Cited Publications

ViVitro Labs products are cited in hundreds of peer reviewed publications. Please contact us if you would like to add your publication to our list.


Applicability of the handmade ePTFE trileaflet-valved conduits for pulmonary valve reconstruction: An ex vivo and in vivo study , Chung-Dann Kan, MD, PhD, Jieh-Neng Wang, PhD, Wei-Ling Chen, PhD, Pong-Jeu Lu, PhD, Ming-Yao Chan, PhD, Chia-Hung Lin, PhD, Wan Chin Hsieh, MD The Journal of Thoracic and Cardiovascular Surgery, September 2017

...The current study investigated: (i) the function of the ePTFE trileaflet-valved conduits in an ex vivo experimental system and (ii) the short-term performance of the conduit in a porcine model to verify their clinical applicability.... ... valves. 168 Right ventricular function was simulated by using a digitally controlled hydraulic piston 169 SuperPump (ViViTro Labs, Victor, British Columbia, Canada), which generated a pulsating 170 flow to drive the chamber and send it into a compliant pulmonary artery. ...

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In vitro biomechanical and hydrodynamic characterisation of decellularised human pulmonary and aortic roots , A. Desai, T. Vafaee, P. Rooney, J.N. Kearney, H.E. Berry, E. Ingham, J. Fisher, L.M. Jennings Journal of the Mechanical Behavior of Biomedical Materials 14 September 2017

The use of decellularised biological heart valves in the replacement of damaged heart valves ... ...The purpose of this study was to assess the effect of low concentration sodium dodecyl sulphate decellularisation on the in vitro biomechanical and hydrodynamic properties of cryopreserved human aortic and pulmonary roots.... ... performance of the valve roots. A viscoelastic impedance adapter (VIA; Vivitro System Inc., Victoria BC, Canada) was used to deliver a more physiological ventricle pressure and flow waveform in the simulator. This system allowed for ...

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In-Vitro Pulsatile Flow Measurement in Prosthetic Heart Valves: An Inter-Laboratory Comparison , Retta SM, Kepner J, Marquez S, Herman BA, S Shu MC, Grossman LW J Heart Valve Dis. 2017 Jan;26(1):72-80.

One of the first steps in qualifying a new prosthetic valve for eventual clinical use is preclinical flow performance testing in vitro... ...This collaborative effort between heart valve manufacturers and the Food and Drug Administration (FDA) was designed to evaluate the variability of the pulse duplicator test technology for pulsatile flow performance measurement in an interlaboratory round robin... ...A commercially available duplicator, the Vivitro system (Vivitro, Inc., Vancouver, Canada), was used at two centers. The design specifications are summarized in Table I....

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Experimental Study of Right Ventricular Hemodynamics After Tricuspid Valve Replacement Therapies to Treat Tricuspid Regurgitation , Yen Ngoc NguyenMunirah IsmailFoad KabinejadianChi Wei OngEdgar Lik Wui TayHwa Liang Leo - Cardiovascular Engineering and Technology 2017

The increased understanding of right heart diseases has led to more aggressive interventions to manage functional tricuspid regurgitation (FTR)... ...In this study, a novel in vitro mock circulatory system that incorporated a realistic tricuspid valve apparatus in a patient-specific silicon right ventricle (RV) was designed and fabricated... ... A closed ventricular chamber housing the silicon RV model was connected to a closed atrial chamber at one end, and was directly connected to the pulsatile wave-generating piston pump (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada) at the other end to simu ...

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in-vitro Assessment of Expanded-Polytetrafluoroethylene Stentless Tri-leaflet Valve Prosthesis for Aortic Valve Replacement , Guangyu Zhu; Masakazu Nakao; Qi Yuan and Joon Hock Yeo Proceedings of the 10th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 1: BIODEVICES, 186-189, 2017, Porto, Portugal

Truly stentless polymeric valve prosthesis can be a viable alternative for aortic valve replacement (AVR). In the present paper, the dynamic and hemodynamic performance of a novel designed expanded-polytetrafluoroethylene (ePTFE) stentless tri-leaflet valve was assessed experimentally.... ... The in-vitro tests were performed under time-varying physiological pressure by using the Vivitro pulse duplicator. ... The Vivitro pulse duplicator (Vivitro Systems Inc., Victoria, BC, Canada) was used to generate the physiological pressure and flow in the left ventricle and aorta. ...

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Leaflet Free Edge Detection for the Automatic Analysis of Prosthetic Heart Valve Opening and Closing Motion Patterns from High Speed Video Recordings , M. Alizadeh, M. Cote, and A Branzan Albu P Sharma, FM Bianchi - Image Analysis 20th Scandinavian Conference, SCIA 2017,

...The valve orifi ce area over time, which informs on the opening and closing motion patterns, constitutes a key quality metric for PHV assessment... ...In this paper, we propose a novel orifi ce segmentation approach for automatic prosthetic heart valves quantitative performance analysis, based on the detection of the leaflet free edges to accurately extract the actual orifi ce area.

