Cardiovascular Engineering and Technology最新文献

{"title":"Development of Novel 3D Spheroids for Discrete Subaortic Stenosis.","authors":"Sunita Brimmer, Pengfei Ji, Ravi K Birla, Jeffrey S Heinle, Jane K Grande-Allen, Sundeep G Keswani","doi":"10.1007/s13239-024-00746-x","DOIUrl":"https://doi.org/10.1007/s13239-024-00746-x","url":null,"abstract":"<p><p>In this study, we propose a new method for bioprinting 3D Spheroids to study complex congenital heart disease known as discrete subaortic stenosis (DSS). The bioprinter allows us to manipulate the extrusion pressure to change the size of the spheroids, and the alginate porosity increases in size over time. The spheroids are composed of human umbilical vein endothelial cells (HUVECs), and we demonstrated that pressure and time during the bioprinting process can modulate the diameter of the spheroids. In addition, we used Pluronic acid to maintain the shape and position of the spheroids. Characterization of HUVECs in the spheroids confirmed their uniform distribution and we demonstrated cell viability as a function of time. Compared to traditional 2D cell cultures, the 3D spheroids model provides more relevant physiological environments, making it valuable for drug testing and therapeutic applications.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142570198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Relative Effects of Wall and Intraluminal Thrombus Constitutive Material Properties in Abdominal Aortic Aneurysm Wall Stress.","authors":"Vivian Reyna, Niusha Fathesami, Wei Wu, Satish C Muluk, Victor De Oliveira, Ender A Finol","doi":"10.1007/s13239-024-00757-8","DOIUrl":"https://doi.org/10.1007/s13239-024-00757-8","url":null,"abstract":"<p><strong>Introduction: </strong>An abdominal aortic aneurysm (AAA) is a dilation localized in the infrarenal segment of the abdominal aorta that can expand continuously and rupture if left untreated. Computational methods such as finite element analysis (FEA) are widely used with in silico models to calculate biomechanical predictors of rupture risk while choosing constitutive material properties for the AAA wall and intraluminal thrombus (ILT).</p><p><strong>Methods: </strong>In the present work, we investigated the effect of different constitutive material properties for the wall and ILT on 21 idealized and 10 unruptured patient-specific AAA geometries. Three material properties were used to characterize the wall and two for the ILT, leading to six material model combinations for each AAA geometry subject to appropriate boundary conditions.</p><p><strong>Results: </strong>The results of the FEA simulations indicate significant differences in the average peak wall stress (PWS), 99th percentile wall stress (99th WS), and spatially averaged wall stress (SAWS) for all AAA geometries subject to the choice of a material model combination. Specifically, using a material model combination with a compliant ILT yielded statistically higher wall stresses compared to using a stiff ILT, irrespective of the constitutive equation used to model the AAA wall.</p><p><strong>Discussion: </strong>This work provides quantitative insight into the variability of the wall stress distributions ensuing from AAA FEA modeling due to its strong dependency on population-averaged soft tissue material characterizations. This dependency leads to uncertainty about the true biomechanical state of stress of an individual AAA and the subsequent assessment of its rupture risk.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142523665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Influence of Material Properties and Wall Thickness on Predicted Wall Stress in Ascending Aortic Aneurysms: A Finite Element Study.","authors":"Yu Zhu, Selene Pirola, M Yousuf Salmasi, Sumesh Sasidharan, Serena M Fisichella, Declan P O'Regan, James E Moore, Thanos Athanasiou, Xiao Yun Xu","doi":"10.1007/s13239-024-00756-9","DOIUrl":"https://doi.org/10.1007/s13239-024-00756-9","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Purpose: &lt;/strong&gt;Finite element analysis (FEA) has been used to predict wall stress in ascending thoracic aortic aneurysm (ATAA) in order to evaluate risk of dissection or rupture. Patient-specific FEA requires detailed information on ATAA geometry, loading conditions, material properties, and wall thickness. Unfortunately, measuring aortic wall thickness and mechanical properties non-invasively poses a significant challenge, necessitating the use of non-patient-specific data in most FE simulations. This study aimed to assess the impact of employing non-patient-specific material properties and wall thickness on ATAA wall stress predictions.