We thank staff members at the UCLA Translational Research Imaging Center and the Department of Laboratory Animal Medicine at University of California, Los Angeles, CA, USA for their assistance. This work is supported in part by the Department of Radiology and Medicine at David Geffen School of Medicine at UCLA, the American Heart Association (18TPA34170049), and by the Clinical Science Research, Development Council of the Veterans Health Administration (VA-MERIT I01CX001901).

We conducted the experiments according to the guidelines by the Animal Welfare Act, the National Institutes of Health, and the American Heart Association on Research Animal Use. Our Institutional Animal Care and Use Committee approved the animal study protocol.
1. Preprocedural preparation of 3D printed coronary stenosis implants
<ol>
	<li>Using tweezers, dip-coat the printed implants in a 25% heparin solution to prevent thrombus formation and allow to air dry for 24 h.</li>
</ol>
2. Preprocedural preparation of animal subjects
<ol>
	<li>Have male Yorkshire swine (SNS Farms, 30&#8211;45 kg) arrive at the institution 1 week prior to the experiment date and allow them to acclimate.</li>
	<li>Keep the swine in a fasting state after midnight the day prior to the procedure.</li>
</ol>
3. Procedural anesthesia
<ol>
	<li>Sedate the swine with intramuscular ketamine (10 mg/kg) and intravenous midazolam (1 mg/kg).</li>
	<li>Ventilate the animals with an oxygen-isoflurane (1&#8211;2%) mixture.</li>
	<li>Perform endotracheal intubation once the animal subject is sedated.</li>
	<li>Infuse intravenous (IV) rocuronium (2.5 mg/kg/h) and give additional boluses (1&#8211;3 mg/kg IV every 20&#8211;30 min) when needed to achieve diaphragmatic immobilization.</li>
	<li>Maintain a surgical plane of anesthesia throughout the procedure by checking for awakening, movements, wide fluctuation in vital signs, and other signs of distress or discomfort throughout the duration of the experiment. We monitored the swine for roughly 6 h under anesthesia.</li>
</ol>
4. Vascular access
<ol>
	<li>Using the Seldinger technique, insert the arterial and venous sheaths into the bilateral femoral arteries and veins of the subjects.</li>
	<li>Flush all catheter ports continuously with heparinized normal saline.</li>
</ol>
5. Preprocedural medication administration
<ol>
	<li>Administer amiodarone intramuscularly (1.5 mg/kg), lidocaine intravenously (2 mg/kg), and esmolol intravenously (1 mg/kg) as needed for prophylaxis against arrhythmia. Give repeat dosages of amiodarone, lidocaine, and esmolol as needed throughout the course of the experiment to suppress ventricular rhythms and control heart rate response.</li>
	<li>After vascular access is obtained, administer heparin (5,000&#8211;10,000 units) to keep an activated clotting time (ACT) &#62;300 s. Check the ACT every hour during the course of the experiment and give additional intravenous heparin as needed to maintain the ACT goal.</li>
</ol>
6. Hemodynamic monitoring
<ol>
	<li>Use a single lateral electrocardiography (ECG) chest lead for recording changes in ST segment, T-waves, and heart rate during the entire experimental period.</li>
	<li>Use a pressure transducer to record continuous femoral arterial pressure throughout the procedure.</li>
	<li>Attach a pulse oximeter to the animal&#39;s ear or lip for continuous pulse oximetry recordings.</li>
</ol>
7. Preparation of implant delivery equipment
<ol>
	<li>Prior to performing coronary angiography, insert a deflated NC Trek over-the-wire coronary balloon through a mother-and-child catheter of the desired size such that the balloon tip extends beyond the tip of the catheter.</li>
	<li>Mount the 3D printed implant onto the deflated angioplasty balloon such that the implant is positioned between the markers of the balloon and close to the proximal marker (Figure 1B).</li>
	<li>Inflate the balloon with an insufflator to 2&#8211;3 atm in order to fix the implant onto the balloon. Verify that the implant is positioned closer to the proximal half of the balloon so it will be closest to the mother-and-child catheter when ready for removal (Figure 1B).</li>
</ol>
8. Coronary angiography and deployment of coronary implant
<ol>
	<li>Position the fluoroscopic C-arm in the anteroposterior (AP) projection.</li>