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In-vitro hemodynamic testing of stentless prosthetic aortic valves , Ng, Daniel Wai Hung. Neo, Si Yang. Ng, Chung Liu. Wong, Benedict Jun Shuan. Singapore Polytechnic School of Mechanical & Aeronautical Engineering

...Mechanical valves usually made from metal and fabrics are very durable but they have poor hemodynamic and are thrombogenic requiring permanent anticoagulation. Tissue heart valves constructed from biological tissues have excellent hemodynamic blood flow, but they lack durability. The project proposed a new valve design that is similar to a stentless tissue valve but made from a synthetic material, Polytetrafluoroethylene (PTFE)... The scope of this project includes designing a fixture to accommodate the valves in the ViVitro System and studying hemodynamic parameters such as pressure drop, flow rate, and dynamic leaflet behaviour of the valves. ...

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JetValve: Rapid manufacturing of biohybrid scaffolds for biomimetic heart valve replacement , Andrew K. Capullia, Maximillian Y. Emmerta, b, c, Francesco S. Pasqualinia, b, Debora Kehlb, Etem Caliskanb, c, Johan U. Linda, Sean P. Sheehya, Sung Jin Parka, Seungkuk Ahna, Benedikt Webera, b, Josue A. Gossa, Simon P. Hoerstrupa, b, Kevin Kit Parkera; Biomaterials Volume 133, July 2017, Pages 229–241

Tissue engineered scaffolds have emerged as a promising solution for heart valve replacement because of their potential for regeneration. However, traditional heart valve tissue engineering has relied on resource-intensive, cell-based manufacturing, which increases cost and hinders clinical translation. ...We demonstrated controlled modulation of these scaffold parameters and show initial biocompatibility and functionality in vitro...

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Design, Analysis and Testing of a Novel Mitral Valve for Transcatheter Implantation Authors Authors and affiliations , Bozkurt, S., Preston-Maher, G.L., Torii, R. et al. Ann Biomed Eng (2017). doi:10.1007/s10439-017-1828-2 First Online: 03 April 2017

Mitral regurgitation is a common mitral valve dysfunction which may lead to heart failure. This paper presents the design, development and hydrodynamic assessment of a novel bi-leaflet mitral valve suitable for transcatheter implantation. ... animal models. Hydrodynamic Tests. The hydrodynamic performances of the three valve prototypes were assessed on a hydro-mechanical cardiovascular pulse duplicator system (ViVitro Superpump SP3891, ViVitro, BC) (Fig. 3 ...

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An In Vitro Feasibility Study of the Influence of Configurations and Leaflet Thickness on the Hydrodynamics of Deformed Transcatheter Aortic Valve , Wentao Feng, Xianda Yang, Yang Liu, Yubo Fan Artificial Organs, 24 February 2017

Clinically, the percutaneous transcatheter aortic valve (TAV) has been reported to be deformed in a noncircular configuration after its implant. The deformation is universal and various, and it leads to serious leakage and durability problems. ...the present study investigated the effects of the aortic annulus deformation and the leaflet tissue thickness on the hydrodynamics of the TAV. ... Hydrodynamic testing. The TAVs were tested in a quasi-physiological artery pulsatile flow duplicator system, which was custom remoulded to adapt the testing of deformed TAV from commercially available pulse duplicator (Pulse Duplicator; Vivitro Labs, Victoria, BC, Canada.). ...

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Hydrodynamic Assessment of Aortic Valves Prepared from Porcine Small Intestinal Submucosa , Sharan Ramaswamy, Makensley Lordeus, Omkar V. Mankame, Lilliam Valdes-Cruz, Steven Bibevski, Sarah M. Bell, Ivan Baez, Frank Scholl: Cardiovasc Eng Tech (2016).

...Assess the functional effectiveness of tri-leaflet PSIS bioscaffolds in the aortic position compared to standard tri-leaflet porcine bioprosthetic valves... ... (b) Pulse duplicator system (Vivitro Laboratories) used for the hydrodynamic evaluation of the valves. ... System calibration, pump control, data collection and analysis are all computer-controlled via software (Vivitest, Vivitro Labs). ...

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Pledget-Armed Sutures Affect the Haemodynamic Performance of Biologic Aortic Valve Substitutes: A Preliminary Experimental and Computational Study , Claudio Capelli, Chiara Corsini, Dario Biscarini, Francesco Ruffini, Francesco Migliavacca, Alfred Kocher, Guenther Laufer, Andrew M. Taylor, Silvia Schievano, Martin Andreas, Gaetano Burriesci, Claus Rath: Cardiovascular Engineering and Technology (2016). doi:10.1007/s13239-016-0284-8

...Recently, novel bioprostheses which include a stent-based anchoring system have been introduced to allow rapid implantation, therefore reducing the duration and invasiveness of the intervention. ...The results showed how the performance of cardiac valve substitutes is negatively affected by the presence of pledget-armed sutures... ...The measurements were collected during ten cardiac cycles and analysed in the VSI software pack- age (VSI, ViVitro, Victoria, BC, Canada). The leaflets kinematics were visualised using a high-speed camera. For ...

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In Vitro Pulsatile Performance Evaluation of the HeartMate PHP TM (Percutaneous Heart Pump) , Onur Dur, Keif Fitzgerald, Paul Muller, Chris Parker Thoratec Corporation, Sunnyvale, CA company slide

The HeartMate PHP is a 13F catheter-based trans-aortic heart pump with a collapsible distal portion that expands to 24F to provide minimally invasive acute hemodynamic stabilization and left ventricular unloading in both prophylactic and emergent clinical settings... Objective: To evaluate the interaction of the HeartMate PHP with native cardiovascular system via in vitro pulsatile mock flow loop testing. A custom-built pulsatile heart simulator adapted from Vivitro Pulse Duplicator (Vivitro Labs Inc., Canada) was tuned to generate physiological flow pressure waveforms while mimicking the preload sensitivity of the native heart.