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;FE simulations were performed on 13 ATAA geometries reconstructed from computed tomography angiography (CTA) images. Patient-specific material properties and wall thicknesses were made available from a previous study where uniaxial tensile testing was performed on tissue samples obtained from the same patients. The ATAA wall models were discretised with hexahedral elements and prestressed. For each ATAA model, FE simulations were conducted using patient-specific material properties and wall thicknesses, and group-mean values derived from all tissue samples included in the same experimental study. Literature-based material property and wall thickness were also obtained from the literature and applied to 4 representative cases. Additional FE simulations were performed on these 4 cases by employing group-mean and literature-based wall thicknesses.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;FE simulations using the group-mean material property produced peak wall stresses comparable to those obtained using patient-specific material properties, with a mean deviation of 7.8%. Peak wall stresses differed by 20.8% and 18.7% in patients with exceptionally stiff or compliant walls, respectively. Comparison to results using literature-based material properties revealed larger discrepancies, ranging from 5.4% to 28.0% (mean 20.1%). Bland-Altman analysis showed significant discrepancies in areas of high wall stress, where wall stress obtained using patient-specific and literature-based properties differed by up to 674 kPa, compared to 227 kPa between patient-specific and group-mean properties. Regarding wall thickness, using the literature-based value resulted in even larger discrepancies in predicted peak stress, ranging from 24.2% to 30.0% (mean 27.3%). Again, using the group-mean wall thickness offered better predictions with a difference less than 5% in three out of four cases. While peak wall stresses were most affected by the choice of mechanical properties or wall thickness, the overall distribution of wall stress hardly changed.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Our study demonstrated the importance of incorporating patient-specific material properties and wall thickness in FEA for risk prediction of aortic dissection or rupture. Our future efforts will focus on developing inverse ","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142512964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Activation of a Soft Robotic Left Ventricular Phantom Embedded in a Closed-Loop Cardiovascular Simulator: A Computational and Experimental Analysis.","authors":"Nele Demeersseman, Maria Rocchi, Heleen Fehervary, Guillermo Fernández Collazo, Bart Meyns, Libera Fresiello, Nele Famaey","doi":"10.1007/s13239-024-00755-w","DOIUrl":"https://doi.org/10.1007/s13239-024-00755-w","url":null,"abstract":"<p><strong>Purpose: </strong>Cardiovascular simulators are used in the preclinical testing phase of medical devices. Their reliability increases the more they resemble clinically relevant scenarios. In this study, a physiologically actuated soft robotic left ventricle (SRLV) embedded in a hybrid (in silico- in vitro) simulator of the cardiovascular system is presented, along with its experimental and computational analysis.</p><p><strong>Methods: </strong>A SRLV phantom, developed from a patient's CT scan using polyvinyl alcohol (PVA), is embedded in a hybrid cardiovascular simulator. We present an activation method in which the hydraulic pressure external ( <math> <mrow><msub><mi>P</mi> <mi>e</mi></msub> <mrow><mo>(</mo> <mi>t</mi> <mo>)</mo></mrow> </mrow> </math> ) to the SRLV is continuously adapted to regulate the left ventricular volume ( <math> <mrow><msub><mi>V</mi> <mi>i</mi></msub> <mrow><mo>(</mo> <mi>t</mi> <mo>)</mo></mrow> </mrow> </math> ), considering the geometry and material behavior of the SRLV and the left ventricular pressure ( <math> <mrow><msub><mi>P</mi> <mi>i</mi></msub> <mrow><mo>(</mo> <mi>t</mi> <mo>)</mo></mrow> </mrow> </math> ). This activation method is verified using a finite element (FE) model of the SRLV and validated in the hybrid simulator. Different hemodynamic profiles are presented to test the flexibility of the method.</p><p><strong>Results: </strong>Both the FE model and hybrid simulator could represent the desired in silico data ( <math> <mrow><msub><mi>P</mi> <mi>i</mi></msub> <mrow><mo>(</mo> <mi>t</mi> <mo>)</mo></mrow> </mrow> </math> , <math> <mrow><msub><mi>V</mi> <mi>i</mi></msub> <mrow><mo>(</mo> <mi>t</mi> <mo>)</mo></mrow> </mrow> </math> ) with the implemented activation method, with deviations below 8.09% in the FE model and mainly < 10% errors in the hybrid simulator. Only two measurements out of 32 exceeded the 10% threshold due to simulator setup limitations.