Name: induction and phenotyping of acute right heart failure in a large animal model of chronic thromboembolic pulmonary hypertension
Uploaded: 2022-03-17T13:00:00
Description: Watch this Scientific Journal Video about Induction and Phenotyping of Acute Right Heart Failure in a Large Animal Model of Chronic Thromboembolic Pulmonary Hypertension at JoVE.com

This work is supported by a public grant overseen by the French National Research Agency (ANR) as part of the&#160;Investissements d&#39;Avenir Program (reference: ANR-15RHUS0002).

The study complied with the principles of laboratory animal care according to the National Society for Medical Research and was approved by the local ethic committee for animal experiments at Hospital Marie Lannelongue.
1. Chronic thromboembolic PH
<ol>
	<li>Induce chronic thromboembolic PH as previously described6,12.</li>
	<li>Briefly, induce a model of chronic thrombo-embolic PH in around 20 kg large white pigs (sus scrofa</em...

<ol>
	<li>Harjola, V. 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=Contemporary+management+of+acute+right+ventricular+failure:+a+statement+from+the+Heart+Failure+Association+and+the+Working+Group+on+Pulmonary+Circulation+and+Right+Ventricular+Function+of+the+European+Society+of+Cardiology.">Contemporary management of acute right ventricular failure: a statement from the Heart Failure Association and the Working Group on Pulmonary Circulation and Right Ventricular Function of the European Society of Cardiology.</a> European Journal of Heart Failure. 18 (3), 226-241 (2016).</li><li>Haddad, F., 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=Characteristics+and+outcome+after+hospitalization+for+acute+right+heart+failure+in+patients+with+pulmonary+arterial+hypertension.">Characteristics and outcome after hospitalization for acute right heart failure in patients with pulmonary arterial hypertension.</a> Circulation: Heart Failure. 4 (6), 692-699 (2011).</li><li>Sztrymf, B., 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=Prognostic+factors+of+acute+heart+failure+in+patients+with+pulmonary+arterial+hypertension.">Prognostic factors of acute heart failure in patients with pulmonary arterial hypertension.</a> European Respiratory Journal. 35 (6), 1286-1293 (2010).</li><li>Huynh, T. N., Weigt, S. S., Sugar, C. A., Shapiro, S., Kleerup, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+factors+and+outcomes+of+patients+with+pulmonary+hypertension+admitted+to+the+intensive+care+unit.">Prognostic factors and outcomes of patients with pulmonary hypertension admitted to the intensive care unit.</a> Journal of Critical Care. 27 (6), 739 (2012).</li><li>Boulate, D., 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=Early+Development+of+Right+Ventricular+Ischemic+Lesions+in+a+Novel+Large+Animal+Model+of+Acute+Right+Heart+Failure+in+Chronic+Thromboembolic+Pulmonary+Hypertension.">Early Development of Right Ventricular Ischemic Lesions in a Novel Large Animal Model of Acute Right Heart Failure in Chronic Thromboembolic Pulmonary Hypertension.</a> Journal of Cardiac Failure. 23 (12), 876-886 (2017).</li><li>Noly, P. 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=Chronic+Thromboembolic+Pulmonary+Hypertension+and+Assessment+of+Right+Ventricular+Function+in+the+Piglet.">Chronic Thromboembolic Pulmonary Hypertension and Assessment of Right Ventricular Function in the Piglet.</a> Journal of Visualized Experiments. (105), e53133 (2015).</li><li>Kerbaul, F., 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=Effects+of+levosimendan+versus+dobutamine+on+pressure+load-induced+right+ventricular+failure.">Effects of levosimendan versus dobutamine on pressure load-induced right ventricular failure.</a> Critical Care Medicine. 34 (11), 2814-2819 (2006).</li><li>Ratliff, N., Peter, R., Ramo, B., Somers, W., Morris, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model+for+the+production+of+right+ventricular+infarction.">A model for the production of right ventricular infarction.</a> The American journal of pathology. 58 (3), 471 (1970).</li><li>Ballard-Croft, C., Wang, D., Sumpter, L. R., Zhou, X., Zwischenberger, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-animal+models+of+acute+respiratory+distress+syndrome.">Large-animal models of acute respiratory distress syndrome.</a> The Annals of Thoracic Surgery. 93 (4), 1331-1339 (2012).