This work was supported by the Canadian Institutes of Health Research and Canada Foundation for Innovation grant to V. K. Mushahwar. A. Toossi was supported by a Vanier Canada Graduate Scholarship, Alberta Innovates - Health Solutions Graduate Studentship and a Queen Elizabeth II Graduate Scholarship. V.K. Mushahwar is a Canada Research Chair in Functional Restoration. We would like to acknowledge Mr. J. Stack of Moss Street Productions for his help with the audio production and staff of the Surgical Medical Research Institute for their assistance with the procedures.

All procedures on experimental animals described in both the video and manuscript were approved by the Institutional Animal Care and Use Committee of the University of Alberta
1. Surgical anesthesia and surgical preparation of the pigs.
<ol>
	<li>Premedicate 50 kg Landrace-Yorkshire commercial pigs intramuscularly with the anesthetic drug cocktail containing ketamine hydrochloride (22 mg/kg,), xylazine hydrochloride (2.2 mg/kg) and glycopyrrolate hydrochloride (10 &#181;g/kg).</li>
	<li>Set up all equipment involved with monitoring clinical parameters at the end of the table near the pig&#39;s head. Ensure the equipment will not restrict access to the pig. Produce accurate arterial blood pressure measurement by placing the pressure transducer in a horizontal plane, level with the heart.</li>
	<li>Anesthetize the pigs with inhaled isoflurane gas (4%-5% isoflurane at 500-1000 mL/min O2) using a properly sized face mask. Visualize the vocal cords with a veterinary laryngoscope (17-25 cm long straight blade) and apply topical 10% lidocaine spay to the vocal cords to limit the risk of laryngospasm and airway obstruction.</li>
	<li>Intubate the pigs by inserting a cuffed endotracheal tube (9.0 mm internal diameter (ID)) through the vocal cords and maintain anesthesia with isoflurane gas (0.5%-3.0% isoflurane at 1000-2000 mL/min O2). Ventilate the pig on a mechanical ventilator (18-22 breaths/min) and ensure all expired anesthetic gas is scavenged and vented outside the surgical suite. Assess the level of anesthesia by jaw tone, and both pedal and palpebral reflex responses. 
	NOTE: Administer intravenous Lactated Ringer&#39;s Solution (LRS, 10-50 mL/kg/h; see step 1.6) to enhance hemodynamic function and reduce isoflurane gas anesthesia induced depression of cardiovascular output in swine26.</li>
	<li>Secure a pulse oximeter to the mucosal surface of the tongue with medical tape to monitor heart rate and the saturation of peripheral blood oxygenation (SpO2). Insert a temperature probe approximately 2-4 cm into the nasal cavity to monitor body temperature. Place the pigs on a heated table to maintain normal body temperature (38-40 &#176;C) during the surgical procedure.</li>
	<li>Ensure surgical sterility with proper tissue preparation.
	<ol>
		<li>Clean the external surface of the ear to prepare for venous catheterization with 10% povidone-iodine surgical scrub solution and allow the solution to air dry.</li>
		<li>With a 20 G, 1 inch intravenous catheter, catheterize a marginal ear vein to deliver either intravenous fluids (LRS; 10-50 mL/kg/h) or the addition of other anesthetic agents.</li>
		<li>Enhance pig anesthesia and analgesia if needed for invasive procedures with continuous intravenous remifentanil hydrochloride infusion (0.05-0.14 &#181;g/kg/min).</li>
	</ol>
	</li>
	<li>Place the pig in a lateral recumbent position and gently extend the front leg approximately 10-12 cm away from the shoulder. Clip the hair on the skin surface of the medial aspect of the brachium (upper forelimb). Landmark the distal brachial artery pulse by palpation. 
	NOTE: The landmarked location of the artery lies along an oblique plane with the brachium approximately 9 cm from the olecranon, and 5 cm from the flexor aspect of the elbow joint. The brachial artery travels proximally towards the caudal third of the scapula traversing the humerus.</li>
	<li>Similarly to step 1.6, ensure surgical sterility with proper tissue preparation. Clean the skin surface with 10% povidone-iodine surgical scrub solution and allow the solution to air dry. Drape the brachial artery catheterization site with four small disposable surgical drapes.</li>
</ol>
2. Tissue dissection and catheterization of the brachial artery
<ol>
	<li>Make a 6 cm skin incision with a scalpel blade to expose the underlying tissue. Bluntly dissect with Metzenbaum scissors along the medial surfaces of the biceps brachii, deepening the dissection, until the pulsating artery is identified.</li>