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Development & Design of Improved Commissure for Tissue-Engineered Transcatheter Heart Valves , Cole Feagler, Zeeshan Syedain and Robert Tranquillo University of Minnesota College of Science and Engineering Poster Report

While most commercial valves today use chemically-fixed porcine tissue in the construction of the replacement valves, the Tranquillo group has been exploring the use of decellularized, engineered tissue as leaflet material... ...The goal of this project was to engineer a commissure design to mitigate valve failure through tissue tearing, and to improve overall valve hemodynamics. (I.e. reduction of PVL)... ...Prototype TEHVs were tested to failure using a ViVitro Labs pulse duplicator, running custom LabView data acquisition software...

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Physiological vortices in the sinuses of Valsalva: An in vitro approach for bio-prosthetic valves , Riccardo Toninatoa, Jacob Salmona, Francesca Maria Susin, Andrea Duccia, Gaetano Burriescia doi:10.1016/j.jbiomech.2016.05.027

The physiological flow dynamics within the Valsalva sinuses, in terms of global and local parameters, are still not fully understood. This study attempts to identify the physiological conditions as closely as possible, and to give an explanation of the different and sometime contradictory results in literature. ... 2. Material and Methods. In this study, all experiments were carried out using a hydro-mechanical pulse duplicator (Vivitro Superpump System SP3891, ViVitro Labs Inc., Canada), with pressure catheters monitoring the pressure upstream and downstream of the aortic valve. ...

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Flow-Induced Damage to Blood Cells in Aortic Valve Stenosis , Koohyar Vahidkhah, Dan Cordasco, Mostafa Abbasi, Liang Ge, Elaine Tseng, Prosenjit Bagchi, Ali N. Azadani Annals of Biomedical Engineering pp 1-13 First online: 05 April 2016

Valvular hemolysis and thrombosis are common complications associated with stenotic heart valves. This study aims to determine the extent to which hemodynamics induce such traumatic events. The viscous shear stress downstream of a severely calcified bioprosthetic valve was evaluated via in vitro 2D particle image velocimetry measurements. ... Calcification was present on all the leaflets with a very small tear, less than 0.5 mm, on one of the leaflets (Figs. 1a, 1b). The bioprosthesis was tested at room temperature in a custom-built pulse duplicator system (ViVitro Systems, Inc., Victoria, Canada). ...

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A Parametric Computational Study of the Impact of Non-circular Configurations on Bioprosthetic Heart Valve Leaflet Deformations and Stresses: Possible Implications for Transcatheter Heart Valves , Nandini Duraiswamy , Jason D. Weaver, Yasamin Ekrami, Stephen M. Retta, Changfu Wu Cardiovascular Engineering and Technology pp 1-13 First online: 10 February 2016

... The hydrodynamic testing was per- formed using 0.9% saline solution in the commercially available Left Heart Simulator (Vivitro Systems), which simulates function of the heart by generating pulsatile flow through prosthetic heart valves. ...In the EllipMinor and EllipMajor configurations, the maximum principal stress occurred near the center of the free edge of the “stretched” leaflets. These results further affirm recommendations by the International Standards Organization (ISO) that pre-clinical testing should consider non-circular configurations for transcatheter valve durability testing.

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In vitro hemodynamic testing of Amplatzer plugs for paravalvular leak occlusion after transcatheter aortic valve implantation , Joseph Calderan, Wenbin Mao, Eric Sirois and Wei Sun* Article first published online: 29 OCT 2015 DOI: 10.1111/aor.12589 Journal of Artificial Organs

In this study, a realistic in vitro model of coronary artery flow was developed and used to investigate the impact of TAV deployed orientations on coronary flow. The coronary hemodynamics was first replicated mathematically using a lumped parameter model with time-varying myocardial resistance. ...based on research performed with the ViVitro Pulse Duplicator.

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Development of an In Vitro Model to Characterize the Effects of Transcatheter Aortic Valve on Coronary Artery Flow , Joseph Calderan, Wenbin Mao, Eric Sirois and Wei Sun-- Artificial Organs article first published online: 29 OCT 2015 DOI: 10.1111/aor.12589

Impairment of coronary artery flow, in either acute or chronic conditions, is a severe complication of transcatheter aortic valve (TAV) implantation, which can arise due to improper TAV positioning. ... LHS. An LHS was designed with the intention of providing physiological flow and pressure waveforms in the left atrium, left ventricle (LV), and ascending aorta, similar to commercially available devices such as the ViVitro LHS (ViVitro Labs, Victoria, Canada) but with additional ...

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Hemodynamic and thrombogenic analysis of a trileaflet polymeric valve using a fluid-structure interaction approach , Filippo Piatti, Francesco Sturla, Gil Marom, Jawaad Sheriff, Thomas E. Claiborne, Marvin J. Slepian, Alberto Redaelli, Danny Bluestein - Journal of Biomechanics, 2015 Published Online: August 21, 2015

... The aim of this study was to characterize the hemodynamics and thrombogenic potential of the Polynova polymeric trileaflet valve prototype using a fluid-structure interaction (FSI) approach. The FSI model replicated experimental conditions of the valve as tested in a ViVitro Left Heart Simulator (ViVitro Labs Inc., Victoria, BC, Canada). ... FSI data, ViVitro data. Cardiac output (L/min), 5.62, 5.50. ...

