BUSCADOR RECOLECTA

Flow-diverting stents (FDSs) show considerable promise for the treatment of cerebral aneurysms by diverting blood flow away from the aneurysmal sacs, however, post-treatment complications such as failure of occlusion and subarachnoid haemorrhaging remain and vary with the FDS used. Based on computational fluid dynamics (CFD), this study aimed to investigate the performance of a new biodegradable stent as compared to two metallic commercially available FDSs. CFD models were developed for an idealized cerebral artery with a sidewall aneurysmal sac treated by deploying the aforementioned stents of different porosities (90, 80, and <mml:semantics>70%</mml:semantics>) respectively. By using these models, the simulation and analysis were performed, with a focus on comparing the local hemodynamics or the blood flow in the stented arteries as compared to the one without the stent deployment. For the comparison, we computed and compared the flow velocity, wall shear stress (WSS) and pressure distributions, as well as the WSS related indices, all of which are of important parameters for studying the occlusion and potential rupture of the aneurysm. Our results illustrate that the WSS decreases within the aneurysmal sac on the treated arteries, which is more significant for the stents with lower porosity or finer mesh. Our results also show that the maximum WSS near the aneurysmal neck increases regardless of the stents used. In addition, the WSS related indices including the time-average WSS, oscillatory shear index and relative residence time show different distributions, depending on the FDSs. Together, we found that the finer mesh stents provide more flow reduction and smaller region characterized by high oscillatory shear index, while the new stent has a higher relative residence time., This research was funded by the Saskatchewan Health Research Foundation (SHRF Grant Reference #2784). M. Malve was supported by the Spanish Ministry of Education, Culture and Sport through the grant PRX17/00335 financed within the National Program 'Salvador de Madariaga'. The authors also acknowledge the support of the Spanish Ministry of Industry and Competitiveness via the research project DP12017-83259-R (AEI/FEDER, UE) and the Instituto de Salud Carlos III (ISCIII) through the CIBER-BBN initiative.

The main goal of this study is the quantification of the particle transport and deposition within the human airways during light, normal and exercise breathing conditions using the computational fluid dynamics. In particular we presented a comparison between healthy and stented airways. The considered tracheobronchial model is based on the Weibel symmetric model in which we have inserted the Dumon prosthesis at different locations and on the CT- based geometries of a healthy and a stented airway. The results indicate an important redistribution of the particle deposition locations. Local overdoses can be found in the proximal regions of the prostheses, independently of the breathing conditions, of the particle size and of the considered geometry. The presented work is aimed to contribute to the understanding of the particle deposition in the human lung and to improve drug-aerosol therapies. For patients that underwent airways reconstructive surgery, it can give detailed information about the deposition efficiency and it may help targeting specific airways regions., The authors gratefully acknowledge the support of the Spanish Ministry of Industry and Competitiveness through the research Project DPI2017-83259-R (AEI/FEDER,UE).

Perturbed aorta hemodynamics, as for the carotid and the coronary artery, has been identified as
potential predicting factor for cardiovascular diseases. In this study, we propose a parametric study
based on the computational fluid dynamics with the aim of providing information regarding aortic
disease. In particular, the blood flow inside a parametrized aortic arch is computed as a function of
morphological changes of baseline aorta geometry. Flow patterns, wall shear stress, time average wall
shear stress and oscillatory shear index were calculated during the cardiac cycle. The influence of
geometrical changes on the hemodynamics and on these variables was evaluated. The results suggest that the distance between inflow and aortic arch and the angle between aortic arch
and descending trunk are the most influencing parameters regarding the WSS-related
indices while the effect of the inlet diameter seems limited. In particular, an increase
of the aforementioned distance produces a reduction of the spatial distribution of the
higher values of the time average wall shear stress and of the oscillatory shear index
independently on the other two parameters while an increase of the angle produce an
opposite effect. Moreover, as expected, the analysis of the wall shear stress descriptors suggests that the inlet diameter influences only the flow intensity. As conclusion, the
proposed parametric study can be used to evaluate the aorta hemodynamics and could be also
applied in the future, for analyzing pathological cases and virtual situations, such as pre- and/or
post-operative cardiovascular surgical states that present enhanced changes in the aorta morphology
yet promoting important variations on the considered indexes., The authors gratefully acknowledge the research support of the Spanish Ministry of Econ339 omy and Competitiveness through the research projects DPI-2016-76630-C2-1-R and DPI2017-83259-R (AEI/FEDER,UE). The support of the Instituto de Salud Carlos III (ISCIII) through
341 the CIBER-BBN initiative and the project Patient-Specific Modelling of the Aortic valve replacement: Advance towards a Decision Support System (DeSSAValve) is highly appreciated.