	<li>Use cotton swabs to gently tease away the adventitia from the brachial artery, median nerve and brachial vein; structures that are in close proximity and within the same fascial plane. Gentle dissection is required, importantly ensuring minimal injury to the median nerve during the procedure. The brachial artery lies approximately 2.0-2.5 cm underneath the skin and is medial to coracobrachialis and lateral to the tensor fasciae antibrachii and overlies a small segment of the medial head of the triceps muscle27,28. 
	NOTE: Place a retractor to keep the skin incision open, allowing easier access to the brachial artery. Place a second retractor (optional) to further assist in vessel exposure.</li>
	<li>Moisten all tissues with warm saline (37 &#176;C) for the entire dissection to retain better structural integrity and improved tissue handling during the procedure.</li>
	<li>Create a tunnel under the artery with blunted forceps, then pass three 2-0 polyglactin sutures underneath the artery. Intentionally, leave the ends of this suture relatively long (3-4 cm) to secure the catheter to the artery. Add a &#34;loose suture tie&#34; allowing for quick catheter fastening, to the first two sutures that are separated 1.0 cm from each other and are approximately 1.5-2.0 cm proximal to the third distal suture. Ligate the most distal suture first to occlude the artery.</li>
	<li>Insert a 22 G, 1 inch peripheral venous catheter into the artery and then advance the catheter (completely to the catheter hub) off the stylet into the vessel. Partially withdraw the stylet from the catheter to visualize arterial blood, ensuring proper vessel placement of the catheter. Then, firmly secure the catheter in the vessel by tying the middle suture. Remove the stylet and quickly cap the catheter to minimize bleeding.</li>
	<li>Flush the incision and catheter with warm saline (37 &#176;C). Tie the most proximal suture and importantly ensure that the distal suture is tightly secured around the catheter hub as this improves catheter stability and reduces accidental slippage of the catheter from the artery (i.e., during pig repositioning). 
	NOTE: If the initial placement of the catheter into the artery fails, or the vessel is injured, reinsert the catheter into the artery at a position approximately 0.25 cm proximal to the initial catheter insertion site.</li>
	<li>Quickly attach the LRS filled intravenous extension line with the connected arterial pressure transducer to the catheter, and then lavage the surgical site with warm saline (37 &#176;C), keeping tissues moist, and clean any blood that spilled into the surrounding tissue. Flush the catheter with saline to ensure catheter patency and prevent blood clots from forming along the catheter wall. 
	NOTE: Check for transducer arterial blood pressure line failures (i.e., leaks), establish transducer baseline by zeroing arterial pressure monitor measurements, and ensure proper arterial blood pressure wave formations.</li>
	<li>Ensure continued catheter patency by maintaining the flush port of the extension line pressurized above 250 mmHg, with a pressure infuser bag delivering 3-5 mL/min LRS.
	<ol>
		<li>Optional: Place either two 2-0 polypropylene or two 2-0 polyglactin sutures around the catheter hub or intravenous extension line hub to further improve catheter stability within the artery.</li>
	</ol>
	</li>
</ol>
3. Tissue closure and body positioning
<ol>
	<li>Close the muscle layers with a simple continuous suture pattern with a 2-0 polyglactin suture on a cutting or tapered needle and close the skin in a simple interrupted suture pattern with a 2-0 polypropylene suture on a cutting needle. 
	NOTE: Interchangeably, 2-0 polyglactin or 2-0 polypropylene sutures can be used to close muscle and skin.</li>
	<li>Place the pig in ventral recumbency by rotating the abdomen of a lateral recumbent pig toward the surgical table. A left sided lateral recumbent pig is rotated in a clockwise direction, while a right sided lateral recumbent pig is rotated in a counter clockwise direction.</li>
	<li>Place the catheterized forelimb at a 40&#176; angle to the midline of the vertebral column of the pig. This forelimb positioning generates the best arterial blood flow and the most accurate arterial blood pressure measurements.</li>
</ol>
4. Monitoring clinical parameters
<ol>
	<li>Measure hemodynamic and respiratory parameters as well as temperature throughout the entire anesthetic and surgical procedure using proper monitoring equipment.</li>
</ol>

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The authors have nothing to disclose.

