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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.
Biomechanics and clinical outcomes of various conduit configurations in valve sparing aortic root replacement
The goal was to preserve the native aortic valve (AV) leaflets in patients with aortic root aneurysm with or without aortic regurgitation (AR). The ex vivo system consists of a linear piston pump (ViVitro Superpump, ViVitro Labs, Victoria, BC, Canada) to generate a physiologic waveform in compliance with ISO 5840 standards. Similar to our previous ex vivo evaluation of the VSARR operation, we again confirmed that SG, compared with sinus containing graft, most closely recapitulated the native aortic root biomechanics.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.Framework Development for Patient-specific Compliant Aortic Dissection Phantom Model Fabrication
Type B aortic dissection is a life-threatening medical emergency that can result in rupture of the aorta. The aortic simulator is a hydraulic model that has physical and dynamical properties similar to the human circulatory system. This hydraulic model consists of a piston-in-cylinder pump (ViVitro Labs Inc.) that generates a physiologically accurate pulsatile flow (using a programmable waveform generator ViVigen) and a pump head, including a silicone ventricle membrane, mitral valve, and aortic valve. Results demonstrate that the deep-learning model can accurately capture the dissection geometry from patients’ medical images.An In-Vitro Experimental Investigation of Oscillatory Flow in the Cerebral Aqueduct
The cerebrospinal fluid filling the ventricles of the brain moves with a cyclic velocity driven by the transmantle pressure, or instantaneous pressure difference between the lateral ventricles and the cerebral subarachnoid space. The periodic flow was generated with a programmable piston pump (SuperPump AR, ViVitro Labs, Victoria, Canada) connected through semi-rigid tubing to a ball valve located near the bottom of one of the reservoirs. MRI-informed in-vitro experiments have been used to evaluate the pressure difference between the third to fourth ventricles in the brain Δp, yielding results in good agreement with those of a previously derived mathematical model.Ultrafast Myocardial Principal Strain Ultrasound Elastography during Stress Tests: in vitro Validation and in vivo Feasibility
Assessment of myocardial contractility during a stress test is of high clinical value for the diagnosis and evaluation of cardiovascular diseases, especially coronary disease and heart failure. Both ends of this left-ventricular mimicking phantom (wall thickness of 15 mm) was then connected to polyvinyl chloride tubing by a pair of loosely attached steel clamps to a pulse duplicator (model #SD2001-1, ViVitro systems Inc., Victoria, BC, Canada). The complex, large, and rapid myocardial deformation during stress tests were also accurately imaged by the proposed strain estimator with close agreement with sonomicrometry.A soft robotic sleeve mimicking the haemodynamics and biomechanics of left ventricular pressure overload and aortic stenosis
Advances in soft robotics have led to the development of high-fidelity simulators of pathophysiology for biomedical applications. An MCL was built using a pulsatile pump (SuperPump, ViVitro Labs), an anatomically accurate compliant silicone aortic vessel (E ≈ 1 MPa, United Biologics) connected to two adjustable compliance chambers (that is, ventricular, systemic), and a resistive valve. The models leverage haemodynamic mimicry and may facilitate the development of patient-specific applications. The models could also facilitate the clinical translation of treatments; in particular, a cohort of AS patients could be recapitulated in an in vivo porcine model, and new treatments could be evaluated preclinically.Trileaflet semilunar valve reconstruction: pulsatile in vitro evaluation
We investigated a new surgical technique of trileaflet semilunar valve reconstruction possessing the potential of remaining sufficient and allowing for some growth with the child. Pulsatile flow was produced by a Series piston pump (SuperPump AR; ViVitro Labs, Victoria, Canada), connected to the ventricular chamber. TSVR was achievable in vitro. Hydrodynamic pressure and echocardiographic evaluations demonstrated a sufficient and non-stenotic neo-valve.Experimental study of flow structure impact on the fluid parameters in saccular aneurysm models
Aneurysms are abnormal expansion of weakened blood vessels which can be debilitating or fatal upon rupture. Previous studies have shown that hemodynamics play a role in aneurysm formation, growth and rupture. Therefore, the objective of this work is to investigate the impact of flow structures on vortex strength, impinging location, and wall shear stress for two aneurysm models. ...The inflow parameters used in this study, and , were controlled using a ViVitro Labs Inc. SuperPump system... ...The flow evolution results showed that impacted the vortex formation, growth, and dissipation processes for the studied aneurysm model...Modal Decomposition Techniques: Application in Coherent Structures for a Saccular Aneurysm Model
Aneurysms are localized expansions of blood vessels which can be fatal upon rupture. Studies have shown that aneurysm flows exhibit complex flow phenomena which consist of single or multiple vortical structures that move within the flow cycle. ...Rep and α were the inflow parameters used to match and simulate the conditions in the human circulatory system. These inflow parameters were precisely controlled with a ViVitro Labs Inc. SuperPump system... ...Both POD and DMD are capable analysis tools to investigate the spatial and temporal behavior of large-scale structures of a given flow field. POD and DMD can be used to create mathematical models to look into the flow evolution in sufficiently high detail and at any time step...The Supera Interwoven Nitinol Stent as a Flow Diverting Device in Popliteal Aneurysms
...To assess this flow diverting strategy for popliteal aneurysms, flow profiles and thrombus formation likelihood were investigated in popliteal aneurysm models... ...The model was placed in a circulating flow set-up with a blood-mimicking fluid (Fig. 3). At the inlet, a hydraulic piston pump (SuperPump, ViVitro labs, Victoria, Canada) was used to enforce time-varying forward flow...Comparison of Flow Behavior in Saccular Aneurysm Models Using Proper Orthogonal Decomposition
...Rep and α were two inflow parameters used in this study, and these were controlled using a ViVitro Labs Inc. (Victoria, BC, Canada) SuperPump system...POD provides a method for analyzing complex flow phenomena in great detail. It can be used to study a variety of unsteady, physiological flows to understand the behavior of energetic flow structures..Comprehensive In-Vitro Neurovascular Model Assessment for Implant Simulation