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Effects of Bileaflet Mechanical Mitral Valve Rotational Orientation on Left Ventricular Flow Conditions , John C. Westerdale, Ronald Adrian, Kyle Squires, Hari Chaliki and Marek Belohlavek --The Open Cardiovascular Medicine Journal, 2015, 9, 62-68

We studied left ventricular flow patterns for a range of rotational orientations of a bileaflet mechanical heart valve (MHV) implanted in the mitral position of an elastic model of a beating left ventricle (LV). The valve was rotated through 3 angular positions (0, 45, and 90 degrees) about the LV long axis. ... MHV angular positions. Heart rate and stroke volume were kept constant. MATERIALS AND METHODOLOGY We utilized a mechanical left heart model (ViVitro Labs, Inc., Victoria, Canada) (Fig. 1A). The model was comprised ...

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Classification of Unsteady Flow Patterns in a Rotodynamic Blood Pump: Introduction of Non-Dimensional Regime Map , F Shu, S Vandenberghe, J Brackett, JF Antaki - Cardiovascular Engineering and Technology July 2015

Rotodynamic blood pumps (also known as rotary or continuous flow blood pumps) are commonly evaluated in vitro under steady flow conditions. However, when these devices are used clinically as ventricular assist devices (VADs), the flow is pulsatile due to the contribution of the native heart. ... Flow Loop The pump prototype was dynamically tested using a cardiovascular simulator circuit (modified from Vivitro Systems Inc., Victoria, British Columbia) built around a silicone mock left ventricle (LV) encased in a rigid acrylic chamber ...

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Evaluating the performance of prosthetic heart valves: transvalvular pressure drop vs. vortex ring formation number , GC D'Antonio, BV Weidner, S Rowe, O Pierrakos - Systems and Information Engineering Design Symposium (SIEDS), 2015

A prominent performance metric used by the FDA to evaluate prosthetic heart valves is transvalvular pressure drop. ... METHODS To investigate vortex ring formation as a function of time relative to changing operating conditions, a piston driven heart simulator (Vivitro Heart system SD2001-1) was used. ... (3) The data collected from the Vivitro Heart system was used to find . ...

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Effect of aortic annulus size and prosthesis oversizing on the hemodynamics and leaflet bending stress of transcatheter valves: an in vitro study , Hoda Maleki, MASc, Shahrokh Shahriari, PhD, Michel Labrosse, PhD, Josep Rodés-Cabau, MD, Philippe Pibarot, PhD, FACC, FAHA, FESC, Lyes Kadem, PhD, Eng. -Canadian Journal of Cardiology 28 March 2015

There is few data about the patient- and prosthesis- related factors influencing the hemodynamics of transcatheter heart valves (THVs). The objective of this in vitro study was to assess the effect of aortic annulus size and prosthesis oversizing on the valve hemodynamics and estimated leaflet bending stress of the SAPIEN balloon-expandable THV. ... THV). Methods. In Vitro Model. For the purpose of this study, a left heart duplicator system was used (ViVitro Labs. Inc, BC, Canada). This simulator is capable of reproducing physiological pressure and flow waveforms. Briefly ...

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Design of a novel polymeric heart valve , Burriesci G, Marincola FC, Zervides C. J Med Eng Technol. 2010 Jan;34(1):7-22. doi: 10.3109/03091900903261241

Polymeric heart valves could offer an optimum alternative to current prostheses, by joining the advantages of mechanical and bioprosthetic valves. Though a number of materials suitable for this application have recently become available, significant improvements in the valve design are still needed. In this paper, a novel polymeric heart valve design is proposed and its optimization procedure, based on the use of finite elements, is described...

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A fluid-structure approach to optimize the thrombogenic potential of artificial heart valves , Filippo Piatti1 , Francesco Sturla 1,2 , Thomas E. Claiborne3 , Danny Bluestein3 , Alberto Redaelli 1

Experimental procedures are commonly used to obtain an overall quantification of the fluid dynamic and thrombogenic performances of cardiovascular devices [1]... (B) ViVitro gold standard testing benchmark (ViVitro Labs, BC, Canada) Boundary conditions ... obtaining comparable working conditions between the computational model and the ViVitro benchmark. Figure 2 – Schematic visualization of the ideal ...

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Finding the ideal biomaterial for aortic valve repair with ex vivo porcine left heart simulator and finite element modeling , Hadi Daood Toeg, Ovais Abessi , Talal Al-Atassi, Laurent de Kerchove, Gebrine El-Khoury, Michel Labrosse, Munir Boodhwani, - Cardiovasc Surg, 2014

ABSTRACT Aortic valve (AV) repair (AVr) has become an attractive alternative to AV replacement for the correction of aortic insufficiency; however, little clinical evidence exists in determining which biomaterial at AVr would be optimal. Cusp replacement in AVr has... All aortic roots were connected to the ViVitro Left Heart Simulator (LHS; ViVitro Systems, Inc, Victoria, British Columbia, Canada) for baseline valve measurements acting as paired controls...

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The congenitally bicuspid aortic valve: how does it function? Why does it fail? , Francis Robicsek MD, PhD, Mano J. Thubrikar PhDb, Joseph W. Cook MDa and Brett Fowler RTb; The Annals of Thoracic Surgery: 77, Issue 1; 177-185.

