Researcher:
Lashkarinia, Seyedeh Samaneh

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Seyedeh Samaneh

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Lashkarinia

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Lashkarinia, Seyedeh Samaneh

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2018 - 201912020 - 20238

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    Embryonic aortic arch material properties obtained by optical coherence tomography-guided micropipette aspiration
    (Elsevier Ltd, 2023) Çoban, Gürşan; Yap, Choon Hwai; Department of Mechanical Engineering; N/A; Department of Mechanical Engineering; Lashkarinia, Seyedeh Samaneh; Siddiqui, Hummaira Banu; Pekkan, Kerem; Researcher; PhD Student; Faculty Member; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 161845
    It is challenging to determine the in vivo material properties of a very soft, mesoscale arterial vesselsof size ∼ 80 to 120 μm diameter. This information is essential to understand the early embryonic cardiovascular development featuring rapidly evolving dynamic microstructure. Previous research efforts to describe the properties of the embryonic great vessels are very limited. Our objective is to measure the local material properties of pharyngeal aortic arch tissue of the chick-embryo during the early Hamburger-Hamilton (HH) stages, HH18 and HH24. Integrating the micropipette aspiration technique with optical coherence tomography (OCT) imaging, a clear vision of the aspirated arch geometry is achieved for an inner pipette radius of Rp = 25 μm. The aspiration of this region is performed through a calibrated negatively pressurized micro-pipette. A computational finite element model is developed to model the nonlinear behaviour of the arch structure by considering the geometry-dependent constraints. Numerical estimations of the nonlinear material parameters for aortic arch samples are presented. The exponential material nonlinearity parameter (a) of aortic arch tissue increases statistically significantly from a = 0.068 ± 0.013 at HH18 to a = 0.260 ± 0.014 at HH24 (p = 0.0286). As such, the aspirated tissue length decreases from 53 μm at HH18 to 34 μm at HH24. The calculated NeoHookean shear modulus increases from 51 Pa at HH18 to 93 Pa at HH24 which indicates a statistically significant stiffness increase. These changes are due to the dynamic changes of collagen and elastin content in the media layer of the vessel during development.
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    In vitro measurement of hepatic flow distribution in Fontan vascular conduits: towards rapid validation techniques
    (Elsevier, 2022) Köse, Banu; Şaşmazel, Ahmet; Department of Mechanical Engineering; Department of Mechanical Engineering; Department of Mechanical Engineering; Rasooli, Reza; Lashkarinia, Seyedeh Samaneh; Pekkan, Kerem; Researcher; Researcher; Faculty Member; Department of Mechanical Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; 161845
    Fontan operation is the last stage of single-ventricle surgical reconstructions that connects superior and inferior vena cava (SVC, IVC) to the pulmonary arteries. The key design objectives in total cavopulmonary connections (TCPC) are to achieve low power loss (PL) and balanced hepatic flow distribution (HFD). Computational fluid dynamics (CFD) played a pivotal role in pre-surgical design of single-ventricle patients. However, the clinical application of current CFD techniques is limited due to their complexity, high computational time and untested accuracy for HFD prediction. This study provides a performance assessment of computationally low-cost steady Reynolds-Averaged Navier-Stokes (RANS) k-epsilon turbulent models for simulation of Fontan hemodynamics. The performance is evaluated based on prediction accuracy for three clinically important Fontan hemodynamic indices: HFD, PL and total pulmonary flow split (TPFS). For this purpose, a low-cost experimental technique is developed for rapid quantification of Fontan performance indices. Experiments and simulations are performed for both an idealized and a complex 3D reconstructed patient-specific TCPC. Time-averaged flow data from phase contrast MRI was used as the boundary conditions for the patient-specific model. For the idealized model, different SVC/IVC flow ratios corresponding to different cardiac outputs and Reynolds' numbers were examined. This study revealed that steady RANS k-epsilon models are able to estimate the Fontan hemodynamic indices with acceptable accuracy within minutes. Among these, standard k-epsilon two-layer was found to deliver the best agreement with the in vitro data with an average error percentage of 1.7, 2.0 and, 3.9 for HFD, TPFS and, PL, respectively for all cases.
