Name: invasive hemodynamic assessment for the right ventricular system and hypoxia-induced pulmonary arterial hypertension in mice
Uploaded: 2019-10-24T13:30:00
Description: Watch this Scientific Journal Video about Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice at JoVE.com

This research is supported by the Postgraduate Education and Teaching Reform Project of Peking Union Medical College (10023-2016-002-03), the Fuwai Hospital Youth Fund (2018-F09), and the Director Fund of Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials (2018-PT2-ZR05).

The animal protocol was reviewed and approved by the Institutional Animal Care and Use Committee at Fuwai Hospital, Chinese Academy of Medical Science, Peking Union Medical College (NO.0000287). The experimental animals were housed and fed according to the guidelines of animal welfare in China.
NOTE: Eight- to 12-week-old male C57BL mice were housed in an environment with a 12 h dark/ 12 h light cycle. The PAH mice were housed for 4 weeks under an oxygen concentration of 10%, maintained by an ...

<ol>
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Tracheal intubation is the first important step for open-chest surgeries. The classic method of tracheal intubation for small animals, such as rats or mice, involves making a T-shaped incision on the trachea and directly inserting Y-type tracheal tubing into the trachea. In practice, we find that this method is not easy during operation. The Y-type tracheal tubing is too large for small animals and forms an angle with the trachea. Thus, it is difficult to fix the tubing in place. Additionally, once the intubation tubing ...

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder with elevation in pulmonary artery pressure (PAP) and right ventricular pressure (RVP) that is caused by cellular proliferation and fibrosis of small pulmonary arteries1. Pulmonary artery catheters, also called Swan-Ganz catheters2, are commonly used in the clinical monitoring of RVP and PAP. Furthermore, a wireless PAP monitoring system has been used clinically3,4,5. To mimic the disease for study in mice, a hypoxic environment is used to simulate human clinical manifestations of PAH6. In the evaluation of PAP in animals, large animals are relatively easy to monitor through pulmonary artery catheters using the same technique as for human subjects, but small animals such as rats and mice are difficult to assess because of their small body size. Hemodynamic measurement of the right ventricular system in mice is possible with an ultrasmall size 1 Fr catheter7. A method for measuring RVP and PAP in mice has been reported in the literature8,9, but the methodology lacks a detailed description. RVP and PAP are more challenging to measure than left ventricular pressure because of the anatomical differences between the left and right heart systems.
To get both PAP and RVP parameters in the same mouse, we describe an open-chest surgery-based approach for right heart hemodynamic measurements, its validation with healthy and PAH mice, and how to avoid generating artificial data during the complicated open-chest surgery. Although this technique is best performed by a well-trained surgeon, it has the advantage of being able to assess PAP and RVP in the same mouse.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">2,2,2-Tribromoethanol</td>
			<td style="width:192px;">Sigma-Aldrich</td>
			<td style="width:157px;">T48402-5G</td>
			<td style="width:183px;">For anesthesia</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Animal temperature controller</td>
			<td style="width:192px;">Physitemp Instruments, Inc.</td>
			<td style="width:157px;">TCAT-2LV</td>
			<td style="width:183px;">For temperature control</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Dissection forceps</td>
			<td style="width:192px;">Fine Science Tools, Inc.</td>
			<td style="width:157px;">11274-20</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Gemini Cautery System</td>
			<td style="width:192px;">Gemini</td>
			<td style="width:157px;">GEM 5917</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Intravenous catheter (22G)</td>
			<td style="width:192px;">BD angiocath</td>
			<td style="width:157px;">381123</td>
			<td style="width:183px;">For intubation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">LabChart 7.3</td>
			<td style="width:192px;">ADInstruments</td>
			<td style="width:157px;"></td>
			<td style="width:183px;">For data analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Light illumination system</td>
			<td style="width:192px;">Olympus</td>
			<td style="width:157px;"></td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Mikro-Tip catheter</td>
			<td style="width:192px;">Millar Instruments, Houston, TX</td>
			<td style="width:157px;">SPR-1000</td>
			<td style="width:183px;">For pressure measurement</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Millar Pressure-Volume Systems</td>
			<td style="width:192px;">Millar Instruments, Houston, TX</td>
			<td style="width:157px;">MVPS-300</td>
			<td style="width:183px;">For pressure measurement</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">O2 Controller and Hypoxia chamber</td>
			<td style="width:192px;">Biospherix</td>
			<td style="width:157px;">ProOx 110</td>
			<td style="width:183px;">For chronic hypoxia</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">PowerLab Data Acquisition System</td>
			<td style="width:192px;">ADInstruments</td>
			<td style="width:157px;">PowerLab 16/30</td>
			<td style="width:183px;">For data recording</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Scissors</td>
			<td style="width:192px;">Fine Science Tools, Inc.</td>
			<td style="width:157px;">14084-08</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Small animal ventilator</td>
			<td style="width:192px;">Harvard Apparatus</td>
			<td style="width:157px;">Mini-Vent 845</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Stereomicroscope</td>
			<td style="width:192px;">Olympus</td>
			<td style="width:157px;">SZ61</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Surgery tape</td>
			<td style="width:192px;">3M</td>
			<td style="width:157px;"></td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Terg-a-zyme enzyme</td>
			<td style="width:192px;">Sigma-Aldrich</td>
			<td style="width:157px;">Z273287-1EA</td>
			<td style="width:183px;">For catheter cleaning</td>
		</tr>
	</tbody>
</table>

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.

