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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.
Using a Mock Circulatory Loop as a Regulatory Science Tool to Simulate Different Heart Failure Conditions
Mechanical circulatory support (MCS) device therapy is one of the primary treatment options for end-stage heart failure (HF), whereby a mechanical pump is integrated with the failing heart to maintain adequate tissue perfusion. In this study, the BAF solution is circulated through the MCL using a piston pump (SuperPump (AR Series), ViVitro Labs, Inc., Victoria, BC, Canada), which is fluid-coupled to a suspended silicone mock LV sac. An MCL can be an effective regulatory tool for simulating different patient disease states and evaluating the flow performance of MCS devices over their entire operating ranges in a well-controlled environment.Comparison of steady-state and transient flow measurements for the characterization of paravalvular leakage of transcatheter-aortic valve prostheses
We investigated the comparability between steady-state and transient PVL measurements as an input parameter for simulations in virtual cohorts. For the pulsatile flow testing we used a commercial pulse duplicator system (ViVitro Labs, Inc., Victoria, BC, Canada). An increasing pressure on the closed Evolut PRO TAVR in different annuls models during the steady flow measurements resulted in an increased flow.Effect of valve leaflet surface patterning on valve hydrodynamic performance
We aimed to elucidate the effects of the micro-structure of the pyrolytic carbon for artificial heart valves on its hydrodynamic performance. A Vivitro PD 2010 pulse duplicator system was used. The parallel-groove pattern on leaflet surface affected the hemodynamic performance of the valve prostheses.Impact of Bioprosthetic Valve Leaflet Stiffness and Anisotropy on TAVR Stent Fatigue Life
Towards developing a simulation methodology for the design of next-generation Transcatheter Aortic Valve Replacement (TAVR) devices, this numerical study investigates the impact of bioprosthetic valve stiffness and anisotropic behaviour on the fatigue of the nitinol stent frame during a single cardiac cycle. The simulation results were compared to in vitro testing of the device in a ViVitro pulse duplicator. The leaflet anisotropy can have a significant impact on how well the valve closes during the diastole phase, as well as whether the stent frame is symmetrically loaded, which may impact the overall fatigue life of the nitinol stent.Analysis of the effects of the aortic conduit’s geometry and mechanical behavior on heart valve prosthesis’ test bench characterization
This work focuses on introducing more physiological conditions for testing of aortic valve prosthesis and comparing the changes in behavior of different valve substitutes in these conditions. The most used commercial test bench is the ViVitro Pulse Duplicator, composed by a pump, a model left heart, a flow measuring system and a data acquisition system. In this work we have shown that it is possible to exploit 3D printing to obtain an aortic phantom with physiological mechanical and geometrical characteristics and use it to perform pulsatile tests on aortic valve prosthesis.On-demand heart valve manufacturing using focused rotary jet spinning
Current valve manufacturing technologies struggle to create valves that facilitate native tissue remodeling for permanent replacements. FibraValve samples were sutured onto 28 mm nitinol stents and positioned into custom made holders for mounting in a pulse duplicator (ViVitro Labs, Victoria, BC, Canada). Here, we show that FRJS can serve as a biofabrication method for implantable heart valves.Novel Expansible Aortic Annuloplasty Ring Exhibits Similar Characteristics as the Dacron Ring
The aim of this study was to evaluate and compare a novel open aortic annuloplasty ring (the A-ring) with the Dacron ring. The ventricular chamber was coupled to a digitally controlled piston pump (SuperPump AR Series, ViVitro Labs, Victoria, Canada), delivering a pulsatile flow to simulate left ventricular ejection into the aortic root. Overall, the echographic data revealed that both interventions had a downsizing effect on the aortic root, while still maintaining the distensibility comparable to the native condition.Chordal force profile after neochordal repair of anterior mitral valve prolapse
This study aimed to biomechanically evaluate the force profiles on the anterior primary and secondary chordae after neochord repair for anterior valve prolapse with varied degrees of residual mitral regurgitation using an ex vivo heart simulator. Briefly, a 3D printer was used to rapidly develop a prototype of a modular left heart coupled to a pulsatile linear actuator (ViVitro Superpump; ViVitro Labs). In our ex vivo AVP model, moderate residual MR following neochord repair was significantly associated with increased forces for both anterior primary and secondary chordae compared with those of less-than-moderate residual MR.Analysis of thrombosis risk of commissural misaligned transcatheter aortic valve prostheses using particle image velocimetry
Durability of transcatheter aortic valve replacement (TAVR) could be limited by leaflet thrombosis. A commercially available pulse duplicator system (ViVitro Inc., Victoria, BC, Canada) was used to generate physiological flow and pressure conditions of the cardiovascular circulation. Since commissural alignment in TAVR has only recently become the focus of clinical research, there is a clear gap in understanding the long-term clinical impact of commissural alignment.Hydrodynamic ex-vivo analysis of valve sparing techniques: assessment and comparison