...Physiologically-relevant patient flow parameters were tuned within the system using a Super Pump AR (ViVitro Labs)...This in-vitro aneurysm flow model utilized the latest in UV-cured 3D-printing techniques to provide a realistic simulation of neurovascular tortuosity and aneurysm device delivery...Biomechanical Engineering Analysis of an Acute Papillary Muscle Rupture Disease Model Using an Innovative 3D-Printed Left Heart Simulator
...The severity of acute papillary muscle (PM) rupture varies according to the extent and site of the rupture. However, the haemodynamic effects of different rupture variations are still poorly understood...A 3D printer (Carbon 3D, Redwood City, CA, USA) was used to prototype a modular left heart (left atrium and ventricle) and was mounted to a pulsatile linear piston pump (ViVitro Superpump; ViVitro Labs, Victoria, BC, Canada)...Ex Vivo Model of Ischemic Mitral Regurgitation and Analysis of Adjunctive Papillary Muscle Repair
Driven by a pulsatile linear piston pump (ViVitro Superpump, ViVitro Labs, Victoria, BC, Canada) which generates physiologic hemodynamics in accordance with ISO 5840 in vitro cardiac valve testing standards.Effect of Leaflet Type and Leaflet-Stent Attachment Height on Transcatheter Aortic Valve Leaflet Thrombosis Potential
The physiologic pressures and flows were achieved by adjustment of systemic resistance and compliance elements, and flow driven from a piston pump (Vivitro Labs Inc. Victoria, Canada).Application of Dynamic Mode Decomposition to Study Temporal Flow Behavior in a Saccular Aneurysm
The inflow conditions are precisely controlled using a ViVitro SuperPump system where nondimensional fluid parameters such as peak Reynolds number (Rep) and Womersely number (α) are varied from 50–270 and 2–5, respectively.Echo planar imaging–induced errors in intracardiac 4D flow MRI quantification
A pulsatile hydraulic piston pump (Vivitro Labs, Victoria, Canada) was connected to the tank with semirigid tubing. This pump, positioned outside the scanner room, generated a sinusoidal-like pulsatile waveform with 70-bpm frequency without net flow, resulting in a pressure waveform inside the tank that created contraction of the filled LV phantom with a 300-ms systolic period and 50-mL stroke volume.Papillary Muscle Approximation Reduces Systolic Tethering Forces and Improves Mitral Valve Closure in the Repair of Functional Mitral Regurgitation
...actuating pump with a viscoelastic impedance (Superpump, Vivitro Labs, London, ON) was connected to the LV, and programmed to generate physiological left ventricular pressures. 0.9% saline was used as the working medium in this flow loop...Application of Proper Orthogonal Decomposition to Study Coherent Flow Structures in a Saccular Aneurysm
… vectors in the sac region. 3.3 Pump System. To generate controlled inflow conditions for this study, a piston pump (ViVitro Labs Inc. SuperPump Sys- tem AR Series, Victoria, BC, Canada) was used. The piston pump system …2D PIV experiments of oscillatory flow in a stenosis: A study into the physics of flow of cerebrospinal fluid
...the Vivitro pump, labeled F, (SuperPump, ViVitro labs,Victoria, Canada) was used to create the oscillatory waveform...Computational modelling of flow in the liver vasculature using the Lattice Boltzmann method to study microsphere distribution
...a hydraulic piston pump (SuperPump, ViVitro labs, Victoria, Canada) was used to generate the pulsatile flow and...Simulating Radial Pressure Waveforms with a Mock Circulatory Flow Loop to Characterize Hemodynamic Monitoring Systems
… Pressure measurement location. ºFlow measurement location. Full size image. Deionized water is circulated through the MCL using a piston pump [ViVitro Labs, Victoria, BC, Canada] that is fluid-coupled to a suspended silicone-based mock ventricular sac …Comprehensive in-vitro neurovascular model assessment for implant simulation
...physiologically-relevant patient flow parameters were tuned within the system using a Super Pump AR (ViVitro Labs). A data acquisition system (DAQ) with LabVIEW® software recorded real time pressure and flow waveforms, mean arterial pressures (MAP) and flows through each inlet and outlet branch of the 3D-printed CW model. The flow model included an introducer for microcatheter and device delivery access...Effect of inhalation on oropharynx collapse via flow visualisation
… Fluorescent spherical particles (500-600 µm diameter, Cospheric LLC, Santa Barbara, USA) were injected into the head of a piston-driven SuperPump (Vivitro Labs, Victoria, Canada) that was connected to an …A novel 3D-Printed preferential posterior mitral annular dilation device delineates regurgitation onset threshold in an ex vivo heart simulator
...This work shows the design and implementation of a 3D-printed valve dilation device to preferentially dilate the posterior mitral valve annulus... ...In brief, a custom 3D-printed left heart chamber (Fig. 2A) was mounted to a pulsatile linear piston pump (ViVitro Superpump, ViVitro Labs, Victoria, BC, Canada) with the ability to generate physiologic conditions … ...this annular dilation device provides the means to investigate the design and optimization of novel annuloplasty rings....Mitral chordae tendineae force profile characterization using a posterior ventricular anchoring neochordal repair model for mitral regurgitation in a three-dimensional-printed ex vivo left heart simulator
Posterior ventricular anchoring neochordal (PVAN) repair is a non-resectional technique for correcting mitral regurgitation (MR) due to posterior leaflet prolapse, utilizing a single suture anchored in the myocardium behind the leaflet... ...Porcine mitral valves were mounted in a 3-dimensional-printed heart simulator and chordal forces, haemodynamics and echocardiography were collected at baseline, after inducing MR by severing chordae, and after PVAN repair.... ...PVAN repair eliminates MR by positioning the posterior leaflet for coaptation, distributing forces throughout the valve....Ventricular vortex loss analysis due to various tricuspid valve repair techniques: an ex vivo study
The deteriorating nature of severe functional tricuspid regurgitation (FTR) has led to the heightened interest in this pathology... ...In this study, the hemodynamics of the right ventricle (RV) after (i) clover edge-to-edge tricuspid repair and (ii) double orifice tricuspid repair was evaluated in three right heart models using an ex vivo pulsatile platform emulating severe FTR with the aid of stereoscopic particle image velocimetry... … circulation (35). A closed ventricular chamber housing the silicon RV model was directly 184 connected to the pulsatile wave-generating piston pump (SuperPump AR series, ViVitro Labs 185 Inc., Victoria, BC, Canada) to …Pulsatile Flow Investigation in Development of Thoracic Aortic Aneurysm: An In-Vitro Validated Fluid Structure Interaction Analysis.
