We would like to thank the lab of Dr. Gordana Vunjak-Novakovic, including Julie Van Hassel, Mohamed Diane, and Panpan Chen, for allowing us to use cardiac waste tissue from their experiments. This work was supported by the Congenital Heart Defect Coalition in Butler, NJ, and the National Institutes of Health in Bethesda, MD (5T32HL007854-27).

All research was performed in compliance with institutional guidelines for the care of animals.
1. Considerations and preparations for the experiment
<ol>
	<li>Utilize a suitable pulse duplicator (PD) for the simulation of cardiac output through the AV. The PD will need to be able to accommodate biological materials and be able to be cleaned.
	<ol>
		<li>Utilize PD settings appropriate for testing the AV: 70 mL displacement volume and 70 beats per minute (5 L/min cardiac output), 35% of the cardiac cycle in systole, 100 mmHg mean transvalvular pressure gradient, 120 maximum pressure gradient, and 80 minimum pressure gradient.</li>
		<li>Use room temperature (RT) normal saline (0.9% NaCl) as the fluid medium.</li>
	</ol>
	</li>
	<li>Locate or create (using 3D printing or a similar method) suitable fixtures for mounting the porcine AV for testing on the PD.
	<ol>
		<li>Utilize fixtures that are modeled on the fixtures provided with the pulse duplicator with the following specifications: ensure that the inner diameter of the fixture is similar to the diameter of the AV being studied, the attachment length is at least 2 cm, and the usable attachment width is at least 4 cm (Figure 1).</li>
		<li>Use rubber O-rings as gaskets on the ends of the fixtures.</li>
	</ol>
	</li>
	<li>Obtain a heart specimen after cardiectomy (Figure 2A).
	<ol>
		<li>Use porcine cardiac specimens from the slaughterhouse or waste tissue from animals that are otherwise healthy and have not been part of any experimental protocols that will affect their hearts.</li>
		<li>Obtain specimen after cardiectomy or perform post-mortem cardiectomy, including transection of the superior vena cava, inferior vena cava, main pulmonary artery (PA), all pulmonary veins, and aorta at the distal aspect of the aortic arch. 
		NOTE: Fresh specimens, less than 6 h post-mortem or stored in sterile saline with a 1% antibiotic solution (penicillin and streptomycin) in a 4 oC refrigerator for up to 7 days, should be used for this experiment. Tissues fixed in formalin or glutaraldehyde will produce altered hydrodynamic results due to increased stiffness.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65885/65885fig01v2.jpg" /> 
Figure 1: Custom 3D printed fixtures for mounting the porcine aortic valves on the pulse duplicator.&#160;As noted in the protocol, the attachment length should be at least 2 cm, and the usable attachment width should be at least 4 cm. <a href="https://www.jove.com/files/ftp_upload/65885/65885fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
2. Resection of right-sided structures
<ol>
	<li>Dissect the PA off the aorta with Metzenbaum scissors until ventricular tissue is visible (Figure 2B).</li>
	<li>Dissect and ligate with silk ties both coronary arteries at their origin from the aortic sinuses, taking care not to narrow the sinuses.</li>
	<li>Transect the coronary arteries distal to the silk ties.</li>
	<li>Incise the right ventricle (RV) between the aorta and the PA at the base of the pulmonary valve using Metzenbaum scissors (Figure 2C).</li>
	<li>Beginning anteriorly, continue the incision circumferentially along the interventricular septum to remove the RV free wall (Figure 2D, E).</li>
	<li>Continue the incision posteriorly through the tricuspid valve annulus along the interatrial septum to remove all right atrial tissue (Figure 2F).</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/65885/65885fig02.jpg" /> 
Figure 2: Cardiectomy specimen and resection of right-sided structures. (A) Cardiectomy specimen. (B) Main pulmonary artery dissected off the aorta until ventricular tissue is visible. (C) Incising the right ventricle (RV) at the base of the pulmonary valve. (D) Continuing the incision along the interventricular septum anteriorly. (E) Removing the RV-free wall by continuing the incision circumferentially along the interventricular septum. (F) Specimen with right-sided structures removed. <a href="https://www.jove.com/files/ftp_upload/65885/65885fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
3. Preparation of the left ventricular outflow tract (LVOT) for cannulation with the PD fixture
<ol>
	<li>Incise the left atrium (LA) through the right pulmonary vein ostium parallel to the aorta using Metzenbaum scissors (Figure 3A). 
	NOTE: Although limited variability exists, porcine pulmonary vein anatomy generally terminates in two pulmonary vein ostia entering the LA8.</li>
	<li>Continue the incision towards the anterolateral commissure of the mitral valve (MV), leaving at least a 3 mm cuff of atrial tissue on the aorta side.</li>
	<li>Trim excess LA tissue, maintaining the 3 mm cuff of atrial tissue on the aorta and the MV annulus circumferentially (Figure 3B).</li>
	<li>Extend the incision onto the left ventricle (LV) through the anterolateral commissure of the MV, taking care to preserve the anterolateral papillary muscle (Figure 3C).</li>
	<li>Divide chordae tendineae from the anterolateral papillary muscle to the posterior MV leaflet, preserving attachments to the anterior MV leaflet.</li>
	<li>Continue the incision to the apex of the heart.</li>
	<li>Trim excess LV tissue below the papillary muscles, preserving both papillary muscles (Figure 3D).</li>
</ol>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/65885/65885fig03.jpg" /> 
