Dynamic finite element analysis of the aortic root from MRI-derived parameters

Biomechanical properties of the Marfan's aortic root and ascending aorta before and after personalised external aortic root support surgery

“…In reality, a zero-stress state does not exist in vivo, however, it was found that the magnitude of residual stresses were negligible (up to 3 kPa [34]) in comparison with the aortic root stresses observed at the peak pressure. However, it must be acknowledged that residual stresses and strains act in homogenising the stress field in the arterial wall and allows greater compliance [35].…”

“…Another boundary condition imposed on the aortic model was the constraining of the aortic root to zero-displacement to simulate the tethering to the rest of the aorta. Although this is a common assumption adopted by other researchers [15,35,36] , in reality the ventricular contraction accompanying every heartbeat results in the motion of the aortic root, which may in turn have a direct influence on the deformation of the ascending aorta and the stress exerted on the aortic wall [37]. Future improvements to the model will involve extracting patient-specific aortic root motion from MR images and applying it as a more realistic boundary condition.…”

Effect of Stent Designs on the Paravalvular Regurgitation of Transcatheter Aortic Valve Implantation

“…The Young modulus, Poisson ratio and density of Nitinol were set at 50,000 Mpa, 0.3 and 6,450 kg/m3, respectively [Tzamtzis et al (2013)]. Because of the negligible effect of sealing skirt and leaflet compared to Nitinol alloy [Conti et al (2010)], the skirt and leaflet were not included in this investigation.…”

Finite Element Analysis to Study Percutaneous Heart Valves

“…13). The aortic roots were assumed to be 2 mm thick, with density equal to 1,120 kg/m 3 (Conti et al, 2010) for all models and meshed with 3D triangular shell general-purpose elements (Table 2). To describe the mechanical behaviour of the aortic roots, Mooney-Rivlin hyperelastic behaviour was adopted incorporating experimental stress-strain data for the ascending aorta (Okamoto et al, 2002) and taking into account the pre-stretching of the aortic root due to the aortic pressure during the cardiac circle.…”

“…The native structures were meshed with 3D triangular shell generalpurpose elements (18,890 elements). Aortic wall and native valve leaflets were assumed to be respectively 2 and 0.5 mm thick (Conti et al, 2010) with density equal to 1,120 kg/m 3 , and Mooney-Rivlin hyperelastic constitutive law was adopted to describe the material behaviour.…”