The study was intended to investigate the reason why congenitally bicuspid valves (CBAVs), which may function hemodynamically and clinically well, have a high early failure rate.

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Pulsatile flow studies of a porcine bioprosthetic aortic valve in vitro: PIV measurements and shear-induced blood damage , W.Lim; Journal of Biomechanics: 34, Issue 11; 1417-1427.

A two-dimensional particle image tracking velocimetry (PIV) system has been used to map the velocity vector fields and Reynolds stresses in the immediate downstream vicinity of a porcine bioprosthetic heart valve at the aortic root region in vitro under pulsatile flow conditions. Measurements were performed at five different time steps...

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Numerical simulation of the dynamics of a bileaflet prosthetic heart valve using a fluid–structure interaction approach: , M. Nobili, U. Morbiducci, R. Ponzini, C. Del Gaudio, A. Balducci, M. Grigioni, F. Maria Montevecchi, A. Redaelli; Journal of Biomechanics: 41, Issue 11; 2539-2550.

The main purpose of this study is to reproduce in silico the dynamics of a bileaflet mechanical heart valve (MHV; St Jude Hemodynamic Plus, 27mm characteristic size) by means of a fully implicit fluid-structure interaction (FSI) method, and experimentally validate the results using an ultrafast cinematographic technique.

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Modified gorlin equation for the diagnosis of mixed aortic valve pathology , Scotten LN**, Walker DK**, Dutton JW; Journal of Heart Valve Disease: 11, Issue 3; 368  **ViVitro Labs Founder

The accuracy of the Gorlin equation when applied to mixed valve pathology has not been investigated. An in-vitro study was performed to determine how a range of valve regurgitations and stenoses affects the Gorlin aortic valve area...

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Geometric modeling of functional trileaflet aortic valves: Development and clinical applications , M. Labrosse, C. Beller, F. Robicsek, M. Thubrikar; Journal of Biomechanics: 39, Issue 14; 2665-2672.

The dimensions of the aortic valve components condition its ability to prevent blood from flowing back into the heart. While the theoretical parameters for best trileaflet valve performance have already been established, an effective approach to describe other less optimal, but functional models has been lacking...

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Fluid dynamics of the CarboMedics Kinetic bileaflet prosthetic heart valve , J. Timothy Baldwin*, Andy Campbell, Christopher Luck, William Ogilvie and Joe Sauter; European Journal of Cardio-Thoracic Surgery: 11, Issue 2; 287-292.

To compare hydrodynamic characteristics of a new bileaflet heart valve, the CarboMedics kinetic cardiac valve prosthesis, with those of a St. Jude Medical (SJM) heart valve...

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Flow instabilities induced by coronary artery stents: Assessment with an in vitro pulse duplicator , Peacock J, Hankins S, Jones T, Lutz R. Journal of Biomechanics: 28, Issue 1; 17-26.

An in vitro pulse duplicator system was used to investigate whether coronary artery stents induce downstream flow instabilities. Hot film or electrochemical probes were used to measure wall shear stress before and after deployment of both single and multiple (overlapping) stents in normal and diseased coronary geometries...

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Arteriovenous fistulas aggravate the hemodynamic effect of vein bypass stenoses: An in vitro study , T.Nielsen, C.Djurhuus, E.Pedersen, J.Laustsen, J.Hasenkam, T.Schroeder; Journal of Vascular Surgery: 24, Issue 6; 1043-1049.

Angiographic Quantification of Contrast Medium Washout from Cerebral Aneurysms after Stent Placement , Chander Sadasivana, Baruch B. Lieberc, Matthew J. Gounisc, Demetrius K. Lopese and L. N. Hopkinsb; American Journal of Neuroradiology: 23; 1214-1221.

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Discrimination in vitro between the acoustic emissions from Bjork-Shiley convexo-concave valves with and without a broken minor strut , D. K. Walker** and L. N. Scotten**; Medical and Biological Engineering and Computing: 29, Issue 5; 457-464; 1991.  **ViVitro Labs Founder

In Vitro Strain Measurement of a Mechanical Heart Valve in a Pulse Simulator , Teoh, S. H.; Lee, K. H.; Nugent, A. H.; Goh, K. S.; ASAIO Journal: 39, Issue 4; 1993.

To ascertain the stress magnitude at the stress concentration areas, in vitro strain measurements on a St. Vincent's mechanical heart valve were carried out in a pulse simulator.

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A Database Obtained From In Vitro Function Testing of Mechanical Heart Valves: , David K. Walker PhD**, Lawrence N. Scotten**: J Heart Valve Dis, Vol. 3 No. 5 Sep. 1994.  **ViVitro Labs Founder

Pressure trap created by vein valve closure and its role in graft stenosis: , Mano J. Thubrikar, PhD, Francis Robicsek, MD, Brett L. Fowler, BS; The Journal of Thoracic and Cardiovascular Surgery: 107; 707-716; 1994.

Saphenous vein graft stenosis has become the leading cause of reoperation in coronary bypass operations. We investigated the role of vein valves in vein graft stenosis by studying 14 human saphenous veins placed in a simulator of the left side of the heart in parallel with the arterial system.

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Hydrodynamic function of tilting disc prostheses and bileaflet valves in double valve replacement: , M. Strüber, A. Campbell, G. Richard and J. Laas; European Journal of Cardio-Thoracic Surgery: 10, Issue 6; 422-427; 1996.