This work investigates the impact of the valve-sparing technique on the aortic valve function. The hydrodynamic performance assessment of each implant was conducted in-vitro on a hydro-mechanical pulse duplicator. This shows that, despite providing generally good performance, current valve sparing techniques are still suboptimal and far from matching the physiological leaflets dynamics.Preventing extrinsic mechanisms of bioprosthetic degeneration using polyphenols
This study was to evaluate the impact of a polyphenols-based treatment on the extrinsic mechanisms responsible for early BHV degeneration. The hydrodynamic performance of the polyphenolic-treated and untreated T-GT commercial BHVs was assessed under simulated pulsatile flow in a Vivitro Pulse Duplicator System. The treatment is chemically stable, improves tissue extensibility, and effectively stabilizes glutaraldehyde.Biomechanical evaluation of aortic regurgitation from cusp prolapse using an ex vivo 3D-printed commissure geometric alignment device
Aortic regurgitation (AR) is one of the most common cardiac valvular diseases, and it is frequently caused by cusp prolapse. The simulator contains a programmable pulsatile linear piston pump (ViVitro Superpump, ViVitro Labs) and a viscoelastic impedance adapter (ViVitro) that is comprised of two compliance chambers and a fixed resistance element and generates a physiologic ventricular waveform. In this study, we successfully designed a commissure geometric alignment device that can manipulate aortic commissure positions to induce aortic cusp prolapse.Bioinspired polymeric heart valves derived from polyurethane and natural cellulose fibers
In this work, bioinspired anisotropic polymeric heart valves were fabricated using composite materials from polyurethane (PU) and natural cellulose fiber bundles. The hydrodynamic performance of the polymeric valve was evaluated by the ViVitro Pulse Duplicator system. Our results demonstrate the potential application of bioinspired anisotropic CPU composites as polymeric heart valves.Use of 3D anatomical models in mock circulatory loops for cardiac medical device testing
The aim of this review is to provide an overview on Mock Circulatory Loops and to discuss the recent developments of 3D anatomical models for cardiovascular Medical Device testing. One example is the ViVitro Pulse Duplicator system. The simulator is provided with a flexible ventricular sac activated by a piston pump. The addition of 3D anatomical models enables more realistic connections of the Medical Device with the implantation site and enhances the testing capabilities of the Mock Circulatory Loop.An In Vitro Circulatory Loop Model of the Pediatric Right Ventricular Outflow Tract as a Platform for Valve Evaluation
The aim of this study was to develop a robust in vitro system for quantifying flow conditions after various RVOT interventions. The MCL was developed around the ViVitro Pulse Duplicator System with the viscoelastic impedance adapter and ventricle chamber attachments. The 3D-printed RVOT anatomical model and in vitro pulmonary circulatory loop developed in this work provide platform for planning and evaluating surgical interventions in the pediatric population.Canary in the cardiac-valve coal mine: Flow velocity and inferred shear during prosthetic valve closure –predictors of blood damage and clotting
To demonstrate a clear link between predicted blood shear forces during valve closure and thrombogenicity that explains the thrombogenic difference between tissue and mechanical valves and provides a practical metric to develop and refine prosthetic valve designs for reduced thrombogenicity. Incorporated as Vivitro Systems Inc (VSI), our primary focus was research, design and development of cardiac valve implant devices and on the laboratory test systems required. In 2009, work transitioned into a separate independent research and development enterprise, ViVitro Laboratories Inc. (VLI). The application of unique technology, rapid prototyping and ranking of flow velocity patterns near valve closure optimized experimental valve geometry for reduced thrombus potential compared with control valves.Impact of Commissural Misalignment on Hydrodynamic Function Following Valve-in-Valve Intervention With the ACURATE neo
The aim of this study was to assess the impact of commissural misalignment (CMA) on hydrodynamic function following VIV intervention with the ACURATE neo THV using a bench model. In VIV using the ACURATE neo THV at deep implantation, increasing degree of CMA was associated with THV leaflet interaction with those of the surgical valve and worsening regurgitant fraction. THV leaflet interaction was prevented when there was CA.Hydrodynamic Performance of a Novel Sutureless Prosthetic Aortic Valve
The aim of the study was an in vitro hydrodynamic study of the developed prosthetic heart valve of the second generation, designed to carry out an implantation using “valve-in-valve” method. ...Prototypes of the developed prosthesis were studied under simulated physiological conditions of the heart using a Vivitro Labs pulse duplicator (Canada) in a comparative aspect with “UniLine” clinical commercial aortic valve bioprosthesis (Russia)... ...The design of the prosthesis under development has shown its consistency in terms of functional characteristics, both in comparison with the original UniLine prosthesis and with literature data....Design and Preliminary Testing of a Quadleaflet ePTFE Pediatric Prosthetic Heart Valve
The aim of this paper is to: 1) showcase the design process of a quadleaflet ePTFE valved conduit with a diameter of 16mm or less and 2) offer a hemodynamic performance comparison. ...The proposed valve was tested using the ViVitro Pulse Duplicator under physiologic cardiac conditions... ...A comparison between the two ePTFE handmade valves (trileaflet and quadleaflet) demonstrated hemodynamic differences in regurgitation due to leaflet number. The handmade valves both showed increased regurgitation compared to a Carbomedics valve (commercially available design). Regurgitation had varying effects on pressure gradients and cardiac output...Study of Biomechanics of the Heart Valve Leaflet Apparatus Using Numerical Simulation Method