Thoracic aortic aneurysm (TAA) is a severe cardiovascular disease with a high mortality rate, if left untreated... ...In order to gain more insight on TAA formation, we developed a computational framework in vitro to investigate and compare the flow patterns between pre-aneurismal and post-aneurismal aorta using a deformable wall model... ...The pulsatile flow was created using a piston pump (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada) generating the inlet velocity profile with the How rate of 4 L/min at the frequency of 1 Hz, extracted from the literature …E-021 In vitro neurovascular model development for liquid embolic implant simulation
Although current microcatheter technologies have advanced in recent years, corresponding endovascular devices still lag behind... ...This research project includes development of innovative in vitro aneurysm vessel model with complex side branching.... … communicating (ACA) bifurcation. Flow is regulated through the use of a Super Pump AR (ViVitro Labs). This 3D printed model will be implemented in an in vitro flow model that enables systemic data collection. A data acquisition … ...The in vitro model is used to simulate and quantify short-and long-term viability of new biomaterials for brain aneurysm embolization...An Evaluation of the Influence of Coronary Flow on Transcatheter Heart Valve Neo-Sinus Flow Stasis
Transcatheter heart valve (THV) leaflet thrombosis in the neo-sinus and associated reduced leaflet motion is of clinical concern due to risks of embolism and worsened valve hemodynamics... ...We tested two replicas of FDA approved commercial THVs—intra-annular and supra-annular (similar to the SAPIEN 3 and CoreValve families)—in a left heart simulator with coronary flow... … The Georgia Tech left heart simulator is shown in Fig. 2a. The main flow rate was driven by the primary piston pump (Vivitro Labs Inc. Victoria, Canada); wall-tapped pressure transducers (Deltran DPT-200, Utah Medical Products IncDevelopment and ex vivo validation of novel force-sensing neochordae for measuring chordae tendineae tension in the mitral valve apparatus using optical fibers with embedded Bragg gratings
Few technologies exist that can provide quantitative data on forces within the mitral valve apparatus... Using FBG sensors, we created a force-sensing neochord that mimics the natural shape and movement of native chordae.... … Redwood City, CA, USA) was mounted to a programmable pulsatile linear piston pump (ViVitro Superpump, ViVitro Labs, Victoria, BC, Canada) with the ability to generate physiologic conditions using the pump controller and …Hemodynamic Analysis of a Novel Stent Graft Design with Slit Perforations in Thoracic Aortic Aneurysm
Thoracic endovascular aortic repair (TEVAR) has been introduced as a less invasive approach to the treatment of thoracic aortic aneurysm (TAA). However, the effectiveness of TEVAR in the treatment of TAA is often limited due to the complex anatomy of aortic arch... ...This study proposes a novel stent graft design with slit perforations that can positively alter the hemodynamics at the aortic arch while maintaining blood flow to supra-aortic branches... … flow preservation at side branches. The system was driven by a pulse generator (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada) at a flow rate of 5 L/min and a pulse rate of 1 Hz. The reservoir level and mechanical …In-vitro and in-vivo evaluation of a novel bioprosthetic pulmonary valve for use in congenital heart surgery
Management of congenital malformations of the pulmonary artery and valve can be challenging. The severity often demands early intervention, which is rarely definitive due to the natural growth and multiple surgeries may be required... ...In this study, a simple valve design supported by an absorbable proximal stabilization ring is evaluated both in-vitro and in-vivo... … In-vitro model and testing. All in-vitro testing was carried out in a pulsatile flow model using water as the test fluid (Fig. 2). Pulsatile flow and pressure were generated with an electromechanical piston pump (VSI Superpump, Vivitro Labs, Victoria, Canada) …Stiffness Evaluation of Aortic Aneurysms Using an Ultrafast Principal Strain Estimator: In Vitro Validation
Aortic stiffness is altered by cardiovascular diseases and exacerbated in innate or pathological conditions, which might be detected by noninvasive vascular elastography.... ...results suggest that the proposed model could detect and evaluate aortic aneurysm stiffness and may be useful clinically for the early and timely detection of degraded mechanical properties to impact patient outcomes.... … Hz. Normal and aneurysm aortic deformations were compared by pulsing mimicing vessels at 60 bpm, using a hydraulic pulse duplicator within a left ventricular model (Superpump system, Vivitro Inc., Victoria, BC, Canada) …Dilation of tricuspid valve annulus immediately after rupture of chordae tendineae in ex-vivo porcine hearts
Chordae rupture is one of the main lesions observed in traumatic heart events that might lead to severe tricuspid valve (TV) regurgitation... ...we investigated the changes on TV geometry, mechanics, and function of ex-vivo porcine hearts following chordae rupture... … The schematic of this apparatus is shown in Fig 1. In short, a positive displacement pump (SuperPump AR Series, Vivitro Labs, Inc., Victoria, BC, Canada) was utilized to induce passive beating in porcine hearts …Synthetic Aperture Cardiac Imaging with Reduced Number of Acquisition Channels. A Feasibility Study
Commercially available cardiac scanners use 64–128 elements phased-array (PA) probes and classical delay-and-sum beamforming to reconstruct a sector B-mode image... ...The goal of this study was to show the feasibility of reducing the channel count in the diverging wave synthetic aperture image reconstruction method for phased-arrays.... … a water tank with dedicated absorbers at- tenuating the reflected waves (Aptflex F28 and Aptflex F28P, Precision Acoustics, UK), tubing system, wind- kessel (to reduce/eliminate phantom vibrations), Viv- itro Superpump …Impact of simulated MitraClip on forward flow obstruction in the setting of mitral leaflet tethering: An in vitro investigatio
...Leaflet tethering commonly seen in functional mitral regurgitation may be a significant factor affecting the severity of MS after MitraClip implantation... … conditions. A piston pump (Vivitro Labs Inc. Victoria, Canada) drove physiological left heart flow within the simulator, while an electromagnetic flow probe (Carolina Medical Electronics, East Bend, NC) measured cardiac output (CO) …Two-dimensional affine model-based estimators for principal strain vascular ultrasound elastography with compound plane wave and transverse oscillation beamforming
Polar strain (radial and circumferential) estimations can suffer from artifacts because the center of a nonsymmetrical carotid atherosclerotic artery, defining the coordinate system in cross-sectional view, can be misregistered... ...Two-affine model-based estimators for vascular ultrasound elastography in cross-sectional view of the artery are evaluated in a common framework of high-frame-rate imaging... ...This paper presents two affine model-based estimators, the affine phase-based estimator (APBE) developed in the framework of transverse oscillation (TO) beamforming, and the Lagrangian speckle model estimator (LSME)...Personalized dynamic phantom of the right and left ventricles based on patient-specific anatomy for echocardiography studies — Preliminary results
This work aims to create a dynamic, ultrasound-compatible, realistic and flexible phantom of the left and right ventricles, with application in the diagnosis, planning, treatment and training in the cardiovascular field for studies using echocardiography. … the real tissues. Then, a commercial available computed-controlled dynamic piston pump (Vivitro Labs, Victoria, British Columbia, Canada) was used to pump water... into the model and consequently deform it. This pump systemExperimental study on impact of inflow conditions on large-scale flow structures in an aneurysm
...This study focuses on investigating the hemodynamics inside an aneurysm for different inflow conditions and varying geometrical shapes. ... … precisely controlled. Re and α were varied between 50-250 and 2-5, respectively. A ViVitro Labs pump system was used to pump the fluid and Particle Image Velocimetry (PIV) was used to perform velocity measurements. The flow …A Semi-Stented and Chorded Mitral Valve Prosthesis: Design and Method of Chordal Setting and In Vitro Testing
