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Kandi R, Pandey PM. Statistical modelling and optimization of print quality and mechanical properties of customized tubular scaffolds fabricated using solvent-based extrusion 3D printing process. Proc Inst Mech Eng H 2021; 235:1421-1438. [PMID: 34269125 DOI: 10.1177/09544119211032012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Tissue-engineered tubular scaffolds offer huge potential to heal or replace the diseased organ parts like blood vessels, trachea, oesophagus and ureter. However, manufacturing these scaffolds in various scales and shapes is always challenging and requires progressive technology. Developing a flexible and accurate manufacturing method is a major developmental direction in the field of tubular scaffold fabrication. In this context, the present work presents a novel solvent-based extrusion 3D printing which allows extruding over a rotating mandrel to fabricate tubular scaffolds of polycaprolactone (PCL) and polyurethane (PU). Experimental runs were planned as per the central composite design (CCD) to evaluate the effects of input parameters like infill density, layer thickness, print speed and percentage of PU on the output responses like printing quality and mechanical characteristics. The printing quality was quantified by measuring average surface roughness of the printed scaffolds and mechanical properties were evaluated by measuring radial compressive load, and percentage of elongation. The experimental investigations revealed that printing quality was improved at higher infill densities and was deteriorated at higher print speeds and layer thicknesses. Similarly, the radial compressive load was improved with the increase in infill density and was decreased with an increase in layer thickness, print speed and percentage of PU. The percentage of elongation was found to improve at higher infill densities and percentages of PU and was reduced with an increase in layer thickness and print speed. Additionally, a multi-objective optimization using Genetic Algorithm was used to evaluate the optimum conditions to minimize surface roughness and maximizing radial compression load and percentage of elongation. Finally, a case study was performed by comparing the mechanical properties of tubular organs and scaffolds from the existing reports and results of the present work.
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Affiliation(s)
- Rudranarayan Kandi
- Department of Mechanical Engineering, Indian Institute of Technology, New Delhi, Delhi, India
| | - Pulak Mohan Pandey
- Department of Mechanical Engineering, Indian Institute of Technology, New Delhi, Delhi, India
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Scafa Udriște A, Niculescu AG, Grumezescu AM, Bădilă E. Cardiovascular Stents: A Review of Past, Current, and Emerging Devices. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2498. [PMID: 34065986 PMCID: PMC8151529 DOI: 10.3390/ma14102498] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/10/2021] [Accepted: 05/10/2021] [Indexed: 12/11/2022]
Abstract
One of the leading causes of morbidity and mortality worldwide is coronary artery disease, a condition characterized by the narrowing of the artery due to plaque deposits. The standard of care for treating this disease is the introduction of a stent at the lesion site. This life-saving tubular device ensures vessel support, keeping the blood-flow path open so that the cardiac muscle receives its vital nutrients and oxygen supply. Several generations of stents have been iteratively developed towards improving patient outcomes and diminishing adverse side effects following the implanting procedure. Moving from bare-metal stents to drug-eluting stents, and recently reaching bioresorbable stents, this research field is under continuous development. To keep up with how stent technology has advanced in the past few decades, this paper reviews the evolution of these devices, focusing on how they can be further optimized towards creating an ideal vascular scaffold.
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Affiliation(s)
- Alexandru Scafa Udriște
- Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.S.U.); (E.B.)
- Cardiology Department, Clinical Emergency Hospital Bucharest, 014461 Bucharest, Romania
| | - Adelina-Gabriela Niculescu
- Faculty of Engineering in Foreign Languages, University Politehnica of Bucharest, 060042 Bucharest, Romania;
| | - Alexandru Mihai Grumezescu
- Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania
- Research Institute of the University of Bucharest—ICUB, University of Bucharest, 050657 Bucharest, Romania
| | - Elisabeta Bădilă
- Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.S.U.); (E.B.)
- Internal Medicine Department, Clinical Emergency Hospital Bucharest, 014461 Bucharest, Romania
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Nada A, Hassan MA, Fakhr MA, El-Wakad MTI. Studying the effect of stent thickness and porosity on post-stent implantation hemodynamics. J Med Eng Technol 2021; 45:408-416. [PMID: 33945392 DOI: 10.1080/03091902.2021.1912204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This study investigates the effect of stent thickness and stent porosity which are important factors determining the post-treatment intra-aneurysmal hemodynamics. The study uses computational fluid dynamics (CFD) to estimate the hemodynamic behaviour: flow velocity, pressure distributions, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), besides relative residence time (RRT) blood flow distribution in a proposed stent and three other commercially available stents. The hemodynamic behaviour is compared between four different cases. In each case, each stent has the specific thickness and porosity values. The results show that the velocity magnitude inside the sac declined in thinner stents and lower porosity stents, TAWSS on the aneurysmal wall declined linearly in lower porosity stents, OSI and RRT increased obviously in thicker stents and higher porosity stents. Finally, the results conclude that the stent with the lowest thickness and porosity has the best performance that leads to post-stent thrombus formation and healing. However, the proposed stent design, a more porous construct, has a higher RRT compared to the used commercially available stents, which helps promote the thrombus growth inside the aneurysm sac.
