This research was supported by the Basic Science Research Program of the National Research Foundation of Korea, which is funded by the Ministry of Education (NRF-2021R1I1A3040346 and NRF-2020R1A4A1019475). This study was also supported by 2018 Research Grant (PoINT) from Kangwon National University.

1. In vitro setup
<ol>
	<li>Prepare the experimental setup on an optic table, including a piston pump, data acquisition device (DAQ), and a computer with the required system engineering software and a motor controlling software (see Table of Materials) (Figure 1). 
	NOTE: The piston pump has been previously tested and calibrated and consists of a motor, motor driver, and linear actuator9.</li>
	<li>Import the spreadshe...

<ol>
	<li>Carabello, B. A., Paulus, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aortic+stenosis.">Aortic stenosis.</a> The Lancet. 373 (9667), 956-966 (2009).</li><li>Jakobsen, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Short-and+long-term+mortality+and+stroke+risk+after+transcatheter+aortic+valve+implantation.">Short-and long-term mortality and stroke risk after transcatheter aortic valve implantation.</a> The American Journal of Cardiology. 121 (1), 78-85 (2018).</li><li>Koo, H. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Computed+tomography+features+of+cuspal+thrombosis+and+subvalvular+tissue+ingrowth+after+transcatheter+aortic+valve+implantation.">Computed tomography features of cuspal thrombosis and subvalvular tissue ingrowth after transcatheter aortic valve implantation.</a> The American Journal of Cardiology. 125 (4), 597-606 (2020).</li><li>Midha, P. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+fluid+mechanics+of+transcatheter+heart+valve+leaflet+thrombosis+in+the+neosinus.">The fluid mechanics of transcatheter heart valve leaflet thrombosis in the neosinus.</a> Circulation. 136 (17), 1598-1609 (2017).</li><li>Abubakar, H., Ahmed, A. S., Subahi, A., Yassin, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thrombus+in+the+Right+Coronary+Sinus+of+Valsalva+Originating+From+the+Left+Atrial+Appendage+Causing+Embolic+Inferior+Wall+Myocardial+Infarction.">Thrombus in the Right Coronary Sinus of Valsalva Originating From the Left Atrial Appendage Causing Embolic Inferior Wall Myocardial Infarction.</a> Journal of Investigative Medicine High Impact Case Reports. 6, 2324709618792023 (2018).</li><li>Charonko, J., Karri, S., Schmieg, J., Prabhu, S., Vlachos, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro,+time-resolved+PIV+comparison+of+the+effect+of+stent+design+on+wall+shear+stress.">In vitro, time-resolved PIV comparison of the effect of stent design on wall shear stress.</a> Annals of Biomedical Engineering. 37 (7), 1310-1321 (2009).</li><li>Hariharan, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inter-laboratory+characterization+of+the+velocity+field+in+the+FDA+blood+pump+model+using+particle+image+velocimetry+(PIV).">Inter-laboratory characterization of the velocity field in the FDA blood pump model using particle image velocimetry (PIV).</a> Cardiovascular Engineering and Technology. 9 (4), 623-640 (2018).</li><li>Lim, W., Chew, Y., Chew, T., Low, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsatile+flow+studies+of+a+porcine+bioprosthetic+aortic+valve+in+vitro:+PIV+measurements+and+shear-induced+blood+damage.">Pulsatile flow studies of a porcine bioprosthetic aortic valve in vitro: PIV measurements and shear-induced blood damage.</a> Journal of Biomechanics. 34 (11), 1417-1427 (2001).</li><li>Kim, J., Lee, Y., Choi, S., Ha, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsatile+flow+pump+based+on+an+iterative+controlled+piston+pump+actuator+as+an+in-vitro+cardiovascular+flow+model.">Pulsatile flow pump based on an iterative controlled piston pump actuator as an in-vitro cardiovascular flow model.</a> Medical Engineering &amp; Physics. 77, 118-124 (2020).</li><li>Moore, B. L., Dasi, L. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+flow+impacts+aortic+leaflet+mechanics+and+aortic+sinus+hemodynamics.">Coronary flow impacts aortic leaflet mechanics and aortic sinus hemodynamics.</a> Annals of Biomedical Engineering. 43 (9), 2231-2241 (2015).</li><li>Evans, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Practical 3D printers: The science and art of 3D printing. , (2012).</li><li>Yudi, M. B., Sharma, S. K., Tang, G. H., Kini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+angiography+and+percutaneous+coronary+intervention+after+transcatheter+aortic+valve+replacement.">Coronary angiography and percutaneous coronary intervention after transcatheter aortic valve replacement.</a> Journal of the American College of Cardiology. 71 (12), 1360-1378 (2018).</li><li>Adrian, R. J., Westerweel, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Particle Image Velocimetry. , (2011).</li><li>Deen, N. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+image+pre-processing+for+PIV+of+single-and+two-phase+flows+over+reflecting+objects.">On image pre-processing for PIV of single-and two-phase flows over reflecting objects.</a> Experiments in Fluids. 49 (2), 525-530 (2010).</li><li>Thielicke, W., Stamhuis, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PIVlab-towards+user-friendly,+affordable+and+accurate+digital+particle+image+velocimetry+in+MATLAB.">PIVlab-towards user-friendly, affordable and accurate digital particle image velocimetry in MATLAB.</a> Journal of Open Research Software. 2 (1), (2014).</li><li>Pizer, S. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptive+histogram+equalization+and+its+variations.">Adaptive histogram equalization and its variations.</a> Computer Vision, Graphics, and Image Processing. 39 (3), 355-368 (1987).</li><li>Garcia, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+smoothing+of+gridded+data+in+one+and+higher+dimensions+with+missing+values.">Robust smoothing of gridded data in one and higher dimensions with missing values.</a> Computational Statistics &amp; Data Analysis. 54 (4), 1167-1178 (2010).</li><li>Elger, D. F., LeBret, B. A., Crowe, C. T., Roberson, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Engineering Fluid Mechanics. , (2020).</li><li>Raghav, V., Sastry, S., Saikrishnan, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+assessment+of+flow+fields+associated+with+heart+valve+prostheses+using+particle+image+velocimetry+(PIV):+recommendations+for+best+practices.">Experimental assessment of flow fields associated with heart valve prostheses using particle image velocimetry (PIV): recommendations for best practices.</a> Cardiovascular Engineering and Technology. 9 (3), 273-287 (2018).</li><li>Ncho, B., Sadri, V., Ortner, J., Kollapaneni, S., Yoganathan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-Vitro+Assessment+of+the+Effects+of+Transcatheter+Aortic+Valve+Leaflet+Design+on+Neo-Sinus+Geometry+and+Flow.">In-Vitro Assessment of the Effects of Transcatheter Aortic Valve Leaflet Design on Neo-Sinus Geometry and Flow.</a> Annals of Biomedical Engineering. 49 (3), 1046-1057 (2021).</li><li>Graftieaux, L., Michard, M., Grosjean, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+PIV,+POD+and+vortex+identification+algorithms+for+the+study+of+unsteady+turbulent+swirling+flows.">Combining PIV, POD and vortex identification algorithms for the study of unsteady turbulent swirling flows.</a> Measurement Science and Technology. 12 (9), 1422 (2001).</li><li>Yap, C. H., Saikrishnan, N., Tamilselvan, G., Yoganathan, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+measurement+of+dynamic+fluid+shear+stress+on+the+aortic+surface+of+the+aortic+valve+leaflet.">Experimental measurement of dynamic fluid shear stress on the aortic surface of the aortic valve leaflet.</a> Biomechanics and Modeling in Mechanobiology. 11 (1), 171-182 (2012).</li><li>Toninato, R., Salmon, J., Susin, F. M., Ducci, A., Burriesci, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+vortices+in+the+sinuses+of+Valsalva:+an+in+vitro+approach+for+bio-prosthetic+valves.">Physiological vortices in the sinuses of Valsalva: an in vitro approach for bio-prosthetic valves.</a> Journal of Biomechanics. 49 (13), 2635-2643 (2016).</li><li>Raghav, V., Midha, P., Sharma, R., Babaliaros, V., Yoganathan, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcatheter+aortic+valve+thrombosis:+a+review+of+potential+mechanisms.">Transcatheter aortic valve thrombosis: a review of potential mechanisms.</a> Journal of the Royal Society Interface. 18 (184), 20210599 (2021).</li><li>Ramanathan, T., Skinner, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+blood+flow.">Coronary blood flow.</a> Continuing Education in Anaesthesia, Critical Care &amp; Pain. 5 (2), 61-64 (2005).</li><li>Nobach, H., Bodenschatz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Limitations+of+accuracy+in+PIV+due+to+individual+variations+of+particle+image+intensities.">Limitations of accuracy in PIV due to individual variations of particle image intensities.</a> Experiments in Fluids. 47 (1), 27-38 (2009).</li><li>G&#252;lan, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+analysis+of+the+transcatheter+aortic+valve+implantation+on+blood+flow+hemodynamics:+An+optical+imaging-based+in+vitro+study.">Performance analysis of the transcatheter aortic valve implantation on blood flow hemodynamics: An optical imaging-based in vitro study.</a> Artificial Organs. 43 (10), 282-293 (2019).</li></ol>

The sinus flow changed due to different sinus geometry after TAVI. The vortex was formed by the aortic valve opening and the interaction with the forward jet of systole22. In the study of the artificial surgical valve without native leaflets, vortex observed in the sinus region at systole was normal23. This study forms the vortex presented at diastole by reducing the forward jet and coming into the sinus. The sinus flow encountered the native leaflet; as a result, it splits...