Figure 3: Preparation of the left ventricular outflow tract for cannulation with the pulse duplicator fixture. (A) Incising the left atrium (LA) through the ostium of the right pulmonary vein. (B) Excess LA tissue trimmed, maintaining at least a 3 mm cuff of atrial tissue on the aorta and maintaining the mitral valve annulus circumferentially. (C) Extending the incision onto the left ventricle (LV) through the anterolateral commissure of the mitral valve. (D) Removing excess LV tissue below the papillary muscles. Scissors are visible in the upper right corner of the image. <a href="https://www.jove.com/files/ftp_upload/65885/65885fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
4. Preparation of the aorta for cannulation with the PD fixture
<ol>
	<li>Trim any excess lymphatic, connective, or pulmonary artery tissue off the aorta (Figure 4A).</li>
	<li>Incise the superior aspect of the aortic arch from the descending aorta to the left subclavian artery using Metzenbaum scissors (Figure 4B).</li>
	<li>Continue the incision on the superior aspect of the aortic arch from the left subclavian artery to the brachiocephalic trunk (Figure 4C, D). 
	&#8203;NOTE: Branches of the porcine aortic arch from distal to proximal include the left subclavian artery and the brachiocephalic trunk, which gives rise to the right subclavian artery, right carotid artery, and left carotid artery9.</li>
</ol>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/65885/65885fig04.jpg" /> 
Figure 4: Preparation of the aorta for cannulation with the pulse duplicator fixture. (A) Aortic arch with excess tissue removed. Note the two arch vessels in the porcine aortic arch, the brachiocephalic trunk, and the left subclavian artery. (B) Starting the incision along the superior aspect of the aortic arch from the descending aorta to the left subclavian artery. (C) Continuing the incision along the superior aspect of the aortic arch from the left subclavian artery to the brachiocephalic trunk. (D) Completed aortic arch incision. <a href="https://www.jove.com/files/ftp_upload/65885/65885fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
5. Cannulation of the LVOT with the PD fixture
<ol>
	<li>Test the positioning of the fixture in the LVOT and trim excess LV tissue.
	<ol>
		<li>Insert the fixture into the LVOT under the anterior leaflet of the MV.</li>
		<li>Wrap the LV-free wall around the fixture.</li>
		<li>Trim excess LV tissue to maintain a tight wrap around the fixture.</li>
		<li>Remove half of the thickness of the LV free wall starting at the interventricular septum, maintaining at least 1 cm of epicardium at the free edge to maintain the integrity of the suture line (Figure 5A).</li>
		<li>Trim 1 cm of tissue off the superior corner of the LV free wall wrap (Figure 5A).</li>
	</ol>
	</li>
	<li>Position the fixture in the LVOT with the supporting rod attachment hole 1 cm behind the LV incision (Figure 5B).
	<ol>
		<li>Take care not to insert the fixture too far into the LVOT such that it dilates the AV annulus.</li>
	</ol>
	</li>
	<li>Fasten the anterior leaflet of the MV to the fixture using one or two 6-inch zip ties positioned between the chordae tendineae of the leaflet (Figure 5C).</li>
	<li>Suture the LV free wall around the fixture (Figure 5D).
	<ol>
		<li>Start by suturing the cuff of LA tissue on the aorta to the MV annulus using a simple running suture with a taper point needle.</li>
		<li>Continue the running stitch onto the LV, not tearing the LV tissue.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/65885/65885fig05.jpg" /> 
Figure 5: Cannulation of the left ventricular outflow tract with the pulse duplicator fixture. (A) One-half thickness of the LV free wall removed with 1 cm of epicardium maintained at the free edge. The dotted line indicates the 1 cm area to be removed from the superior corner of the LV free wall wrap. (B) Supporting rod attachment hole positioned 1 cm behind the LV free wall incision. (C) Zip tie fastening the anterior leaflet of the MV to the proximal fixture. (D) LV free wall sutured around the fixture. <a href="https://www.jove.com/files/ftp_upload/65885/65885fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
6. Cannulation of the aorta with PD fixture and final preparation for PD testing
<ol>
	<li>Measure the diameter of the AV using Hegar dilators to assist with the interpretation of the results of PD testing.</li>
	<li>Identify the neutral position of the aorta by lifting the specimen off the table by grasping the aorta (Figure 6A).</li>
	<li>Insert the PD fixture into the aorta, taking care to line up the rod attachment holes in the neutral position of the aorta.</li>
	<li>Check the length of the specimen by inserting the support rods.</li>
	<li>Secure the PD fixture to the aorta using one or two 6-inch zip ties (Figure 6B).</li>
	<li>Secure the LVOT around the PD fixture using one or two 8-inch zip ties.</li>
	<li>Secure the support rods in place using screws provided with the PD set.</li>
	<li>Place the specimen in PD and start the test (Figure 6C, Video 1, and Video 2).</li>
	<li>Suture any leaks as needed.</li>
</ol>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/65885/65885fig06.jpg" /> 
Figure 6: Cannulation of the aorta and testing in the pulse duplicator. (A) Lifting the specimen off the table by the aorta to identify the neutral position of the aorta. (B) Distal fixture secured in the aorta with zip ties. (C) Specimen mounted in the pulse duplicator for hydrodynamic testing. <a href="https://www.jove.com/files/ftp_upload/65885/65885fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
7. Perform experimental procedure
NOTE: Perform experimental procedures like, the Ozaki procedure as previously described5,6,7, and repeat PD testing.
<ol>
	<li>If the tissue has become desiccated during the procedure, tighten the zip ties and reinforce the suture line as needed.</li>
</ol>
8. Long-term storage of specimen (if desired)
<ol>
	<li>Place specimen in formalin 10% for 168 h (1 week)10,11.</li>
	<li>After tissue fixation, wash the specimen with deionized water and place it in ethanol 70% for long-term storage.</li>
</ol>