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    Computational modeling of vascular growth in patient-specific pulmonary arterial patch reconstructions
    (Elsevier Sci Ltd, 2021) Coban, Gursan; Kose, Banu; Salihoglu, Ece; Department of Mechanical Engineering; Department of Mechanical Engineering; Lashkarinia, Seyedeh Samaneh; Pekkan, Kerem; Researcher; Faculty Member; Department of Mechanical Engineering; College of Engineering; College of Engineering
    Recent progress in vascular growth mechanics has involved the use of computational algorithms to address clinical problems with the use of three-dimensional patient specific geometries. The objective of this study is to establish a predictive computational model for the volumetric growth of pulmonary arterial (PA) tissue following complex cardiovascular patch reconstructive surgeries for congenital heart disease patients. For the first time in the literature, the growth mechanics and performance of artificial cardiovascular patches in contact with the growing PA tissue domain is established. An elastic growing material model was developed in the open source FEBio software suite to first examine the surgical patch reconstruction process for an idealized main PA anatomy as a benchmark model and then for the patient-specific PA of a newborn. Following patch reconstruction, high levels of stress and strain are compensated by growth on the arterial tissue. As this growth progresses, the arterial tissue is predicted to stiffen to limit elastic deformations. We simulated this arterial growth up to the age of 18 years, when somatic growth plateaus. Our research findings show that the non-growing patch material remains in a low strain state throughout the simulation timeline, while experiencing high stress hot-spots. Arterial tissue growth along the surgical stitch lines is triggered mainly due to PA geometry and blood pressure, rather than due to material property differences in the artificial and native tissue. Thus, nonuniform growth patterns are observed along the arterial tissue proximal to the sutured boundaries. This computational approach is effective for the pre-surgical planning of complex patch surgeries to quantify the unbalanced growth of native arteries and artificial non-growing materials to develop optimal patch biomechanics for improved postoperative outcomes.
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    Microstructure of early embryonic aortic arch and its reversibility following mechanically altered hemodynamic load release
    (Amer Physiological Soc, 2020) Department of Mechanical Engineering; N/A; N/A; N/A; N/A; Department of Mechanical Engineering; Department of Mechanical Engineering; Department of Mechanical Engineering; Çelik, Merve; Göktaş, Selda; Karakaya, Cansu; Çakıroğlu, Ayşe İdil; Karahüseyinoğlu, Serçin; Lashkarinia, Seyedeh Samaneh; Ermek, Erhan; Pekkan, Kerem; Undergraduate Student; Resercher; Master Student; Researcher; Faculty Member; Researcher; Other; Faculty Member; Department of Mechanical Engineering; College of Sciences; N/A; Graduate School of Sciences and Engineering; N/A; School of Medicine; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; N/A; N/A; 110772; N/A; N/A; 161845
    In the embryonic heart, blood flow is distributed through a bilaterally paired artery system composed of the aortic arches (AAs). The purpose of this study is to establish an understanding of the governing mechanism of microstructural maturation of the AA matrix and its reversibility, toward the desired macroscopic vessel lumen diameter and thickness for healthy, abnormal, and in ovo repaired abnormal mechanical loading. While matrix-remodeling mechanisms were significantly different for normal versus conotruncal banding (CTB), both led to an increase in vessel lumen. Correlated with right-sided flow increase at Hamburger & Hamilton stages 21, intermittent load switching between collagen I and III with elastin and collagen-IV defines the normal process. However, decreases in collagen I. elastin, vascular endothelial growth factor-A, and fibrillin-1 in CTB were recovered almost fully following the CTB-release model, primarily because of the pressure load changes. The complex temporal changes in matrix proteins are illustrated through a predictive finite-element model based on elastin and collagen load-sharing mechanism to achieve lumen area increase and thickness increase resulting from wall shear stress and tissue strain, respectively. The effect of embryonic timing in cardiac interventions on AA microstructure was established where abnormal mechanical loading was selectively restored at the key stage of development. Recovery of the normal mechanical loading via early fetal intervention resulted in delayed microstructural maturation. Temporal elastin increase, correlated with wall shear stress, is required for continuous lumen area growth. NEW & NOTEWORTHY The present study undertakes comparative analyses of the mechanistic differences of the arterial matrix microstructure and dynamics in the three fundamental processes of control, conotruncal banded, and released conotruncal band in avian embryo. Among other findings, this study provides specific evidence on the restorative role of elastin during the early lumen growth process. During vascular development. a novel intermittent load-switching mechanism between elastin and collagen, triggered by a step increase in wall shear stress, governs the chronic vessel lumen cross-sectional area increase. Mimicking the fetal cardiovascular interventions currently performed in humans, the early release of the abnormal mechanical load rescues the arterial microstructure with time lag.