Mitral subvalvular apparatus plays an important role in mitral and ventricular dynamics by preserving annuloventricular continuity, known to be fundamental for ventricular function... ...We address these issues through the design of a novel semistented and chorded mitral valve that better mimics the native mitral annulus, leaflets and chordae function and can be made from off-the-shelf biomaterials with the potential to be implanted percutaneously... … Pulse duplicator setup We performed hydrodynamic testing in the mitral position on a hydro-mechanical pulse duplicator system (Vivitro Superpump System SP3891, Vivitro, Victoria, BC, Canada), described elsewhere [4]. We used a 25mm Sorin Bicarbon bileaflet …In Vitro Evaluation of Hemodynamic Performance for Right Ventricular Outflow Tract RVOT Reconstruction with Trileaflet ePTFE Valved Conduit
...Percutaneous pulmonary valve implantation (PPVI) has evolved as most exciting development surgical strategy with dysfunctional right ventricle-pulmonary artery conduits. ... ...The purpose of this study is to investigate the hemodynamic and functional consequences of the new design using a mock circulation system... … vasculature. Blood pressures and flows are driven by a digitally controlled hydraulic piston pump (ViViTro Labs Inc., Super Pump System, Victor, BC) to produce pulsatile waves with heart rates of 60 and 80 beats/min from ARV to ARA …Assistive technology using regurgitation fraction and fractional-order integration to assess pulmonary valve insufficiency for pre-surgery decision making and post-surgery outcome evaluation
...This study proposes an assistive technology to quantify regurgitation using the regurgitation fraction (RF) and heart pump efficiency (HPE). … pulmonary valves. The blood pressure and flow were driven by a digitally controlled hydraulic piston pump (ViViTro Labs Inc., Super Pump System, Victor, BC) to produce pulsatile waves with heart rates of 60 and 80 beats/min. The …Transvalvular pressure gradients for different methods of mitral valve repair: only neochordoplasty achieves native valve gradients
Many surgical and interventional methods are available to restore patency for patients with degenerative severe mitral valve regurgitation... ...Eight porcine mitral valves were tested under pulsatile flow conditions in an in vitro pulsatile flow loop for haemodynamic quantification.... ...All surgical reconstruction techniques were able to sufficiently correct the acute mitral valve regurgitation.... ...The LV chamber was actuated using a computer-controlled piston pump (ViVitro Systems Inc., Victoria, Canada) attached to the LV chamber...Can bioprosthetic valve thrombosis be promoted by aortic root morphology? An in vitro study
Bioprosthetic valve thrombosis has been considered uncommon, but recent studies have shown that it is more frequent than previously thought. ...Two compliant aortic root phantoms with different morphologies (symmetrical and patient-specific) were fabricated with silicone. A bioprosthetic aortic valve was inserted in both phantoms.... ...Blood flow in the aortic root and the washout of the sinus portion are significantly affected by aortic root morphology.... ...The flow loop was actuated by a piston pump (ViVitro Systems Inc., Victoria, BC, Canada)...Development of a validation instrument in myocardial perfusion imaging: results of first flow experiments
...Myocardial perfusion imaging (MPI) is a commonly used diagnostic method in coronary artery disease (CAD)... ... In line with proper clinical decision-making, it is essential to assess institutional MPI test validity by confronting MBF assessment to a ground truth. Our research focuses on developing such validation instrument/method for MPI by means of simulating controlled myocardial perfusion in a phantom flow setup.... … All the data presented in this paper were obtained with the open circuit setup to prevent contrast recirculation. The used piston pump (Vivitro Superpump, Vivitro Labs, Victoria, Canada) generates programmable pulsatile flowFlow visualization of the non-parallel jet-vortex interaction
...The objective of this study was to characterize three distinct orientations (30°, 60° and 90°) of the non-parallel jet–vortex interaction in a simplified flow loop... … 1 Experimental setup of jet–vortex interaction flow loop. A programmable pulsatile pump (ViVitro SuperPump) allowed for controlled, isolated vortex rings to be ejected into the chamber, as shown in Fig. 2. The flow profile for vortex ring ejection is shown in Fig …Hemodynamic assessment of extra-cardiac tricuspid valves using particle image velocimetry
...The study utilises both 2-D and 3-D particle image velocimetry (PIV) to interrogate the flow patterns in the vicinity of the extra-cardiac tricuspid valves in an in vitro physiological flow loop, specifically at four measurement locations in the cavo-atrial anatomy. ... ... of the hepatic vein. In contrast, the SVC valve was fully implanted in the SVC. The mock circulatory system was driven by a pulse generator (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada). It comprised of an ultrasonic ...Application of Dynamic Mode Decomposition: Temporal Evolution of Flow Structures in an Aneurysm
...The objective of this study is to identify the large-scale structures in the aneurysm, study temporal behavior, and quantify their interaction with the inflow condition. ... ... For this purpose, detailed Particle Image Velocimetry (PIV) measurements were performed at the center plane of an idealized aneurysm model for a range of inflow conditions. Inflow conditions were precisely controlled using a ViVitro SuperPump system. ...Impact of Inflow Conditions on Coherent Structures in an Aneurysm
...Studies have shown that hemodynamics is integral to developing an understanding of aneurysm formation, growth, and rupture. This investigation focuses on a comprehensive study of the impact of varying inflow conditions and aneurysm shapes on spatial and temporal behavior of flow parameters and structures in an aneurysm.... ... For this purpose, detailed Particle Image Velocimetry (PIV) measurements were performed at the center plane of an idealized aneurysm model for a range of inflow conditions. Inflow conditions were precisely controlled using a ViVitro SuperPump system. ...An improved implementation of block matching for motion estimation in ultrasound imaging
Ultrasound elastography has become an important procedure that provides information about the tissue dynamics and may help on the detection of tissue abnormalities. We propose a novel algorithm to perform speckle tracking, which consists in an implementation of 2D Block Matching with two enhancements: sub-pixel linear interpolation and displacement propagation, which are able to increase resolution, reduce computation time and prevent kernel mismatching errors. ... studies on their numerical analogs. Fig. 1 Section of the f20dX LV phantom. Dimensions in [mm]. METHODS Fig. 2 Experimental setup. 1 – GE Vivid 6 scanner; 2 – water tank; 3 – LV model; 4 – M4S-RS probe; 5 – windkessel; 6 – Vivitro Superpump; 7 – Pump Controller; 8 – PC. ...In-vitro investigation of coronary atherosclerosis on a modified vivitro system
Coronary heart disease (CHD) is a common cardiac disorder in which a portion of the coronary artery is blocked, leading to a potential heart attack. Timely and accurate evaluation of suspected CHD patients is critical. Computer Tomography Angiography (CTA)... In order to streamline the evaluation of suspected CHD patients, we propose to create a more accurate and consistent diagnostic method of interpreting CTA results.A Tri-Leaflet Nitinol Mesh Scaffold for Engineering Heart Valves
...The main problem with the tissue engineered heart valves is their progressive deterioration that leads to regurgitation and/or leaflet thickening a few months after implantation... ...The current work aims to study the effects of the design features on mechanical characteristics of this valve scaffold to attain proper function prior to in vivo implantation. ... The heart flow simulator system was adjusted for left ventricular pressure waveform with diastolic/systolic pressures of 80/120 mmHg produced by a hydraulic pump system (Superpump system, VSI, SPS3891, Vivitro systems Inc., Victoria, BC, Canada).10 The scaffolds were ...The Impact of Intimal Tear Location and Partial False Lumen Thrombosis in Acute Type B Aortic Dissection