Evaluation of Hydrodynamic Properties in Mounted Porcine Aortic Valves

<ol>
	<li>Aluru, J. S., Barsouk, A., Saginala, K., Rawla, P., Barsouk, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Valvular+heart+disease+epidemiology.">Valvular heart disease epidemiology.</a> Medical Science. 10 (2), 32 (2022).</li><li>Herrmann, J. L., Brown, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seven+decades+of+valved+right+ventricular+outflow+tract+reconstruction:+The+most+common+heart+procedure+in+children.">Seven decades of valved right ventricular outflow tract reconstruction: The most common heart procedure in children.</a> The Journal of Thoracic and Cardiovascular Surgery. 160 (5), 1284-1288 (2020).</li><li>Rotman, O. M., Bianchi, M., Ghosh, R. P., Kovarovic, B., Bluestein, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Principles+of+TAVR+valve+design,+modelling,+and+testing.">Principles of TAVR valve design, modelling, and testing.</a> Expert Review of Medical Devices. 15 (11), 771-791 (2018).</li><li>Pibarot, 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=Imaging+for+predicting+and+assessing+prosthesis-patient+mismatch+after+aortic+valve+replacement.">Imaging for predicting and assessing prosthesis-patient mismatch after aortic valve replacement.</a> JACC Cardiovascular Imaging. 12 (1), 149-162 (2019).</li><li>Ozaki, S., 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=Aortic+valve+reconstruction+using+self-developed+aortic+valve+plasty+system+in+aortic+valve+disease.">Aortic valve reconstruction using self-developed aortic valve plasty system in aortic valve disease.</a> Interactive Cardiovascular and Thoracic Surgery. 12 (4), 550-553 (2011).</li><li>Krane, M., Amabile, A., Ziegelm&#252;ller, J. A., Geirsson, A., Lange, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aortic+valve+neocuspidization+(the+Ozaki+procedure).">Aortic valve neocuspidization (the Ozaki procedure).</a> Multimedia Manual of Cardiothoracic Surgery. , (2021).</li><li>Ozaki, S., 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=A+total+of+404+cases+of+aortic+valve+reconstruction+with+glutaraldehyde-treated+autologous+pericardium.">A total of 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium.</a> The Journal of Thoracic and Cardiovascular Surgery. 147 (1), 301-306 (2014).</li><li>Vandecasteele, T., 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+pulmonary+veins+of+the+pig+as+an+anatomical+model+for+the+development+of+a+new+treatment+for+atrial+fibrillation.">The pulmonary veins of the pig as an anatomical model for the development of a new treatment for atrial fibrillation.</a> Anatomia Histollogia Embryologia. 44 (1), 1-12 (2015).</li><li>G&#243;es, A. M. O., 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=Comparative+angiotomographic+study+of+swine+vascular+anatomy:+contributions+to+research+and+training+models+in+vascular+and+endovascular+surgery.">Comparative angiotomographic study of swine vascular anatomy: contributions to research and training models in vascular and endovascular surgery.</a> Journal Vascular Brasilerio. 20, 20200086 (2021).</li><li>Ho&#322;da, M. K., Klimek-Piotrowska, W., Koziej, M., Pi&#261;tek, K., Ho&#322;da, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+different+fixation+protocols+on+the+preservation+and+dimensions+of+cardiac+tissue.">Influence of different fixation protocols on the preservation and dimensions of cardiac tissue.</a> Journal of Anatomy. 229 (2), 334-340 (2016).</li><li>Ho&#322;da, M. K., Klimek-Piotrowska, W., Koziej, M., Tyrak, K., Ho&#322;da, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Penetration+of+formaldehyde+based+fixatives+into+heart.">Penetration of formaldehyde based fixatives into heart.</a> Folia Medica Cracoviensia. 57 (4), 63-70 (2017).</li><li>Spampinato, R. 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=Grading+of+aortic+regurgitation+by+cardiovascular+magnetic+resonance+and+pulsed+Doppler+of+the+left+subclavian+artery:+harmonizing+grading+scales+between+imaging+modalities.">Grading of aortic regurgitation by cardiovascular magnetic resonance and pulsed Doppler of the left subclavian artery: harmonizing grading scales between imaging modalities.</a> International Journal of Cardiovascular Imaging. 36 (8), 1517-1526 (2020).</li><li>Capps, S. B., Elkins, R. C., Fronk, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Body+surface+area+as+a+predictor+of+aortic+and+pulmonary+valve+diameter.">Body surface area as a predictor of aortic and pulmonary valve diameter.</a> The Journal of Thoracic and Cardiovascular Surgery. 119 (5), 975-982 (2000).</li><li>Baumgartner, H., 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=Recommendations+on+the+echocardiographic+assessment+of+aortic+valve+stenosis:+a+focused+update+from+the+European+Association+of+Cardiovascular+Imaging+and+the+American+Society+of+Echocardiography.">Recommendations on the echocardiographic assessment of aortic valve stenosis: a focused update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography.</a> European Heart Journal - Cardiovascular Imaging. 18 (3), 254-275 (2017).</li><li>Saisho, H., 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=An+ex+vivo+evaluation+of+two+different+suture+techniques+for+the+Ozaki+aortic+neocuspidization+procedure.">An ex vivo evaluation of two different suture techniques for the Ozaki aortic neocuspidization procedure.</a> Interactive Cardiovascular and Thoracic Surgery. 33 (4), 518-524 (2021).</li><li>Saisho, H., 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=Ex+vivo+evaluation+of+the+Ozaki+procedure+in+comparison+with+the+native+aortic+valve+and+prosthetic+valves.">Ex vivo evaluation of the Ozaki procedure in comparison with the native aortic valve and prosthetic valves.</a> Interactive Cardiovascular and Thoracic Surgery. 35 (3), (2022).</li><li>Paulsen, M. 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=Comprehensive+ex+vivo+comparison+of+5+clinically+used+conduit+configurations+for+valve-sparing+aortic+root+replacement+using+a+3-dimensional-printed+heart+simulator.">Comprehensive ex vivo comparison of 5 clinically used conduit configurations for valve-sparing aortic root replacement using a 3-dimensional-printed heart simulator.</a> Circulation. 142 (14), 1361-1373 (2020).</li><li>Al-Atassi, T., 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=Impact+of+aortic+annular+geometry+on+aortic+valve+insufficiency:+Insights+from+a+preclinical,+ex+vivo,+porcine+model.">Impact of aortic annular geometry on aortic valve insufficiency: Insights from a preclinical, ex vivo, porcine model.</a> The Journal of Thoracic and Cardiovascular Surgery. 150 (3), 656-664 (2015).</li><li>Sun, 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=A+biomimetic+multilayered+polymeric+material+designed+for+heart+valve+repair+and+replacement.">A biomimetic multilayered polymeric material designed for heart valve repair and replacement.</a> Biomaterials. 288, 121756 (2022).</li><li>Waller, B. F., McKay, C., Van Tassel, J., Allen, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catheter+balloon+valvuloplasty+of+stenotic+porcine+bioprosthetic+valves:+Part+I:+Anatomic+considerations.">Catheter balloon valvuloplasty of stenotic porcine bioprosthetic valves: Part I: Anatomic considerations.</a> Clinical Cardiology. 14 (8), 686-691 (1991).</li><li>Crick, S. J., Sheppard, M. N., Ho, S. Y., Gebstein, L., Anderson, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+of+the+pig+heart:+comparisons+with+normal+human+cardiac+structure.">Anatomy of the pig heart: comparisons with normal human cardiac structure.</a> Journal of Anatomy. 193, 105-119 (1998).</li></ol>