</li><li>Dixon, J. A., Spinale, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large+animal+models+of+heart+failure:+a+critical+link+in+the+translation+of+basic+science+to+clinical+practice.">Large animal models of heart failure: a critical link in the translation of basic science to clinical practice.</a> Circulation: Heart Failure. 2 (3), 262-271 (2009).</li><li>Letsou, G. V., 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=Improved+left+ventricular+unloading+and+circulatory+support+with+synchronized+pulsatile+left+ventricular+assistance+compared+with+continuous-flow+left+ventricular+assistance+in+an+acute+porcine+left+ventricular+failure+model.">Improved left ventricular unloading and circulatory support with synchronized pulsatile left ventricular assistance compared with continuous-flow left ventricular assistance in an acute porcine left ventricular failure model.</a> The Journal of Thoracic and Cardiovascular Surgery. 140 (5), 1181-1188 (2010).</li><li>Mercier, 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=Piglet+model+of+chronic+pulmonary+hypertension.">Piglet model of chronic pulmonary hypertension.</a> Pulmonary Circulation. 3 (4), 908-915 (2013).</li><li>Seldinger, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catheter+replacement+of+the+needle+in+percutaneous+arteriography:+a+new+technique.">Catheter replacement of the needle in percutaneous arteriography: a new technique.</a> Acta Radiologica. (5), 368-376 (1953).</li><li>Lang, R. 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=Recommendations+for+cardiac+chamber+quantification+by+echocardiography+in+adults:+an+update+from+the+American+Society+of+Echocardiography+and+the+European+Association+of+Cardiovascular+Imaging.">Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.</a> European Heart Journal - Cardiovascular Imaging. 16 (3), 233-270 (2015).</li><li>Guihaire, 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=Right+ventricular+reserve+in+a+piglet+model+of+chronic+pulmonary+hypertension.">Right ventricular reserve in a piglet model of chronic pulmonary hypertension.</a> European Respiratory Journal. 45 (3), 709-717 (2015).</li><li>Burkhoff, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure-volume+loops+in+clinical+research:+a+contemporary+view.">Pressure-volume loops in clinical research: a contemporary view.</a> Journal of the American College of Cardiology. 62 (13), 1173-1176 (2013).</li><li>Sagawa, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+end-systolic+pressure-volume+relation+of+the+ventricle:+definition,+modifications+and+clinical+use.">The end-systolic pressure-volume relation of the ventricle: definition, modifications and clinical use.</a> Circulation. 63 (6), 1223-1227 (1981).</li><li>Amsallem, 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=Load+Adaptability+in+Patients+With+Pulmonary+Arterial+Hypertension.">Load Adaptability in Patients With Pulmonary Arterial Hypertension.</a> The American Journal of Cardiology. 120 (5), 874-882 (2017).</li><li>Dandel, M., Knosalla, C., Kemper, D., Stein, J., Hetzer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+right+ventricular+adaptability+to+loading+conditions+can+improve+the+timing+of+listing+to+transplantation+in+patients+with+pulmonary+arterial+hypertension.">Assessment of right ventricular adaptability to loading conditions can improve the timing of listing to transplantation in patients with pulmonary arterial hypertension.</a> The Journal of Heart and Lung Transplantation. 34 (3), 319-328 (2015).</li><li>Vanderpool, R. R., 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=RV-pulmonary+arterial+coupling+predicts+outcome+in+patients+referred+for+pulmonary+hypertension.">RV-pulmonary arterial coupling predicts outcome in patients referred for pulmonary hypertension.</a> Heart. 101 (1), 37-43 (2015).</li><li>Boulate, D., 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> Pulmonary Hypertension. , 241-253 (2016).</li><li>Cheng, H. W., 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=Assessment+of+right+ventricular+structure+and+function+in+mouse+model+of+pulmonary+artery+constriction+by+transthoracic+echocardiography.">Assessment of right ventricular structure and function in mouse model of pulmonary artery constriction by transthoracic echocardiography.</a> Journal of Visualized Experiments. (84), e51041 (2014).</li></ol>