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Affiliation(s)
- Ayat Nada
- Department of Computers and Systems, Electronics Research Institute, Giza, Egypt
| | - Mohammed A Hassan
- Department of Biomedical Engineering, Faculty of Engineering, Helwan University, Cairo, Egypt
| | - Mahmoud A Fakhr
- Department of Computers and Systems, Electronics Research Institute, Giza, Egypt
| | - Mohamed Tarek I El-Wakad
- Department of Biomedical Engineering, Faculty of Engineering and Technology, Future University, Cairo, Egypt
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Yan S, Song C, Si Y, Zhao Y. Design of non-equal-strut stent hoops for structural optimization of thoracic aortic stent-grafts. MINIM INVASIV THER 2020; 31:58-71. [PMID: 32233714 DOI: 10.1080/13645706.2020.1745849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Background: Endovascular aortic aneurysm repair (EVAR) with stent-grafts is used widely for the treatment of thoracic aortic aneurysms (TAA). Inappropriate design of stent-grafts may lead to complications such as endoleak, stent-graft migration and new entries, causes of which may be inappropriate radial support force or insufficient longitudinal flexibility of the stent-grafts.Material and methods: To improve the mechanical performance of the stent-grafts, a type of non-equal-strut stent hoops was proposed, and the influence of structural parameters on the mechanical performance was studied.Results: Results of numerical simulation and physical experiments show that by using the proposed non-equal-strut stent hoops, radial support force and longitudinal flexibility of stent-grafts can be reconciled and balanced.Conclusion: Results of this study could be used to facilitate radial force control and longitudinal flexibility enhancement in the design of aortic stent-grafts.
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Affiliation(s)
- Shiju Yan
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Chengli Song
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Yi Si
- Department of Vascular Surgery, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China
| | - Yiwen Zhao
- School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai, China
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CFD-Based Comparison Study of a New Flow Diverting Stent and Commercially-Available Ones for the Treatment of Cerebral Aneurysms. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9071341] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
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 70 % ) 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.
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Chepelev L, Wake N, Ryan J, Althobaity W, Gupta A, Arribas E, Santiago L, Ballard DH, Wang KC, Weadock W, Ionita CN, Mitsouras D, Morris J, Matsumoto J, Christensen A, Liacouras P, Rybicki FJ, Sheikh A. Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios. 3D Print Med 2018; 4:11. [PMID: 30649688 PMCID: PMC6251945 DOI: 10.1186/s41205-018-0030-y] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/19/2018] [Indexed: 02/08/2023] Open
Abstract
Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.
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Affiliation(s)
- Leonid Chepelev
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Nicole Wake
- Center for Advanced Imaging Innovation and Research (CAI2R), Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, NY USA
- Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY USA
| | | | - Waleed Althobaity
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Ashish Gupta
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Elsa Arribas
- Department of Diagnostic Radiology, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Lumarie Santiago
- Department of Diagnostic Radiology, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - David H Ballard
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis, MO USA
| | - Kenneth C Wang
- Baltimore VA Medical Center, University of Maryland Medical Center, Baltimore, MD USA
| | - William Weadock
- Department of Radiology and Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI USA
| | - Ciprian N Ionita
- Department of Neurosurgery, State University of New York Buffalo, Buffalo, NY USA
| | - Dimitrios Mitsouras
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
| | | | | | - Andy Christensen
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Peter Liacouras
- 3D Medical Applications Center, Walter Reed National Military Medical Center, Washington, DC, USA
| | - Frank J Rybicki
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Adnan Sheikh
- Department of Radiology and The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON Canada
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Abstract
Non-invasive delivery of artificial implants, stents or devices in patients is vital for rapid and successful recovery. Unfortunately, because the delivery passage is often narrower than the size of the delivered object, a compromise between the shape that is effective at the targeted location and a thin form that allows smooth unobstructed travel to the destination is needed. We address this problem through two key technologies: 3D printing and shape memory polymers (SMPs). 3D printing can produce patient-customizable objects, and SMPs can change their initially formed shape to the final desired shape through external stimulation. Using these two technologies, we examine the design and fabrication of bifurcated stents. This study presents a mock-up where blood vessels are fabricated using moulded silicon, which supports the effectiveness of the proposed method. The experimental results reveal that a bifurcated stent with a kirigami structure can smoothly travel inside a vessel without being obstructed by branched parts. We believe that this work can improve the success rate of stent insertion operations in medicine.
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Affiliation(s)
- Taeyoung Kim
- School of Mechanical Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Yong-Gu Lee
- School of Mechanical Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea.
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Jia H, Gu SY, Chang K. 3D printed self-expandable vascular stents from biodegradable shape memory polymer. ADVANCES IN POLYMER TECHNOLOGY 2018. [DOI: 10.1002/adv.22091] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Han Jia
- Department of Polymeric Materials; School of Materials Science and Engineering; Tongji University; Shanghai China
| | - Shu-Ying Gu
- Department of Polymeric Materials; School of Materials Science and Engineering; Tongji University; Shanghai China
- Key Laboratory of Advanced Civil Engineering Materials; Ministry of Education; Tongji University; Shanghai China
| | - Kun Chang
- Department of Polymeric Materials; School of Materials Science and Engineering; Tongji University; Shanghai China
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