	<li>Attach a control valve (see Table of Materials) to a left or right coronary guide catheter (see Table of Materials).</li>
	<li>Introduce the guide catheter over a J-tipped wire through the right femoral artery sheath and, under fluoroscopic guidance, advance the catheter to the aortic root.</li>
	<li>Selectively (or nonselectively) engage the catheter into the left main coronary artery (LMCA) and inject 5 mL of iodinated contrast under fluoroscopy to visualize the left coronary system.</li>
	<li>Position the guide catheter towards the LMCA for the second angiogram (Figure 2). If coronary artery engagement proves difficult, due in part to the short aortic arch of the swine, consider performing non-selective angiograms as long as they provide adequate visualization of the vessels.</li>
	<li>Once engaged within, or positioned near the LMCA, under fluoroscopy, advance a 0.014&#34;, 300 cm coronary wire (see Table of Materials) into the LMCA and further advance the wire to the distal left anterior descending artery (LAD) or left circumflex coronary artery (LCX) if desired (Figure 3).</li>
	<li>Under fluoroscopic guidance, insert the previously assembled mother-and-child catheter with the inflated coronary angioplasty balloon and implant over the coronary wire and advance to the desired location along the coronary vessel. Inject 5 mL of iodinated contrast to visualize a discrete narrowing at the desired location where the coronary implant should be deployed (Figure 4).</li>
	<li>Once the implant is in position, advance the mother-and-child catheter to the proximal marker of the inflated balloon.</li>
	<li>Deflate the balloon and retract it through the mother-and-child catheter. This process allows the mother-and-child catheter to shear the implant off the balloon as it is retracted and fixes the position of the implant in the designated segment of the vessel.</li>
	<li>Remove the balloon, mother-and-child catheter, and coronary wire.</li>
	<li>Perform final angiograms to document the location of the new artificial stenosis within the vessel. When feasible, angiograms should be performed in two orthogonal views to acquire visual estimation of stenosis severity. A final angiography (Figure 5) can also be performed with subselective positioning of the mother-and-child catheter in the proximal vessel, which provides excellent opacification with minimal contrast.</li>
	<li>Immediately transfer the animal to the MR suite to undergo cardiac stress perfusion MRI using gadobutrol (0.1 mM/kg) injected at a rate of 2 mL/sec. 
	NOTE: The stress agent used was a 4 min infusion of adenosine at 300 &#181;g/kg/min. The imaging protocol included 1) cine imaging (field of view [FOV] = 292 x 360 mm, matrix size = 102 x 126, repetition time [TR] = 5.22 ms, echo time [TE] = 2.48 ms, slice thickness = 6 mm, pixel bandwidth = 450 Hz, flip angle = 12&#730;); 2) first-pass perfusion at rest and at peak adenosine vasodilator stress using a spoiled gradient echo sequence (FOV = 320 x 320 mm, matrix size = 130 x 130, TR = 2.5 ms, TE = 1.1 ms, slice thickness = 10 mm, pixel bandwidth = 650 Hz, flip angle = 12&#730;; and 3) late gadolinium enhancement imaging using an ECG-gated, segmented, spoiled gradient-echo phase-sensitive-inversion-recovery sequence (FOV = 225 x 340 mm, matrix size = 131 x 175 mm, TR = 5.2 ms, TE = 1.96 ms, slice thickness = 8 mm, inversion time (TI) = optimized to null the myocardium, pixel bandwidth = 465 Hz, flip angle = 20&#730;). An illustrative first-pass perfusion image is shown in Figure 6.</li>
	<li>After completion of the MRI protocol, euthanize the swine by an infusion of sodium pentobarbital (100 mg/kg).</li>
	<li>Perform a lateral thoracotomy, excise the heart, and dissect the ex vivo heart to expose the coronary vessels. Note the location of the implant in relationship to either the diagonal branches (LAD territory) or obtuse marginal branches (LCX territory), and retrieve the implants.</li>
	<li>Using blunted and curved Metzenbaum scissors, open the coronary vessel and inspect the vessel for gross injury (see Figure 7). Photograph the heart tissue for gross pathology and stain with triphenyltetrazolium chloride to exclude myocardial infarction (see Figure 8).</li>
</ol>