Partial false lumen (FL) thrombosis is a risk factor for long-term mortality in acute type B aortic dissection (ATBAD). This study investigates FL pressures in models of ATBAD with patent and partially thrombosed FL... ...A programmable pulsatile pump (SuperPump; ViVitro Systems, Victoria, BC, Canada) was connected to the left ventricle through a cannula inserted into the apex... ...In a biologic model of ATBAD, the number, location, and FL thrombosis status determine FL pressure. In the setting of partial FL thrombosis, the FL pressure is reduced with proximal tear occlusion and increased with distal tear occlusion. Reduced FL pressure is related to retrograde flow...A calcified polymeric valve for valve-in-valve applications
...developed a novel polymeric valve whose leaflets possess calcium hydroxyapatite inclusions immersed in them. This study reports the characteristics and feasibility of these valves. ... The system is connected and actuated by a pulsatile pump system (Superpump system, VSI, SPS3891, Vivitro systems Inc., Victoria, BC, Canada), which operates based on a VSI Wave Generator VG2001 (Vivitro Systems Inc., Victoria, BC, Canada) and controlled by a ...Dynamics Mechanical Strains of Tricuspid Valve Septal Leaflets
...study to establish a framework for the measurement of the deformation of TV leaflets in a passive ex-vivo beating heart that mimicked the right ventricular dynamic pressure of the normal hearts. ...apexes of fresh porcine hearts (n= 8) were connected to a positive displacement pump (SuperPump AR Series, Vivitro Labs Inc., BC) to generate pulsatile flow in the right side of the hearts. The superior vena cava was connected to a reservoir as the inflow pathway and the pulmonary artery was used for the outflow pathway...On the pulsatile flow through a coronary bifurcation with stent
...study investigates pulsatile flow through models of junctions corresponding to geometries most usually observed in the major coronary artery, with and without stent. ... 31] and [32]. 2.2. Experimental setup. The mean flow has its source in a tank set at constant height, the oscillatory flow is driven by a piston pump (Model SPS 3891,Vivitro Systems, Canada) as shown in Fig. 1. The oscillatory ...Feasibility and Technical Aspects of Proximal Nellix-in-Nellix Extension for Late Caudal Endograft Migration
Purpose: To describe the feasibility and technical aspects of a proximal Nellix-in-Nellix extension to treat caudal stent-graft migration after endovascular aneurysm sealing (EVAS) in the in vitro and in vivo settings. ... Silicone anatomical models were used in conjunction with a pulsatile flow pump (SuperPump; Vivitro Labs Inc, Victoria, British Columbia, Canada). The system was tuned to a pressure of ~120/80 mm Hg, with 4.5- to 5-L/min flow at a rate of 70 beats/min. ...Surface Strains of Porcine Tricuspid Valve Septal Leaflets Measured in Ex-vivo Beating Hearts
...For the first time, the porcine valve leaflets deformation was measured in a passive ex-vivo beating heart without isolating and remounting the valve annuli. In particular, the right ventricular apexes of porcine hearts (n = 8) were connected to a pulse-duplicator pump that maintained a pulsatile flow from and to a reservoir connected to the right atrium and the pulmonary arteries... A positive displacement pump 116 (SuperPump AR Series, Vivitro Labs Inc., BC, Canada) was connected to the apex of the right 117 ventricle after an incision was carefully made at this location (as described in more detail below)...An Experimental and Computational Study on the Effect of Caval Valved Stent Oversizing
Transcatheter tricuspid valves are implanted onto the cavoatrial junction in order to avoid the challenging task of anchoring the valve onto the complex tricuspid valve annulus. ...little is known about optimum extent of oversizing of the valved stent in a vena cava. In this study, we implanted valves of the same diameter onto the larger sized inferior vena cava (IVC) and a smaller sized superior vena cava (SVC). ... that half of the valve protrudes out of the vena cava. This is to comply with the anatomical constraint of not occluding the hepatic vein. The pulsatile flow loop was driven by a wave-generating piston pump (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada). ...A biomimetic bi-leaflet mitral prosthesis with enhanced physiological left ventricular swirl restorative capability
Mechanical heart valve prostheses are often implanted in young patients due to their durability and long-term reliability. However, existing designs are known to induce elevated levels of blood damage and blood platelet activation... ...This study proposes a bi-leaflet mechanical heart valve design (Bio-MHV) that mimics the geometry of a human mitral valve, with the aim of reducing turbulence levels in the left ventricle by replicating physiological flow patterns... ... A pulsatile pump (ViVitro Labs Inc., Victoria, BC) attached to the working chamber drove the blood analog around the flow loop, via the pumping action of the silicon left ventricle, as shown in Fig. 1c. Fig. 2 a A mitral flow waveform sample observed in the experiments. ...High-speed visualization of soap bubble blowing and image-processing-based analysis of pinch-off dynamics
Soap bubble blowing has long been an amusement for humans, and the process involves pinch-off similarly to liquid drops and gas bubbles. ... 2.4.2 Measurement using a Pitot tube. To validate the image-based speed measurement, we measured the airflow speed at the center of the nozzle outlet (U e ) using a Pitot static tube (PAA-8-KL, United Sensor Corp.) with pressure transducers (Pulse Duplicator, ViVitro Labs). ...Time-Resolved Micro PIV in the Pivoting Area of the Triflo Mechanical Heart Valve
The Lapeyre-Triflo FURTIVA valve aims at combining the favorable hemodynamics of bioprosthetic heart valves with the durability of mechanical heart valves (MHVs). ... physiological con- ditions. It is driven by a peristaltic pump (Superpump, Vivitro Systems, Victoria, BC, Canada) (1) which generates a directed pulsatile flow through the test section (3). The net flow through the transparent test section is ...A D-Shaped Bileaflet Bioprosthesis Which Replicates Physiological Left Ventricular Flow Patterns
... physiological conditions. It is driven by a peristaltic pump (Superpump, Vivitro Systems, Victoria, BC, Canada) (1) which generates a directed pulsatile flow through the test section (3). The net flow through the transparent test section is ...A Novel Method for Optical High Spatiotemporal Strain Analysis for Transcatheter Aortic Valves In Vitro
The aim of this study was to develop a platform for noncontact TAVI valve deformation analysis with both high temporal and spatial resolutions based on stereophotogrammetry and digital image correlation (DIC). A left-heart pulsatile in vitro flow loop system for mounting of TAVI valves was designed. ... Based on a piston pump (ViVitro SuperDup'r pump, ViVitro systems, Victoria, BC, Canada) a left-heart in vitro flow loop with peripheral units comprising a ventricular chamber, an atrial reservoir, an aortic root in which test valves can be installed, an arterial compliance section ...Are the Current Doppler Echocardiography Criteria Able to Discriminate Mitral Bileaflet Mechanical Heart Valve Malfunction? An In Vitro Study
... Jude Medical size 23 mm, a resistance and a compliance). The BMHV to be tested is placed directly between the left atrium and the left ventricle molds. The activation of the left ventricle is performed by a Vivitro superpump (VivitroLabs, Victoria, BC, Canada). ...Effect of oversizing and elliptical shape of aortic annulus on transcatheter valve hemodynamics: An in vitro study
This in-vitro study aims to assess and compare the valve hemodynamic performances of the Edwards SAPIEN transcatheter heart valve (THV) in the different current conditions of use: important oversizing in small circular annuli and in elliptical annuli, moderate oversizing in circular and in elliptical annuli of various degrees of eccentricity.Role of mitral annulus diastolic geometry on intraventricular filling dynamics
...The results support the hypothesis that a D-shaped mitral annulus reduces dissipative energy losses in ventricular filling during diastole, and in turn suggests that a symmetric stent design does not provide lower filling efficiency than an equivalent asymmetric design. ...fluctuations were imposed in a fluid-filled chamber housing the LV physical model using a programmable piston pump (Superpump, Vivitro Systems; British Columbia, Canada). The pressure fluctuations resulted in the deformation of the LV model, driving flow through ...6-Month Aortic Valve Implantation of an Off-the-Shelf Tissue-engineered Valve in Sheep