To determine the energy loss attributable to prosthetic valve size and design in double valve replacement, energy consumption of mitral valves (size #25 to #29), of two different designs (Bjork Shiley tilting disc and Carbomedics bileaflet valves), in combination with a small (#21) and large sized (#27) aortic prosthesis, were analyzed in a flow simulator.

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Fluid dynamics of the CarboMedics kinetic bileaflet prosthetic heart valve , JT Baldwin, A Campbell, C Luck, W Ogilvie and J Sauter; Eur J Cardiothorac Surg 1997;11:287-292.

Analysis of regurgitation, mean systolic pressure drop and energy losses for two artificial aortic valves , A. A. Sakhaeimanesh; Y. S. Morsi; Journal of Medical Engineering & Technology: 23, Issue 2; 63 – 68; 1999.

Transpecies heart valve transplant: advanced studies of a bioengineered xeno-autograft , Steven Goldstein, PhDa, David R. Clarke, MDb, Steven P. Walsh, PhDa, Kirby S. Black, PhDa, Mark F. O’Brien, MDc; The Annals of Thoracic Surgery: 70; 1962-1969; 2000.

Tissue engineering approaches utilizing biomechanically suitable cell-conductive matrixes should extend xenograft heart valve performance, durability, and growth potential to an extent presently attained only by the pulmonary autograft. To test this hypothesis, we developed an acellular, unfixed porcine aortic valve-based construct. The performance of this valve has been evaluated in vitro under simulated aortic conditions, as a pulmonary valve replacement in sheep, and in aortic and pulmonary valve replacement in humans.

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Influence of sizing and subcoronary implantation technique on the function of porcine aortic homografts , M. J. Thubrikar; G. G. Gong; I. E. Konstantinov; G. A. Selim; B. L. Fowler; F. Robicsek; Journal of Medical Engineering & Technology: 24, Issue 4; 173 – 180; 2000.

The function and longevity of the homograft aortic valve may be influenced by valve size and subcoronary implantation technique. Dynamic function and leaflet configuration of the porcine aortic valve were analysed first in its natural root in a left heart simulator using glycerol at 120/80 mm Hg pressure and 4 l min-1 Cardiac Output (C.O.)...

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Method of ranking of heart valve characteristics at mitral position based on statistical model analysis , Makoto Arita, Kiyotaka Iwasaki, Mitsuo Umezu, Masanori Yoshida, Tetsuo Fujimoto, Hisayoshi Suma and Tadashi Isomura; Journal of Artificial Organs: 4, Issue 2; 131-137; 2001

The purpose of this study was to explore a valve selection criterion based on the impact force generated at valve closure, and to test a statistical mathematical model for comparing valve performance. The impact force generated at valve closure in the mitral position was measured continuously, using a load cell mounted in the left atrial section of a mock circulatory system...

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Decellularized human valve allografts , Ronald C. Elkins, MDa, Patti E. Dawson, BSb, Steven Goldstein, PhDb, Steven P. Walsh, PhDb, Kirby S. Black, PhDb; The Annals of Thoracic Surgery: 71; S428-S432; 2001.

A new aortic root prosthesis with compliant sinuses for valve-sparing operations , Mano J. Thubrikar, PhDa, Francis Robicsek, MD, PhDa, Geoffrey G. Gong, MDa, Brett L. Fowler, BSa; The Annals of Thoracic Surgery: 71; S318-S322; 2001.

Particle Image Velocimetry Assessment of Stent Design Influence on Intra-Aneurysmal Flow , Baruch B. Lieber1, Veronica Livescu, L. N. Hopkins and Ajay K. Wakhloo; Annals of Biomedical Engineering: 30, Issue 6; 768-777; 2002.

Hydrodynamic function of the second-generation mitroflow pericardial bioprosthesis , Louise M. Jennings, MEngb, Abdusalam El-Gatit, MDa, Zsolt L. Nagy, PhDa, John Fisher, DEngb, Peter G. Walker, PhDb, Kevin G. Watterson, FRACS; The Annals of Thoracic Surgery: 74; 63-68; 2002.

What parameters affect left ventricular diastolic flow propagation velocity? in vitro studies using color m-mode doppler echocardiography , Toshihiro Ogawa, Lawrence N Scotten,** David K Walker**, Ajit P Yoganathan, Renee L Bess, Cheryl K Nordstrom, and Julius M Gardin; Cardiovasc Ultrasound; 2005.  **ViVitro Labs Founder

Insufficient data describe the relationship of hemodynamic parameters to left ventricular (LV) diastolic flow propagation velocity (Vp) measured using color M-mode Doppler echocardiography.

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Three-Dimensional Numeric Simulation of Flow Through an Aortic Bileaflet Valve in a Realistic Model of Aortic Root , Grigioni, Mauro; Daniele, Carla; Del Gaudio, Costantino; Morbiducci, Umberto; Balducci, Antonio; D’Avenio, Giuseppe; Barbaro, Vincenzo; ASAIO Journal: 51, Issue 3; 176-183; 2005.

A three-dimensional, realistic model of an aortic mechanical heart valve and Valsalva sinuses was developed to predict, by means of a numerical time dependent simulation, the flow field during a fraction of the systolic period. The numeric simulation was performed upon a model of valve similar to a Carbomedics 27 mm placed in a physiologic aortic root shaped model,...