</p><p><strong>Conclusion: </strong>The activation method effectively allows to represent various pressure-volume loops, as verified numerically, and validated experimentally in the hybrid simulator. This work presents a high-fidelity platform designed to simulate cardiovascular conditions, offering a robust foundation for future testing of cardiovascular medical devices under physiological conditions.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142480770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Characterisation of a Novel Z-Shaped Inductor-Based Wireless Implantable Sensor for Surveillance of Abdominal Aortic Aneurysm Post-Endovascular Repair.","authors":"Nuno P Silva, Bilal Amin, Eoghan Dunne, Martin O'Halloran, Adnan Elahi","doi":"10.1007/s13239-024-00753-y","DOIUrl":"https://doi.org/10.1007/s13239-024-00753-y","url":null,"abstract":"<p><strong>Purpose: </strong>An abdominal aortic aneurysm (AAA) is a dilation of the aorta over its normal diameter (> 3 cm). The minimally invasive treatment adopted uses a stent graft to be deployed into the aneurysm by a catheter to flow blood through it. However, this approach demands frequent monitoring using imaging modalities that involve radiation and contrast agents. Moreover, the multiple follow-ups are expensive, time-consuming, and resource-demanding for healthcare systems. This study proposes a novel wireless implantable medical sensor (WIMS) to measure the aneurysm growth after the endovascular repair.</p><p><strong>Methods: </strong>The proposed sensor is composed of a Z-shaped inductor, similar to a stent ring. The proposed design of the sensor is explored by investigating the inductance, resistance, and quality factor of different possible geometries related to a Z-shaped configuration, such as the height and number of struts. The study is conducted through a combination of numerical simulations and experimental tests, with the assessment being carried out at a frequency of 13.56 MHz.</p><p><strong>Results: </strong>The results show that a higher number of struts result in higher values of inductance and resistance. On the other hand, the increase in the number of struts decreases the quality factor of the Z-shaped inductor due to the presence of high resistance from the inductor. Moreover, it is observed that the influence of the number of struts present in the Z-shaped inductor tends to decrease for larger radii.</p><p><strong>Conclusions: </strong>The numerical and experimental evaluation concludes the ability of the proposed sensor to measure the size of the aneurysm.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142395287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite Element Simulation of Opening Angle Response of Porcine Aortas Using Layer Specific GAG Distributions in One and Two Layered Solid Matrices.","authors":"Noor M Ghadie, Jean-Philippe St-Pierre, Michel R Labrosse","doi":"10.1007/s13239-024-00754-x","DOIUrl":"https://doi.org/10.1007/s13239-024-00754-x","url":null,"abstract":"<p><strong>Purpose: </strong>Recent studies have identified an effect of glycosaminoglycans (GAG) on residual stresses in the aorta, underscoring the need to better understand their biomechanical roles.</p><p><strong>Methods: </strong>Aortic ring models for each of the ascending, arch and descending thoracic regions of the porcine thoracic aorta were created in FEBioStudio, using a framework that incorporates the Donnan osmotic swelling in a porous solid matrix. The distribution of fixed charge densities (FCD) through the thickness of the tissue was prescribed as calculated from experimentally quantified sulfated GAG mural distributions. Material parameters for the solid matrix, modeled using a Holmes-Mow constitutive law, were optimized using data from biaxial tensile tests. In addition to modelling the solid matrix as one layer, two layers were considered to capture the differences between the intima-media and the adventitia, for which various stiffness ratios were explored.</p><p><strong>Results: </strong>As the stiffness of the adventitia with respect to that of the media increased, the simulated opening angle increased. The opening angle also decreased from the ascending to the descending thoracic region in both one- and two-layered solid matrices models. The simulated results were compared against the experimental contribution of GAG to the opening angle, as previously quantified via enzymatic GAG-depletion. When using one layer for the solid matrix, the errors between the simulated opening angles and the experimental contribution of GAG to the opening angle were respectively 28%, 15% and 23% in the ascending, arch and descending thoracic regions. When using two layers for the solid matrix, the smallest errors in the ascending and arch regions were 21% and 5% when the intima-media was modelled as 10 times stiffer, and as twice stiffer than the adventitia, respectively, and 23% in the descending thoracic regions when the intima-media and adventitia shared similar mechanical properties.