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    Spatiotemporal remodeling of embryonic aortic arch: stress distribution, microstructure, and vascular growth in silico
    (Springer Heidelberg, 2020) N/A; Department of Mechanical Engineering; Department of Mechanical Engineering; Department of Mechanical Engineering; Department of Mechanical Engineering; Department of Mechanical Engineering; Lashkarinia, Seyedeh Samaneh; Çoban, Gürsan; Ermek, Erhan; Çelik, Merve; Pekkan, Kerem; Researcher; Researcher; Other; Undergraduate Student; Faculty Member; Department of Mechanical Engineering; College of Engineering; College of Engineering; College of Engineering; College of Sciences; College of Engineering; N/A; 148688; N/A; N/A; 161845
    The microstructure formaturevessels has been investigated in detail, while there is limited information about theembryonicstages, in spite of their importance in the prognosis of congenital heart defects. It is hypothesized that the embryonic vasculature represents a disorganized but dynamic soft tissue, which rapidly evolves toward a specialized multi-cellular vascular structure under mechanical loading. Here the microstructural evolution process of the embryonic pharyngeal aortic arch structure was simulated using an in ovo validated long-term growth and remodeling computational model, implemented as an in-house FEBio plug-in. Optical coherence tomography-guided servo-null pressure measurements are assigned as boundary conditions through the critical embryonic stages. The accumulation of key microstructural constituents was recorded through zoom confocal microscopy for all six embryonic arch arteries simultaneously. The total amount and the radial variation slope of the collagen along the arch wall thickness in different arch types and for different embryonic times, with different dimension scales, were normalized and compared statistically. The arch growth model shows that the stress levels around the lumen boundary increase from approximate to 270Pa (Stage 18) to a level higher than approximate to 600Pa (Stage 24), depending on matrix constituent production rates, while the homeostatic strain level is kept constant. The statistical tests show that although the total collagen levels differentiate among bilateral positions of the same arch, the shape coefficient of the matrix microstructural gradient changes with embryonic time, proving radial localization, in accordance with numerical model results. In vivo cell number (DAPI) and vascular endothelial growth factor distributions followed similar trends.
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    Computational pre-surgical planning of arterial patch reconstruction: parametric limits and in vitro validation
    (Springer, 2018) Salihoglu, Ece; Yerebakan, Can; Department of Mechanical Engineering; Department of Molecular Biology and Genetics; Department of Mechanical Engineering; N/A; Lashkarinia, Seyedeh Samaneh; Pişkin, Şenol; Pekkan, Kerem; Bozkaya, Tijen Alkan; Researcher; Researcher; Faculty Member; Doctor; Department of Molecular Biology and Genetics; Department of Mechanical Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; N/A; N/A; Koç University Hospital; N/A; 148702; 161845; 143793
    Surgical treatment of congenital heart disease (CHD) involves complex vascular reconstructions utilizing artificial and native surgical materials. A successful surgical reconstruction achieves an optimal hemodynamic profile through the graft in spite of the complex post-operative vessel growth pattern and the altered pressure loading. This paper proposes a new in silico patient-specific pre-surgical planning framework for patch reconstruction and investigates its computational feasibility. The proposed protocol is applied to the patch repair of main pulmonary artery (MPA) stenosis in the Tetralogy of Fallot CHD template. The effects of stenosis grade, the three-dimensional (3D) shape of the surgical incision and material properties of the artificial patch are investigated. The release of residual stresses due to the surgical incision and the extra opening of the incision gap for patch implantation are simulated through a quasi-static finite-element vascular model with shell elements. Implantation of different unloaded patch shapes is simulated. The patched PA configuration is pressurized to the physiological post-operative blood pressure levels of 25 and 45 mmHg and the consequent post-operative stress distributions and patched artery shapes are computed. Stress-strain data obtained in-house, through