The authors have no relevant financial conflicts of interest to disclose.

The method presented here provides a platform for hydrodynamic testing of the AV in order to examine the effect of an experimental procedure or a novel medical device. By mounting the native aortic valve on a pulse duplicator machine, we are able to determine the effect of the experimental procedure on all the hydrodynamic parameters used in the investigation and approval of novel valve prostheses (ISO 5840). This provides an opportunity to fine-tune procedures and prostheses prior to use in a large animal model.
<p ...

Aortic valve disease represents a significant public health burden, particularly aortic stenosis, which affects 9 million people worldwide1. Strategies to address this disease are currently evolving and include aortic valve repair and aortic valve replacement. In the pediatric population especially, there is a significant incentive to repair rather than replace the valve since currently available prostheses are prone to structural valve degeneration (SVD) and are not growth tolerant, requiring reoperation for re-replacement as the patient grows. Even the Ross procedure, which replaces the diseased aortic valve (AV) with the native pulmonary valve (PV), requires a prosthesis or graft in the pulmonary position that is also subject to SVD and often limited growth tolerance2. New approaches to aortic valve disease are being developed, and there is a need for testing in a biologically relevant context prior to application in a large animal model.
We have developed a method for testing a porcine AV that can provide insights into the function of the valve before and after an investigational procedure or application of a novel medical device. By mounting the porcine AV on a commercially available pulse duplicator machine, we are able to compare the hydrodynamic characteristics that are commonly used in the investigation and ultimately approval of valve prostheses, including regurgitation fraction (RF), effective orifice area (EOA), and mean positive pressure difference (PPD)3,4. The intervention can then be fine-tuned in a biologically relevant context before use in a large animal model, thus limiting the number of animals needed to produce a procedure or prosthesis that can be used in humans. The hearts used for this experiment can be obtained from the local abattoir or waste tissue from other experiments, so it is not necessary to sacrifice an animal solely for the purposes of this experiment.
In our work, we used this method to develop a novel patch material for valve repair and replacement. We tested the hydrodynamic function of a variety of patch materials by performing an aortic valve neocuspidization procedure (Ozaki procedure5,6,7) on porcine AVs and testing them in the pulse duplicator before and after the procedure. This enabled us to fine-tune the material based on its hydrodynamic performance. Thus, this method provides a platform for hydrodynamic testing of experimental procedures and novel medical devices for use on the AV prior to application&#160;in a large animal model.