We describe a method to model major pathophysiological features of ARHF on chronic PH in a large animal model including volume and pressure overload and hemodynamic restoration with dobutamine. We also reported how to acquire hemodynamic and imaging data to phenotype the dynamic changes of the right ventricle at each condition created during the protocol. These methods can provide background data to build up future research protocols in the field of ARHF, particularly regarding fluid management and inotropic support....

Acute right heart failure (ARHF) has been recently defined as a rapidly progressive syndrome with systemic congestion resulting from impaired right ventricular (RV) filling and/or reduced RV flow output1. ARHF may occur in several conditions such as left-sided heart failure, acute pulmonary embolism, acute myocardial infarction or pulmonary hypertension (PH). In the case of PH, ARHF onset is associated with a 40% risk of short-term mortality or urgent lung transplantation2,3,4. Here, we describe how to create a large animal model of ARHF in the setting of chronic pulmonary hypertension and how to evaluate the right ventricle using echocardiography and pressure-volume loops.
Pathophysiological features of ARHF include RV pressure overload, volume overload, a decrease in RV output, an increase in central venous pressure and/or a decrease in systemic pressure. In chronic PH, there is an initial increase in RV contractility allowing to preserve cardiac output despite the increase in pulmonary vascular resistance. Therefore, in the context of ARHF on chronic PH, the right ventricle can generate nearly isosystemic pressures, particularly under inotropic support. Taken together, ARHF on chronic PH and hemodynamic restoration with inotropes lead to the development of acute RV ischemic lesions, as recently described in our large animal model5. The increase in inotropes creates an increased energetic demand that may further develop ischemic lesions, and finally lead to the development of end-organ dysfunction and poor clinical outcomes. However, there is no consensus about how to manage patients with ARHF on PH, mainly regarding fluid management, inotropes and the role of extra-corporeal circulatory support. Consequently, a large animal model of acute right heart failure may help to provide pre-clinical data on ARHF clinical management.
As a first step to quantify the response to therapy, simple and reproducible methods to phenotype the right ventricle are needed. To date, there is no consensus about how to better phenotype the RV morphology and function of patients with ARHF. The gold standard method to evaluate RV contractility (i.e., intrinsic capacity to contract) and ventriculo-arterial coupling (i.e., contractility normalized by ventricular afterload; an index of ventricular adaptation) is the analysis of pressure-volume (PV) loops. This method is twice invasive because it requires right heart catheterization and a transient reduction in RV preload using a balloon inserted in the inferior vena cava. In clinical practice, non-invasive and repeatable methods to evaluate the right ventricle are needed. Cardiac magnetic resonance (CMR) is considered as the gold standard for non-invasive evaluation of the right ventricle. In patients with ARHF on chronic PH who are managed in intensive care unit (ICU), the use of CMR may be limited because of the patient&#39;s unstable hemodynamic condition; moreover, repeated CMR evaluations, several times a day, including at night, may be limited because of its cost and limited availability. Conversely, echocardiography allows non-invasive, reproducible and low-cost RV morphology and function evaluations in ICU patients.
Large animal models are ideal to perform preclinical studies focusing on the relationship between invasive hemodynamic parameters and non-invasive parameters. The large white pig anatomy is close to humans. Consequently, most of the echocardiographic parameters described in humans are quantifiable in pigs. Some minor variations exist between human and pig heart that must be taken into account for echocardiographic studies. Pigs present a constitutional dextrocardia and a slightly counterclockwise rotation of the heart axis. As a result, the apical 4-chamber view becomes an apical 5-chamber view and the acoustic window is situated below the xiphoid appendix. Additionally, parasternal long and short axis views acoustic windows are situated on the right side of the sternum.
Here, we describe a novel method to induce ARHF in a large animal model of chronic thromboembolic PH and to restore hemodynamic using dobutamine. We also report RV ischemic lesions present in the model within 2&#8722;3 hours after hemodynamic restoration with dobutamine. Moreover, we describe how to acquire RV PV-loops and echocardiographic RV parameters at each condition providing insights on the dynamic changes in RV morphology and function. As the large animal model of chronic thromboembolic PH and the PV-loop methods were previously described6, these sections will be briefly described. Also, we reported results of echocardiographic evaluations which are deemed potentially difficult in porcine models. We will explain the methods to achieve repeated echocardiographic in the model.
The model of ARHF on chronic PH reported in this study can be used to compare different therapeutic strategies. The methods of RV phenotyping can be used in other large animal models mimicking clinically relevant situations such as acute pulmonary embolism7, RV myocardial infarction8, acute respiratory distress syndrome9 or right heart failure associated with left ventricular failure10 or left ventricular mechanical circulatory support11.

<table border="0" cellpadding="0" cellspacing="0" style="width:911px;" width="910">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:215px;">Radiofocus Introducer II</td>
			<td style="width:123px;">Terumo</td>
			<td style="width:344px;">RS+B80K10MQ</td>
			<td style="width:229px;">catheter sheath</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Equalizer, Occlusion Ballon Catheter</td>
			<td>Boston Scientific</td>
			<td>M001171080</td>
			<td>ballon for inferior vena cava occlusion</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Guidewire</td>
			<td>Terumo</td>
			<td>GR3506</td>
			<td>0.035; angled</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Vigilance monitor</td>
			<td>Edwards</td>
			<td>VGS2V</td>
			<td>Swan-Ganz associated monitor</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Swan-Ganz</td>
			<td>Edwards</td>
			<td>131F7</td>
			<td>Swan-Ganz catheter 7 F; usable lenghth 110 cm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Echocardiograph; Model: Vivid 9</td>
			<td>General Electrics</td>
			<td>GAD000810 and H45561FG</td>
			<td>Echocardiograph</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Probe for echo, M5S-D</td>
			<td>General Electrics</td>
			<td>M5S-D</td>
			<td>Cardiac ultrasound transducer</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">MPVS-ultra Foundation system</td>
			<td>Millar</td>
			<td>PL3516B49</td>
			<td>Pressure-volume loop unit; includes a powerLab16/35, MPVS-Ultra PV Unit, bioamp and bridge amp and cables</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Ventricath 507</td>
			<td>Millar</td>
			<td>VENTRI-CATH-507</td>
			<td>conductance catheter</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Lipiodol ultra-fluid</td>
			<td>Guerbet</td>
			<td>306 216-0</td>
			<td>lipidic contrast dye</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">BD Insyte Autoguard</td>
			<td>Becton, Dickinson and Company</td>
			<td align="right">381847</td>
			<td>IV catheter</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Arcadic Varic</td>
			<td>Siemens</td>
			<td>A91SC-21000-1T-1-7700</td>
			<td>C-arm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Prolene 5.0</td>
			<td>Ethicon</td>
			<td style="width:344px;">F1830</td>
			<td style="width:229px;">polypropilene monofil</td>
		</tr>
	</tbody>
</table>