</p><p><strong>Conclusions: </strong>Overall, this study demonstrates that GAG partially contribute to circumferential residual stress, and that GAG swelling is one of several regulators of the opening angle. The minor discrepancies between simulated and experimental opening angles imply that the contribution of GAG extends beyond mere swelling, aligning with previous experimental indications of their interaction with ECM fibers in determining the opening angle.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142367334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deforming Patient-Specific Models of Vascular Anatomies to Represent Stent Implantation via Extended Position Based Dynamics.","authors":"Jonathan Pham, Fanwei Kong, Doug L James, Jeffrey A Feinstein, Alison L Marsden","doi":"10.1007/s13239-024-00752-z","DOIUrl":"10.1007/s13239-024-00752-z","url":null,"abstract":"<p><strong>Purpose: </strong>Angioplasty with stent placement is a widely used treatment strategy for patients with stenotic blood vessels. However, it is often challenging to predict the outcomes of this procedure for individual patients. Image-based computational fluid dynamics (CFD) is a powerful technique for making these predictions. To perform CFD analysis of a stented vessel, a virtual model of the vessel must first be created. This model is typically made by manipulating two-dimensional contours of the vessel in its pre-stent state to reflect its post-stent shape. However, improper contour-editing can cause invalid geometric artifacts in the resulting mesh that then distort the subsequent CFD predictions. To address this limitation, we have developed a novel shape-editing method that deforms surface meshes of stenosed vessels to create stented models.</p><p><strong>Methods: </strong>Our method uses physics-based simulations via Extended Position Based Dynamics to guide these deformations. We embed an inflating stent inside a vessel and apply collision-generated forces to deform the vessel and expand its cross-section.</p><p><strong>Results: </strong>We demonstrate that this technique is feasible and applicable for a wide range of vascular anatomies, while yielding clinically compatible results. We also illustrate the ability to parametrically vary the stented shape and create models allowing CFD analyses.</p><p><strong>Conclusion: </strong>Our stenting method will help clinicians predict the hemodynamic results of stenting interventions and adapt treatments to achieve target outcomes for patients. It will also enable generation of synthetic data for data-intensive applications, such as machine learning, to support cardiovascular research endeavors.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142362462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comments on: \"Preclinical Proof-of-Concept of a Minimally Invasive Direct Cardiac Compression Device for Pediatric Heart Support\".","authors":"T Triwiyanto, I Putu Alit Pawana, Sari Luthfiyah","doi":"10.1007/s13239-024-00751-0","DOIUrl":"https://doi.org/10.1007/s13239-024-00751-0","url":null,"abstract":"","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142332382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a High-Fidelity Benchtop Model for Simultaneous Flow, Pressure, and Imaging Assessment of Transarterial Embolization Procedures","authors":"Prateek C. Gowda, Robert M. Weinstein, Akanksha Bhargava, Janaka Senarathna, Ryan Q. Stewart, Pallavi V. Ekbote, Mantej Singh, Emily Guan, Serena Banghar, Arvind P. Pathak, Clifford R. Weiss","doi":"10.1007/s13239-024-00749-8","DOIUrl":"https://doi.org/10.1007/s13239-024-00749-8","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Purpose</h3><p>The development of new endovascular technologies for transarterial embolization has relied on animal studies to validate efficacy before clinical trials are undertaken. Because embolizations in animals and patients are primarily conducted with fluoroscopy alone, local hemodynamic changes are not assessed during testing. However, such hemodynamic metrics could be important indicators of procedure efficacy that could support improved patient outcomes, such as via the determination of procedural endpoints. The purpose of this study is to create a high-fidelity benchtop system for multiparametric (i.e., hemodynamic and imaging) assessment of transarterial embolization procedures.