<table><tbody><tr><td>3D Printer</td><td>Ultimaker</td><td>Ultimaker S5</td><td>Used for printing custom fixtures for hydrodynamic testing</td></tr><tr><td>Crile-Wood Needle Driver</td><td>Emerald Instruments</td><td>2.0638.15</td><td>Used for suturing ventricle</td></tr><tr><td>Debakey Forceps</td><td>Jarit</td><td>320-110</td><td>Used for dissection and sample preparation (can use multiple if working with an assistant)</td></tr><tr><td>Ethanol 200 proof</td><td>Decon Labs Inc.</td><td>DSP-MD.43</td><td>Used for fixed tissue storage</td></tr><tr><td>Formalin 10%</td><td>Epredia</td><td>5701</td><td>Used for tissue fixation</td></tr><tr><td>Gerald Forceps</td><td>Jarit</td><td>285-126</td><td>Used for dissection and sample preparation</td></tr><tr><td>Glass jars</td><td>QAPPDA</td><td>B07QCP54Z3</td><td>Used for tissue storage</td></tr><tr><td>Glutaraldehyde 25%</td><td>Electron Microscopy Sciences</td><td>16400</td><td>Used for tissue fixation</td></tr><tr><td>HEPES 1 M buffer solution</td><td>Fisher</td><td>BP299-100</td><td>Used to make glutaraldehyde 0.6%</td></tr><tr><td>Mayo Scissors</td><td>Jarit</td><td>099-200</td><td>Used for cutting suture</td></tr><tr><td>Metzenbaum Scissors</td><td>Jarit</td><td>099-262</td><td>Used for dissection and sample preparation</td></tr><tr><td>O-ring</td><td>Sterling Seal &amp;amp; Supply Inc.</td><td>AS568-117</td><td>Used as a gasket on the end of the 3D printed fixtures</td></tr><tr><td>Polylactic acid resin</td><td>Ultimaker</td><td>1609</td><td>Used for 3D printing fixtures</td></tr><tr><td>Polyproplene suture</td><td>Covidien</td><td>VP-762-X</td><td>Used for suturing ventricle, tapered needle</td></tr><tr><td>Pulse Duplicator</td><td>BDC Laboratories</td><td>HDTi-6000</td><td>Used for hydrodynamic testing</td></tr><tr><td>Silk ties</td><td>Covidien</td><td>S-193</td><td>Used for ligating coronary arteries</td></tr><tr><td>Tonsil Clamp</td><td>Aesculap</td><td>BH957R</td><td>Used for coronary artery dissection</td></tr><tr><td>Zip ties (6 inch)</td><td>Advanced Cable Ties, Inc.</td><td>AL-06-18-9-C</td><td>Used for securing sample to fixtures, 157.14 mm long (6 inches), 2.5 mm wide</td></tr><tr><td>Zip ties (8 inch)</td><td>GTSE</td><td>GTSE-20025B.1000</td><td>Used for securing sample to fixtures, 203 mm long (8 inches), 2.5 mm wide</td></tr></tbody></table>

an ex vivo porcine model for hydrodynamic testing of experimental aortic valve procedures and novel medical devices

The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a method for mounting a porcine aortic valve in a pulse duplicator to evaluate its hydrodynamic properties. These properties can then be evaluated before and after the procedure under investigation is performed and/or the investigative medical device is applied. Securing the inflow segment presents some difficulty owing to the lack of circumferential myocardium in the left ventricular outflow tract. This method addresses that issue by securing the inflow segment using the anterior leaflet of the mitral valve and then suturing the left ventricular free wall around the inflow fixture. The outflow segment is secured simply by inserting the fixture into an incision in the superior aspect of the aortic arch. We found that specimens had significantly different hydrodynamic properties before and after tissue fixation. This finding induced us to use fresh specimens in our testing and should be considered when using this method. In our work, we used this method to test novel intracardiac patch materials for use in the valvular position by performing an aortic valve neocuspidization procedure (Ozaki procedure) on the mounted porcine aortic valves. These valves were tested before and after the procedure to assess the change in hydrodynamic properties in comparison to the native valve. Herein, we report a platform for hydrodynamic testing of experimental aortic valve procedures that enables comparison with the native valve and between different devices and techniques used for the procedure under investigation.

The representative data collected from the pulse duplicator includes regurgitation fraction (RF), effective orifice area (EOA), and mean positive pressure difference (PPD). The RF and EOA, in particular, are used in the ISO standards for prosthetic valves (ISO 5840) and will be important to collect if prosthetic valve products are under investigation. The PPD offers information regarding how much pressure is required to open the valve and is commonly referenced when discussing prosthetic valve replacement<sup class="xref...