induction and phenotyping of acute right heart failure in a large animal model of chronic thromboembolic pulmonary hypertension

The development of acute right heart failure (ARHF) in the context of chronic pulmonary hypertension (PH) is associated with poor short-term outcomes. The morphological and functional phenotyping of the right ventricle is of particular importance in the context of hemodynamic compromise in patients with ARHF. Here, we describe a method to induce ARHF in a previously described large animal model of chronic PH, and to phenotype, dynamically, right ventricular function using the gold standard method (i.e., pressure-volume PV loops) and with a non-invasive clinically available method (i.e., echocardiography). Chronic PH is first induced in pigs by left pulmonary artery ligation and right lower lobe embolism with biological glue once a week for 5 weeks. After 16 weeks, ARHF is induced by successive volume loading using saline followed by iterative pulmonary embolism until the ratio of the systolic pulmonary pressure over systemic pressure reaches 0.9 or until the systolic systemic pressure decreases below 90 mmHg. Hemodynamics are restored with dobutamine infusion (from 2.5 &#181;g/kg/min to 7.5 &#181;g/kg/min). PV-loops and echocardiography are performed during each condition. Each condition requires around 40 minutes for induction, hemodynamic stabilization and data acquisition. Out of 9 animals, 2 died immediately after pulmonary embolism and 7 completed the protocol, which illustrates the learning curve of the model. The model induced a 3-fold increase in mean pulmonary artery pressure. The PV-loop analysis showed that ventriculo-arterial coupling was preserved after volume loading, decreased after acute pulmonary embolism and was restored with dobutamine. Echocardiographic acquisitions allowed to quantify right ventricular parameters of morphology and function with good quality. We identified right ventricular ischemic lesions in the model. The model can be used to compare different treatments or to validate non-invasive parameters of right ventricular morphology and function in the context of ARHF.

Feasibility 
We describe the results of 9 consecutive procedures of ARHF induction in a large animal CTEPH model previously reported5. The duration of the protocol was around 6 hours to complete, including anesthesia induction, installation, vascular access/catheter placements, induction of volume/pressure overload and hemodynamic restoration, data acquisitions and euthanasia. Each hemodynamic condition requires around 40 minutes to achieve in...

Watch this Scientific Journal Video about Induction and Phenotyping of Acute Right Heart Failure in a Large Animal Model of Chronic Thromboembolic Pulmonary Hypertension at JoVE.com

Induction and Phenotyping of Acute Right Heart Failure in a Large Animal Model of Chronic Thromboembolic Pulmonary Hypertension

We present a protocol to induce and phenotype an acute right heart failure in a large animal model with chronic pulmonary hypertension. This model can be used to test therapeutic interventions, to develop right heart metrics&#160;or to improve the understanding of acute right heart failure pathophysiology.

The development of acute right heart failure (ARHF) in the context of chronic pulmonary hypertension (PH) is associated with poor short-term outcomes. The ...