<ol>
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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=Production+of+advanced+coronary+atherosclerosis,+myocardial+infarction+and+"sudden+death"+in+swine.">Production of advanced coronary atherosclerosis, myocardial infarction and "sudden death" in swine.</a> Experimental and Molecular Pathology. 15 (2), 170-190 (1971).</li><li>Colbert, C. 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+Swine+Model+of+Selective+Coronary+Stenosis+using+Transcatheter+Delivery+of+a+3D+Printed+Implant:+A+Feasibility+MR+Imaging+Study.">A Swine Model of Selective Coronary Stenosis using Transcatheter Delivery of a 3D Printed Implant: A Feasibility MR Imaging Study.</a> Proceedings of the International Society for Magnetic Resonance in Medicine 27th Scientific Sessions. , (2019).</li><li>Kovacic, 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=GuideLiner+Mother-and-Child+Guide+Catheter+Extension:+A+Simple+Adjunctive+Tool+in+PCI+for+Balloon+Uncrossable+Chronic+Total+Occlusions.">GuideLiner Mother-and-Child Guide Catheter Extension: A Simple Adjunctive Tool in PCI for Balloon Uncrossable Chronic Total Occlusions.</a> Journal of Interventional Cardiology. 26 (4), 343-350 (2013).</li><li>Fabris, E., 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=Guide+Extension,+Unmissable+Tool+in+the+Armamentarium+of+Modern+Interventional+Cardiology.+A+Comprehensive+Review.">Guide Extension, Unmissable Tool in the Armamentarium of Modern Interventional Cardiology. 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C., Ikeno, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+representative+porcine+model+for+human+cardiovascular+disease.">The representative porcine model for human cardiovascular disease.</a> Journal of Biomedical Biotechnology. 2011, 195483 (2010).</li><li>Eldar, 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+closed+chest+pig+model+of+sustained+ventricular+tachycardia.">A closed chest pig model of sustained ventricular tachycardia.</a> Pacing Clinical Electrophysiology. 17, 1603-1609 (1994).</li><li>Reffelmann, 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=A+novel+minimal-invasive+model+of+chronic+myocardial+infarction+in+swine.">A novel minimal-invasive model of chronic myocardial infarction in swine.</a> Coronary Artery Disease. 15 (1), 7-12 (2004).</li><li>Haines, D. 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The authors have nothing to disclose.

In this work, we focused on a novel percutaneous deployment strategy for coronary stenosis-inducing implants and showed that a mother-and-child catheter can be repurposed for effective percutaneous delivery of 3D printed coronary implants. Discrete artificial coronary stenoses of variable severity can be created quickly in swine models with a high success rate and in a minimally invasive manner using standard human percutaneous coronary interventional techniques and equipment. These implants were shown to be safe in the ...