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First Human Case of Retrograde Transcatheter Implantation of an Aortic Valve Prosthesis , David Paniagua, MD, José A. Condado, MD, José Besso, MD, Manuel Vélez, MD, Bruno Burger, MD, Salvatore Bibbo, MD, Douglas Cedeno, MD, Harry Acquatella, MD, Carlos Mejia, BA, Eduardo Induni, MD, and R. David Fish, MD; Texas Heart Institute Journal: 32, Issue 3; 393–398; 2005.

The transcatheter route is an emerging approach to treating valvular disease in high-risk patients. The 1st clinical antegrade transcatheter placement of an aortic valve prosthesis was reported in 2002. We describe the first retrograde transcatheter implantation of a new aortic valve prosthesis, in a 62-year-old man with inoperable calcific aortic stenosis and multiple severe comorbidities.

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Comparison of the flow downstream two prototypes of a new monoleaflet artificial aortic heart valve by means of PIV visualization , R. K. Kaminsky; H. J. Weber; A. P. Simons; S. Kallweit; K. Kramm; P. R. Verdonck; Computer Methods in Biomechanics and Biomedical Engineering: 8, Issue 4; 159 – 160; 2005.

Quantitative approach to aortic valve-sparing surgery , Carsten J. Bellera, Michel R. Labrosseb, Francis Robicsek and Mano J. Thubrikar; Interactive Cardiovascular and Thoracic Surgery: 5; 526-530; 2006.

Our goal was to understand why it is difficult to achieve reliable valve competence after aortic valve-sparing surgery, and to propose quantitative data aimed at improving the outcome of the procedure. Valve-sparing procedures were performed in patients with dilated aortic roots and aortic regurgitation, and reproduced in physical models to explore what should be the restored dimensions of the aortic root and leaflets for valve sparing to be successful.

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Development of Squeeze Flow in Mechanical Heart Valve: A Particle Image Velocimetry Investigation , Zhang, Pei; Yeo, Joon Hock; Hwang, N H. C.; ASAIO Journal: 52, Issue 4; 391-397; 2006.

Energy Loss Due to Paravalvular Leak With Transcatheter Aortic Valve Implantation , Ali N. Azadani, PhD, Nicolas Jaussaud, MD, Peter B. Matthews, BS, Liang Ge, PhD, T. Sloane Guy, MD, Timothy A.M. Chuter, MD, Elaine E. Tseng, MD.; Ann Thorac Surg 2009;88:1857-1863, Aug 11, 2009.

A method for the measurement of left ventricular overload for aortic valve insufficiency , Travis BR, Fowler BL, Robicsek F.; J Heart Valve Dis. (5):499-506; Sep 18, 2009.

Development and evaluation of a novel artificial catheter-deliverable prosthetic heart valve and method for in vitro testing , Thomas E. Claiborne, Danny Bluestein, Richard T. Schoephoerster, The International Journal of Artificial Organs, Vol. 32, no. 5, pp. 262-271; 2009.

Revisiting the Simplified Bernoulli Equation , Jeffrey J. Heys, Nicole Holyoak, Anna M. Calleja, Marek Belohlavek and Hari P. Chaliki, The Open Biomedical Engineering Journal 4, 123-128; 2010.

The assessment of the severity of aortic valve stenosis is done by either invasive catheterization or non-invasive Doppler Echocardiography in conjunction with the simplified Bernoulli equation. The catheter measurement is generally considered more accurate, but the procedure is also more likely to have dangerous complications.

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Structural analysis of the natural aortic valve in dynamics: From unpressurized to physiologically loaded , Michel R. Labrosse, Keegan Lobo, Carsten J. Beller, Journal of Biomechanics 43, 1916–1922; 2010.

A novel finite element model of the natural aortic valve was developed implementing anisotropic hyperelastic material properties for the leaflets and aortic tissues, and starting from the unpressurized geometry. Static pressurization of the aortic root, silicone rubber moulds and published data helped to establish the model parameters, while high-speed video recording of the leaflet motion in a left-heart simulator allowed for comparisons with simulations.

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Ex vivo hemodynamic assessment of mechanical aortic valve gradients using a high-fidelity pressure wire , Andrew D. Michaels MD, David Mester, Catheterization and Cardiovascular Interventions Vol. 77, issue 5, pages 726-732, April 2011.

Abstract OBJECTIVES: Accurate assessment of prosthetic mechanical valve malfunction is challenging for non-invasive and invasive techniques. We evaluated a 0.014-inch pressure-sensing coronary guidewire to assess mechanical valve dysfunction.

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Evaluation of an asymmetric stent patch design for a patient specific intracranial aneurysm using Computational Fluid Dynamic (CFD) calculations in the Computed Tomography (CT) derived lumen , Minsuok Kim, Ciprian Ionita, Rekha Tranquebar, Kenneth R. Hoffmann, Dale B. Taulbee, Hui Meng, and Stephen Rudin Proc Soc Photo Opt Instrum Eng. Author manuscript; available in PMC February 8, 2011

Product Development Cycle of a Surgical Device for Mitral Valve Repair and Surgical Training Simulator Development Plan for the Same , A Saini - 2011 - conservancy.umn.edu

The objective of this thesis is to 1) describe the product development cycle for the DS1000, a surgical instrument for Mitral Valve repair. A chapter is then provided for 2) adapting the device development cycle to a development cycle for a simulator. This is followed by 3)...