The aim of the study was to study the complex biomechanics of the aortic valve prosthesis and to analyze the effect of frame mobility on the stress-strain state and geometry of the valve leaflet apparatus using a numerical simulation method, which reproduces the qualitative and quantitative results of its bench tests. ...The simulation was validated by comparing the results of numerical and bench simulation on the ViVitro Labs hydrodynamic system (ViVitro Labs Inc., Canada)... ...The results of the UniLine prosthesis biomechanics modeling have demonstrated that mobility of the frame struts of the heart valve prosthesis is a crucial aspect in assessing the effectiveness of the leaflet apparatus geometry and may be a negative factor in case of a highly elastic leaflet material...Validating In Silico and In Vitro Patient-Specific Structural and Flow Models with Transcatheter Bicuspid Aortic Valve Replacement Procedure
Bicuspid aortic valve (BAV) is the most common congenital cardiac malformation, which had been treated off-label by transcatheter aortic valve replacement (TAVR) procedure for several years, until its recent approval by the Food and Drug Administration (FDA) and Conformité Européenne (CE) to treat BAVs. ...Materials and Methods Patient-specific in silico models and 3D printed replicas of 3 BAV patients with different degrees of post-TAVR paravalvular leakage (PVL) were created. Patient-specific TAVR device deployment was modeled in silico and in vitro—following … ...PVL degree and locations were consistent with the clinical data. Cross-validation comparing the stent deformation and the flow parameters between the in silico and the in vitro models demonstrated good agreement....The Technological Basis of a Balloon-Expandable TAVR System: Non-occlusive Deployment, Anchorage in the Absence of Calcification and Polymer Leaflets
...Hydrodynamic testing to determine gradients (ΔP), effective orifice areas (EOA) and regurgitant fractions was performed in a pulse duplicator (Cardiac Output: 5 L/min; 37°C; 70 bpm; Stroke Volume: 32 ± 5 ml; Systolic Phase Duration of 35 ± 5%) (ViVitro Labs Inc; Victoria, BC, Canada)...The BE TAVR system met all requirements for which it was developed...Ex vivo biomechanical analysis of flexible versus rigid annuloplasty rings in mitral valves using a novel annular dilation system
...The left heart simulator, which has been previously described, features a pulsatile linear piston pump (ViVitro Superpump, ViVitro Labs, Victoria, British Columbia, Canada) to generate physiologic parameters using the pump controller and software (ViVitest Software, ViVitro Labs) programmed in accordance with ISO 5840 standards for in vitro valve testing...The mitral annular dilation system successfully generated an ex vivo mitral annular dilation model with MR...Towards Durability Estimation of Bioprosthetic Heart Valves Via Motion Symmetry Analysis
...Our experimental setup to collect high-quality videos and pressure and velocity data involves tricupsid BHVs mounted in the Pulse Duplicator device from ViVitro Labs...Experiments on four cases that include three different tricuspid BHVs yielded promising results, with the DTW scores showing a good coherence with respect to the simulations...In Silico Modelling of Aortic Valve Implants – Predicting In Vitro Performance using Finite Element Analysis
...To evaluate the hydrodynamic performance of each valve, in vitro bench testing was performed using a Vivitro Pulse Duplicator (Figure 2a) (Vivitro Labs, Inc. Victoria, B.C.) according to ISO 5840...Tricuspid Versus Mitral Performance of Cylindrical Porcine Small Intestinal Submucosa Valves
...hydrodynamic testing of the valves mounted in mitral and tricuspid positions were performed using a pulse duplicator system (ViVitro Labs) using 0.9% saline solution...4-D Echo-Particle Image Velocimetry in a Left Ventricular Phantom
Left ventricular (LV) blood flow is an inherently complex time-varying 3-D phenomenon, where 2-D quantification often ignores the effect of out-of-plane motion. In this study, we describe high frame rate 4-D echocardiographic particle image velocimetry (echo-PIV) using a prototype matrix transesophageal transducer and a dynamic LV phantom for testing the accuracy of echo-PIV in the presence of complex flow patterns.... … 1a). The mitral and aortic tracts of the LV were connected to atrial and compliance chambers (transparent acrylic, built in-house), which were connected via a tube with an adjustable resistance valve (ViVitro Labs … ... We demonstrate that 4-D echo-PIV could be performed in just four heart cycles, which would require only a short breath-hold, providing promising results. However, methods for resolving high velocity gradients in regions of poor spatial resolution are required before clinical translation....Fluid-Structure Interaction Models of Bioprosthetic Heart Valve Dynamics in an Experimental Pulse Duplicator
Computer modeling and simulation (CM&S) is a powerful tool for assessing the performance of medical devices such as bioprosthetic heart valves (BHVs) and promises to accelerate device design and regulation. This study describes work to develop dynamic computer models of BHVs in the aortic test section of an experimental pulse duplicator platform that is used in academia, industry, and regulatory agencies to assess BHV performance... ...This work represents a step towards the experimental validation of this FSI modeling platform for evaluating BHVs.... … In vitro experiments are performed using two different experimental platforms, including a ViVitro Pulse Duplicator (ViVitro Labs, Inc., Victoria, BC, Canada) available through the FDA Cardiac Device Flow Lab and a customized …Bio-inspired anisotropic polymeric heart valves exhibiting valve-like mechanical and hemodynamic behavior
