Meet Our New Staff
Left to Right: Oleksandr, Mike, and Matthias
Dr. Oleksandr Barannyk joins ViVitro as a Research Mechanical Engineer after completing his Ph.D. degree in Mechanical Engineering at the University of Victoria. His current research will provide information on the mechanism of premature calcification in heart valves through a complete investigation of the physicochemical factors influencing the process. It evaluates the functional efficiency and biocompatibility of the implant prototypes with respect to flow-induced calcification, to help predetermine the associated risk in a second operation to replace a defective implant.
Michael Harding is our new Customer Support Trainer bringing many years of experience building and testing ViVitro products. He will be our first point of contact for customer support while enhancing our training and installation qualification programs.
Matthias Menne is a mechanical engineering intern while he works on his Master's thesis for RWTH Aachen, Germany. The thesis involves an ex-Vivo simulator that uses the SuperPump. Check out the article on Matthias' thesis for more details and video.
PIV testing increases regulatory confidence of ISO 5840 compliance
, a Professor in the Aerospace Engineering and Mechanics at the University of Minnesota, explains the merit of using particle image velocimetry
(PIV) as appropriate test modality to assess flow fields. “PIV provides the means to quantify instantaneous three-component velocity vectors throughout planar or volumetric flow fields. High repetition rate PIV also allows determination of time variations and acceleration at all points within these fields. The method thus makes it possible to characterize the existence, size, and strength of recirculation zones as well as local spatial and temporal velocity gradients. Based on these instantaneous (as opposed to average) gradients, one can quantify any regions of high and low strain and shear that might occur upstream and downstream of prosthetic valves.”
Industry scientist, Neelakantan Saikrishnan, confirms these physical parameters are well documented
as indicators for platelet activation, hemolysis, and thrombus formation.
Regulatory bodies typically require manufacturers to perform bench top testing of devices as proof of safety and efficacy. They use ISO 5840 as their guideline for testing heart valve substitutes. The 2005 release of ISO 5840 indicates the importance for manufacturers to assess the flow fields in the immediate vicinity of surgical heart valve substitutes. In the 2013 release as it applies to transcatheter valves, manufacturers are still guided to assess the flow fields. There are various modalities capable of bench top assessment of flow fields.
ViVitro Labs provides independent testing expertise for flow assessment through our high-speed PIV system
. Documented levels of uncertainties in our data measurement are provided with our test reports reassuring to regulatory bodies that testing have been conducted at an independent, high quality level. Additionally, our operator proficiency and system qualification is confirmed by our ability to reproduce FDA published
interlaboratory results in the attached video
Ex-Vivo Simulator Based on the Principle of a Passive Beating Heart
and the ViVitro Labs team are working to prove that an ex-vivo simulator reliably duplicates the movement of the mitral and aortic heart valve. Anticipated advantages are expected to include reduced time associated with each trial especially in comparison with animal tests and lower experimental costs while still being able to test in an intact heart.
cardiac simulators test opportunities for transcatheter valve therapies by replicating the physiological flow and pressure accurately. However, anatomical similarity needed for some transcatheter device testing is not supported, nor is some types of physician training and teaching. An ex-vivo simulator would combine the additional anatomical similarity with physiological flow and pressure signatures. Matthias explains the parameters: "We run the system at the nominal values stated in the standard which is 70 beats per minute, 75 ml stroke volume, aortic mean pressure of 100 mmHg. Other values like the flow are subject to those standard conditions and they differ from heart to heart."
Interview with Larry Scotten on VSI’s prototype Leonardo
30 years from their creation as research tools for ViVitro Systems co-founders, ViVitro products remain the trusted standard for cutting edge researchers and regulatory agencies.
To celebrate, we interviewed ViVitro Systems co-founder, Larry Scotten
, at our lab in Victoria BC. He generously shared thoughts and stories from the early years and gave us a preview of his current work.
Testing Tips: Eliminating Noise on Pressure Signals
Noise on pressure and flow signals can introduce uncertainty in test results during hydrodynamic performance testing. ViVitro has designed the Pulse Duplicator to simulate physiological conditions for testing heart valve substitutes, noise-free signals can be expected from our system.
If you notice noise on the pressure signals the most likely culprit is the lack of compliance or impedance at the Ventricle chamber. The waveforms you get might look like the following image, notice the Ventricular pressure (yellow), defining the transvalvular positive pressure periods can be difficult.
ViVitro offers our VIA (Viscoelastic Impedance Adapter) for such cases. The VIA can be installed between the SuperPump and the Ventricle Chamber to provide air compliance and impedance, providing waveforms in the image below. If you still have noise, make sure there are no small air bubbles in the system, these can “ring”, adding noise to the pressure traces.
If you see noise on the flow signal like the traces below, check that the flow meter ground cable is connected to the ground pin nearest the flow probe. Make sure the alligator clip on the cable is not corroded and that the ground pin is free of saline residue etc.
Team ViVitro Cycles to the Lab for #biketoworkvic
The entire ViVitro Labs team participated in Bike To Work Week Victoria
. Long-time participant, Ted Hodson, was joined by Joe McMahen, Gerry Wight, Matthias Menne, Lori Woodman, Janet Murray, Dev Amatya, and Marshall Kilduff. Rob Fraser, was out of office for this picture, but raring to return to his regular bike commute to work. The combined ViVitro-StarFish team biked 1,026 kilometers to and from the office with an average rider completing 54 kms over the week.
“Victoria is a great town for biking. We encourage healthy and ecological initiatives like Bike to Work BC with bike storage racks and on-site shower facilities at ViVitro.”, said General Manager, Gerry Wight.