Ischemic heart disease continues to be the number one cause of death in the United States1. Large animal models have been used experimentally to understand and characterize mechanisms driving coronary artery disease (CAD) and associated complications (including myocardial infarction, arrhythmic events, and heart failure), as well as for testing of new therapeutics or diagnostic modalities. Results from these studies have helped to broaden the understanding, diagnosis, and monitoring of ischemic heart disease and to advance clinical practice2. Several animal models including rabbits, dogs, and swine have been used. However, coronary stenoses, particularly discrete lesions, occur very rarely in these animals and are difficult to induce reproducibly3. Prior work described the creation of artificial coronary stenoses using ligation, occluders, or external clamps. Recently, we described how to use 3D printing technology to manufacture coronary implants that can be used to percutaneously create discrete artificial coronary narrowing4. Using computer-aided design software, we designed coronary artery implants as hollow tubes with varying inner and outer diameters as well as implant length and then fabricated them using commercially available additive materials. The implants are smooth, hollow, 3D printed tubes with rounded edges. We designed a library of implant sizes with a range of inner diameter, outer diameter, and length. The outer diameter of the implant is based on the size of the coronary guide catheter. The inner diameter is based on the size of a deflated coronary angioplasty balloon. We varied the length of the implant to tailor the desired severity of perfusion. However, safe percutaneous delivery of such devices can be challenging due to the lack of wires and catheters manufactured specifically for large animal use. In contrast, an extensive collection of catheters, wires, and supportive equipment are available for clinical use in human coronary arteries. In this work, we show how to repurpose a clinical grade mother-and-child coronary guide catheter for the delivery of the 3D printed coronary implants.
The GuideLiner catheter (Figure 1A) was developed for percutaneous coronary intervention (PCI) to allow for deep catheter seating and increased support for complex cases5. In our investigation, the GuideLiner catheter was chosen due to familiarity of use and availability, but similar catheters, where available, may also be considered. Considered a &#34;mother-and-child&#34; guide catheter (Figure 1B), the device fits inside a typical coronary guide catheter (&#34;mother&#34;) and is a coaxial flexible tube (&#34;child&#34;). This catheter can be inserted over a guidewire and effectively lengthens the reach of a typical coronary guide catheter by extending beyond the end of the coronary guide. The GuideLiner or a similar mother-and-child catheter can be used as added support for deployment of the 3D printed coronary implants. Because the implants are mounted over angioplasty balloons to be inserted as a unit over a coronary wire into the vessel (Figure 1B,1C), the catheter offers additional support to deliver the implant to the desired site. By positioning the mother-and-child catheter just proximal to the balloon, the implant remains at the desired location during balloon deflation and retraction. Despite having some firmness to its structure, the mother-and-child catheter&#39;s unique ability to be advanced deep into coronary arteries over a guidewire and the radiopaque marker at the catheter tip were essential characteristics for implantation.
Our assembled delivery apparatus consisted of a typical coronary guide catheter, the mother-and-child catheter, and a 3D printed implant fixed onto a deflated coronary angioplasty balloon (Figure 1B). As a functional delivery unit, the mother-and-child catheter not only provided stable additional support for the delivery of the equipment but was also uniquely applied as a shearing device to keep the implants in place during deflation and removal of the balloon. The radiopaque marker at the catheter tip served as a positioning guide for the assembled apparatus and sits proximal to the angioplasty balloon. These characteristics allowed for precise deployment of the flow-limiting implants. The process was designed to be reproducible, efficient, and humane for the animal subjects.
In our application, the mother-and-child percutaneous delivery technique was used to create swine models with focal coronary stenosis for evaluation of contrast-enhanced stress cardiac perfusion magnetic resonance imaging (MRI). However, the technique may be employed in other investigations including vascular systems outside the coronary vessels.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3D-Printed coronary implants</td>
			<td>Study Site Manufactured</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Amiodarone IV solution</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Amplatz Left-2 (AL-2) guide catheter (8F)</td>
			<td>Boston Scientific, Marlborough, Massachusetts, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Balance Middleweight coronary wire (0.014&#34; 300cm)</td>
			<td>Abbott Laboratories, Abbott Park, Illinois, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>COPILOT Bleedback Control valve</td>
			<td>Abbott Laboratories, Abbott Park, Illinois, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Esmolol IV solution (1 mg/kg)</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Formlabs Form 2 3D-printer with a minimum XY feature size of 150 &#181;m</td>
			<td>Formlabs Inc., Somerville, Massachusetts, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Formlabs Grey Resin (implant material)</td>
			<td>Formlabs Inc., Somerville, Massachusetts, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gadobutrol 0.1 mmol/kg</td>
			<td>Gadvist, Bayer Pharmaceuticals, Wayne, NJ</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>GuideLiner catheter (6F)</td>
			<td>Vascular Solutions Inc., Minneapolis, Minnesota, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin IV solution</td>
			<td>Surface Solutions Laboratories Inc., Carlisle, Massachusetts, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamine IM solution (10 mg/kg)</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lidocaine IV solution</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Male Yorkshire swine (30-45 kg)</td>
			<td>SNS Farms</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Midazolam IV solution</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NC Trek over-the-wire coronary balloon</td>
			<td>Abbott Laboratories, Abbott Park, Illinois, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen-isoflurane 1-2% inhaled mixture</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Rocuronium IV solution</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Pentobarbital IV solution (100mg/kg)</td>
			<td>Study Site Pharmacy</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Triphenyltetrazolium chloride stain</td>
			<td>Institution Pathology Lab</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