This model of acute right heart failure in the context of coronary pulmonary hypertension can help to better understand the pathophysiology of this clinically relevant situation. Induction of acute right heart failure by the mean of volume and pressure overload is easily reproducible and duplicates the main pathophysiological aspects of the corresponding clinical situation. After confirming an appropriate level of sedation, place a central venous catheter through the jugular vein up to the superior vena cava using the Seldinger method.Next, make a four centimeter transverse incision at the groin and insert a Beckman retractor into the incision. Using Debakey forceps and Metzenbaum scissors, divide the anterior face of the femoral vein and artery and place a 20 gauge catheter into the femoral artery. Then connect the catheter to a disposable transducer with a fluid-filled catheter to obtain systemic and central venous blood pressure.Using an 18 gauge catheter and a fluoroscope with a C-arm and an interior-posterior view, insert a guidewire into the femoral vein through the inferior vena cava. Place a balloon dilation catheter over the guidewire at the intrapericardial level and place the visible markers of the balloon immediately above the diaphragm level. Then remove the guidewire.Immediately after the catheters have been placed, acquire an apical five-chamber view under the xiphoid process in two dimensions and in the tissue Doppler mode. Acquire the parasternal short and long axis views on the right side of the sternum in 2D and tissue Doppler modes and an image of the valvular flow using continuous and pulsed Doppler modes. Then acquire tissue Doppler signals of the lateral tricuspid annulus and the lateral and septal mitral annulus.For catheterization of the right heart, introduce the Swan-Ganz catheter into the jugular 8 French sheath inserted into the jugular vein and acquire the mean right atrial, right ventricular, and pulmonary artery pressures. Next, measure the cardiac output with the thermodilution method according to the manufacturer's instructions while simultaneously measuring the heart rate for the stroke volume calculation. Connect the disposable transducer to the pressure volume loop workstation for live acquisitions of the pressures derived from the fluid-filled catheters and use fluoroscopy to introduce the conductance catheter into the right ventricle.Then verify the quality signal using in live acquisition of the pressure volume loops and acquire pressure volume loop families in the steady state and during acute preload reduction induced by inflating the balloon inserted into the inferior vena cava during end expiratory apnea. To induce acute right heart failure, first use a free flow infusion output to start a 15 milliliters per kilogram saline infusion. Five minutes after hemodynamic stabilization and at the end of each infusion, obtain the right heart catheterism, pressure volume loop, and echocardiographic measurements.Then start the second infusion of 15 milliliters per kilogram of saline immediately after the end of the measurements and start the third infusion of 30 milliliters per kilogram of saline immediately after the end of the second set of measurements. To induce hemodynamic pressure overload, use the fluoroscope to insert a 5 French angiographic catheter through the jugular sheath into the right lower lobe pulmonary artery. Embolize the right lower lobe pulmonary artery with a 150 microliter bolus containing n-butyl-2-cyanoacrylate lipidic contrast dye, washing out the catheter with 10 milliliters of saline once the bolus has been delivered.Two minutes after the embolization, measure the systemic and pulmonary artery pressures to evaluate the hemodynamic response, then repeat the bolus delivery every two minutes until hemodynamic compromise is achieved. After reaching hemodynamic compromise, acquire pressure volume loop and echocardiographic measurements before starting a dobutamine infusion at 2.5 micrograms per kilogram per minute. Wait 10-15 minutes for hemodynamic stabilization before performing right heart catheterization, pressure volume loop, and echocardiographic measurements.When all of the measurements have been acquired, increase the dobutamine infusion dose to five micrograms per kilogram per minute and repeat the right heart catheterization, pressure volume loop, and echocardiographic measurements once hemodynamic stabilization has been achieved as just demonstrated. Then increase the dobutamine infusion dose to 7.5 micrograms per kilogram per minute. Acute volume loading does not induce acute right heart failure, but rather highlights the adaptive phenotype of the chronic pulmonary hypertension model.With volume loading, the cardiac output increases without an increase in the right atrial pressure and with ventriculo-arterial coupling remaining stable. Hemodynamic compromise is associated with a significant decrease in cardiac output, stroke volume, and ventriculo-arterial coupling, whereas right ventricle contractility remained stable. A twofold increase in the right atrial pressure and mean pulmonary artery pressure are also typically observed.Dobutamine delivery as demonstrated restores cardiac output, stroke volume, and ventriculo-arterial coupling within the normal range. Echocardiography can be used to quantify dynamic changes in right ventricle size and function throughout the experiment. Pressure volume loop analysis allows the dynamic quantification of right ventricle end-systolic elastins and ventriculo-arterial coupling.In this representative study, the two deaths that occurred immediately after acute pulmonary embolism were associated with acute thrombosis of the right heart cavities. After hematoxylin eosin and saffron staining, right ventricular ischemic lesions characterized by clusters of hypereosinophilic cardiomyositis with pyknotic nuclei can be observed in the sub-endocardial and sub-pericardial layers of the right ventricle free wall. The magnitude of acute volume and pressure overload required to induce acute right heart failure phenotype of the right ventricle in the context of pulmonary hypertension.Hemodynamic restoration could be used by drugs or intervention in order to determine the best therapeutic option.

induction-phenotyping-acute-right-heart-failure-large-animal-model

Research

JoVE Journal

Medicine

Echocardiographic Assessment of the Right Heart in Mice

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential therapies. Given the expense and time involved in creating animal models of disease, it is critical that researchers have tools to accurately assess phenotypic expression of disease. Right ventricular dysfunction is the major manifestation of pulmonary hypertension. Echocardiography is the mainstay of the noninvasive assessment of right ventricular function in rodent models and has the advantage of clear translation to humans in whom the same tool is used. Published echocardiography protocols in murine models of PAH are lacking.
In this article, we describe a protocol for assessing RV and pulmonary vascular function in a mouse model of PAH with a dominant negative BMPRII mutation; however, this protocol is applicable to any diseases affecting the pulmonary vasculature or right heart. We provide a detailed description of animal preparation, image acquisition and hemodynamic calculation of stroke volume, cardiac output and an estimate of pulmonary artery pressure.