Herein, two types of silk fibroin (SF) fiber membranes with anisotropic (ASF) and isotropic (ISF) properties were prepared by electrospinning, and were further combined with poly(ethylene glycol) diacrylate (PEGDA) hydrogels to serve as polymeric heart valve (PHV) substitutes (PEGDA-ASF and PEGDA-ISF)... ...The PHVs from both PEGDA-ASF and PEGDA-ISF presented appropriate hydrodynamic properties from pulse duplicator tests according to the ISO 5840-3 standard.... ...The Gauss curvature analysis also indicated that the anisotropic PEGDA-ASF valve can produce appropriate surface morphology by dynamically adjusting the movement of bending area during the opening process... … 1c, d). Pulse duplicator tests In vitro hemodynamic properties of PHVs were tested in a 0.9% saline solution using a pulse duplicator system (Vivitro Labs, Inc., British Columbia, Canada) according to the ISO 5840-3 standard [21] …Porcine small intestinal submucosa mitral valve material responses support acute somatic growth
Conceptually, a tissue engineered heart valve (TEHV) would be especially appealing in the pediatric setting since small size and somatic growth constraints would be alleviated. Here, we utilized porcine small intestinal submucosa (PSIS) for valve replacement... … the Dacron tubes housing the PSIS valves were measured in order to secure the valve‐in‐ conduit (Figure 1) in the mitral position within a pulse duplicator system (ViVitro Labs, Victoria, BC) … A pulse duplicator system… ... Our findings suggest that the altered structural responses of PSIS, post-fatigue, rather than de novo tissue formation, are primarily responsible for the valve’s ability to accommodate somatic growth during the acute phase (90 days) following mitral valve replacement...Implications of hydrodynamic testing to guide sizing of self‐expanding transcatheter heart valves for valve‐in‐valve procedures
...Bench study assessed the hydrodynamic performance of different sizes of self‐expanding supra‐annular THVs in three different surgical aortic bioprostheses at different implantation depths.... ...A small versus medium ACURATE neo (ACn), and a 26 mm versus 29 mm Evolut R were assessed after VIV implantation in 25 mm Mitroflow, Mosaic, and Magna Ease aortic surgical bioprostheses, at three implantation depths (+2 mm, ‐2 mm, and ‐6 mm).... ...Use of a larger self‐expanding THV was associated with superior hydrodynamic performance if the THV was implanted high....Fluid-Structure Interaction Models of an Experimental Pulse Duplicator for Simulating Bioprosthetic Heart Valve Dynamics
This study describes work to develop dynamic computer models of BHVs in the aortic test section of an experimental pulse duplicator platform... ...We compare our numerical simulations to experimental data from two similar pulse duplicators, including a commercial ViVitro system and a custom platform related to the ViVitro pulse duplicator.... ...This work represents a step towards the experimental validation of this FSI modeling platform for evaluating BHVs....Biomechanical modeling and hemorheological assessment of ascending thoracic aortic aneurysm, aortic heart valve, and blood clot
... thesis firstly evaluated the biomechanical contributions to ATAA progression under the influence of anatomy, hypertension, and hematocrit using fully coupled fluid-structure interaction (FSI) with arterial wall anisotropy to provide additional information in patient evaluations... ...The three different ATAA models identified different aortic expansions that were not uniform under pulsatile pressure and a geometry depended on elevated wall stress under hypertension.... ... A commercially available, 23 mm BMHV with a tissue annulus diameter / internal diameter (TAD/ID) of 18.5 mm (Figure 3.2), was used as the test model. ViVitro pulse duplicator was used to assess the performance and function of prosthetic heart valves under simulated cardiac conditions. ...Aortic Valve Leaflet Curvature as a Function of Elastin Degradation
... Aortic valve calcification (AVC) is caused by defects in the valves and it is a health condition which usually requires surgical valve replacement... ...The proposed project aims to capture images of the aortic leaflet curvature while cyclic flexure is conducted... The curvature of the leaflets will be captured using two high-frame rate video systems. The aortic valve leaflet flexure experiments will be produced using a Vivitro Pulse Duplicator (Vivitro Labs Inc. Victoria, BC, Canada) …Bioinspired Heart Valve Prosthesis Made by Silicone Additive Manufacturing
Synthetic implants made by traditional fabrication routes are not patient specific and rarely match the performance of their biological counterparts. We present an additive manufacturing approach for the digital fabrication of tissue-like aortic heart valves featuring customizable geometry and leaflet architectures that resemble those of native valve tissue... ...Flow was driven by a forward pressure of 100 mmHg imposed across the valve using a pulsatile testing machine (PD2010; ViVitro, Victoria, BC, Canada)... ...The ability to fabricate synthetic implants with tailored designs at multiple length scales is a key contribution toward the digital fabrication of functional implants that perform on par with native body parts...In-Vitro Pulsatile Flow Testing of Prosthetic Heart Valves: A Round-Robin Study by the ISO Cardiac Valves Working Group