Watch this Scientific Journal Video about Advancing Cardiac Procedure Testing Prior to Embarking on Large Animal Studies at JoVE.com

Author Spotlight: Advancing Cardiac Procedure Testing Prior to Embarking on Large Animal Studies 

We present a method for mounting a porcine aortic valve on a pulse duplicator to test its hydrodynamic properties. This method can be used to determine the change in hydrodynamics after the application of an experimental procedure or novel medical device prior to use in a large animal model.

An Ex Vivo Porcine Model for Hydrodynamic Testing of Experimental Aortic Valve Procedures and Novel Medical Devices

The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a ...

an-ex-vivo-porcine-model-for-hydrodynamic-testing-experimental-aortic

Research

JoVE Journal

Bioengineering

893 Views.  Columbia University Medical Center. Er zijn beperkte mogelijkheden voor het testen van nieuwe cardiale procedures en medische hulpmiddelen voor onderzoek voordat ze in een groot diermodel worden gebruikt. Ons protocol biedt de mogelijkheid om dergelijke procedures en apparaten te verfijnen in een biologisch en anatomisch relevante context voordat aan grote dierstudies wordt begonnen. Andere technieken voor het monteren van een aortaklep op een pulsduplicator vereisen het inbrengen of bevestigen van een stijve structuur aan de a...

Video: Auteur in de schijnwerpers: het testen van cardiale procedures bevorderen voordat aan grote dierstudies wordt begonnen 

Autologous Endothelial Progenitor Cell-Seeding Technology and Biocompatibility Testing For Cardiovascular Devices in Large Animal Model

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk of thromboemboli formation1,2,3. We have developed a method to line the inside surface of Ti tubes with autologous blood-derived human or porcine endothelial progenitor cells (EPCs)4. By implanting Ti tubes containing a confluent layer of porcine EPCs in the inferior vena cava (IVC) of pigs, we tested the improved biocompatibility of the cell-seeded surface in the prothrombotic environment of a large animal model and compared it to unmodified bare metal surfaces5,6,7 (Figure 1). This method can be used to endothelialize devices within minutes of implantation and test their antithrombotic function in vivo. 
Peripheral blood was obtained from 50 kg Yorkshire swine and its mononuclear cell fraction cultured to isolate EPCs4,8. Ti tubes (9.4 mm ID) were pre-cut into three 4.5 cm longitudinal sections and reassembled with heat-shrink tubing. A seeding device was built, which allows for slow rotation of the Ti tubes. 
We performed a laparotomy on the pigs and externalized the intestine and urinary bladder. Sharp and blunt dissection was used to skeletonize the IVC from its bifurcation distal to the right renal artery proximal. The Ti tubes were then filled with fluorescently-labeled autologous EPC suspension and rotated at 10 RPH x 30 min to achieve uniform cell-coating9. After administration of 100 USP/ kg heparin, both ends of the IVC and a lumbar vein were clamped. A 4 cm veinotomy was performed and the device inserted and filled with phosphate-buffered saline. As the veinotomy was closed with a 4-0 Prolene running suture, one clamp was removed to de-air the IVC. At the end of the procedure, the fascia was approximated with 0-PDS (polydioxanone suture), the subcutaneous space closed with 2-0 Vicryl and the skin stapled closed. 
After 3 - 21 days, pigs were euthanized, the device explanted en-block and fixed. The Ti tubes were disassembled and the inner surfaces imaged with a fluorescent microscope.
We found that the bare metal Ti tubes fully occluded whereas the EPC-seeded tubes remained patent. Further, we were able to demonstrate a confluent layer of EPCs on the inside blood-contacting surface.
Concluding, our technology can be used to endothelialize Ti tubes within minutes of implantation with autologous EPCs to prevent thrombosis of the device. Our surgical method allows for testing the improved biocompatibility of such modified devices with minimal blood loss and EPC-seeded surface disruption.

A method for seeding titanium blood-contacting biomaterials with autologous cells and testing biocompatibility is described. This method uses endothelial progenitor cells and titanium tubes, seeded within minutes of surgical implantation into porcine venae cavae. This technique is adaptable to many other implantable biomedical devices.

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk ...

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage1-3. Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease4. 
The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve5. Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves6-9. Pulsatile bioreactors have also been developed to study a range of tissues including cartilage10, bone11 and bladder12. The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. 
The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed air into the system at the appropriate rate. The system mimicked the dynamic transvalvular pressure levels associated with the aortic valve; a saw tooth wave produced a gradual increase in pressure, typical of the transvalvular pressure gradient that is present across the valve during diastole, followed by a sharp pressure drop depicting valve opening in systole. The LabVIEW program allowed users to control the magnitude and frequency of cyclic pressure. The system was able to subject tissue samples to physiological and pathological pressure conditions. This device can be used to increase our understanding of how heart valves respond to changes in the local mechanical environment.

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

A cyclic pressure bioreactor capable of subjecting heart valve tissue to physiological and pathological pressure conditions has been designed. A LabVIEW program allows users to control pressure magnitude, amplitude and frequency. This device can be used to study the mechanobiology of heart valve tissue or isolated cells.

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage&#160;and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide insights on functional aspects of polymer valve design.

There has been renewed interest in developing polymer valves. Here, the objectives are to demonstrate the feasibility of modifying a commercial pulse duplicator to accommodate tri-leaflet geometries and to define a protocol to present polymer valve hydrodynamic data in comparison to native and prosthetic valve data collected under near-identical conditions.

Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of ...

In vitro Assessment of Aortic Regurgitation Using Four-Dimensional Flow Magnetic Resonance Imaging

Aortic regurgitation (AR) refers to backward blood flow from the aorta into the left ventricle (LV) during ventricular diastole. The regurgitant jet arising from the complex shape is characterized by the three-dimensional flow and high-velocity gradient, sometimes limiting an accurate measurement of the regurgitant volume using 2D echocardiography. Recently developed four-dimensional flow magnetic resonance imaging (4D flow MRI) enables three-dimensional volumetric flow measurements, which can be used to accurately quantify the amount of the regurgitation. This study focuses on (i) magnetic resonance compatible AR model fabrication (dilatation, perforation, and prolapse) and (ii) systematic analysis of the performance of 4D flow MRI in AR quantification. The results indicated that the formation of the forward and backward jets over time was highly dependent on the types of AR origin. The amount of regurgitation volume bias for the model types were -7.04%, -33.21%, 6.75%, and 37.04% compared to the ground truth (48 mL) volume measured from the pump stroke volume. The largest error of the regurgitation fraction was around 12%. These results indicate that careful selection of imaging parameters is required when absolute regurgitation volume is important. The suggested in vitro flow phantom can easily be modified to simulate other valvular diseases such as aortic stenosis or bicuspid aortic valve (BAV) and can be used as a standard platform to test different MRI sequences in the future.

In vitro Assessment of Aortic Regurgitation Using Four-Dimensional Flow Magnetic Resonance Imaging

Aortic regurgitation is an aortic valve heart disease. This manuscript demonstrates how four-dimensional flow magnetic resonance imaging can evaluate aortic regurgitation using in vitro heart valves mimicking aortic regurgitation.

Aortic regurgitation (AR) refers to backward blood flow from the aorta into the left ventricle (LV) during ventricular diastole. The regurgitant jet ...

Engineering

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.
Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G&#160;catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.
After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.
The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study.

Here we present a protocol to assess cardiopulmonary function in awake swine, at rest and during graded treadmill exercise. Chronic instrumentation allows for repeated hemodynamic measurements uninfluenced by cardiodepressive anesthetic agents.

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early ...

Medicine

Novel Percutaneous Approach for Deployment of 3D Printed Coronary Stenosis Implants in Swine Models of Ischemic Heart Disease

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally (3D) printed coronary implants can be employed to percutaneously create a focal coronary stenosis. However, reliable delivery of the implants can be difficult without the use of ancillary equipment. We describe the use of a mother-and-child coronary guide catheter for stabilization of the implant and for effective delivery of the 3D printed implant to any desired location along the length of the coronary vessel. The focal coronary narrowing was confirmed under coronary cineangiography and the functional significance of the coronary stenosis was assessed using gadolinium-enhanced first-pass cardiac perfusion MRI. We showed that reliable delivery of 3D printed coronary implants in swine models (n = 11) of ischemic heart disease can be achieved through repurposing mother-and-child coronary guide catheters. Our technique simplifies the percutaneous delivery of coronary implants to create closed-chest swine models of focal coronary artery stenosis and can be performed expeditiously, with a low procedural failure rate.

We describe a novel, cost-effective, and efficient technique for percutaneous delivery of three-dimensionally printed coronary implants to create closed-chest swine models of ischemic heart disease. The implants were fixed in place using a mother-and-child extension catheter with high success rate.

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally ...

Measuring Cardiac Output in a Swine Model

Swine are frequently used in medical research given their similar cardiac physiology to that of humans. Measuring cardiac parameters such as stroke volume and cardiac output are essential in this type of research. Contrast ventriculography, thermodilution, and pressure-volume loop (PV-loop) catheters can be used to accurately obtain cardiac performance data depending on which resources and expertise are available. For this study,five Yorkshire swine were anesthetized and intubated. Central venous and arterial access was obtained to place the necessary measurement instruments.A temperature probe was placed in the aortic root. A cold saline bolus was delivered to the right atrium and temperature deflection curve was recorded. Integration of the area under the curve allowed for the calculation of the current cardiac output.A pigtail catheter was percutaneously placed in the left ventricle and 30 mL of iodinated contrast was power injected over 2 seconds. Digital subtraction angiography images were uploaded to volumetric analysis software to calculate the stroke volume and cardiac output. A pressure volume-loop catheter was placed into the left ventricle (LV) and provided continuous pressure and volume data of the LV, which allowed the calculation of both stroke volume and cardiac output.All three methods demonstrated good correlation with each other. The PV-loop catheter and thermodilution exhibited the best correlation with a 3% error and a Pearson coefficient of 0.99, with 95% CI=0.97 to 1.1, (p=0.002). The PV-loop catheter against ventriculography also showed good correlation with a 6% error and a Pearson coefficient of 0.95, 95% CI=0.96 to 1.1 (p=0.01). Finally, thermodilution against ventriculography had a 2% error with r=0.95, 95% CI=0.93 to 1.11, (p=0.01). In conclusion, we state that the PV-loop catheter, contrast ventriculography, and thermodilution each offer certain advantages depending on the researcher's requirements. Each method is reliable and accurate for measuring various cardiac parameters in swine such as the stroke volume and cardiac output.