Arterial catheterization to measure arterial blood pressures and collect blood samples for arterial blood gas measurements has been established in a wide range of animal species5,6,7,8,9,10,11,12,13,<sup class="...

Surgical intervention is used in experimental research to develop animal models that enhance scientific development. The scientific literature is filled with examples of novel surgical animal models1,2,3. Surgical procedures are a complex process involving not only the manipulation of anatomical structures but also complicated physiological interactions with various drugs required for anesthesia and analgesia. This interplay can induce major changes in physiological processes within the animal and as such requires vigilant monitoring of the animal4. Clinically successful surgical outcomes have been associated with measurements of arterial blood gases and arterial blood pressures5. These clinical parameters require the ability to measure arterial blood pressure and collect arterial blood effectively, which in turn requires the successful catheterization of an artery6,7.
Arterial catheterization to collect arterial blood and measure pressure has been used in various animal species5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21 and in animals at different ages of development19,20,21 and has been directed at both recovery (clinical and diagnostic) procedures4,5,6,7,8 and non-recovery (experimental) procedures14,15,16,17,18. Moreover, the ease of arterial access and the location of the artery in the context of the surgical procedure are also important considerations when choosing an artery for arterial blood measurements. For example, the median caudal artery in dogs and the facial artery in horses, as well as the pedal artery in both dogs and horses, are used for diagnostic measurement and monitoring during recovery procedures6,7,8. In contrast, the carotid and femoral arteries are often catheterized in swine for either non-recovery or long-term catheter implantation experiments14,15,18.
In swine, arterial catheterization to measure either arterial blood pressure or collect arterial blood has routinely employed either the carotid, femoral, medial saphenous, or auricular arteries22,23. For specialized non-routine procedures, other more unusual arteries have been used, including the subclavian and iliac arteries, to measure the brachial artery anatomical tortuosity17 and image the aorta16, respectively. Regardless of which artery is chosen for catheterization, each artery has inherent advantages and disadvantages for its use. For instance, the auricular artery is anatomically easy to access, but its use may be limited to its close proximity to the marginal ear veins11,12. In comparison, the carotid artery is relatively large and robust24, but it lies deep within the jugular furrow and requires substantive tissue dissection25. As such, identifying another artery that could be catheterized to measure arterial pressure and collect arterial blood is warranted. This video and manuscript describe in detail the catheterization of the distal brachial artery in swine, a technique that could be applied to non-recovery procedures. Notably, the pig brachial artery catheterization was used to measure arterial blood pressures and arterial blood gas parameters during a lumbar spine surgery with hind limb measurements (the data from this part of the surgery is not presented).

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brachial artery catheterization in swine

The video describes in detail the catheterization of the distal brachial artery in swine. This technique enables researchers to measure arterial blood pressure continuously and collect arterial blood samples to assess arterial blood gas measurements. Arterial blood pressures and arterial blood gases are important physiological parameters to monitor during experimental procedures. In swine, four common methods of arterial catheterization have been described, including catheterization of the carotid, femoral, auricular, and medial saphenous arteries. Each of these techniques have advantages, such as ease of access for the auricular artery, and disadvantages that include deep tissue dissection for carotid artery catheterization. The described alternative method of arterial catheterization in swine, the catheterization of the distal aspect of the brachial artery, is a rapid procedure that requires relatively minimal tissue dissection and provides information that is in line with data collected from other arterial catheterization sites. The procedure uses a medial approach along an oblique plane of the lower brachium, positioned between the olecranon and the flexor aspect of the elbow joint, and this approach allows researchers the major advantage of unimpeded freedom for procedures that involve the caudoventral, caudodorsal back, or hind limbs of the pig. Due to the location of the upper forelimb of the catheterized vessel and potential challenges of effective homeostasis following catheter removal from the artery, this technique may be limited to non-recovery procedures.