After initial optimization of the procedure, the intervention component was completed within 30 min. The implants were successfully delivered in all 11 subjects (100%). The implant was retrieved at the autopsy in all 11 subjects (100%). Using the diagonal branches (along the LAD) or obtuse marginal branches (along the LCX) as positional markers, we found the position of the implant at fluoroscopic-guided deployment and at autopsy to be consistent in 10 of the 11 (91%) subjects where the implant was retrievable. In one su...

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

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 ...

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Research

JoVE Journal

Medicine

6.7K Views.  University of California Los Angeles. 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.

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

Gene Transfer for Ischemic Heart Failure in a Preclinical Model

Various emerging technologies are being developed for patients with heart failure. Well-established preclinical evaluations are necessary to determine their efficacy and safety.
Gene therapy using viral vectors is one of the most promising approaches for treating cardiac diseases. Viral delivery of various different genes by changing the carrier gene has immeasurable therapeutic potential.
In this video, the full process of an animal model of heart failure creation followed by gene transfer is presented using a swine model. First, myocardial infarction is created by occluding the proximal left anterior descending coronary artery. Heart remodeling results in chronic heart failure. Unique to our model is a fairly large scar which truly reflects patients with severe heart failure who require aggressive therapy for positive outcomes. After myocardial infarct creation and development of scar tissue, an intracoronary injection of virus is demonstrated with simultaneous nitroglycerine infusion. Our injection method provides simple and efficient gene transfer with enhanced gene expression. This combination of a myocardial infarct swine model with intracoronary virus delivery has proven to be a consistent and reproducible methodology, which helps not only to test the effect of individual gene, but also compare the efficacy of many genes as therapeutic candidates.

A method of gene transfer for the treatment of ischemic heart failure is described using a swine model of myocardial infarction. Our simple and reproducible method enables us to readily evaluate the efficacy of various gene transfers with a very simple and reproducible way.

Various emerging technologies are being developed for patients with heart failure. Well-established preclinical evaluations are necessary to determine ...

Implantation of Total Artificial Heart in Congenital Heart Disease

In patients with end-stage heart failure (HF), a total artificial heart (TAH) may be implanted as a bridge to cardiac transplant. However, in congenital heart disease (CHD), the malformed heart presents a challenge to TAH implantation. 
In the case presented here, a 17 year-old patient with congenital transposition of the great arteries (CCTGA) experienced progressively worsening HF due to his congenital condition. He was hospitalized multiple times and received an implantable cardioverter defibrillator (ICD). However, his condition soon deteriorated to end-stage HF with multisystem organ failure. 
Due to the patient's grave clinical condition and the presence of complex cardiac lesions, the decision was made to proceed with a TAH. The abnormal arrangement of the patient's ventricles and great arteries required modifications to the TAH during implantation.
With the TAH in place, the patient was able to return home and regain strength and physical well-being while awaiting a donor heart. He was successfully bridged to heart transplantation 5 months after receiving the device. This report highlights the TAH is feasible even in patients with structurally abnormal hearts, with technical modification.

This is a case report of a patient with congenitally corrected transposition of the great arteries (CCTGA) who received a total artificial heart (TAH) as a bridge to heart transplant. The TAH was successfully implanted with modifications to accommodate the patient's congenitally malformed heart.

In patients with end-stage heart failure (HF), a total artificial heart (TAH) may be implanted as a bridge to cardiac transplant. However, in congenital ...

