Manufacturing and hydrodynamic assessment of a novel aortic valve made of a new nanocomposite polymer

Rahmani, B; Tzamtzis, S; Ghanbari, Hossein; Burriesci, G; Seifalian, Alexander M.

doi:10.1016/j.jbiomech.2012.01.046

Cited by 88 publications

(53 citation statements)

References 46 publications

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“…Yet, no PHV is currently used in clinical practice; several PHV prototypes, mainly composed of polyurethane-based materials, have been developed since 1960s [1] but, despite their promising short-term outcomes [2][3][4][5][6], none have shown satisfactory long-term reliability, due primarily to calcification and tearing of the leaflets [7][8][9][10]. The achievement of an adequate device lifetime remains the main challenge in the development of a clinically viable polymeric prosthesis.…”

Section: Introductionmentioning

confidence: 99%

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

Serrani

Brubert

Stasiak

et al. 2016

Journal of Biomechanical Engineering

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Styrene-based block copolymers are promising materials for the development of a polymeric heart valve prosthesis (PHV), and the mechanical properties of these polymers can be tuned via the manufacturing process, orienting the cylindrical domains to achieve material anisotropy. The aim of this work is the development of a computational tool for the optimization of the material microstructure in a new PHV intended for aortic valve replacement to enhance the mechanical performance of the device. An iterative procedure was implemented to orient the cylinders along the maximum principal stress direction of the leaflet. A numerical model of the leaflet was developed, and the polymer mechanical behavior was described by a hyperelastic anisotropic constitutive law. A custom routine was implemented to align the cylinders with the maximum Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts principal stress direction in the leaflet for each iteration. The study was focused on valve closure, since during this phase the fibrous structure of the leaflets must bear the greatest load. The optimal microstructure obtained by our procedure is characterized by mainly circumferential orientation of the cylinders within the valve leaflet. An increase in the radial strain and a decrease in the circumferential strain due to the microstructure optimization were observed. Also, a decrease in the maximum value of the strain energy density was found in the case of optimized orientation; since the strain energy density is a widely used criterion to predict elastomer's lifetime, this result suggests a possible increase of the device durability if the polymer microstructure is optimized. The present method represents a valuable tool for the design of a new anisotropic PHV, allowing the investigation of different designs, materials, and loading conditions. Keywordspolymeric heart valve; heart valve prosthesis; computational modeling

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Section: Introductionmentioning

confidence: 99%

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

Serrani

Brubert

Stasiak

et al. 2016

Journal of Biomechanical Engineering

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“…The wall thickness resulting from 10 layers, needed for durability, was 1.7 ± 0.3 mm, substantially higher than values found in vivo [27]. The variability in thickness can be improved by a dip-coating approach with the use of an automated robotic arm [28].The MCS presented here focuses on hydrodynamic measurements in the pulmonary arterial model. Hence, water alone was used as the flowing medium, which is in line with work on other MCS [1,29].…”

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confidence: 95%

A Mock Circulatory System Incorporating a Compliant 3D‐Printed Anatomical Model to Investigate Pulmonary Hemodynamics