...A round-robin study carried out in 2005 in accordance with ISO 5840:2005 revealed significant variabilities in prosthetic heart valve hydrodynamic performance measurements among the participating laboratories. In order to re-examine the inter-laboratory variability based on the “state-of-the-art” under ISO 5840-1 and 5840-2:2015, the ISO Cardiac Valve Working Groups decided in 2016 to repeat the round-robin study.... … took part in the round-robin study, including one academic laboratory (Helmholtz Institute of the RWTH University, Aachen, Germany), three testing service providers (BDC Laboratories, Wheat Ridge, CO; Medical Implant …Performance Analysis of the Transcatheter Aortic Valve Implantation (TAVI) on Blood Flow Hemodynamics: An Optical Imaging‐based In Vitro Study
...In this study, we aimed at investigating the impact of transcatheter aortic valve implantation (TAVI) devices on blood flow patterns that develop in the ascending aorta under physiological flow conditions in vitro... … Graphics, Heidelberg, Germany). Valve hydrodynamics A Pulse Duplicator System (ViVitro Labs Inc) was used for the assessment of heart valve performance and function under simulated cardiac conditions. The system is a … ...We conclude that the characteristics and material designs of TAVI devices have strong influences on the hemodynamics in the ascending aorta...The influence of hematocrit on the hemodynamics of artificial heart valve using fluid-structure interaction analysis
...the objective of this study is to analyze the hemodynamics and valve mechanics of a bileaflet mechanical heart valve and investigate the hemorheological characteristics under the change of hematocrit.... … Fig. 2. Schematic illustrating DPIV test set-up used in the current experiment (Image courtesy of ViVitro Labs Inc.). To simulate the physiological flow conditions, an acrylic test chamber, that represented a simplified model of … ...The current numerical analysis revealed the hematocrit influenced the shear stress distributions over a cardiac cycle...In vitro assessment of pacing as therapy for aortic regurgitation
Clinical evaluation of pacing therapy in mitigating the aortic insufficiency after transchateter aortic valve implantation often gives contradictory outcomes... ...A series of in vitro tests reproducing the heart operating changes clinically obtained by pacing was carried out in a 26 mm Edwards Sapien XT prosthesis with mild paravalvular leakage. The effect of pacing on the regurgitant volumes per cycle and per minute was quantified, and the energy and power consumed by the left ventricle were calculated... … Following well-developed methodologies for evaluation of cardiovascular devices and in vitro haemodynamics features,14 15 physiological pulsatile flow conditions were replicated in a hydromechanical pulse duplicator …Direct Ex Vivo Measurement of the Real Geometric Orifice Area to Assess the Hemodynamic Performance of Bioprosthetic Heart Valves
...the debate about the clinical evidence of the so-called patient-prosthesis mismatch (PPM) arose again. In this context it was discussed which valve specific parameter has the biggest evidence for the PPM and therefore the geometric orifice area (GOA) was pointed out as an important factor... …Methods: Commercially available surgical aortic bioprosthetic heart valves from different manufacturers were tested in a FDA / DIN conform Pulse Duplicator System (ViVitro Labs Inc., Victoria, Canada). The system … ...it was clearly demonstrated, that this GOA is a dynamic process over the whole ejection period, which significantly differed from the maximum reached GOA...Valve-in-Valve Transcatheter Aortic Valve Replacement and Bioprosthetic Valve Fracture Comparing Different Transcatheter Heart Valve Designs
The authors assessed the effect of valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) followed by bioprosthetic valve fracture (BVF), testing different transcatheter heart valve (THV) designs in an ex vivo bench study... ...The authors assessed the effect of valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) followed by bioprosthetic valve fracture (BVF), testing different transcatheter heart valve (THV) designs in an ex vivo bench study....Bioprosthetic Valves with a Novel Support System with Heart Shape Commissural Posts
Continuous improvement in the mechanics, preservation and anticalcification treatment made bioprostheses the standard mode of valve replacement in the aging population. A novel Support System with large openings at the Commissural posts has been developed and the performance and durability of bioprostheses constructed went under evaluation. … Heart valve pulse duplicator. A heart valve pulse duplicator Vivitro SPS3891 (Vivitro Systems Inc., Victoria, BC Canada) was used to measure hemodynamic parameters. All tests were performed with the standard FDA waveform …The application of biomimicry to a mechanical valve design for the abatement of flow instabilities
Studies have suggested that the anterior leaflet of the native mitral valve aid in the formation of an asymmetric vortex ring similar to that seen in healthy left ventricles... ...we seek to investigate if this physiological left ventricular vortex can be replicated solely by the inclusion of an “anterior leaflet-like” feature within a mechanical valve design and its subsequent effects on downstream turbulence.... ...Situated within the working chamber was the left ventricular silicon phantom actuated by a pulsatile pump (ViVitro Labs Inc., Victoria, BC), the resulting ventricular pumping motion circulated a mixture of glycerin and water (40 …Cardiac Valve Bioreactor for Physiological Conditioning and Hydrodynamic Performance Assessment