Aortic stenosis is a common disease in older adults, and it is when the aortic valve doesn&#39;t open, reducing blood flow. The problem is caused by the thickening or calcification of the aortic valve1. Therefore, it is a necessary treatment to enhance the blood flow and decrease the load on the heart. It is treated by remodeling the aortic valve or replacing it with an artificial valve. This study focuses on transcatheter aortic valve implantation (TAVI), replacing the malfunctioning aortic valve with an artificial one using a catheter.
TAVI has been recommended for patients challenged in surgery, and the mortality has also been low2. Recently, it has been reported that thrombus in patients after TAVI caused valve dysfunction and stroke3,4. Thrombus in the aortic sinus and neo-sinus is suspected, with its cause probably being the changes in the hemodynamics caused by TAVI. It is performed without removing the native leaflets; these leaflets can disturb the sinus flow and elevate the risk of thrombosis5.
It is difficult to determine how blood flow is affected by TAVI and how thrombosis is induced in patients. It is desirable to elucidate the relationship between blood flow and thrombus formation in vivo. However, a lack of practical techniques for measuring blood flow makes this problematic. On the other hand, in vitro techniques have the advantage of allowing one to monitor the changes in the blood flow by limiting the parameters that must be investigated. In vitro setup and particle image velocimetry (PIV) have been used to identify velocity in medical fields6,7,8. Therefore, in vitro and PIV are sufficient for determining the parameters to be reported by mimicking the patient&#39;s condition: the heart rate and pressure, viscosity, and sinus geometry, and allowing one to control these parameters.
In this study, in vitro setup and PIV are used to investigate the flow in the aortic sinus after TAVI. The aortic phantom and TAVI for the PIV and the data acquisition process and post-processing flow analysis are described in this protocol. Various hemodynamic parameters are derived, including the velocity, stasis, vortex, vorticity, and particle residence. The results demonstrate that in vitro setup and PIV help investigate the hemodynamic features in the aortic sinus.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3D Printer</td>
			<td>Prusa Research</td>
			<td></td>
			<td>Original Prusa i3 MK2; FDM printer</td>
		</tr>
		<tr>
			<td>Aluminum bar (square)</td>
			<td>APSPRO</td>
			<td>KHP-3030, KHP-6060</td>
			<td>Dimension: 30 mm x 30 mm, 60 mm x 60 mm</td>
		</tr>
		<tr>
			<td>Bulb pump</td>
			<td>Skyhope</td>
			<td></td>
			<td>MHL-1</td>
		</tr>
		<tr>
			<td>Camera controlling software</td>
			<td>Phantom</td>
			<td>PCC 3.4 software</td>
			<td>The software controll the high speed camera</td>
		</tr>
		<tr>
			<td>Check valve</td>
			<td>HANJU STEEL PIPE</td>
			<td></td>
			<td>Check valve; 1/2 inch (15A)</td>
		</tr>
		<tr>
			<td>Digital Aqusition device</td>
			<td>National Instruments</td>
			<td></td>
			<td>USB-6001</td>
		</tr>
		<tr>
			<td>Glycerin</td>
			<td>ANU Korea</td>
			<td></td>
			<td>It used for making a working fluid</td>
		</tr>
		<tr>
			<td>High-speed camera</td>
			<td>Phantom</td>
			<td></td>
			<td>Phantom VEO 710E-L</td>
		</tr>
		<tr>
			<td>Laser</td>
			<td>Changchun New Industries Optoelectronics Technology</td>
			<td></td>
			<td>MGL-W-532; CW Nd:YAG Laser</td>
		</tr>
		<tr>
			<td>Linear actuator</td>
			<td>THOMSON</td>
			<td></td>
			<td>PC-40; it converts the rotational motion to lenear motion</td>
		</tr>
		<tr>
			<td>Macro lens</td>
			<td>Nikon</td>
			<td></td>
			<td>VR Micro-NIKKOR 105mm, f/1.4</td>
		</tr>
		<tr>
			<td>Motor</td>
			<td>KOLLMORGEN</td>
			<td></td>
			<td>AKM33H-ANCNR-00; DC servo motor</td>
		</tr>
		<tr>
			<td>Motor controlling software</td>
			<td>KOLLMORGEN</td>
			<td></td>
			<td>Kollmorgen software; the software controll the motor driver</td>
		</tr>
		<tr>
			<td>Motor driver</td>
			<td>KOLLMORGEN</td>
			<td></td>
			<td>AKD-B00606-NBAN-0000</td>
		</tr>
		<tr>
			<td>Open-source electronic prototypic platform</td>
			<td>Arduino</td>
			<td>A000066</td>
			<td>Arduino Uno R3. It used for making a external trigger</td>
		</tr>
		<tr>
			<td>Optic table</td>
			<td>SMTECH</td>
			<td></td>
			<td>1800 (W) x 900 (B) x 800 (H)</td>
		</tr>
		<tr>
			<td>Particle</td>
			<td>Dantec Dynamics</td>
			<td>80A6011</td>
			<td>Hollow Glass Sphere. Mean diameter:10 &#181;m, Density: 1090 kg/m3</td>
		</tr>
		<tr>
			<td>PIVlab</td>
			<td>PIVlab</td>
			<td></td>
			<td>Open source algorithm based on MATLAB 
			https://kr.mathworks.com/matlabcentral/fileexchange/27659-pivlab-particle-image-velocimetry-piv-tool-with-gui</td>
		</tr>
		<tr>
			<td>Pressure gauge</td>
			<td>OMEGA</td>
			<td></td>
			<td>PX309-015A5V. Measurement range: 0~15psi</td>
		</tr>
		<tr>
			<td>Refractometer</td>
			<td>ATAGO</td>
			<td>2350</td>
			<td>R-5000. Hand held refractometer; measurement range: 1.333-1.520</td>
		</tr>
		<tr>
			<td>Resistance valve</td>
			<td>HANJU STEEL PIPE</td>
			<td></td>
			<td>Ball valve; 1/2 inch (15A)</td>
		</tr>
		<tr>
			<td>Saline</td>
			<td>DAI HAN PHARM</td>
			<td></td>
			<td>It is used for making a working fluid and for preserving the TAV</td>
		</tr>
		<tr>
			<td>Silicone hose</td>
			<td>HSW</td>
			<td></td>
			<td>Inner diameter 26mm, Outter diameter 30mm; Inlet length 5m, Outlet length 1.5m</td>
		</tr>
		<tr>
			<td>System enginnering software</td>
			<td>National Instruments</td>
			<td></td>
			<td>LabVIEW software. The software controlls the DAQ.</td>
		</tr>
		<tr>
			<td>Transcatheter Aortic Valve, TAV (23 mm) and TAV (26 mm)</td>
			<td>Edwards Lifesciences</td>
			<td></td>
			<td>SAPIEN3 23mm, SAPIEN3 26mm. It is supported by Seoul Asan Medical</td>
		</tr>
		<tr>
			<td>Viscosmeter</td>
			<td>Brookfiled</td>
			<td></td>
			<td>DVELV; Measurement range: 1-2x109 cp</td>
		</tr>
	</tbody>
</table>