Model of Ischemic Heart Disease and Video-Based Comparison of Cardiomyocyte Contraction Using hiPSC-Derived Cardiomyocytes

Ischemic heart disease is a significant cause of death worldwide. It has therefore been the subject of a tremendous amount of research, often with small-animal models such as rodents. However, the physiology of the human heart differs significantly from that of the rodent heart, underscoring the need for clinically relevant models to study heart disease. Here, we present a protocol to model ischemic heart disease using cardiomyocytes differentiated from human induced pluripotent stem cells (hiPS-CMs) and to quantify the damage and functional impairment of the ischemic cardiomyocytes. Exposure to 2% oxygen without glucose and serum increases the percentage of injured cells, which is indicated by staining of the nucleus with propidium iodide, and decreases cellular viability. These conditions also decrease the contractility of hiPS-CMs as confirmed by displacement vector field analysis of microscopic video images. This protocol may furthermore provide a convenient method for personalized drug screening by facilitating the use of hiPS cells from individual patients. Therefore, this model of ischemic heart disease, based on iPS-CMs of human origin, can provide a useful platform for drug screening and further research on ischemic heart disease.

We present a model of ischemic heart disease using cardiomyocytes derived from human induced pluripotent stem cells, together with a method for quantitative evaluation of tissue damage caused by ischemia. This model can provide a useful platform for drug screening and further research on ischemic heart disease.

Ischemic heart disease is a significant cause of death worldwide. It has therefore been the subject of a tremendous amount of research, often with ...

Development and Evaluation of 3D-Printed Cardiovascular Phantoms for Interventional Planning and Training

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training physicians&#39; wire-skills as well as improving planning of interventional procedures. The aim of this study was to develop a manufacturing process of patient-specific 3D-printed models for cardiovascular interventions.
To create a 3D-printed elastic phantom, different 3D-printing materials were compared to porcine biological tissues (i.e., aortic tissue) in terms of mechanical characteristics. A fitting material was selected based on comparative tensile tests and specific material thicknesses were defined. Anonymized contrast-enhanced CT-datasets were collected retrospectively. Patient-specific volumetric models were extracted from these datasets and subsequently 3D-printed. A pulsatile flow loop was constructed to simulate the intraluminal blood flow during interventions. Models&#39; suitability for clinical imaging was assessed by x-ray imaging, CT, 4D-MRI and (Doppler) ultrasonography. Contrast medium was used to enhance visibility in x-ray-based imaging. Different catheterization techniques were applied to evaluate the 3D-printed phantoms in physicians&#39; training as well as for pre-interventional therapy planning.
Printed models showed a high printing resolution (~30 &#181;m) and mechanical properties of the chosen material were comparable to physiological biomechanics. Physical and digital models showed high anatomical accuracy when compared to the underlying radiological dataset. Printed models were suitable for ultrasonic imaging as well as standard x-rays. Doppler ultrasonography and 4D-MRI displayed flow patterns and landmark characteristics (i.e., turbulence, wall shear stress) matching native data. In a catheter-based laboratory setting, patient-specific phantoms were easy to catheterize. Therapy planning and training of interventional procedures on challenging anatomies (e.g., congenital heart disease (CHD)) was possible.
Flexible patient-specific cardiovascular phantoms were 3D-printed, and the application of common clinical imaging techniques was possible. This new process is ideal as a training tool for catheter-based (electrophysiological) interventions and can be used in patient-specific therapy planning.

Here we present development of a mock circulation setup for multimodal therapy evaluation, pre-interventional planning, and physician-training on cardiovascular anatomies. With the application of patient-specific tomographic scans, this setup is ideal for therapeutic approaches, training, and education in individualized medicine.

Catheter-based interventions are standard treatment options for cardiovascular pathologies. Therefore, patient-specific models could help training ...

Use of a Percutaneous Ventricular Assist Device/Left Atrium to Femoral Artery Bypass System for Cardiogenic Shock

The left atrial to femoral artery bypass (LAFAB) system is a mechanical circulatory support (MCS) device used in cardiogenic shock (CS) that bypasses the left ventricle by draining blood from the left atrium (LA) and returning it to the systemic arterial circulation via the femoral artery. It can provide flows ranging from 2.5-5 L/min depending on the size of the cannula. Here, we discuss the mechanism of action of LAFAB, available clinical data, indications for its use in cardiogenic shock, steps of implantation, post-procedural care, and complications associated with the use of this device and their management.
We also provide a brief video of the procedural component of device therapy, including the pre-placement preparation, percutaneous placement of the device via transseptal puncture under echocardiographic guidance and the post-operative management of device parameters.