Tissue engineered heart valves (TEHV) are being investigated to address the limitations of currently available valve prostheses... ...A bioreactor system was designed based on the Windkessel approach. Novel features including a purpose-built valve chamber and pressure feedback control were incorporated to maintain asepsis while achieving a range of hydrodynamic conditions.... … The bioreactor was used to assess the hydrodynamic performance of a bioprosthesis and the results were compared to those obtained with a ViVitro Pulse Duplicator system (ViVitro Labs, Victoria, BC, Canada)... ...The bioreactor system was able to produce a range of pressure and flow conditions from static to resting adult left ventricular outflow tract to pathological including hypertension...Novel transcatheter aortic heart valves exhibiting excellent hemodynamic performance and low-fouling property
Transcatheter aortic heart valves (TAHVs) have been widely used for aortic valve replacements, with less trauma and lower clinical risk compared with traditional surgical heart valve replacements. In the present study, composites of poly(ethylene glycol) diacrylate (PEGDA) hydrogels and anisotropic high-shrinkage polyethylene terephthalate/polyamide6 (PET-PA6) fabric (PEGDA/PET-PA6) were fabricated as artificial heart valve leaflets... … 2.6. Pulse duplicator test. Hemodynamic performance of the TAHVs was assessed using a pulse duplicator system (ViVitro Labs, British Columbia, Canada) under physiological conditions according to ISO 5840-3 standards [21] …Novel Polymeric Valve for Transcatheter Aortic Valve Replacement Applications: In Vitro Hemodynamic Study
Transcatheter aortic valve replacement (TAVR) is a minimally-invasive approach for treating severe aortic stenosis. All clinically-used TAVR valves to date utilize chemically-fixed xenograft as the leaflet material... ... this study, we experimentally evaluated the hemodynamic performance of the valve and compared its performance to clinically-used valves: a gold standard surgical tissue valve, and a TAVR valve.... … Testing was performed in a Vivitro Pulse Duplicator (Vivitro Labs, Victoria, BC) at average Cardiac Out- puts (CO) of 4, 5, 6, and 7 L/min, Heart Rate (HR) of 70bpm, systole-diastole ratio of 0.35–0.65, aortic pressure of …Overexpansion of the SAPIEN 3 Transcatheter Heart Valve
Objectives This study assessed the effect of overexpansion beyond labeled size (diameter) of transcatheter heart valves through an ex vivo bench study... Background Transcatheter heart valves function optimally when expanded to specific dimensions. However, clinicians may sometimes wish to overexpand balloon-expandable valves to address specific clinical challenges. The implications of overexpansion have assumed considerable importance, and objective information to guide practice is limited...Impact of Clinically Relevant Elliptical Deformations on the Damage Patterns of Sagging and Stretched Leaflets in a Bioprosthetic Heart Valve
After implantation of a transcatheter bioprosthetic heart valve its original circular circumference may become distorted, which can lead to changes in leaflet coaptation and leaflets that are stretched or sagging.... … Valve hydrodynamic performance data were collected using a commercially available left heart Pulse Duplicator (Vivitro Systems) at 0, 41, 80, and 123 M cycles; at these intervals, the valves mounted in the metallic adapter …Evaluating the impact of air compliance chamber volumes on valve performance for three different heart valves
...The air volume shifts the pressure and flow rate waveforms in time and impact the physical operating conditions of the valves with constant input settings in the ViVitest software... … Results obtained from current pulse duplicators are subject to the setup and physical testing settings. The ViVitro Pulse Duplicator from ViVitroLabs Inc … Three different valves were tested in a ViVitro pulse duplicator where...Over‐expansion of balloon‐expandable transcatheter heart valves
Transcatheter aortic valve implantation can be successful in selected patients with annuli beyond the current recommended limits for available transcatheter heart valves.… Hopefully in future we will have both a broader understanding and a broader range of options. Conflict of interest. Dr. Webb is a consultant to Edwards Lifesciences and ViVitro Labs. Publication cover image. Volume 91, Issue 6. May 1, 2018. Pages 1157-1158Single calibration multiplane stereo-PIV: the effect of mitral valve orientation on three-dimensional flow in a left ventricle model
...The effects of the orientation of a prosthetic mitral valve in anatomical and anti-anatomical configurations have been investigated during the diastolic filling time... … A commercially available cardiovascular simulator (Vivitro Systems, Inc., Victoria, BC, Canada) that can impose and monitor different physiological pressure and flow conditions was adopted. The hydraulic piston pump was connected to the inner tank …Comparative Fluid-Structure Interaction Analysis of Polymeric Transcatheter and Surgical Aortic Valves' Hemodynamics and Structural Mechanics
...All currently FDA-approved TAVR devices use tissue valves that were adapted to but not specifically designed for TAVR use. Emerging clinical evidence indicates that these valves may get damaged during crimping and deployment- leading to valvular calcification, thrombotic complications, and limited durability... ...Our research group has developed a novel polymeric prosthetic valve, which was optimized to reduce stresses on the leaflets, improve hemodynamics and has thrombogenic performance similar to that of a tissue valve... … The valves are then sutured to a nitinol stent for completion of the process. The valves' durability is now being assessed using a Vivitro Hi-Cycle System (Vivitro Labs, Inc … Hydrodynamic performance is being evaluated using the Vivitro left heart simulator (Vivitro Labs, Inc …Experimental Investigation of Left Ventricular Flow Patterns After Percutaneous Edge‐to‐Edge Mitral Valve Repair