Diseased aortic valves often require replacement, with over 30% of the current aortic valve surgeries performed in patients who will outlive a bioprosthetic valve. While many promising tissue-engineered valves have been created in the lab using the cell-seeded polymeric scaffold paradigm, none have been successfully tested long-term in the aortic position of pre-clinical model. ... A customized pulse duplicator system was designed based on a commercial wave generator and pump (ViVitro Systems). ...The combined role of sinuses of Valsalva and flow pulsatility improves energy loss of the aortic valve
Normal aortic valve opening and closing movement is a complex mechanism mainly regulated by the blood flow characteristics and the cyclic modifications of the aortic root. Our previous in vitro observations demonstrated that the presence of the Valsalva sinuses, independently from root compliance, is important in reducing systolic pressure drop across the aortic valve. ... The hydrodynamic performances under pulsatile flow regimen were investigated, using a Vivitro System, Inc. ... Direct visualization of valve operating condition was performed, using an ultrafast speed camera (Casio Exlim Ex F1), mounted on top of the Vivitro system [19, 20]. ...Hemodynamic Performance of Edwards Intuity Valve in a Compliant Aortic Root Model
...It was the aim of this study to perform hemodynamic and kinematic measurements for this type of valves to serve as a baseline for following studies which investigate the effect of the aortic root on the valve performance. To this end, the Edwards Intuity aortic valve was investigated in a new in vitro flow loop mimicking the left heart...Hemodynamics in the Pivoting area of the Triflo Mechanical Heart Valve
...so called hot spots, where activated platelets might aggregate and form a thrombus that can ultimately lead to leaflet blockage. It is the aim of this study to assess the hemodynamics in the pivoting area of the Triflo valve.Cardiovascular magnetic resonance compatible physical model of the left ventricle for multi-modality characterization of wall motion and hemodynamics
... A programmable piston pump (PPP; Vivitro Systems Inc., Victoria, Canada) was used to induce the LV wall motion by altering the pressure of the fluid in the space between the interior of acrylic chamber housing the LV model and the exterior of the LV model. ...Generation of Simulated Calcific Lesions in Valve Leaflets for Flow Studies
The study aim was to develop a laboratory protocol for the fabrication of tissue valve models mimicking mild and moderate calcific stenosis, for future use in flow studies. ... near-physiologic hemodynamics. The flow loop was driven by a programmable piston pump (Vivitro), and included resistance and compliance units to mimic the characteristics of the systemic vascular tree (Fig. 3A). The system ...In Vitro Investigation of the Hemodynamics of Transcatheter Heterotopic Valves Implantation in the Cavo‐Atrial Junction
Severe tricuspid regurgitation (TR) is life-threatening but is often undertreated. Many patients with severe TR are denied heart valve replacement surgery because their old age or comorbidities predispose them to a higher risk of surgical complications associated with open-heart surgery. ... by 19% as an initial study. The silicone atrium was incorporated into a pulsatile flow loop that was driven by a wave-generating piston pump (SuperPump AR series, ViVitro Labs Inc., Victoria, BC, Canada). The flow rate in the ...Strain examinations of the left ventricle phantom by ultrasound and multislices computed tomography imaging
The main aim of this study was to verify the suitability of the hydrogel sonographic model of the left ventricle (LV) in the computed tomography (CT) environment and echocardiography and compare the radial strain calculations obtained by two different techniques: the speckle tracking ultrasonography and the multislices computed tomography (MSCT). ... equal to 0.28 dB/cm (at 2.95 MHz). Our model of the LV was driven by a computer-controlled hydraulic piston Super-Pump (Vivitro Inc., Canada) with adjustable fluid volumes and various loads. During a cycle of the pump, the ...Normal physiological conditions maintain the biological characteristics of porcine aortic heart valves: an ex vivo organ culture study.
The aortic valve functions in a complex mechanical environment which leads to force-dependent cellular and tissue responses. Characterization of these responses provides a fundamental understanding of valve pathogenesis. The aim of this work was to study the biological characteristics of native porcine aortic valves cultured in an ex vivo pulsatile organ culture system capable of maintaining physiological pressures (120/80 mmHg) and cardiac output (4.2 l/min).Comparison of Three Dimensional Proximal Isovelocity Surface Area to Cardiac Magnetic Resonance Imaging for Quantifying Mitral Regurgitation
The aim of our study was, to evaluate 3-D color Doppler proximal isovelocity surface area (PISA) as a tool for quantitative assessment of mitral regurgitation (MR) against in vitro and in vivo reference methods. A customized 3-D PISA software was validated in vitro against a flowmeter MR phantom. Sixty consecutive patients, with ≥mild MR of any etiology, were recruited and the regurgitant volume (RVol) was measured by 2-D PISA, 3-D peak PISA, 3-D integrated PISA, using transthoracic (TTE) and transesophageal echocardiography (TEE).Assessment of radial strain in ultrasonographic model of left ventricle using speckle tracking ultrasound technique and multislice computed tomography.
... Model of the LV was made from solution of POLY(VINYL ALCOHOL). Pulsatile filling of the LV phantom was driven by automatic and computer controlled hydraulic piston pump (Vivitro Inc., Canada) with stroke volume of 20 ml and the frequency of 60 impactions per minute. ...Three-dimensional reconstruction of cardiac flows based on multi-planar velocity fields
... We used a heart-flow simulator consisting of a hydraulic pump system (Superpump system, VSI, SPS3891, Vivitro systems Inc., Victoria, BC, Canada) that operates based on a VSI Wave Generator VG2001 (Vivitro Systems Incorporated, Victoria, BC, Canada), as previously ...Evaluation of Left Ventricle Phantom by Ultrasound and Multislices Computer Tomography Imaging
... Our model of the LV was driven by the computer-controlled hydraulic piston Super-Pump (Vivitro Inc., Canada) with adjustable fluid volumes. ... The data were reconstructed every 10% of the R-to-R interval of the ECG signal produced by the Vivitro SuperPump control device. ...Quantification of mitral regurgitation with MR phase-velocity mapping using a control volume method
Reliable diagnosis and quantification of mitral regurgitation are important for patient management and for optimizing the time for surgery. Previous methods have often provided suboptimal results. The aim of this in vitro study was to evaluate MR phase-velocity mapping in quantifying the mitral regurgitant volume (MRV) using a control volume (CV) method.Mitral mechanical heart valves: in vitro studies of their closure, vortex and microbubble formation with possible medical implications
The goal of the present work was to create the closest possible in vitro fluid dynamic environment in which prosthetic mitral valves in the patients' hearts function, in order to demonstrate whether microbubbles are generated, and if yes, under what conditions and at which stage of the cardiac cycle...Measurement of volumetric flow with no angle correction using multiplanar pulsed Doppler ultrasound
In this paper we show that by scanning at points on the surface of a sphere that the normal angle correction used in pulsed Doppler flow measurements is no longer necessary.Fluid Dynamic Characteristics of the VentrAssist Rotary Blood Pump
The VentrAssist pump has no shaft or seal, and the device is unique in design because the rotor is suspended passively by hydrodynamic forces, and urging is accomplished by an integrated direct current motor rotor that also acts as the pump impeller. This device has led to many challenges in its fluidic design...Experimental Stent-Graft Treatment of Ascending Aortic Dissection