This article provides a protocol for the echocardiographic assessment of right ventricular size and pulmonary hypertension in mice. Applications include phenotype determination and serial assessment in transgenic and toxin-induced mouse models of cardiomyopathy and pulmonary vascular disease.

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential ...

An Isolated Working Heart System for Large Animal Models

Since its introduction in the late 19th century, the Langendorff isolated heart perfusion apparatus, and the subsequent development of the working heart model, have been invaluable tools for studying cardiovascular function and disease1-15. Although the Langendorff heart preparation can be used for any mammalian heart, most studies involving this apparatus use small animal models (e.g., mouse, rat, and rabbit) due to the increased complexity of systems for larger mammals1,3,11. One major difficulty is ensuring a constant coronary perfusion pressure over a range of different heart sizes &#8211; a key component of any experiment utilizing this device1,11. By replacing the classic hydrostatic afterload column with a centrifugal pump, the Langendorff working heart apparatus described below allows for easy adjustment and tight regulation of perfusion pressures, meaning the same set-up can be used for various species or heart sizes. Furthermore, this configuration can also seamlessly switch between constant pressure or constant flow during reperfusion, depending on the user&#8217;s preferences. The open nature of this setup, despite making temperature regulation more difficult than other designs, allows for easy collection of effluent and ventricular pressure-volume data.

Most studies involving the Langendorff apparatus use small animal models due to the increased complexity of systems for larger mammals. We describe a Langendorff system for large animal models that allows for use across a range of species, including humans, and relatively easy data acquisition.

Since its introduction in the late 19th century, the Langendorff isolated heart perfusion apparatus, and the subsequent development of the working heart ...

Chronic Thromboembolic Pulmonary Hypertension and Assessment of Right Ventricular Function in the Piglet

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. Pulmonary Hypertension (PH) was induced in 3-week-old piglets by a progressive obstruction of the pulmonary vascular bed. A ligation of the left Pulmonary Artery (PA) was performed first through a mini-thoracotomy. Second, weekly embolizations of the right lower pulmonary lobe were done under fluoroscopic guidance with n-butyl-2-cyanoacrylate during 5 weeks. Mean Pulmonary Arterial Pressure (mPAP) measured by ritght heart catheterism, increased progressively, as well as Right Atrial pressure and Pulmonary Vascular Resistances (PVR) after 5 weeks compared to sham animals. Right Ventricular (RV) structural and functional remodeling were assessed by transthoracic echocardiography (RV diameters, RV wall thickness, RV systolic function). RV elastance and RV-pulmonary coupling were assessed by Pressure-Volume Loops (PVL) analysis with conductance method. Histologic study of the lung and the right ventricle were also performed. Molecular analyses on RV fresh tissues could be performed through repeated transcutaneous endomyocardial biopsies. Pulmonary microvascular disease in obstructed and unobstructed territories was studied from lung biopsies using molecular analyses and pathology. Furthermore, the reliability and the reproducibility was associated with a range of PH severity in animals. Most aspects of the human CTEPH disease were reproduced in this model, which allows new perspectives for the understanding of the underlying mechanisms (mitochondria, inflammation) and new therapeutic approaches (targeted, cellular or gene therapies) of the overloaded right ventricle but also pulmonary microvascular disease.

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) and Right Ventricular (RV) dysfunction were induced in piglets by progressive obstruction of the pulmonary arteries. Consequences were remarkably similar to those observed in CTEPH patients. This animal model would be a very useful tool for pathophysiology and therapeutic experiments on CTEPH and RV failure.

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. ...

Shunt Surgery, Right Heart Catheterization, and Vascular Morphometry in a Rat Model for Flow-induced Pulmonary Arterial Hypertension

In this protocol, PAH is induced by combining a 60 mg/kg monocrotalin (MCT) injection with increased pulmonary blood flow through an aorto-caval shunt (MCT+Flow). The shunt is created by inserting an 18-G needle from the abdominal aorta into the adjacent caval vein. Increased pulmonary flow has been demonstrated as an essential trigger for a severe form of PAH with distinct phases of disease progression, characterized by early medial hypertrophy followed by neointimal lesions and the progressive occlusion of the small pulmonary vessels. To measure the right heart and pulmonary hemodynamics in this model, right heart catheterization is performed by inserting a rigid cannula containing a flexible ball-tip catheter via the right jugular vein into the right ventricle. The catheter is then advanced into the main and the more distal pulmonary arteries. The histopathology of the pulmonary vasculature is assessed qualitatively, by scoring the pre- and intra-acinar vessels on the degree of muscularization and the presence of a neointima, and quantitatively, by measuring the wall thickness, the wall-lumen ratios, and the occlusion score.

This protocol describes a surgical procedure to create a model for flow-induced pulmonary arterial hypertension (PAH) in rats and the procedures to analyze the principle hemodynamic and histological end-points in this model.

