Objective To explore the effectiveness and predictive value of computer simulated thoracic endovascular aortic repair (TEVAR). Methods The clinical data of the patients with Stanford type B aortic dissection who underwent TEVAR from February 2019 to February 2022 in our hospital was collected. According to whether there was residual false cavity around the stent about 1 week after TEVAR, the patients were divided into a false cavity closure group and a false cavity residual group. Based on computer simulation, personalized design and three-dimensional construction of the stent framework and covering were carried out. After the stent framework and membrane were assembled, they were pressed and placed into the reconstructed aortic dissection model. TEVAR computer simulation was performed, and the simulation results were analyzed for hemodynamics to obtain the maximum blood flow velocity and maximum wall shear stress at the false lumen outlet level at the peak systolic velocity of the ventricle, which were compared with the real hemodynamic data of the patient after TEVAR surgery. The impact of hemodynamics on the residual false lumen around the stent in the near future based on computer simulation of hemodynamic data after TEVAR surgery was further explored. Results Finally a total of 28 patients were collected, including 24 males and 4 females aged 53.390±11.020 years. There were 18 patients in the false cavity closure group, and 10 patients in the false cavity residual group. The error rate of shear stress of the distal decompression port of the false cavity after computer simulation TEVAR was 6%-25%, and the error rate of blood flow velocity was 3%-31%. There was no statistical difference in age, proportion of male, history of hypertension, history of diabetes, smoking history, prothrombin time or activated partial thromboplatin time at admission between the two groups (all P>0.05). The blood flow velocity and shear stress after TEVAR were statistically significant (all P<0.05). The maximum shear stress (OR=1.823, P=0.010) of the false cavity at the level of the distal decompression port after simulated TEVAR was an independent risk factor for the residual false cavity around the stent. Receiver operating characteristic curve analysis showed that the area under the curve corresponding to the maximum shear stress of false cavity at the level of distal decompression port after simulated TEVAR was 0.872, the best cross-sectional value was 8.469 Pa, and the sensitivity and specificity were 90.0% and 83.3%, respectively. Conclusion Computers can effectively simulate TEVAR and perform hemodynamic analysis before and after TEVAR surgery through simulation. Maximum shear stress at the decompression port of the distal end of the false cavity is an independent risk factor for the residual false cavity around the stent. When it is greater than 8.469 Pa, the probability of residual false cavity around the stent increases greatly.
The hemodynamic parameters in arteries are difficult to measure non-invasively, and the analysis and prediction of hemodynamic parameters based on computational fluid dynamics (CFD) has become one of the important research hotspots in biomechanics. This article establishes 15 idealized left coronary artery bifurcation models with concomitant stenosis and aneurysm lesions, and uses CFD method to numerically simulate them, exploring the effects of left anterior descending branch (LAD) stenosis rate and curvature radius on the hemodynamics inside the aneurysm. This study compared models with different stenosis rates and curvature radii and found that as the stenosis rate increased, the oscillatory shear index (OSI) and relative residence time (RRT) showed a trend of increase; In addition, the decrease in curvature radius led to an increase in the degree of vascular curvature and an increased risk of vascular aneurysm rupture. Among them, when the stenosis rate was less than 60%, the impact of stenosis rate on aneurysm rupture was greater, and when the stenosis rate was greater than 60%, the impact of curvature radius was more significant. Based on the research results of this article, it can be concluded that by comprehensively considering the effects of stenosis rate and curvature radius on hemodynamic parameters, the risk of aneurysm rupture can be analyzed and predicted. This article uses CFD methods to deeply explore the effects of stenosis rate and curvature radius on the hemodynamics of aneurysms, providing new theoretical basis and prediction methods for the assessment of aneurysm rupture risk, which has important academic value and practical guidance significance.
The diagnostic and therapeutic paradigm for lower extremity arteriosclerosis obliterans (ASO) is undergoing a fundamental shift from conventional morphology-based assessment toward functional evaluation and predictive medicine. Numerical simulation techniques that integrate computational fluid dynamics (CFD) and finite element analysis (FEA), grounded in patient-specific imaging data, have emerged as a central driving force of this transformation. This review systematically elucidates how these approaches enable the construction of vascular “digital twins” to achieve precise quantification of the hemodynamic environment associated with ASO lesions, virtual monitoring of disease progression, and preoperative optimization of therapeutic strategies. Particular emphasis is placed on the critical role of numerical simulation in supporting clinical decision-making, such as evaluating the necessity of interventional treatment and predicting the mechanical responses of endovascular devices. Furthermore, the potential, current challenges, and future directions of numerical simulation in advancing personalized and precision management of ASO are comprehensively discussed.
Quantitative measurement of strain distribution of arterial vessel walls due to pulsatile blood flow within the vascular lumen is valuable for evaluating the elasticity of arterial wall and predicting the evolution of plaques. The present paper shows that the three-dimensional (3D) strain distribution are estimated through uni-directional coupling for 3D vessel and blood models reconstructed from intravascular ultrasound (IVUS) images with the computational fluid dynamics (CFD) numerical simulation technique. The morphology of vessel wall and plaques as well as strain distribution can be visually displayed with pseudo-color coding.