particle image velocimetry investigation of hemodynamics via aortic phantom

Aortic valve dysfunction and stroke have recently been reported in transcatheter aortic valve implantation (TAVI) patients. Thrombus in the aortic sinus and neo-sinus due to hemodynamic changes has been suspected. In vitro experiments help investigate the hemodynamic characteristics in the cases where an in vivo assessment proves to be limited. In vitro experiments are also more robust, and the variable parameters are controlled readily. Particle image velocimetry (PIV) is a popular velocimetry method for in vitro studies. It provides a high-resolution velocity field such that even small-scale flow features are observed. The purpose of this study is to show how PIV is used to investigate the flow field in the aortic sinus after TAVI. The in vitro setup of the aortic phantom, TAVI for PIV, and the data acquisition process and post-processing flow analysis are described. The hemodynamic parameters are derived, including the velocity, flow stasis, vortex, vorticity, and particle residence. The results confirm that in vitro experiments and PIV help investigate the hemodynamic features in the aortic sinus.

The velocity fields showed a different sinus flow structure depending on the valve diameter in Figure 4. For TAV (23 mm), the velocity was higher than 0.05 m/s between TAV and STJ from early systole to peak systole that TAV was opened using the forwarding jet. High velocity was then distributed in a narrow range near the stent at late systole. The velocity at diastole was lower than 0.025 m/s, and two vortexes with low velocity appeared. For TAV (26 mm), when the valve opened, high velocity ...