In this protocol, PAH is induced by combining a 60 mg/kg monocrotalin (MCT) injection with increased pulmonary blood flow through an aorto-caval shunt ...

A Chronic Cardiac Ischemia Model in Swine Using an Ameroid Constrictor

Cardiovascular disease remains the number one cause of mortality in the United States. There are numerous approaches to treating these diseases, but regardless of the approach, an in vivo model is needed to test each treatment. The pig is one of the most used large animal models for cardiovascular disease. Its heart is very similar in anatomy and function to that of a human. The ameroid placement technique creates an ischemic area of the heart, which has many useful applications in studying myocardial infarction. This model has been used for surgical research, pharmaceutical studies, imaging techniques, and cell therapies.
There are several ways of inducing an ischemic area in the heart. Each has its advantages and disadvantages, but the placement of an ameroid constrictor remains the most widely used technique. The main advantages to using the ameroid are its prevalence in existing research, its availability in various sizes to accommodate the anatomy and size of the vessel to be constricted, the surgery is a relatively simple procedure, and the post-operative monitoring is minimal, since there are no external devices to maintain. This paper provides a detailed overview of the proper technique for the placement of the ameroid constrictor.

The purpose of this protocol is to demonstrate the placement of a delayed constricting device (an ameroid constrictor) around a coronary artery in a swine model. This device creates an ischemic area of the heart that is useful for studying new diagnostic imaging techniques and new methods of treatment.

Cardiovascular disease remains the number one cause of mortality in the United States. There are numerous approaches to treating these diseases, but ...

Tachycardia-Induced Cardiomyopathy As a Chronic Heart Failure Model in Swine

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment methods. Here, we present such a model by tachycardia-induced cardiomyopathy, which can be produced by rapid cardiac pacing in swine.
A single pacing lead is introduced transvenously into fully anaesthetized healthy swine, to the apex of the right ventricle, and fixated. Its other end is then tunneled dorsally to the paravertebral region. There, it is connected to an in-house modified heart pacemaker unit that is then implanted in a subcutaneous pocket. 
After 4 - 8 weeks of rapid ventricular pacing at rates of 200 - 240 beats/min, physical examination revealed signs of severe heart failure - tachypnea, spontaneous sinus tachycardia, and fatigue. Echocardiography and X-ray showed dilation of all heart chambers, effusions, and severe systolic dysfunction. These findings correspond well to decompensated dilated cardiomyopathy and are also preserved after the cessation of pacing.
This model of tachycardia-induced cardiomyopathy can be used for studying the pathophysiology of progressive chronic heart failure, especially hemodynamic changes caused by new treatment modalities like mechanical circulatory supports. This methodology is easy to perform and the results are robust and reproducible.

Here, we present a protocol to produce tachycardia-induced cardiomyopathy in swine. This model represents a potent way to study the hemodynamics of progressive chronic heart failure and the effects of applied treatment.

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment ...

Invasive Hemodynamic Monitoring of Aortic and Pulmonary Artery Hemodynamics in a Large Animal Model of ARDS

One of the leading causes of morbidity and mortality in patients with heart failure is right ventricular (RV) dysfunction, especially if it is due to pulmonary hypertension. For a better understanding and treatment of this disease, precise hemodynamic monitoring of left and right ventricular parameters is important. For this reason, it is essential to establish experimental pig models of cardiac hemodynamics and measurements for research purpose. 
This article shows the induction of ARDS by using oleic acid (OA) and consequent right ventricular dysfunction, as well as the instrumentation of the pigs and the data acquisition process that is needed to assess hemodynamic parameters. To achieve right ventricular dysfunction, we used oleic acid (OA) to cause ARDS and accompanied this with pulmonary artery hypertension (PAH). With this model of PAH and consecutive right ventricular dysfunction, many hemodynamic parameters can be measured, and right ventricular volume load can be detected. 
All vital parameters, including respiratory rate (RR), heart rate (HR) and body temperature were recorded throughout the whole experiment. Hemodynamic parameters including femoral artery pressure (FAP), aortic pressure (AP), right ventricular pressure (peak systolic, end systolic and end diastolic right ventricular pressure), central venous pressure (CVP), pulmonary artery pressure (PAP) and left arterial pressure (LAP) were measured as well as perfusion parameters including ascending aortic flow (AAF) and pulmonary artery flow (PAF). Hemodynamic measurements were performed using transcardiopulmonary thermodilution to provide cardiac output (CO). Furthermore, the PiCCO2 system (Pulse Contour Cardiac Output System 2) was used to receive parameters such as stroke volume variance (SVV), pulse pressure variance (PPV), as well as extravascular lung water (EVLW) and global end-diastolic volume (GEDV). Our monitoring procedure is suitable for detecting right ventricular dysfunction and monitoring hemodynamic findings before and after volume administration.