The following article describes the stepwise procedure for placement of a device (e.g., Tandemheart) in cardiogenic shock (CS) that is a percutaneous left ventricular assist device (pLVAD) and a left atrial to femoral artery bypass (LAFAB) system that bypasses and supports the left ventricle (LV) in CS.

The left atrial to femoral artery bypass (LAFAB) system is a mechanical circulatory support (MCS) device used in cardiogenic shock (CS) that bypasses the ...

Myocardial Infarction by Percutaneous Embolization Coil Deployment in a Swine Model

Myocardial infarction (MI) is the leading cause of mortality worldwide. Despite the use of evidence-based treatments, including coronary revascularization and cardiovascular drugs, a significant proportion of patients develop pathological left-ventricular remodeling and progressive heart failure following MI. Therefore, new therapeutic options, such as cellular and gene therapies, among others, have been developed to repair and regenerate injured myocardium. In this context, animal models of MI are crucial in exploring the safety and efficacy of these experimental therapies before clinical translation. Large animal models such as swine are preferred over smaller ones due to the high similarity of swine and human hearts in terms of coronary artery anatomy, cardiac kinetics, and the post-MI healing process. Here, we aimed to describe an MI model in pig by permanent coil deployment. Briefly, it comprises a percutaneous selective coronary artery cannulation through retrograde femoral access. Following coronary angiography, the coil is deployed at the target branch under fluoroscopic guidance. Finally, complete occlusion is confirmed by repeated coronary angiography. This approach is feasible, highly reproducible, and emulates the pathogenesis of human non-revascularized MI, avoiding the traditional open-chest surgery and the subsequent postoperative inflammation. Depending on the time of follow-up, the technique is suitable for acute, sub-acute, or chronic MI models.

Myocardial infarction (MI) animal models that emulate the natural process of the disease in humans are crucial to understanding pathophysiological mechanisms and testing the safety and efficacy of new emergent therapies. Here, we describe an MI swine model created by deploying a percutaneous embolization coil.

Myocardial infarction (MI) is the leading cause of mortality worldwide. Despite the use of evidence-based treatments, including coronary revascularization ...

Combining 3D-Printing and Electrospinning to Manufacture Biomimetic Heart Valve Leaflets

Electrospinning has become a widely used technique in cardiovascular tissue engineering as it offers the possibility to create (micro-)fibrous scaffolds with adjustable properties. The aim of this study was to create multilayered scaffolds mimicking the architectural fiber characteristics of human heart valve leaflets using conductive 3D-printed collectors.
Models of aortic valve cusps were created using commercial computer-aided design (CAD) software. Conductive polylactic acid was used to fabricate 3D-printed leaflet templates. These cusp negatives were integrated into a specifically designed, rotating electrospinning mandrel. Three layers of polyurethane were spun onto the collector, mimicking the fiber orientation of human heart valves. Surface and fiber structure was assessed with a scanning electron microscope (SEM). The application of fluorescent dye additionally permitted the microscopic visualization of the multilayered fiber structure. Tensile testing was performed to assess the biomechanical properties of the scaffolds.
3D-printing of essential parts for the electrospinning rig was possible in a short time for a low budget. The aortic valve cusps created following this protocol were three-layered, with a fiber diameter of 4.1 &#177; 1.6 &#181;m. SEM imaging revealed an even distribution of fibers. Fluorescence microscopy revealed individual layers with differently aligned fibers, with each layer precisely reaching the desired fiber configuration. The produced scaffolds showed high tensile strength, especially along the direction of alignment. The printing files for the different collectors are available as Supplemental File 1, Supplemental File 2, Supplemental File 3, Supplemental File 4, and Supplemental File 5.
With a highly specialized setup and workflow protocol, it is possible to mimic tissues with complex fiber structures over multiple layers. Spinning directly on 3D-printed collectors creates considerable flexibility in manufacturing 3D shapes at low production costs.