Brachial artery catheterization allows for continuous monitoring of arterial blood pressure and intermittent sampling of arterial blood during extended surgical procedures in swine. Measured parameters were collected from seven 50 kg Landrace-Yorkshire commercial pigs as described. The total time required to catheterize the brachial artery was 35.2 &#177; 4.4 min from the initial artery landmarking to final surgical incision closure (Figure 1). The arterial p...

Watch this Scientific Journal Video about Brachial Artery Catheterization in Swine at JoVE.com

Brachial Artery Catheterization in Swine

Cateterização da artéria braquial em suínos

The video describes in detail the catheterization of the distal brachial artery in swine. This procedure accurately measures arterial blood pressure and is a simple and fast method to collect samples for arterial blood gas measurements.

The video describes in detail the catheterization of the distal brachial artery in swine. This technique enables researchers to measure arterial blood ...

Research

JoVE Journal

Medicine

10.9K visualizações.  University of Alberta. Medir a pressão arterial e coletar gás arterial para analisar gases sanguíneos arterials são considerações importantes ao monitorar animais submetidos à cirurgia. Este vídeo descreve em detalhes o cateterismo da artéria braquial, um procedimento relativamente rápido e simples, que é particularmente útil para procedimentos que envolvem os caudais ventral e caudal dorsais nas costas e membros traseiros dos porcos. Este vídeo é uma compilação do cateterismo da artéria braquial d...

Vídeo: Brachial Artery Catheterization in Swine

Basic Surgical Techniques in the G&ouml;ttingen Minipig: Intubation, Bladder Catheterization, Femoral Vessel Catheterization, and Transcardial Perfusion

The emergence of the G&ouml;ttingen minipig in research of topics such as neuroscience, toxicology, diabetes, obesity, and experimental surgery reflects the close resemblance of these animals to human anatomy and physiology 1-6.The size of the G&ouml;ttingen minipig permits the use of surgical equipment and advanced imaging modalities similar to those used in humans 6-8. The aim of this instructional video is to increase the awareness on the value of minipigs in biomedical research, by demonstrating how to perform tracheal intubation, transurethral bladder catheterization, femoral artery and vein catheterization, as well as transcardial perfusion. 
Endotracheal Intubation should be performed whenever a minipig undergoes general anesthesia, because it maintains a patent airway, permits assisted ventilation and protects the airways from aspirates. Transurethral bladder catheterization can provide useful information about about hydration state as well as renal and cardiovascular function during long surgical procedures. Furthermore, urinary catheterization can prevent contamination of delicate medico-technical equipment and painful bladder extension which may harm the animal and unnecessarily influence the experiment due to increased vagal tone and altered physiological parameters. Arterial and venous catheterization is useful for obtaining repeated blood samples and monitoring various physiological parameters. Catheterization of femoral vessels is preferable to catheterization of the neck vessels for ease of access, when performing experiments involving frame-based stereotaxic neurosurgery and brain imaging. When performing vessel catheterization in survival studies, strict aseptic technique must be employed to avoid infections6. Transcardial perfusion is the most effective fixation method, and yields preeminent results when preparing minipig organs for histology and histochemistry2,9. For more information about anesthesia, surgery and experimental techniques in swine in general we refer to Swindle 2007. Supplementary information about premedication and induction of anesthesia, assisted ventilation, analgesia, pre- and postoperative care of G&ouml;ttingen minipigs are available via the internet at <a href="http://www.minipigs.com">http://www.minipigs.com</a>10. For extensive information about porcine anatomy we refer to Nickel et al. Vol. 1-511.

Basic Surgical Techniques in the G&amp;#246;ttingen Minipig: Intubation, Bladder Catheterization, Femoral Vessel Catheterization, and Transcardial Perfusion

The use of domestic and miniature pigs in science has increased significantly in recent years. By demonstrating how to perform intubation, transurethral bladder catheterization, femoral artery and vein catheterization, as well as transcardial perfusion, we aim to further increase the value of G&ouml;ttingen minipigs in biomedical research.

Básico Técnicas Cirúrgicas na Minipig Göttingen: Intubação, cateterismo vesical, cateterização veia femoral e perfusão Transcardial

The emergence of the G&ouml;ttingen minipig in research of topics such as neuroscience, toxicology, diabetes, obesity, and experimental surgery reflects ...