Computational fluid dynamics was used to investigate the effect of the pathogenesis of membranous obstruction of inferior vena cava of Budd-Chiari syndrome with various angles between right hepatic vein and inferior vena cava. Mimics software was used to reconstruct the models from magnetic resonance imaging (MRI) angiograms of inferior vena cava, right hepatic vein, middle hepatic vein and left hepatic vein, and 3DMAX was used to construct the models of 30°, 60°, 90° and 120° angles between right hepatic vein and inferior vena cava, which was based on the reconstructed models.The model was conducted with clinical parameters in terms of wall shear stress distribution, static pressure distribution and blood velocity. The results demonstrated that the differences between wall shear stress and static pressure had statistical significance with various angles between right hepatic vein and inferior vena cava by SPSS. The pathogenesis of membranous obstruction of inferior vena cava had a correlation with the angles between right hepatic vein and inferior vena cava.
Due to their diverse types, complex causes, high incidence, and difficult treatment, lung diseases have become major killers threatening human life and health, and some lung diseases have a significant impact on alveolar morphology and histology. Numerical simulation of alveolar mechanical response, alveolar flow field information, multiphase flow, and material transport based on computational fluid dynamics is of great significance for lung disease diagnosis, clinical treatment, and in vitro experiments. Starting from the simplification and pathological differences of geometric and mechanical models, this paper analyzes and summarizes the conditions and application scenarios of the airflow dynamics calculation method in pulmonary alveoli, to provide a reference for further simulation and application of the alveolar region.
In order to investigate the application of lattice Boltzmann method (LBM) in the numerical simulation of computed tomography angiography-derived fractional flow reserve (FFRCT), an idealized narrowed tube model and two coronary stenosis arterymodels are studied. Based on the open source code library (Palabos), the relative algorithm program in the development environment (Codeblocks) was improved. Through comparing and analyzing the results of FFRCT which is simulated by LBM and finite element analysis software ANSYS, and the feasibility of the numerical simulation of FFRCT by LBM was verified . The results show that the relative error between the results of LBM and finite element analysis software ANSYS is about 1%, which vertifies the feasibility of simulating the coronary FFRCT by LBM. The simulation of this study provides technical support for developing future FFRCT application software, and lays the foundation for the calculation of clinical FFRCT.
This paper aims to analyze the impact of splenic vein thrombosis (SVT) on the hemodynamic parameters in hepatic portal vein system. Based on computed tomography (CT) images of a patient with portal hypertension and commercial software MIMICS, the patient's portal venous system model was reconstructed. Color Doppler ultrasound method was used to measure the blood flow velocity in portal vein system and then the blood flow velocities were used as the inlet boundary conditions of simulation. By using the computational fluid dynamics (CFD) method, we simulated the changes of hemodynamic parameters in portal venous system with and without splenic vein thrombosis and analyzed the influence of physiological processes. The simulation results reproduced the blood flow process in portal venous system and the results showed that the splenic vein thrombosis caused serious impacts on hemodynamics. When blood flowed through the thrombosis, blood pressure reduced, flow velocity and wall shear stress increased. Flow resistance increased, blood flow velocity slowed down, the pressure gradient and wall shear stress distribution were more uniform in portal vein. The blood supply to liver decreased. Splenic vein thrombosis led to the possibility of forming new thrombosis in portal vein and surroundings.
The pulsatile flow experiment can not only evaluate the preclinical safety and risk of prosthetic heart valve (PHV) but also play an important role in the computational model and fluid simulation, providing an experimental basis for the performance optimization of PHV. This paper mainly reviews the development and the latest progress of PHV pulsatile flow experiments and the characteristics of experimental pulse duplicator, and discuss the research direction of pulsatile flow experiments, expecting a further development in this field.
ObjectiveTo investigate the application of computational fluid dynamics (CFD) in hemodynamic evaluation of aortic root reconstruction.MethodsThe clinical data of 1 patient with severe aortic valve stenosis was analyzed. Enhanced CT images were used as the original data, and professional software was used to reconstruct the three-dimensional (3D) model and fluid mechanics simulation of the aorta (including preoperative, postoperative and ideal conditions).ResultsThe 3D reconstruction model could directly present the distribution of valve calcification and the dilatation of the ascending aorta. The remodeled sinotubular junction and sinus structure were observed in the model under postoperative and ideal conditions. The improvement of ascending aorta dilatation was evaluated statistically by the diameter distribution before and after surgery. CFD simulation showed that the area of high flow velocity, pressure intensity and wall shear stress before surgery were consistent with the expansion area of the ascending aorta, and the restricted blood flow acceleration was observed at the angle between the arch and the descending aorta. In the ideal condition, the streamline of blood at the descending aorta was more stable and flat compared with preoperative or postoperative conditions, and there was no obvious abnormal high pressure and high wall shear stress area in the ascending aorta. The cardiopulmonary bypass time was 106 min, of which the aortic cross-clamp time was 60 min. The cardiac echocardiography indicated that the aortic valve worked well, and the peak systolic blood velocity was 1.7 m/s. The length of hospital stay after surgery was 12 d, including 2 d in ICU. The ventilator use time was 11.6 h. The patient did not have any remarkable discomfort during the 1-year follow-up.ConclusionCFD can be used to evaluate anatomic and hemodynamic abnormalities before aortic root reconstruction surgery. Postoperative reconstruction simulation can be performed again to evaluate the surgical effect, and meanwhile, virtual improvement can be tried for the unresolved problems to accumulate diagnosis and treatment experience, so as to provide patients with more accurate and personalized diagnosis and treatment procedure.