Brachycephalic dog breeds are prone to breathing difficulties because of their upper airway anatomy. Several surgical techniques exist to correct anatomical pathologies and common surgical approaches aim to correct functional abnormalities in the nares and/or the soft palate. However, further research is needed to improve clinical outcomes. This study evaluated air pressure and airflow resistance in the upper airways and trachea in nine sedated, sternally recumbent dogs of different skull types (dolichocephalic, n=3; mesocephalic, n=3; brachycephalic, n=3). CT images were acquired from the nostrils to the caudal border of the lungs and geometrical reconstruction of the upper airway and trachea was performed. Analysis of computational fluid dynamics was performed using inspiratory flow adapted to bodyweight for each dog. Flow (L/min) and pressure (cmH2O) were computed for the entire upper airway and trachea. Resistance (cmH2O/L/min) was calculated using pressure differences between the nose, larynx, and trachea. In this pilot study, statistical comparisons were not performed., Dr. Malvè and Dr. Fernández-Parra gratefully acknowledge the support of the Spanish Ministry of Economy, Industry and Competitiveness through the research project DPI2017-83259-R (AEI/FEDER,UE). The support of the Institute of Health Carlos III (ISCIII) through the CIBER-BBN initiative is highly appreciated.

Flow diverting stents are deployed to reduce the blood flow into the aneurysm, which would thereby induce thrombosis in the aneurysm sac; the stents prevent its rupture. The present study aimed to examine and quantify the impacts of different flow stents on idealized configurations of the cerebral artery. In our study, we considered a spherical sidewall aneurysm located on curved and tortuous idealized artery vessels and three stents with different porosities (70, 80 and 90%) for deployment. Using computational fluid dynamics, the local hemodynamics in the presence and absence of the stents were simulated, respectively, under the assumption that the blood flow was unsteady and non-Newtonian. The hemodynamic parameters, such as the intra-aneurysmal flow, velocity field and wall shear stress and its related indices, were examined and compared among the 12 cases simulated. The results illustrated that with the stent deployment, the intra-aneurysmal flow and the wall shear stress and its related indices were considerably modified depending on both stent and aneurysm/artery geometries, and that the intra-aneurysmal relative residence time increased rapidly with decreasing stent porosity in all the vessel configurations. These results also inform the rationale for selecting stents for treating aneurysms of different configurations., This research was funded by the Saskatchewan Health Research Foundation (SHRF grant reference #2784). M. Malvè was supported by grant PRX17/00335 financed by the Spanish Ministry of Education within the National Program 'Salvador de Madariaga'. The support of the Spanish Ministry of Economy, Industry and Competitiveness through research project DPI2017-83259-R (AEI/FEDER, UE) and of the Department of Economic Development of the Navarra Government through research project PC086-087-088 CONDE is highly appreciated. Finally, we gratefully acknowledge the Instituto de Salud Carlos III (ISCIII) through the CIBER-BBN initiative., This research was funded by the Saskatchewan Health Research Foundation (SHRF grant reference #2784). M. Malvé was supported by grant PRX17/00335 financed by the Spanish Ministry of Education within the National Program "Salvador de Madariaga." The support of the Spanish Ministry of Economy, Industry and Competitiveness through research project DPI2017-83259-R (AEI/FEDER, UE) and of the Department of Economic Development of the Navarra Government through research project PC086-087-088 CONDE is highly appreciated. Finally, we gratefully acknowledge the Instituto de Salud Carlos III (ISCIII) through the CIBER-BBN initiative.