Knoops

Biglino

Hughes³

et al. 2016

Artificial Organs

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A realistic mock circulatory system (MCS) could be a valuable in vitro testbed to study human circulatory hemodynamics. The objective of this study was to design a MCS replicating the pulmonary arterial circulation, incorporating an anatomically representative arterial model suitable for testing clinically relevant scenarios. A second objective of the study was to ensure the system's compatibility with magnetic resonance imaging (MRI) for additional measurements. A latex pulmonary arterial model with two generations of bifurcations was manufactured starting from a 3D-printed mold reconstructed from patient data. The model was incorporated into a MCS for in vitro hydrodynamic measurements. The setup was tested under physiological pulsatile flow conditions and results were evaluated using wave intensity analysis (WIA) to investigate waves traveling in the arterial system. Increased pulmonary vascular resistance (IPVR) was simulated as an example of one pathological scenario. Flow split between right and left pulmonary artery was found to be realistic (54 and 46%, respectively). No substantial difference in pressure waveform was observed throughout the various generations of bifurcations. Based on WIA, three main waves were identified in the main pulmonary artery (MPA), that is, forward compression wave, backward compression wave, and forward expansion wave. For IPVR, a rise in mean pressure was recorded in the MPA, within the clinical range of pulmonary arterial hypertension. The feasibility of using the MCS in the MRI scanner was demonstrated with the MCS running 2 h consecutively while Address correspondence and reprint requests to: Paul Knoops, 30 Guilford Street, London WC1N 1EH, UK. paul.knoops. 14@ucl.ac.uk. Author ContributionsConception and design of the work: PGMK, GB, ADH, SS, RT; experimental setup, data acquisition and analysis: PGMK, GB, LX; interpretation of the data: PGMK, GB, ADH, KHP, RT; drafting the manuscript: PGMK, GB, RT; all authors critically revised the manuscript, read and approved the final manuscript. Conflict of InterestThe authors declare no conflict of interest. Europe PMC Funders GroupAuthor Manuscript Artif Organs. Author manuscript; available in PMC 2017 July 15. Published in final edited form as:Artif Organs. 2017 July ; 41(7): 637-646. doi:10.1111/aor.12809. Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts acquiring preliminary MRI data. This study shows the development and verification of a pulmonary MCS, including an anatomically correct, compliant latex phantom. The setup can be useful to explore a wide range of hemodynamic questions, including the development of patientand pathology-specific models, considering the ease and low cost of producing rapid prototyping molds, and the versatility of the setup for invasive and noninvasive (i.e., MRI) measurements.Mock circulatory systems (MCS) are widely used to gather hydrodynamic data in vitro. They allow investigation of the cardiovascular system in both healthy and pathological scenarios, with t...

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“…It is based on the attachment of polyhedral oligomeric silsesquioxanes (POSS) nanoparticles as pendant chain functional groups to a poly(carbonate urea)urethane (PCU) backbone. POSS-PCU has shown promising mechanical and antithrombogenic properties for cardiovascular applications such as small diameter (5 mm) vascular grafts Ahmed et al 2011] and heart valves [Rahmani et al 2012].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of experimental methods for nitric oxide release from cardiovascular implants; bypass grafts as an exemplar

Naghavi

Seifalian

Hamilton

et al. 2015

Therapeutic Advances in Cardiovascular Disease

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Background: There is a great potential for nitric oxide (NO) eluting biomaterials in biomedical applications. These include the development of cardiovascular implants, wound healing products, or applications in cancer and respiratory therapy. While the potential of these materials as a therapy is becoming clearer, the real-time monitoring of NO is not easy and the success in the development of such materials depends on the accurate quantification of NO release. Method: To emphasize on the importance of a measurement technique on the outcome of an experiment, we compared total NO released from S-nitroso-N-acetyl-d-penicillamine (SNAP) incorporated nanocomposite polymer in the form of bypass grafts under simulated physiological conditions using amperometric and chemiluminescence techniques. Results: We found that the total amount of NO measured by the amperometric technique was 35.8% of the theoretical amount. Similarly, on measuring NO release from the bypass grafts, we demonstrated that the chemiluminesence technique detected NO at a relatively higher level. Conclusions:The results of this study clearly demonstrate the relative difference between analysis techniques for accurate NO detection that can be applied to distinct experimental models associated with NO-eluting cardiovascular implants.

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Manufacturing and hydrodynamic assessment of a novel aortic valve made of a new nanocomposite polymer

Cited by 88 publications

References 46 publications

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis

A Mock Circulatory System Incorporating a Compliant 3D‐Printed Anatomical Model to Investigate Pulmonary Hemodynamics

Evaluation of experimental methods for nitric oxide release from cardiovascular implants; bypass grafts as an exemplar

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