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Optimization and Verification of a Novel Trileaflet Polymeric Prosthetic Heart Valve , TE Claiborne III - dspace.sunyconnect.suny.edu

Valvular heart disease remains a significant public health issue with Calcific Aortic Valve Disease (CAVD) its most life threatening form. Current treatment for CAVD involves open-heart surgical replacement of the diseased aortic valve (AV) with either a tissue (THV) or mechanical (MHV) prosthesis, with THVs being mostly nonthrombogenic but vulnerable to structural valve deterioration (SVD) and MHVs being highly durable but thrombogenic, thus requiring lifelong anticoagulant therapy.

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Signal processing of heart signals for the quantification of non-deterministic events ,  V Millette, N Baddour - Biomedical engineering online, 2011 - biomedcentral.com

Heart signals represent an important way to evaluate cardiovascular function and often what is desired is to quantify the level of some signal of interest against the louder backdrop of the beating of the heart itself. An example of this type of application is the quantification of cavitation in mechanical heart valve patients.

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Design conception and experimental setup for in vitro evaluation of mitral prosthetic valves , O Bazan, JP Ortiz - Revista Brasileira de Cirurgia Cardiovascular, 2011 - SciELO Brasil

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Valve-in-valve hemodynamics of 20-mm transcatheter aortic valves in small bioprostheses , AN Azadani, N Jaussaud, L Ge, … - The Annals of thoracic …, 2011 - Elsevier

Transcatheter aortic valve (TAV) implantation is a treatment for selected patients with failing bioprostheses. We previously showed that currently available SAPIEN (Edwards Lifesciences, Irvine, CA) TAV sizes did not yield acceptable valve-in-valve (VIV) hemodynamics in small degenerated bioprostheses because optimal TAV function requires full stent expansion to its nominal size.

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Dilatation of the ascending aorta in patients with congenitally bicuspid aortic valves ,  F Robicsek, RF Padera Jr… - HSR proceedings in …, 2012 - ncbi.nlm.nih.gov

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Importance of Shear in Prosthetic Valve Closure Dynamics , LN Scotten**, R Siegel - The Journal of heart valve disease, 2011 - icr-heart.com  **ViVitro Labs Founder

The results of recent hematological studies have suggested that, under non-physiological flow conditions, circulating procoagulant proteins activate the coagulation cascade. In the present study, in-vitro estimates of flow transients at or near the time of valve closure, including regional backflow velocity (RBV, m/s), flow acceleration (m/s2), and rate of acceleration (jerk, m/s3), have shed new light on the blood-damage potential of prosthetic valves.

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Manufacturing and hydrodynamic assessment of a novel aortic valve made of a new nanocomposite polymer , B Rahmani, S Tzamtzis, H Ghanbari, G Burriesci… - Journal of …, 2012 - Elsevier

Synthetic leaflet heart valves have been widely studied as possible alternatives to the current mechanical and bioprosthetic valves. Assessing the in vitro hydrodynamic function of these prostheses is of great importance to predict their hemodynamic behaviour prior to implantation. This study introduces an innovative concept of a low-profile semi-stented surgical aortic valve (SSAV) made of a novel nanocomposite polyurethane with a polycarbonate soft segment (PCU) and polyhedral oligomeric silsesquioxane (POSS) nanoparticles covalently bonded as a pendant cage to the hard segment.

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Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves. ,  S Ramaswamy, M Salinas, R Carrol… - Journal of visualized …, 2012 - europepmc.org

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process.

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A Direct In Vitro Comparison of the Edwards SAPIEN and Medtronic CoreValve Transcatheter Aortic Valve implantation (TAVI) Devices and a Surgical Counterpart ,  S Tzamtzis, J Yap, M Mullen, G Burriesci - 2011 - discovery.ucl.ac.uk

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Role of the sinuses of Valsalva on the opening of the aortic valve , G Pisani, R Scaffa, O Ieropoli, EM Dell’Amico… – The Journal of Thoracic …, 2013 – Elsevier

The present in vitro study was designed to ascertain whether the presence of sinuses of Valsalva in the aortic root were able to regulate the valve effective orifice area and modulate the gradient across the valve independently from root compliance.

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An in vitro model of aortic stenosis for the assessment of transcatheter aortic valve implantation , Journal of Biomechanical Engineering, doi:10.1115/1.4026576. H. Maleki, S. Shahriari, M. Labrosse, P. Pibarot and L. Kadem

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A metric for the stiffness of calcified aortic valves using a combined computational and experimental approach , Medical & Biological Engineering & Computing, January 2014, Volume 52, Issue 1, pp 1-8. H. Maleki, S. Shahriari, L. G. Durand, M. R. Labrosse, L. Kadem

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Development and characterization of acellular porcine pulmonary valve scaffolds for tissue engineering , J Luo, SA Korossis, SPP Wilshaw, LM Jennings… – Tissue Engineering, 2014

… testing. The flow simulator has been described previously. 27 It mimicked the right heart and was controlled and monitored by the ViviTest software (Vivitro Systems Inc). The simulator was set up as described by Korossis et al. …

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A novel flow performance metric for the assessment of prosthetic heart valves , DE Vargas, BV Weidner, GC D’Antonio, O Pierrakos – Systems and Information …, 2014

METHODS A commercially available heart simulator (Vivitro Heart system: SD2001-1) was utilized in this study as shown in Figure 2. This system has been utilized in previous studies supporting its efficacy and implementation [9-12]. … FIGURE 2 VIVITRO HEART SIMULATOR …

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