The presented method offers an innovative way for engineering biomimetic fiber structures in three-dimensional (3D) scaffolds (e.g., heart valve leaflets). 3D-printed, conductive geometries were used to determine shape and dimensions. Fiber orientation and characteristics were individually adjustable for each layer. Multiple samples could be manufactured in one setup.

Electrospinning has become a widely used technique in cardiovascular tissue engineering as it offers the possibility to create (micro-)fibrous scaffolds ...

Fully Endoscopic Mitral Valve Repair with Percutaneous Cannulation of Groin Vessels

Endoscopic mitral valve surgery (EMS) has become a standard of care at specialized heart centers, further reducing surgical trauma compared to a traditional minimally invasive, thoracotomy-based approach. Exposure of the groin vessels for the establishment of cardiopulmonary bypass (CPB) via surgical cutdown in minimally invasive surgery (MIS) may result in wound healing disorders or seroma formation. The avoidance of surgical exposure of the groin vessels by using fully percutaneous techniques for the insertion of a CPB cannula with the implementation of vascular pre-closure devices has the potential to reduce these complications and improve clinical results. Herein, we present the utilization of a novel plug based vacsular closure device with a resobable collagen plug and the absence of suture material for closure of the arterial access for CPB in MIS. While this device was initially predominantly used in transcatheter aortic valve implantation (TAVI) procedures, with its safety and feasibility shown, we herein show that it can be used in CPB cannulation, since it is capable of closing arterial access sites up to 25 French (Fr.) in size. This device may be suitable to significantly reduce groin complications in MIS and simplify the establishment of CPB. Here, we describe the fundamental steps of EMS, including percutaneous groin cannulation and decannulation using a vascular closure device.

This protocol demonstrates in detail how to perform fully endoscopic mitral valve surgery (EMS) with percutaneous cannulation of the groin vessels, using a percutaneous plug-based vascular closure device. Fundamental steps and useful instructions are described in detail for each step.

Endoscopic mitral valve surgery (EMS) has become a standard of care at specialized heart centers, further reducing surgical trauma compared to a ...

Evaluation of Hydration Status by Bioelectrical Impedance Vector Analysis in Patients with Ischemic Heart Disease Undergoing Exercise Stress Test

Ischemic heart disease (IHD) represents a group of clinical syndromes characterized by myocardial ischemia, leading to an impairment in the myocardial blood supply and compromised perfusion. Several clinical variables assessed through a stress test, such as oxygen uptake (VO2) and heart rate oxygen pulse (HR/O2), have been attributed as cardiopulmonary prognostic factors in patients with IHD. However, other factors like hydration status (HS), potentially affecting the cardiopulmonary response, have been barely addressed. Unbalanced HS has a short-term effect on plasma volume and the sympathetic nervous system, which impacts blood volume, and lowers VO2 and HR/O2. Recently, bioelectrical impedance analysis (BIA), a method based on the opposition of body tissues (including fluid volume) to a low electrical current, has been widely used to assess HS by obtaining two components: resistance (R) and reactance (Xc) and using prediction formulas. However, several limitations as chronic illness or abnormal fluid status, may affect the results. In this sense, alternative BIA methods, such as bioelectrical impedance vector analysis (BIVA), have become relevant. R and Xc (adjusted by height) result in a vector plotted on the R/Xc graph, which allows interpreting the HS as normal or abnormal according to the distance of the mean vector. This study aims to describe how to determine HS by BIVA using a single-frequency device and compare the results with the cardiopulmonary response in patients with IHD.

Hydration status imbalances can have a short-term effect on direct and indirect determinants of oxygen uptake and pulse, and morbidity and mortality prognostic factors in ischemic heart disease. This protocol describes the technique for assessment of hydration status through bioelectrical impedance vector analysis and cardiopulmonary response during exercise stress test.

Ischemic heart disease (IHD) represents a group of clinical syndromes characterized by myocardial ischemia, leading to an impairment in the myocardial ...

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 ...