the biaxial tensile tests for the mechanical properties of common surgical patch materials, Dacron, Polytetrafluoroethylene, human pericardium and porcine xenopericardium, are employed to represent the mechanical behavior of the patch material. Finite-element model is experimentally validated through the actual patch surgery reconstructions performed on the 3D printed anatomical stenosis replicas. The post-operative recovery of the initially narrowed lumen area and post-optortuosity are quantified for all modeled cases. A computational fluid dynamics solver is used to evaluate post-operative pressure drop through the patch-reconstructed outflow tract. According to our findings, the shorter incisions made at the throat result in relatively low local peak stress values compared to other patch design alternatives. Longer cut and double patch cases are the most effective in repairing the initial stenosis level. After the patch insertion, the pressure drop in the artery due to blood flow decreases from 9.8 to 1.35 mm Hg in the conventional surgical configuration. These results are in line with the clinical experience where a pressure gradient at or above 50 mm Hg through the MPA can be an indication to intervene. The main strength of the proposed pre-surgical planning framework is its capability to predict the intraoperative and post-operative 3D vascular shape changes due to intramural pressure, cut length and configuration, for both artificial and native patch materials.
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    PublicationOpen Access
    Patient-specific hemodynamics of new coronary artery bypass configurations
    (Springer, 2020) Pişkin, Senol; Tenekecioğlu, Erhan; Karagöz, Haldun; N/A; Department of Mechanical Engineering; Rezaeimoghaddam, Mohammad; Oğuz, Gökçe Nur; Lashkarinia, Seyedeh Samaneh; Pekkan, Kerem; Ateş, Mehmet Şanser; Bozkaya, Tijen Alkan; Researcher; Faculty Member; Doctor; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; Koç University Hospital; N/A; N/A; N/A; 161845; N/A; N/A
    Purpose: this study aims to quantify the patient-specific hemodynamics of complex conduit routing configurations of coronary artery bypass grafting (CABG) operation which are specifically suitable for off-pump surgeries. Coronary perfusion efficacy and local hemodynamics of multiple left internal mammary artery (LIMA) with sequential and end-to-side anastomosis are investigated. Using a full anatomical model comprised of aortic arch and coronary artery branches the optimum perfusion configuration in multi-vessel coronary artery stenosis is desired. Methodology: two clinically relevant CABG configurations are created using a virtual surgical planning tool where for each configuration set, the stenosis level, anastomosis distance and angle were varied. A non-Newtonian computational fluid dynamics solver in OpenFOAM incorporated with resistance boundary conditions representing the coronary perfusion physiology was developed. The numerical accuracy is verified and results agreed well with a validated commercial cardiovascular flow solver and experiments. For segmental performance analysis, new coronary perfusion indices to quantify deviation from the healthy scenario were introduced. Results: the first simulation configuration set;-a CABG targeting two stenos sites on the left anterior descending artery (LAD), the LIMA graft was capable of 31 mL/min blood supply for all the parametric cases and uphold the healthy LAD perfusion in agreement with the clinical experience. In the second end-to-side anastomosed graft configuration set;-the radial artery graft anastomosed to LIMA, a maximum of 64 mL/min flow rate in LIMA was observed. However, except LAD, the obtuse marginal (OM) and second marginal artery (m2) suffered poor perfusion. In the first set, average wall shear stress (WSS) were in the range of 4 to 35 dyns/cm(2)for in LAD. Nevertheless, for second configuration sets the WSS values were higher as the LIMA could not supply enough blood to OM and m2. Conclusion: the virtual surgical configurations have the potential to improve the quality of operation by providing quantitative surgical insight. The degree of stenosis is a critical factor in terms of coronary perfusion and WSS. The sequential anastomosis can be done safely if the anastomosis angle is less than 90 degrees regardless of degree of stenosis. The smaller proposed perfusion index value,O(0.04 - 0) x 10(2), enable us to quantify the post-op hemodynamic performance by comparing with the ideal healthy physiological flow.