Watch this Scientific Journal Video about Particle Image Velocimetry Investigation of Hemodynamics via Aortic Phantom at JoVE.com

Particle Image Velocimetry Investigation of Hemodynamics via Aortic Phantom

The present protocol describes particle image velocimetry (PIV) measurements performed to investigate the sinus flow through the in vitro setup of the transcatheter aortic valve (TAV). The hemodynamic parameters based on velocity are also determined.

Particle Image Velocimetry Investigation of Hemodynamics via Aortic Phantom

Aortic valve dysfunction and stroke have recently been reported in transcatheter aortic valve implantation (TAVI) patients. Thrombus in the aortic sinus ...

Velocity information is essential for evaluating valvular blood flow. Our protocol acquires instance velocity fields, leading to a detailed analysis of hemodynamics. The main advantage of this protocol is that it can acquire instance velocity fields in the aortic sinus with the prosthetic heart valve implantation, which is hard to obtain from in-vivo experiments.The current protocol would help characterize the abnormal hemodynamics after transcatheter aortic valve implantation. Based on the obtained hemodynamics, researchers would be able to develop a better heart valve. The process of obtaining good particle images for particle image velocimetry is complicated.For a beginner, it is recommended to acquire particle images with different frame rates and compare each result. To begin, prepare the experimental setup on an optic table, including a piston pump, data acquisition device, and a computer with the required system engineering software and motor controlling software. Import the spreadsheet file to the system engineering software with the flow rate information.Fix the acrylic sinus model to the optic table with a square aluminum bar. Connect the reservoir, piston pump, and the acrylic sinus model with a silicone hose. Combine the fixed TAV on the native leaflet with the acrylic sinus model.Place the high-speed camera on a two-axis traverse and move the traverse. Turn on the laser, set it to seven watts, and place the laser sheet to the center of the TAV. Take a picture and check the maximum particle distance is less than four to six pixels.Set the camera controlling software parameters starting with a Resolution of 1, 280 by 720, a frame Rate of 300 frames per second, exposure forced by the Burst period, Burst count of three, and Burst period of 200 microseconds and 150 microseconds. Capture particle images for 14 continuous cycles and repeat it a total of seven times. Make the mask by separating the areas to be analyzed from those to be discarded.Using an open source tool, PIVlab, based on MATLAB, perform PIV by importing particle images saved by the time-resolved method or pair-wise method. Import the mask and apply it to all the particle images. Execute contrast-limited adaptive histogram equalization, execute the cross correlation about the particle image pair converted into the frequency domain using fast Fourier transform.Set the multi-pass interrogation window, find the peak value using a two-by-three Gaussian fit in correlation result. Calculate the velocity field, derive hemodynamics parameters using the in-house code and built-in function. For the 23-millimeter TAV, the velocity was higher than 0.05 meters per second between TAV and sino-tubular junction from early systole to peak systole.The velocity at diastole was lower than 0.025 meters per second and two vortexes with low velocity appeared. For 26 millimeter TAV in time except for early systole, velocity distribution in sinus was lower than 0.05 meters per second. Specifically, at late systole, the velocity was lower than at another time.The peak velocity in 23-millimeter TAV was higher than 26-millimeter TAV. The stasis area formed in 23-millimeter TAV was broad, but the fraction of stasis was low. Two similar vortices were noticed above and below the native leaflet for the 23-millimeter TAV.However, for the 26-millimeter TAV the clockwise vortex was unclear and the counterclockwise vortex had an elliptical shape. The vorticity showed similar results to the vortex. The snapshots of particle residence showed particle distribution in the sinus region for two seconds, and the percentage of particle residence showed that fraction of remaining particles in the sinus region for 14 seconds.The 26-millimeter TAV decreased faster than 23-millimeter TAV, however, the release of particles was not identical in both cases. The derivation of velocity fields is the most crucial step. The preceding steps are processes for deriving velocity fields, and are suitable for PIV.This protocol can be used to investigate hemodynamics in various cardiovascular systems, such as the stenotic arteries and heart valves.

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JoVE Journal

Engineering

3.0K vistas.  Kangwon National University. La información sobre la velocidad es esencial para evaluar el flujo sanguíneo valvular. Nuestro protocolo adquiere campos de velocidad de instancia, lo que lleva a un análisis detallado de la hemodinámica. La principal ventaja de este protocolo es que puede adquirir campos de velocidad de instancia en el seno aórtico con la implantación de la válvula cardíaca protésica, que es difícil de obtener de experimentos in vivo.El protocolo actual ayudaría a caracterizar la hemodiná...