BACKGROUND: This study assessed the feasibility of stent graft treatment of ascending aortic dissections in a porcine in vitro model. METHODS: The entire thoracic aortic aorta including the supraaortic branches was harvested from 12 adult pigs and an intimal tear was artificially created. ...Evidence of nonlinear response of hydrocephalus shunt valves to pulsating flow:
Doppler Echocardiographic Assessment of Valvular Regurgitation Severity by Measurement of the Vena Contracta: An In Vitro Validation Study
Blood Flow in Distal End-to-side Anastomoses with PTFE and a Venous Patch: Results of an In vitro Flow Visualisation Study
Unsteady entrance flow in a 90° curved tube
The effects of dynamic cardiac compression on ventricular mechanics and energetics: Role of ventricular size and contractility
The purpose of this study was to determine the role of ventricular size or contractility in the effectiveness of dynamic cardiac compression in terms of the pressure-volume relationship and myocardial oxygen consumption. In 10 isolated cross-circulated dog hearts, the ventricle was directly compressed during systole.Experimental analysis of fluid mechanical energy losses in aortic valve stenosis
Current methods for assessing the severity of aortic stenosis depend primarily on measures of maximum systolic pressure drop at the aortic valve orifice and related calculations such as valve area. It is becoming increasingly obvious, however, that the impact of the obstruction on the left ventricle is equally important in assessing its severity and could potentially be influenced by geometric factors of the valve, causing variable degrees of downstream pressure recovery...The importance of slice location on the accuracy of aortic regurgitation measurements with magnetic resonance phase velocity mapping
Although several methods have been used clinically to evaluate the severity of aortic regurgitation, there is no purely quantitative approach for aortic regurgitant volume (ARV) measurements. Magnetic resonance phase velocity mapping can be used to quantify the ARV, with a single imaging slice in the ascending aorta, from through-slice velocity measurements.DYNAMIC CARDIAC COMPRESSION IMPROVES CONTRACTILE EFFICIENCY OF THE HEART
Correlation of radionuclide and optical tracer assessments of fluid flow in artificial ventricles
Anterior and posterior left ventricular sarcomere lengths behave similarly during ejection:
Assessment of Small-Diameter Aortic Mechanical Prostheses
Accuracy of Arterial Pulse-Wave Velocity Measurement Using MR
Prosthetic heart valve evaluation by magnetic resonance imaging
To evaluate the potential of magnetic resonance imaging (MRI) for evaluation of velocity fields downstream of prosthetic aortic valves. Furthermore, to provide comparative data from bileaflet aortic valve prostheses in vitro and in patients.Independent effects of preload, afterload, and contractility on left ventricular torsion
Shortening of oblique left ventricular (LV) fibers results in torsion. A unique relationship between volume and torsion is therefore expected, and the effects of load and contractility on torsion should be predictable. However, volume-independent behavior of torsion has been observed, and the effects of load on this deformation remain controversial....A Physical Model Describing the Mechanism for Formation of Gas Microbubbles in Patients with Mitral Mechanical Heart Valves
This study was aimed at developing a physical model, supported by experimental observations, to describe the formation and growth of microbubbles seen in patients with mitral mechanical heart valves (MHV). This phenomenon, often referred to as high intensity transient signals (HITS), appears as bright, intense, high-velocity and persistent echoes detected by Doppler ultrasonography at the instant of closure.Motion correction for the quantification of mitral regurgitation using the control volume method
Quantifying mitral regurgitation is difficult because of the complexity of the flow, geometry and motion of the mitral valve. In this paper a MRI compatible phantom was built incorporating a left ventricle and mitral valve motion. Valve motion was obtained using a pneumatic piston. The mitral valve was made regurgitant and the regurgitant volume quantified using a modified control volume method. The modification to the method was the addition of mitral motion correction...In vitro comparison of steady and pulsatile flow characteristics of jellyfish heart valve
In examining the hydrodynamic performance of artificial heart valves in vitro, experiments are carried out under either steady or pulsatile flow conditions. Steady flow experiments are simple to set up and analysis of the data is also simple; however, their validity and accuracy have been questioned...Pressure-Volume Relationship of a Pulsatile Blood Pump for Ventricular Assist Device Development
A mathematical model describing the pressure-volume relationship of the Novacor left ventricular assist system (LVAS) was developed. The model consists of lumped resistance, capacitance, and inductance elements with one time varying capacitor to estimate the cyclic pressure generation of the pump using pump volume measurement.Flow Characteristics Past Jellyfish and St. Vincent Valves in the Aortic Position Under Physiological Pulsatile Flow Conditions:
Thrombus formation and hemolysis have been linked to the dynamic flow characteristics of heart valve prostheses. To enhance our understanding of the flow characteristics past the aortic position of a Jellyfish (JF) valve in the left ventricle, in vitro laser Doppler anemometry (LDA) measurements were carried out under physiological pulsatile flow conditions...Evaluation of the Precision of Magnetic Resonance Phase Velocity Mapping for Blood Flow Measurements
Ultrafast Flow Quantification With Segmented k-Space Magnetic Resonance Phase Velocity Mapping
Magnetic resonance (MR) phase-velocity mapping (PVM) is routinely being used clinically to measure blood flow velocity. Conventional nonsegmented PVM is accurate but relatively slow (3-5 min per measurement). Ultrafast k-space segmented PVM offers much shorter acquisitions (on the order of seconds instead of minutes).Prosthetic replacement of the aorta is a risk factor for aortic root aneurysm development
Aortic root replacement for prosthetic aortic valve endocarditis with accompanying destruction of the aortic root is a well-established surgical intervention. However, there is still no consensus whether prosthetic material or allogeneic material should be used. Here we report on our experience with prosthetic composite and aortic allograft root replacement in such patients during a 10-year interval.Accurate quantification of steady and pulsatile flow with segmented k-space magnetic resonance velocimetry
Value and limitations of aortic valve resistance with particular consideration of low flow–low gradient aortic stenosis: an in vitro study
The calculation of valve resistance (R) rather than aortic valve area (AVA) has been proposed for the assessment of aortic stenosis (AS), based on the claim that it is less flow-dependent. Even more importantly, valve resistance has been reported to distinguish between truly severe and "pseudosevere" AS in patients with low cardiac output. However, the diagnostic value of valve resistance remains controversial.Fast Measurements of Flow through Mitral Regurgitant Orifices with Magnetic Resonance Phase Velocity Mapping
Magnetic-resonance (MR) phase velocity mapping (PVM) shows promise in measuring the mitral regurgitant volume. However, in its conventional nonsegmented form, MR-PVM is slow and impractical for clinical use. The aim of this study was to evaluate the accuracy of rapid, segmented k-space MR-PVM in quantifying the mitral regurgitant flow through a control volume (CV) method.Slice location dependence of aortic regurgitation measurements with MR phase velocity mapping
Although several methods have been used clinically to assess aortic regurgitation (AR), there is no "gold standard" for regurgitant volume measurement. Magnetic resonance phase velocity mapping (PVM) can be used for noninvasive blood flow measurements.Motion correction for the quantification of mitral regurgitation using the control volume method