The management of complex airway disorders is challenging, as the airway stent placement usually results in several complications. Tissue reaction to the foreign body, poor mechanical properties and inadequate fit of the stent in the airway are some of the reported problems. For this reason, the design of customized biomedical devices to improve the accuracy of the clinical results has recently gained interest. The aim of the present study is to introduce a parametric tool for the design of a new tracheo-bronchial stent that could be capable of improving some of the performances of the commercial devices. The proposed methodology is based on the computer aided design software and on the finite element modeling. The computational results are validated by a parallel experimental work that includes the production of selected stent configurations using the 3D printing technology and their compressive test., The research is supported by the Spanish Ministry of Economy, Industry and Competitiveness through research project DPI2017-83259-R (AEI/FEDER,UE).The support of the Instituto de Salud Carlos III (ISCIII) through the CIBER-BBN initiative is gratefully acknowledged.

Pressurized metered-dose inhalers (pMDI) with or without spacers are commonly used for the treatment of feline inflammatory airway disease. During traditional airways treatments, a substantial amount of drugs are wasted upstream of their target. To study the efficiency of commonly used devices in the transport of inhaled salbutamol, different computational models based on two healthy adult client-owned cats were developed. Computed tomographic images from one cat were used to generate a three-dimensional geometry, and two masks (spherical and conical shapes) and two spacers (10 and 20 cm) completed the models. A second cat was used to generate a second model having an endotracheal tube (ETT) with and without the same spacers. Airflow, droplet spray transport, and deposition were simulated and studied using computational fluid dynamics techniques. Four regions were evaluated: device, upper airways, primary bronchi, and downstream lower airways/parenchyma ('lung'). Regardless of the model, most salbutamol is deposited in devices and/or upper airways. In the first model, particles reaching the lung varied between 5.8 and 25.8%. Compared with the first model, pMDI application through the ETT with or without a spacer had significantly higher percentages of particles reaching the lung (p = 0.006)., Mauro Malvè and Rocío Fernández-Parra gratefully acknowledge the support of the Spanish Ministry of Economy, Industry, and Competitiveness through the research project DPI2017-83259-R (AEI/FEDER, UE).

Tissue engineering scaffolds combined with bioreactors are used to cultivate cells with
the aim of reproducing tissues and organs. The cultivating process is critical due to
the delicate in-vitro environment in which the cells should reproduce. The distribu-
tion of nutrients within the engineered construct depend on the scaffold morphology
and the analysis of the fluid flow and transport phenomena under mechanical loading
when the scaffold is coupled with a bioreactor is crucial for this scope. Unfortunately,
due to the complicated microstructure of the scaffold, it is not possible to perform
this analysis with experiments and numerical simulation can help in this sense. In
this study we have computed the fluid flow and the mass transport of a parametrized
scaffold in perfusion bioreactors analyzing the influence of the microstructure of the
scaffold using the fluid-structure interaction approach. The latter allows considering
the porous construct as compliant yet determining important structural parameters
such as stresses and strains that could be sensed by the cells. The presented model
considered flow perfusion that provided nutrients and mechanical compression. In
particular, we have studied the effect of controllable parameters such as the diam-
eter of the scaffold strand and the porosity on the mechanical stresses and strains,
shear stress and mass transport. The results of this work will help to shed light on
the necessary microenvironment surrounding the cultivated cells improving culturing
scaffold fabrication., The authors acknowledge the financial supports to this project from the Spanish Ministry of Education, Culture and Sport via the National Program“Salvador de Madariaga”(PRX17/00335) and the Saskatchewan Health Research Foundation via the Health Research Group Program (SHRF Reference #2784). Also, the authors thank the CIBER-BBN financed by the Instituto de Salud Carlos III and the Spanish Ministry of Education, Industry and Competitiveness via the research project (DP12017-83259-R).