</p><h3 data-test=\"abstract-sub-heading\">Methods</h3><p>The benchtop system consists of a 3D printed, anatomically accurate vascular phantom; a flow loop with a cardiac output simulator; a high-speed video camera; and pressure transducers and flow meters. This system enabled us to vary the heart rate and blood pressure and to simulate clinically relevant hemodynamic states, such as healthy adult, aortic regurgitation, and hypovolemic shock.</p><h3 data-test=\"abstract-sub-heading\">Results</h3><p>With our radiation-free angiography-mimetic imaging system, we could simultaneously assess gauge pressure and flow values during transarterial embolization. We demonstrated the feasibility of recapitulating the digital subtraction angiography workflow. Finally, we highlighted the utility of this system by characterizing the relationship between an imaging-based metric of procedural endpoint and intravascular flow. We also characterized hemodynamic changes associated with particle embolization within a branch of the hepatic artery and found them to be within reported patient data.</p><h3 data-test=\"abstract-sub-heading\">Conclusion</h3><p>Our benchtop vascular system was low-cost and reproduced transarterial embolization-related hemodynamic phenomena with high fidelity. We believe that this novel platform enables the characterization of patient physiology, novel catheterization devices, and techniques.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benchtop Flow Stasis Quantification: In Vitro Methods and In Vivo Possibilities","authors":"Vahid Sadri, Prem A. Midha, Immanuel David Madukauwa-David, Norihiko Kamioka, Phillip M. Trusty, Priya J. Nair, Samuel Cohen, Vrishank Raghav, Rahul Sharma, Vasilis Babaliaros, Ajit P. Yoganathan","doi":"10.1007/s13239-024-00750-1","DOIUrl":"https://doi.org/10.1007/s13239-024-00750-1","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Purpose</h3><p>Neo-sinus flow stasis has ben correlated with transcatheter heart valve (THV) thrombosis severity and occurrence. Standard benchtop flow field quantification techniques require optical access or modified prosthesis models that may not reflect the true nature of the original valve. <i>En face</i> and fluoroscopic videodensitometry enable visualization of washout in regions otherwise unviewable.</p><h3 data-test=\"abstract-sub-heading\">Methods</h3><p>This study compares two in vitro methods of assessing flow stasis in scenarios with insufficient optical access for traditional techniques such as particle image velocimetry (PIV). A series of seven paired experiments were conducted using a previously described laser-enhanced video densitometry (LEVD) and fluoroscopic video densitometry (FVD). Both sets of experiments were analyzed to calculate washout time as a measure of flow stasis. A novel flow stasis measure termed contrast attenuation ratio (CAR) is proposed as a viable single measure of flow stasis obtainable from only a small number of cardiac cycles of in vitro or in vivo fluoroscopic data. Retrospective fluoroscopic datasets (<i>n</i> = 72) were analyzed to assess the feasibility of obtaining this metric from routine clinical practice and its ability to stratify results.</p><h3 data-test=\"abstract-sub-heading\">Results</h3><p>Neo-sinus flow stasis calculated from in vitro fluoroscopy was well correlated with LEVD (r² = 0.77, <i>p</i> = 0.009). The newly proposed CAR metric showed good agreement with the commonly used “washout time” measure of flow stasis (r² = 0.91, <i>p</i> &lt; 0.001) while allowing for assessment with incomplete or truncated data. As a proof of concept, CAR was measured in 72 consecutive retrospective fluoroscopic datasets. CAR averaged 10.6 ± 4.6% with a range of 1.5–20.3% in these patients.</p><h3 data-test=\"abstract-sub-heading\">Conclusions</h3><p>This study demonstrates two in vitro methods that can be used to assess relative flow stasis in otherwise optically inaccessible regions surrounding cardiac or vascular implants. In addition, the fluoroscopic benchtop technique was used to validate a metric that allows for extension to routine clinical fluoroscopy. This contrast attenuation ratio (CAR) metric was found to be both accurate and clinically obtainable, and potentially offers a new method for valve thrombosis risk stratification.</p>","PeriodicalId":54322,"journal":{"name":"Cardiovascular Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":1.8,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}