This in vitro study aims to evaluate the hemodynamic modifications following a simulated PEtER. A custom-made mitral valve was developed, and two configurations were tested: (i) a single-orifice valve with mitral regurgitation and (ii) a double-orifice mitral valve configuration following PEtER. … MATERIALS AND METHODS In vitro model For the purpose of this study, a ViVitro pulse duplicator (ViVitro Labs, Victoria, BC, Canada) was used (Fig. 1). This system is capable of reproducing physiological flow and pressure waveforms in left heart cavity models …Applicability of the handmade ePTFE trileaflet-valved conduits for pulmonary valve reconstruction: An ex vivo and in vivo study
...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. ...In vitro biomechanical and hydrodynamic characterisation of decellularised human pulmonary and aortic roots
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 ...In-Vitro Pulsatile Flow Measurement in Prosthetic Heart Valves: An Inter-Laboratory Comparison
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....Experimental Study of Right Ventricular Hemodynamics After Tricuspid Valve Replacement Therapies to Treat Tricuspid Regurgitation
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 ...in-vitro Assessment of Expanded-Polytetrafluoroethylene Stentless Tri-leaflet Valve Prosthesis for Aortic Valve Replacement
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. ...Leaflet Free Edge Detection for the Automatic Analysis of Prosthetic Heart Valve Opening and Closing Motion Patterns from High Speed Video Recordings
...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.In-vitro hemodynamic testing of stentless prosthetic aortic valves
...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. ...JetValve: Rapid manufacturing of biohybrid scaffolds for biomimetic heart valve replacement
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...Design, Analysis and Testing of a Novel Mitral Valve for Transcatheter Implantation Authors Authors and affiliations
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 ...An In Vitro Feasibility Study of the Influence of Configurations and Leaflet Thickness on the Hydrodynamics of Deformed Transcatheter Aortic Valve
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.). ...Hydrodynamic Assessment of Aortic Valves Prepared from Porcine Small Intestinal Submucosa
...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). ...Pledget-Armed Sutures Affect the Haemodynamic Performance of Biologic Aortic Valve Substitutes: A Preliminary Experimental and Computational Study
...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 ...In Vitro Pulsatile Performance Evaluation of the HeartMate PHP TM (Percutaneous Heart Pump)
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.Development & Design of Improved Commissure for Tissue-Engineered Transcatheter Heart Valves
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...Physiological vortices in the sinuses of Valsalva: An in vitro approach for bio-prosthetic valves
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. ...Flow-Induced Damage to Blood Cells in Aortic Valve Stenosis
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). ...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
... 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.In vitro hemodynamic testing of Amplatzer plugs for paravalvular leak occlusion after transcatheter aortic valve implantation
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.Development of an In Vitro Model to Characterize the Effects of Transcatheter Aortic Valve on Coronary Artery Flow
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 ...Hemodynamic and thrombogenic analysis of a trileaflet polymeric valve using a fluid-structure interaction approach
... 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. ...Effects of Bileaflet Mechanical Mitral Valve Rotational Orientation on Left Ventricular Flow Conditions
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 ...Classification of Unsteady Flow Patterns in a Rotodynamic Blood Pump: Introduction of Non-Dimensional Regime Map
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 ...Evaluating the performance of prosthetic heart valves: transvalvular pressure drop vs. vortex ring formation number
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 . ...Effect of aortic annulus size and prosthesis oversizing on the hemodynamics and leaflet bending stress of transcatheter valves: an in vitro study
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 ...The influence of the aortic root geometry on flow characteristics of a prosthetic heart valve
...he objective of this investigation is to establish a set of parameters, which are associated with abnormal flow patterns due to the flow through a prosthetic heart valve implanted in the patients that had certain types of valve diseases prior to the valve replacement.... ...By varying the aortic root geometry, while keeping the diameter of the orifice constant, it was possible to investigate corresponding changes in the levels of Reynolds shear stress and establish the possibility of platelet activation and, as a result of that, the formation of blood clots....Design of a novel polymeric heart valve
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...A fluid-structure approach to optimize the thrombogenic potential of artificial heart valves
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 ...Finding the ideal biomaterial for aortic valve repair with ex vivo porcine left heart simulator and finite element modeling
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...The congenitally bicuspid aortic valve: how does it function? Why does it fail?