Medicina

A Swine Model of Neonatal Asphyxia

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, perfusion deficit, hypoxic-ischemic encephalopathy, pulmonary hypertension, vasculopathic enterocolitis, renal failure and thrombo-embolic complications. Animal models are developed to help us understand the patho-physiology and pharmacology of neonatal asphyxia. In comparison to rodents and newborn lambs, the newborn piglet has been proven to be a valuable model. The newborn piglet has several advantages including similar development as that of 36-38 weeks human fetus with comparable body systems, large body size (&tilde;1.5-2 kg at birth) that allows the instrumentation and monitoring of the animal and controls the confounding variables of hypoxia and hemodynamic derangements.
We here describe an experimental protocol to simulate neonatal asphyxia and allow us to examine the systemic and regional hemodynamic changes during the asphyxiating and reoxygenation process as well as the respective effects of interventions. Further, the model has the advantage of studying multi-organ failure or dysfunction simultaneously and the interaction with various body systems. The experimental model is a non-survival procedure that involves the surgical instrumentation of newborn piglets (1-3 day-old and 1.5-2.5 kg weight, mixed breed) to allow the establishment of mechanical ventilation, vascular (arterial and central venous) access and the placement of catheters and flow probes (Transonic Inc.) for the continuously monitoring of intra-vascular pressure and blood flow across different arteries including main pulmonary, common carotid, superior mesenteric and left renal arteries. Using these surgically instrumented piglets, after stabilization for 30-60 minutes as defined by Z&lt;10% variation in hemodynamic parameters and normal blood gases, we commence an experimental protocol of severe hypoxemia which is induced via normocapnic alveolar hypoxia. The piglet is ventilated with 10-15% oxygen by increasing the inhaled concentration of nitrogen gas for 2h, aiming for arterial oxygen saturations of 30-40%. This degree of hypoxemia will produce clinical asphyxia with severe metabolic acidosis, systemic hypotension and cardiogenic shock with hypoperfusion to vital organs. The hypoxia is followed by reoxygenation with 100% oxygen for 0.5h and then 21% oxygen for 3.5h. Pharmacologic interventions can be introduced in due course and their effects investigated in a blinded, block-randomized fashion.

Large animal models have good translational values in the examination of physiology and pharmacology of neonatal asphyxia. Using newborn piglets, we develop an experimental protocol to simulate neonatal asphyxia which has advantages of studying the systemic and regional hemodynamics, oxygen transport with biochemical and pathologic pathways and correlations.

Um Modelo de Suínos de asfixia neonatal

Annually more than 1 million neonates die worldwide as related to asphyxia. Asphyxiated neonates commonly have multi-organ failure including hypotension, ...

Catheterization of the Carotid Artery and Jugular Vein to Perform Hemodynamic Measures, Infusions and Blood Sampling in a Conscious Rat Model

The success of a small animal model to study critical illness is, in part, dependent on the ability of the model to simulate the human condition. Intra-tracheal inoculation of a known amount of bacteria has been successfully used to reproduce the pathogenesis of pneumonia which then develops into sepsis. Monitoring hemodynamic parameters and providing standard clinical treatment including infusion of antibiotics, fluids and drugs to maintain blood pressure is critical to simulate routine supportive care in this model but to do so requires both arterial and venous vascular access. The video details the surgical technique for implanting carotid artery and common jugular vein catheters in an anesthetized rat. Following a 72 hr recovery period, the animals will be re-anesthetized and connected to a tether and swivel setup attached to the rodent housing which connects the implanted catheters to the hemodynamic monitoring system. This setup allows free movement of the rat during the study while continuously monitoring pressures, infusing fluids and drugs (antibiotics, vasopressors) and performing blood sampling.

Vascular accesses to measure hemodynamics, provide fluids and perform blood sampling are important to any small animal model study. We present a technique for implanting catheters into the carotid artery and the common jugular vein in an anesthetized rat for connecting to a system to perform monitoring, infusions and sampling.