The pressure transducer catheter was inserted into the right ventricle (Figure 3A) through a tunnel expanded by a 25 G needle, and a typical RVP waveform (Figure 3C) was obtained. The catheter was continually adjusted and slowly advanced and kept in the same axis as the pulmonary artery while passing through the pulmonary valve (Figure 3B). When the pressure sensor was successfully ...

Watch this Scientific Journal Video about Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice at JoVE.com

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

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. ...

This protocol is an open chest surgery based hemodynamic assessment and it is useful for the right ventricular and pulmonary artery pressure evaluation in small animals such as mice. The advantage of this procedure is that it can generate both VP and PAP parameters at the same time. So it is preferable for evaluations of PAH models.Begin by setting up the equipment for surgery. Soak the pressure transducer catheter in 0.9%saline at room temperature for at least 30 minutes before the hemodynamic experiment. Then, connect the catheter to a pressure volume system.Calibrate the pressure transducer by turning the calibration knob to zero and 25 millimeters of mercury to send a verification pressure signal to the data acquisition software, then configure the calibration setting. Turn the knob to transducer, and adjust the balance valve to zero baseline. Set up a standard stereo microscope, temperature controlled small animal surgical table, and a light illumination system for microsurgery.Once the mouse is properly anesthetized, remove the chest and neck fur using a shaver and hair removal lotion. Secure the mouse in the supine position on the temperature controlled surgical table. After ensuring that the anesthesia is in effect, make a midline incision on the neck skin.Dissect the skeletal muscle using curved forceps and expose the trachea. Perform intubation through the mouth with a 22 gauge intravenous sheath catheter, confirming that the tubing is in the trachea with forceps. Connect the tubing to a small animal ventilator and secure it for ventilation using tape.Then, make a midline incision on the chest skin and carefully dissect the chest muscle using a cautery tool. Cut the sternum using scissors across the middle, and expose the thoracic cavity. Make sure to prevent any bleeding using the cautery tool.Expose the right ventricle with retractors, then insert the saline soaked pressure transducer catheter through a small tunnel created with a 25 gauge needle into the right ventricle to measure right ventricular pressure, or RVP. Hold the catheter cable and cross the pulmonary valve in a coaxial manner with the pulmonary artery. Observe the pressure waveform, and obtain a stable pulmonary artery pressure or PAP signal.Next, record the hemodynamic data using the data acquisition software. Carefully remove the catheter from the right heart system and place it into a one milliliter syringe containing 1%digestive enzyme solution. This protocol was successfully used to obtain RVP and PAP waveforms in mice by inserting a pressure transducer catheter into the right ventricle and the pulmonary artery.In order to avoid generating artificial data, segments with noise were excluded from the data analysis and corrections were made if the zero level of the catheter had drifted. RVP and PAP were measured in mice with induced chronic hypoxia, and the results were compared to those obtained from a control group. Systolic PAP, diastolic PAP, mean PAP, and right ventricular systolic pressure were all significantly increased in the chronic hypoxia group.The most important thing to remember is to insert the pressure transducer catheter into the right ventricle carefully, making sure to avoid damage to the catheter and confirm the smooth RVP waveform appears on the screen.

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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 ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

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. ...

Hemodynamic Characterization of Rodent Models of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle proliferation and obliteration of pulmonary arterioles. This in turn results in right ventricular (RV) failure, with significant morbidity and mortality. Rodent models of PAH, in the mouse and the rat, are important for understanding the pathophysiology underlying this rare disease. Notably, different models of PAH may be associated with different degrees of pulmonary hypertension, RV hypertrophy and RV failure. Therefore, a complete hemodynamic characterization of mice and rats with PAH is critical in determining the effects of drugs or genetic modifications on the disease. 
Here we demonstrate standard procedures for assessment of right ventricular function and hemodynamics in both rat and mouse PAH models. Echocardiography is useful in determining RV function in rats, although obtaining standard views of the right ventricle is challenging in the awake mouse. Access for right heart catheterization is obtained by the internal jugular vein in closed-chest mice and rats. Pressures can be measured using polyethylene tubing with a fluid pressure transducer or a miniature micromanometer pressure catheter. Pressure-volume loop analysis can be performed in the open chest. After obtaining hemodynamics, the rodent is euthanized. The heart can be dissected to separate the RV free wall from the left ventricle (LV) and septum, allowing an assessment of RV hypertrophy using the Fulton index (RV/(LV+S)). Then samples can be harvested from the heart, lungs and other tissues as needed.

Pulmonary arterial hypertension (PAH) is a disease of pulmonary arterioles that leads to their obliteration and the development of right ventricular failure. Rodent models of PAH are critical in understanding the pathophysiology of PAH. Here we demonstrate hemodynamic characterization, with right heart catheterization and echocardiography, in the mouse and rat.

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle ...

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 ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

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 ...

Echocardiographic Measurement of Right Ventricular Diastolic Parameters in Mouse

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling associated with conditions of pressure overload. However, the RV diastolic function is rarely quantified in experimental studies. This might be due to technical difficulties in the visualization of the RV in the apical four-chamber view in rodents. Here we describe two positions facilitating the visualization of the apical four-chamber view in mice to assess the RV diastolic function.
The apical four-chamber view is enabled by tilting the mouse fixation platform to the left and caudally (LeCa) or to the right and cranially (RiCr). Both positions provide images of comparable quality. The results of the RV diastolic function obtained from two positions are not significantly different. Both positions are comparably easy to perform. This protocol can be incorporated into published protocols and enables detailed investigations of the RV function.

Here we describe and compare two positions for obtaining the apical four-chamber view in mice. These positions enable the quantification of the right ventricular function, provide comparable results, and can be used interchangeably.

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling associated with conditions of pressure overload. However, the RV ...

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 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.

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 ...