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.Pulsatile flow studies of a porcine bioprosthetic aortic valve in vitro: PIV measurements and shear-induced blood damage
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...Numerical simulation of the dynamics of a bileaflet prosthetic heart valve using a fluid–structure interaction approach:
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.Modified gorlin equation for the diagnosis of mixed aortic valve pathology
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...Geometric modeling of functional trileaflet aortic valves: Development and clinical applications
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...Fluid dynamics of the CarboMedics Kinetic bileaflet prosthetic heart valve
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...Flow instabilities induced by coronary artery stents: Assessment with an in vitro pulse duplicator
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...Arteriovenous fistulas aggravate the hemodynamic effect of vein bypass stenoses: An in vitro study
Angiographic Quantification of Contrast Medium Washout from Cerebral Aneurysms after Stent Placement
Discrimination in vitro between the acoustic emissions from Bjork-Shiley convexo-concave valves with and without a broken minor strut
In Vitro Strain Measurement of a Mechanical Heart Valve in a Pulse Simulator
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.A Database Obtained From In Vitro Function Testing of Mechanical Heart Valves:
Pressure trap created by vein valve closure and its role in graft stenosis:
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.Hydrodynamic function of tilting disc prostheses and bileaflet valves in double valve replacement:
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.Fluid dynamics of the CarboMedics kinetic bileaflet prosthetic heart valve
Analysis of regurgitation, mean systolic pressure drop and energy losses for two artificial aortic valves
Transpecies heart valve transplant: advanced studies of a bioengineered xeno-autograft
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.Influence of sizing and subcoronary implantation technique on the function of porcine aortic homografts
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.)...Method of ranking of heart valve characteristics at mitral position based on statistical model analysis
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...Decellularized human valve allografts
A new aortic root prosthesis with compliant sinuses for valve-sparing operations
Particle Image Velocimetry Assessment of Stent Design Influence on Intra-Aneurysmal Flow
Hydrodynamic function of the second-generation mitroflow pericardial bioprosthesis
What parameters affect left ventricular diastolic flow propagation velocity? in vitro studies using color m-mode doppler echocardiography
Insufficient data describe the relationship of hemodynamic parameters to left ventricular (LV) diastolic flow propagation velocity (Vp) measured using color M-mode Doppler echocardiography.Three-Dimensional Numeric Simulation of Flow Through an Aortic Bileaflet Valve in a Realistic Model of Aortic Root
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,...First Human Case of Retrograde Transcatheter Implantation of an Aortic Valve Prosthesis
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.Comparison of the flow downstream two prototypes of a new monoleaflet artificial aortic heart valve by means of PIV visualization
Quantitative approach to aortic valve-sparing surgery
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.Development of Squeeze Flow in Mechanical Heart Valve: A Particle Image Velocimetry Investigation
Energy Loss Due to Paravalvular Leak With Transcatheter Aortic Valve Implantation
A method for the measurement of left ventricular overload for aortic valve insufficiency
Development and evaluation of a novel artificial catheter-deliverable prosthetic heart valve and method for in vitro testing
Revisiting the Simplified Bernoulli Equation
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.Structural analysis of the natural aortic valve in dynamics: From unpressurized to physiologically loaded
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.Ex vivo hemodynamic assessment of mechanical aortic valve gradients using a high-fidelity pressure wire
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.Product Development Cycle of a Surgical Device for Mitral Valve Repair and Surgical Training Simulator Development Plan for the Same
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)...Optimization and Verification of a Novel Trileaflet Polymeric Prosthetic Heart Valve
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.Signal processing of heart signals for the quantification of non-deterministic events
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.Design conception and experimental setup for in vitro evaluation of mitral prosthetic valves
Valve-in-valve hemodynamics of 20-mm transcatheter aortic valves in small bioprostheses
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.Dilatation of the ascending aorta in patients with congenitally bicuspid aortic valves
Importance of Shear in Prosthetic Valve Closure Dynamics
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.Manufacturing and hydrodynamic assessment of a novel aortic valve made of a new nanocomposite polymer
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.Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves.
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.A Direct In Vitro Comparison of the Edwards SAPIEN and Medtronic CoreValve Transcatheter Aortic Valve implantation (TAVI) Devices and a Surgical Counterpart
Role of the sinuses of Valsalva on the opening of the aortic valve
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.An in vitro model of aortic stenosis for the assessment of transcatheter aortic valve implantation
A metric for the stiffness of calcified aortic valves using a combined computational and experimental approach
Development and characterization of acellular porcine pulmonary valve scaffolds for tissue engineering
… 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. …A novel flow performance metric for the assessment of prosthetic heart valves
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 …