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    PublicationOpen Access
    Soft-tissue material properties and mechanogenetics during cardiovascular development
    (Multidisciplinary Digital Publishing Institute (MDPI), 2022) Department of Mechanical Engineering; Pekkan, Kerem; Siddiqui, Hummaira Banu; TRUE, Sedat; Lashkarinia, Seyedeh Samaneh; Faculty Member; Master Student; Researcher; Department of Mechanical Engineering; College of Engineering; Graduate School of Social Sciences and Humanities; 161845; N/A; N/A; N/A
    During embryonic development, changes in the cardiovascular microstructure and material properties are essential for an integrated biomechanical understanding. This knowledge also enables realistic predictive computational tools, specifically targeting the formation of congenital heart defects. Material characterization of cardiovascular embryonic tissue at consequent embryonic stages is critical to understand growth, remodeling, and hemodynamic functions. Two biomechanical loading modes, which are wall shear stress and blood pressure, are associated with distinct molecular pathways and govern vascular morphology through microstructural remodeling. Dynamic embryonic tissues have complex signaling networks integrated with mechanical factors such as stress, strain, and stiffness. While the multiscale interplay between the mechanical loading modes and microstructural changes has been studied in animal models, mechanical characterization of early embryonic cardiovascular tissue is challenging due to the miniature sample sizes and active/passive vascular components. Accordingly, this comparative review focuses on the embryonic material characterization of developing cardiovascular systems and attempts to classify it for different species and embryonic timepoints. Key cardiovascular components including the great vessels, ventricles, heart valves, and the umbilical cord arteries are covered. A state-of-the-art review of experimental techniques for embryonic material characterization is provided along with the two novel methods developed to measure the residual and von Mises stress distributions in avian embryonic vessels noninvasively, for the first time in the literature. As attempted in this review, the compilation of embryonic mechanical properties will also contribute to our understanding of the mature cardiovascular system and possibly lead to new microstructural and genetic interventions to correct abnormal development.
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    PublicationOpen Access
    A novel Fontan Y-graft for interrupted inferior vena cava and azygos continuation
    (Oxford University Press (OUP), 2022) Çicek, Murat; Köse, Banu; Yılmaz, Emine Hekim; Aydemir, Numan Ali; Özkök, Serçin; Yurtseven, Nurgül; Erdem, Hasan; Sasmazel, Ahmet; Department of Mechanical Engineering; Lashkarinia, Seyedeh Samaneh; Pekkan, Kerem; Rezaeimoghaddam, Mohammad; Rasooli, Reza; Faculty Member; Researcher; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 161845; N/A; N/A
    Objectives: to evaluate the hemodynamicdynamic advantage of a new Fontan surgical template that is intended for complex single-ventricle patients with interrupted inferior vena cava-azygos and hemi-azygos continuation. The new technique has emerged from a comprehensive pre-surgical simulation campaign conducted to facilitate a balanced hepatic flow and somatic Fontan pathway growth after Kawashima procedure. Methods: for 9 patients, aged 2 to 18 years, majority having poor preoperative oxygen saturation, a pre-surgical computational fluid dynamics customization is conducted. Both the traditional Fontan pathways and the proposed novel Y-graft templates are considered. Numerical model was validated against in vivo phase-contrast magnetic resonance imaging data and in vitro experiments. Results: the proposed template is selected and executed for 6 out of the 9 patients based on its predicted superior hemodynamic performance. Pre-surgical simulations performed for this cohort indicated that flow from the hepatic veins (HEP) do not reach to the desired lung. The novel Y-graft template, customized via a right- or left-sided displacement of the total cavopulmonary connection anastomosis location resulted a drastic increase in HEP flow to the desired lung. Orientation of HEP to azygos direct shunt is found to be important as it can alter the flow pattern from 38% in the caudally located direct shunt to 3% in the cranial configuration with significantly reversed flow. The postoperative measurements prove that oxygen saturation increased significantly (P-value = 0.00009) to normal levels in 1 year follow-up. Conclusions: the new Y-graft template, if customized for the individual patient, is a viable alternative to the traditional surgical pathways. This template addresses the competing hemodynamic design factors of low physiological venous pressure, high postoperative oxygen saturation, low energy loss and balanced hepatic growth factor distribution possibly assuring adequate lung development.