stiffness higher group than that longitudinal direction at stretch 1.30 (p = 0.0068), while no found other types. Even though there difference densities two groups, generally had lower density, but density for all layers. Compared tissues, lower, significantly higher, indicating could be potential indicator dissection.

Язык: Английский

---

Traction-separation law parameters for the description of age-related changes in the delamination strength of the human descending thoracic aorta

Research Square (Research Square), Год журнала: 2024, Номер unknown

Опубликована: Март 22, 2024

Abstract Aortic dissection is a life-threatening disease that consists in the development of tear wall aorta. The initial propagates as discontinuity leading to separation within aortic wall, which can result creation so-called false lumen. A fatal threat occurs if rupture extends through whole thickness blood may then leak. It generally accepted dissection, sometime extend along entire length aorta, via delamination mechanism. aim present paper provide experimentally validated parameters mathematical model for description wall’s cohesion. peeling experiment was built Abaqus. interface described by linear traction-separation law. bulk behavior aorta assumed be nonlinearly elastic, anisotropic, and incompressible. numerical values material constitutive were adopted from literature. Our simulations resulted estimates law human descending thoracic obtained minimizing differences between FEM predicted force observed experiment. results show that, since strength decreases with age, are also age-dependent. provided our study used biomechanics propagation especially when age-associated phenomena studied.

Язык: Английский

---

Fracture mechanics modeling of aortic dissection

Biomechanics and Modeling in Mechanobiology, Год журнала: 2024, Номер 23(4), С. 1377 - 1391

Опубликована: Апрель 24, 2024

Abstract Aortic dissection, a critical cardiovascular condition with life-threatening implications, is distinguished by the development of tear and its propagation within aortic wall. A thorough understanding initiation progression these tears, or cracks, essential for accurate diagnosis effective treatment. This paper undertakes fracture mechanics approach to delve into in dissection. Our objective elucidate impact geometric material parameters, providing valuable insights determinants this pivotal event. Through our investigation, we have gained an how various parameters influence energy release rate both longitudinal circumferential directions, aligning findings clinical data.

Язык: Английский

---