We present a protocol of creating right ventricular dysfunction in a pig model by inducing ARDS. We demonstrate invasive monitoring of left and right ventricular cardiac output using flow probes around the aorta and the pulmonary artery, as well as blood pressure measurements in the aorta and pulmonary artery.

One of the leading causes of morbidity and mortality in patients with heart failure is right ventricular (RV) dysfunction, especially if it is due to ...

A Pulmonary Trunk Banding Model of Pressure Overload Induced Right Ventricular Hypertrophy and Failure

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary disorders. Reliable and reproducible animal models of RV failure are therefore warranted in order to investigate disease mechanisms and effects of potential therapeutic strategies. Banding of the pulmonary trunk is a common method to induce isolated RV hypertrophy but in general, previously described models have not succeeded in creating a stable model of RV hypertrophy and failure.
We present a rat model of pressure overload induced RV hypertrophy caused by pulmonary trunk banding (PTB) that enables different phenotypes of RV hypertrophy with and without RV failure. We use a modified ligating clip applier to compress a titanium clip around the pulmonary trunk to a pre-set inner diameter. We use different clip diameters to induce different stages of disease progression from mild RV hypertrophy to decompensated RV failure.
RV hypertrophy develops consistently in rats subjected to the PTB procedure and depending on the diameter of the applied banding clip, we can accurately reproduce different disease severities ranging from compensated hypertrophy to severe decompensated RV failure with extra-cardiac manifestations.
The presented PTB model is a valid and robust model of pressure overload induced RV hypertrophy and failure that has several advantages to other banding models including high reproducibility and the possibility of inducing severe and decompensated RV failure.

We present a surgical method to induce right ventricular hypertrophy and failure in rats.

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary ...

Induction and Characterization of Pulmonary Hypertension in Mice using the Hypoxia/SU5416 Model

Pulmonary Hypertension (PH) is a pathophysiological condition, defined by a mean pulmonary arterial pressure exceeding 25 mm Hg at rest, as assessed by right heart&#160;catheterization. A broad spectrum of diseases can lead to PH, differing in their etiology, histopathology, clinical presentation, prognosis, and response to&#160;treatment. Despite significant progress in the last years, PH remains an uncured disease. Understanding the underlying mechanisms can pave the way for the development of new therapies. Animal models are important research tools to achieve this goal. Currently, there are several models available for recapitulating PH. This protocol describes a two-hit mouse PH model. The stimuli for PH development are hypoxia and the injection of SU5416, a vascular endothelial growth factor (VEGF) receptor antagonist. Three weeks after initiation of Hypoxia/SU5416, animals develop pulmonary vascular remodeling imitating the histopathological changes observed in human PH (predominantly Group 1). Vascular remodeling in the pulmonary circulation results in the remodeling of the right&#160;ventricle (RV). The procedures for measuring RV pressures (using the open chest method), the morphometrical analyses of the RV (by dissecting and weighing both cardiac ventricles) and the histological assessments of the remodeling (both pulmonary by assessing vascular remodeling and cardiac by assessing RV cardiomyocyte hypertrophy and fibrosis) are described in detail. The advantages of this protocol are the possibility of the application both in wild type and in genetically modified mice, the relatively easy and low-cost implementation, and the quick development of the disease of interest (3 weeks). Limitations of this method are that mice do not develop a severe phenotype and PH is reversible upon return to normoxia. Prevention, as well as therapy studies, can easily be implemented in this model, without the necessity of advanced skills (as opposed to surgical rodent models).

This protocol describes the induction of pulmonary hypertension (PH) in mice based on the exposure to hypoxia and the injection of a VEGF receptor antagonist. The animals develop PH and right ventricular (RV) hypertrophy 3 weeks after the initiation of the protocol. The functional and morphometrical characterization of the model is also presented.

Pulmonary Hypertension (PH) is a pathophysiological condition, defined by a mean pulmonary arterial pressure exceeding 25 mm Hg at rest, as assessed by ...

Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder. Mice are a popular animal model used to mimic this disease. However, the evaluation of right ventricular pressure (RVP) and pulmonary artery pressure (PAP) remains technically challenging in mice. RVP and PAP are more difficult to measure than left ventricular pressure because of the anatomical differences between the left and right heart systems. In this paper, we describe a stable right heart hemodynamic measurement method and its validation using healthy and PAH mice. This method is based on open-chest surgery and mechanical ventilation support. It is a complicated procedure compared to closed chest procedures. While a well-trained surgeon is required for this surgery, the advantage of this procedure is that it can generate both RVP and PAP parameters at the same time, so it is a preferable procedure for the evaluation of PAH models.

Here, we present a protocol to perform an invasive hemodynamic assessment of the right ventricle and pulmonary artery in mice using an open-chest surgery approach.

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder. Mice are a popular animal model used to mimic this disease. ...