scholarly journals Cardiac remodelling following thoracic endovascular aortic repair for descending aortic aneurysms

2018 ◽  
Vol 55 (6) ◽  
pp. 1061-1070 ◽  
Author(s):  
Theodorus M J van Bakel ◽  
Christopher J Arthurs ◽  
Foeke J H Nauta ◽  
Kim A Eagle ◽  
Joost A van Herwaarden ◽  
...  

Abstract OBJECTIVES Current endografts for thoracic endovascular aortic repair (TEVAR) are much stiffer than the aorta and have been shown to induce acute stiffening. In this study, we aimed to estimate the impact of TEVAR on left ventricular (LV) stroke work (SW) and mass using a non-invasive image-based workflow. METHODS The University of Michigan database was searched for patients treated with TEVAR for descending aortic pathologies (2013–2016). Patients with available pre-TEVAR and post-TEVAR computed tomography angiography and echocardiography data were selected. LV SW was estimated via patient-specific fluid–structure interaction analyses. LV remodelling was quantified through morphological measurements using echocardiography and electrocardiographic-gated computed tomography angiography data. RESULTS Eight subjects were included in this study, the mean age of the patients was 68 (73, 25) years, and 6 patients were women. All patients were prescribed antihypertensive drugs following TEVAR. The fluid–structure interaction simulations computed a 26% increase in LV SW post-TEVAR [0.94 (0.89, 0.34) J to 1.18 (1.11, 0.65) J, P = 0.012]. Morphological measurements revealed an increase in the LV mass index post-TEVAR of +26% in echocardiography [72 (73, 17)  g/m2 to 91 (87, 26)  g/m2, P = 0.017] and +15% in computed tomography angiography [52 (46, 29)  g/m2 to 60 (57, 22)  g/m2, P = 0.043]. The post- to pre-TEVAR LV mass index ratio was positively correlated with the post- to pre-TEVAR ratios of SW and the mean blood pressure (ρ = 0.690, P = 0.058 and ρ = 0.786, P = 0.021, respectively). CONCLUSIONS TEVAR was associated with increased LV SW and mass during follow-up. Medical device manufacturers should develop more compliant devices to reduce the stiffness mismatch with the aorta. Additionally, intensive antihypertensive management is needed to control blood pressure post-TEVAR.

2013 ◽  
Vol 11 (5) ◽  
pp. 589-606 ◽  
Author(s):  
Nila J Akhtar ◽  
Gustavo S Oderich ◽  
Terri J Vrtiska ◽  
Eric E Williamson ◽  
Philip A Araoz

Author(s):  
Sang Hyuk Lee ◽  
Nahmkeon Hur ◽  
Seongwon Kang

Recently, the rapid evolution of numerical methodologies for CFD and structural analyses has made it possible to predict the arterial hemodynamics closely related to vascular disease. In the present study, a framework for fluid-structure interaction (FSI) analysis was developed to accurately predict the arterial hemodynamics. The numerical results from the FSI analysis of the hemodynamics inside aneurysms of various shapes were compared to the results without FSI analysis. The results showed that FSI analysis needs to be performed in order to accurately predict the blood flow affected by the wall motion of compliant arteries. FSI analysis is essential to predict the hemodynamics in a saccular aneurysm because the arterial wall’s movement, which is a result of the variation of blood pressure in the aneurysmal sac, mainly produces the blood flow to a saccular aneurysm.


Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2217 ◽  
Author(s):  
Mujahid Badshah ◽  
Saeed Badshah ◽  
James VanZwieten ◽  
Sakhi Jan ◽  
Muhammad Amir ◽  
...  

Velocity profiles in tidal channels cause cyclic oscillations in hydrodynamic loads due to the dependence of relative velocity on angular position, which can lead to fatigue damage. Therefore, the effect of velocity profile on the load variation and fatigue life of large-scale tidal turbines is quantified here. This is accomplished using Fluid Structure Interaction (FSI) simulations created using the ANSYS Workbench software, which couples the fluid solver ANSYS CFX to the structural solver ANSYS transient structural. While these load oscillations only minimally impact power and thrust fluctuation for rotors, they can significantly impact the load variations on individual rotor blades. To evaluate these loadings, a tidal turbine within a channel with a representative flow that follows a 1/7th power velocity profile and an onset turbulence intensity of 5% is simulated. This velocity profile increases the thrust coefficient variation from mean cycle value of an individual blade from 2.8% to 9% and the variation in flap wise bending moment coefficient is increased from 4.9% to 19%. Similarly, the variation from the mean cycle value for blade deformation and stress of 2.5% and 2.8% increased to 9.8% and 10.3%, respectively. Due to the effect of velocity profile, the mean stress is decreased, whereas, the range and variation of stress are considerably increased.


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