Quantifying mitral regurgitation is difficult because of the complexity of the flow, geometry and motion of the mitral valve. In this paper a MRI compatible phantom was built incorporating a left ventricle and mitral valve motion. Valve motion was obtained using a pneumatic piston. The mitral valve was made regurgitant and the regurgitant volume quantified using a modified control volume method. The modification to the method was the addition of mitral motion correction. TFaster flow quantification using sensitivity encoding for velocity-encoded cine magnetic resonance imaging: In vitro and in vivo validation
To test the agreement between conventional and sensitivity-encoded (SENSE) velocity encoded cine (VEC) MRI in a flow phantom and in subjects with congenital and acquired heart disease...An In Vitro Study of Changing Profile Heights in Mitral Bioprostheses and Their Influence on Flow
Influence of Ventricular Pressure Drop on Mitral Annulus Dynamics Through the Process of Vortex Ring Formation:
Several studies have suggested that the mitral annulus displacement and velocity in early diastole can be used as indicators of diastolic performance.Correlation Between Vortex Ring Formation and Mitral Annulus Dynamics During Ventricular Rapid Filling
Systemic pressure does not directly affect pressure gradient and valve area estimates in aortic stenosis in vitro
Hypertension is a frequent finding in patients with aortic stenosis (AS). However, controversial data about the influence of systemic blood pressure on the quantification of AS have been published.Effect of oscillation on elevating shear stresses
A Novel, Low Cost, Disposable, Pediatric Pulsatile Rotary Ventricular Pump For Cardiac Surgery that Provides a Physiological Flow Pattern
On Mitral Valve Dynamics and its Connection to Early Diastolic Flow
In the field of cardiology, the current ability to accurately detect diastolic dysfunction is unsatisfactory due to the lack of an effective diagnostic index. Isolated indexes obtained from echocardiography are all restricted to a certain aspect of ventricular diastolic function only, and individually cannot be regarded...Flow analysis in patient specific lower airways using PIV
ABSTRACT The objective of this study is to analyze the flow pattern trough a patient specific lower airway under multiple breathing conditions. The measured Particle Image Velocimetry (PIV) results are quantitatively and quantitatively compared ...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
Stenting may provide a new, less invasive therapeutic option for cerebral aneurysms. However, a conventional porous stent may be insufficient in modifying the blood flow for clinical aneurysms. We designed an asymmetric stent consisting of a low porosity patch welded onto a porous stent for an anterior cerebral artery aneurysm of a specific patient geometry to block the strong inflow jet... … 2.5. Angiographic flow visualization The rapid prototype aneurysm model was inserted in a flow loop consisting of a waveform generator, a pump, and a flow meter; the flow was activated by a heart simulating pump (Vivitro Systems Inc., Canada) …A flowmeter for unsteady liquid flow measurements in total liquid ventilation
Phase-resolved velocity measurements in the Valsalva sinus downstream of a Transcatheter Aortic Valve.
Two sets of phase resolved PIV measurements were performed in the Valsalva sinuses of a glass mock aortic root including three polymeric valve leaflets, before and after the implant of a Medtronic CoreValve TAVI device. The experiments were carried out in a hydro-mechanical cardiovascular pulse duplicator system (Vivitro Superpump System SP3891) r...TCT-81 Ex-Vivo Simulator for Training, Teaching, and Testing of Transcatheter Valve Therapies Based on the Principle of a Passive Beating Heart
Commercially available in-vitro cardiac simulators offer testing opportunities for transcatheter valve therapies (TVT) as they are able to replicate the physiological flow and pressure accurately.High-speed particle image velocimetry to assess cardiac fluid dynamics in vitro: From performance to validation
Abnormality in cardiac fluid dynamics is highly correlated with several heart conditions. This is particularly true in valvular heart diseases and congenital heart defects where changes in flow-field accompany significant variations in chambers’ pressure gradients. Particle Image Velocimetry (PIV) is a convenient technique in assessing cardiac fluid dynamics in vitro...Experimental and Computational Studies of the Aortic Bi-leaflet Mechanical Heart Valve (BMHV) Hemodynamics in an Idealized Left Ventricle
We aim to validate the performance of our fluid structure interaction (FSI) simulations of a bi-leaflet mechanical heart valve in the aortic position., whose motion is driven by the beating left ventricle. We compare in vitro experiments and computations performed on an idealized model of the left ventricle (LV) with a St. Jude Medical Regent heart valve in the aortic position.Particle Image Velocimetry (PIV) Flow Measurements of Carotid Artery Bifurcation with Application to a Novel Covered Carotid Stent Design
Stenosed carotid artery is responsible for 60% of strokes in the United States and is the third major cause of death. Recently, there is an increasing interest in carotid artery stenting for treatment of cervical carotid artery bifurcation atherosclerotic disease. The ultimate goal of this study is to develop, prototype, test, and optimize a novel design of a covered carotid stent, in order to achieve emboli prevention and...Manufacturing of patient-specific optically accessible airway models by fused deposition modeling
The purpose of this paper is to use rapid prototyping technology, in this case fused deposition modeling (FDM), to manufacture 2D and 3D particle image velocimetry (PIV) compatible patient‐specific airway models.In-vitro investigation of a potential wave pumping effect in human aorta
An impedance pump – also known as Liebau pump – is a simple valveless pump that operates based on the principles of wave propagation and reflection. It has been shown in embryonic zebrafish that a similar mechanism is responsible for the pumping action in the embryonic heart during the early stages before valve formation...Vortex Phenomena in Sidewall Aneurysm Hemodynamics: Experiment and Numerical Simulation
We carry out high-resolution laboratory experiments and numerical simulations to investigate the dynamics of unsteady vortex formation across the neck of an anatomic in vitro model of an intracranial aneurysm. A transparent acrylic replica of the aneurysm is manufactured and attached to a pulse duplicator system in the laboratory.A Physical Model of the Human Circulatory System for the Modeling, Control and Diagnostic of Cardiac Support Processes
Tubular Heart Valves from Decellularized Engineered Tissue
A novel tissue-engineered heart valve (TEHV) was fabricated from a decellularized tissue tube mounted on a frame with three struts, which upon back-pressure cause the tube to collapse into three coapting "leaflets." The tissue was completely biological, fabricated from ovine fibroblasts dispersed within a fibrin gel,...A Bio-Inspired Approach for the Reduction of Left Ventricular Workload
… doi:10.1371/journal.pone.0087122.g001. The left ventricle was simulated by a piston-in-cylinder pump (ViVitro Labs Inc. … The signals were collected using the Tri-pack pressure measuring systems (TP8891, Vivitro Labs Inc.).IMPLANTABLE PROSTHETIC VALVES AND METHODS
… The ventricular sac was suspended over a plexiglas atria 204 to be free-floating inside a rigid, water-filled, container made from plexiglas (not shown) and connected to a hydraulic pump system (Superpump system; Vivitro Systems Inc., Victoria, BC, Canada—not shown). …A Wave Dynamics Criterion for Optimization of Mammalian Cardiovascular System
A piston-in-cylinder pump (ViVitro Labs Inc. SuperPump System: Model … DPT-400). Tri-pack pressure measuring systems TP8891 (Vivitro Labs Inc.) consisting of three bridge amplifiers were used to collect the signals. Volume …Design considerations and quantitative assessment for the development of percutaneous mitral valve stent
… The ventricular chamber was connected to a program-controlled piston pump (Vivitro Superpump, AR Series). The piston’s movement dilates and contracts the transparent silicone sac (ie left ventricle) to mimic the beating ventricle. …The Effects of Positioning of Transcatheter Aortic Valve on Fluid Dynamics of the Aortic Root
… Experimental setup Pulsatile pump system: The heart-flow simulator consists of a hydraulic pump system (Superpump system, VSI, SPS3891, Vivitro systems Inc., Victoria, BC, Canada), which operates based on a VSI Wave Generator VG2001 (Vivitro Systems Incorporated, …