Thermodilution, pressure-volume loop catheters, and contrast ventriculography are reliable and accurate methods for determining cardiac physiology such as stroke volume and cardiac output in a laboratory setting in swine.

Swine are frequently used in medical research given their similar cardiac physiology to that of humans. Measuring cardiac parameters such as stroke volume ...

Transcatheter Pulmonary Valve Replacement from Autologous Pericardium with a Self-Expandable Nitinol Stent in an Adult Sheep Model

Transcatheter pulmonary valve replacement has been established as a viable alternative approach for patients suffering from right ventricular outflow tract or bioprosthetic valve dysfunction, with excellent early and late clinical outcomes. However, clinical challenges such as stented heart valve deterioration, coronary occlusion, endocarditis, and other complications must be addressed for lifetime application, particularly in pediatric patients. To facilitate the development of a lifelong solution for patients, transcatheter autologous pulmonary valve replacement was performed in an adult sheep model. The autologous pericardium was harvested from the sheep via left anterolateral minithoracotomy under general anesthesia with ventilation. The pericardium was placed on a 3D shaping heart valve model for non-toxic cross-linking for 2 days and 21 h. Intracardiac echocardiography (ICE) and angiography were performed to assess the position, morphology, function, and dimensions of the native pulmonary valve (NPV). After trimming, the crosslinked pericardium was sewn onto a self-expandable Nitinol stent and crimped into a self-designed delivery system. The autologous pulmonary valve (APV) was implanted at the NPV position via left jugular vein catheterization. ICE and angiography were repeated to evaluate the position, morphology, function, and dimensions of the APV. An APV was successfully implanted in&#160;sheep J. In this paper, sheep J was selected to obtain representative results. A 30 mm APV with a Nitinol stent was accurately implanted at the NPV position without any significant hemodynamic change. There was no paravalvular leak, no new pulmonary valve insufficiency, or stented pulmonary valve migration. This study demonstrated the feasibility and safety, in a long-time follow-up, of developing an APV for implantation at the NPV position with a self-expandable Nitinol stent via jugular vein catheterization in an adult sheep model.

This study demonstrates the feasibility and safety of developing an autologous pulmonary valve for implantation at the native pulmonary valve position by using a self-expandable Nitinol stent in an adult sheep model. This is a step toward developing transcatheter pulmonary valve replacement for patients with right ventricular outflow tract dysfunction.

Transcatheter pulmonary valve replacement has been established as a viable alternative approach for patients suffering from right ventricular outflow ...

Preclinical Evaluation of Coronary Artery Stents

Coronary artery disease is a major contributor to morbidity and mortality worldwide. While lifestyle changes and medication are the cornerstones of treatment, coronary artery balloon angioplasty and stenting are routinely performed on patients with acute coronary syndromes and chronic coronary artery disease who remain symptomatic with optical medical treatment. Several generations of coronary stents have been developed over recent decades. Balloon angioplasty and stenting are supported by the use of pharmaceutical agents applied onto balloons and the stent surface, either to advance the healing properties of the artery post-intervention or to prevent the formation of restenosis. New devices need to be rigorously tested for safety and efficacy before acceptance into clinical practice; thus, there is a continuing need for reliable and reproducible preclinical methods of stent evaluation. We describe here a pig coronary artery model as well as an atherosclerotic rabbit model for coronary artery stent research and describe basic steps in intravascular imaging and stent histology.

New coronary artery stent designs and materials must be tested before clinical use in relevant preclinical models. Here we describe an atherosclerotic rabbit aorta model and a pig coronary artery model for stent research with in vivo and histological analyses.

Coronary artery disease is a major contributor to morbidity and mortality worldwide. While lifestyle changes and medication are the cornerstones of ...

Ascending Aortic Banding for Studying Pressure-Overload Induced Heart Failure

A Minimally Invasive Model of Aortic Stenosis in Swine

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological similarities to humans. Efforts have been dedicated to creating a model of pressure-overload induced heart failure, and ascending aortic banding while still supra-coronary and not a perfect mimic of aortic stenosis in humans, closely resembling the human condition.
The purpose of this study is to demonstrate a minimally invasive approach to induce left ventricular pressure overload by placing an aortic band, precisely calibrated with percutaneously introduced high-fidelity pressure sensors. This method represents a refinement of the surgical procedure (3Rs), resulting in homogenous trans-stenotic gradients and reduced intragroup variability. Additionally, it enables swift and uneventful animal recovery, leading to minimal mortality rates. Throughout the study, animals were followed for up to 2 months after surgery, employing transthoracic echocardiography and pressure-volume loop analysis. However, longer follow-up periods can be achieved if desired. This large animal model proves valuable for testing new drugs, particularly those targeting hypertrophy and the structural and functional alterations associated with left ventricular pressure overload.

Author Spotlight: Development of a Minimally Invasive Large-Animal Model for Reliable and Reproducible Cardiovascular Research 

This protocol describes a minimally invasive surgical procedure for ascending aortic banding in swine.

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological ...

An Ex Vivo Porcine Model for Hydrodynamic Testing of Experimental Aortic Valve Procedures and Novel Medical Devices

Samenvatting

Meer video's verkennen