Cateterismo da artéria carótida e jugular para executar as medidas hemodinâmicas, infusões e Sangue de amostragem em um Rat Consciente Modelo

The success of a small animal model to study critical illness is, in part, dependent on the ability of the model to simulate the human condition. ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

Infusões artéria carótida para farmacocinéticas e farmacodinâmicas Análise de taxanos em Ratos

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Ultrasound Assessment of Endothelial-Dependent Flow-Mediated Vasodilation of the Brachial Artery in Clinical Research

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The endothelium acts as a barrier, preventing leukocyte adhesion and aggregation, as well as controlling permeability to plasma components. Functionally, the endothelium affects vessel tone.
Endothelial dysfunction is an imbalance between the chemical species which regulate vessel tone, thombroresistance, cellular proliferation and mitosis. It is the first step in atherosclerosis and is associated with coronary artery disease, peripheral artery disease, heart failure, hypertension, and hyperlipidemia.
The first demonstration of endothelial dysfunction involved direct infusion of acetylcholine and quantitative coronary angiography. Acetylcholine binds to muscarinic receptors on the endothelial cell surface, leading to an increase of intracellular calcium and increased nitric oxide (NO) production. In subjects with an intact endothelium, vasodilation was observed while subjects with endothelial damage experienced paradoxical vasoconstriction.
There exists a non-invasive, in vivo method for measuring endothelial function in peripheral arteries using high-resolution B-mode ultrasound. The endothelial function of peripheral arteries is closely related to coronary artery function. This technique measures the percent diameter change in the brachial artery during a period of reactive hyperemia following limb ischemia.
This technique, known as endothelium-dependent, flow-mediated vasodilation (FMD) has value in clinical research settings. However, a number of physiological and technical issues can affect the accuracy of the results and appropriate guidelines for the technique have been published. Despite the guidelines, FMD remains heavily operator dependent and presents a steep learning curve. This article presents a standardized method for measuring FMD in the brachial artery on the upper arm and offers suggestions to reduce intra-operator variability.

Endothelial dysfunction is associated with numerous disease states and is predictive of adverse cardiovascular events in humans. Flow-mediated vasodilation (FMD) is a non-invasive ultrasound method of evaluating endothelial function. Methodological choices and operator experience may affect results. A systematic approach to FMD in human studies is discussed here.

Avaliação ultra-som de endotelial-dependente do fluxo vasodilatação mediada da artéria braquial em Pesquisa Clínica

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The ...

Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery

Chronic cardiac ischemia that impairs cardiac function, but does not result in infarct, is termed hibernating myocardium (HM). A large clinical subset of coronary artery disease (CAD) patients have HM, which in addition to causing impaired function, puts them at higher risk for arrhythmia and future cardiac events. The standard treatment for this condition is revascularization, but this has been shown to be an imperfect therapy. The majority of pre-clinical cardiac research focuses on infarct models of cardiac ischemia, leaving this subset of chronic ischemia patients largely underserved. To address this gap in research, we have developed a well-characterized and highly reproducible model of hibernating myocardium in swine, as swine are ideal translational models for human heart disease. In addition to creating this unique disease model, we have optimized a clinically relevant treatment model of coronary artery bypass surgery in swine. This allows us to accurately study the effects of bypass surgery on heart disease, as well as investigate additional or alternate therapies. This model surgically induces single vessel stenosis by implanting a constrictor on the left anterior descending (LAD) artery in a young pig. As the pig grows, the constrictor creates a gradual stenosis, resulting in chronic ischemia with impaired regional function, but preserving tissue viability. Following the establishment of the hibernating myocardium phenotype, we perform off-pump coronary artery bypass graft surgery to revascularize the ischemic region, mimicking the gold-standard treatment for patients in the clinic.

This protocol presents a surgical large animal model of chronic, single vessel ischemia that results in regional abnormalities but does not create infarct, known as hibernating myocardium. Following establishment of chronic ischemia, animals are treated with off-pump LIMA-LAD coronary artery bypass graft surgery to revascularize the ischemic tissue.

Modelo de suíno cirúrgico da isquemia cardíaca crônica, tratado pela cirurgia de Bypass coronário de bomba

Chronic cardiac ischemia that impairs cardiac function, but does not result in infarct, is termed hibernating myocardium (HM). A large clinical subset of ...

Middle Cerebral Artery Occlusion Allowing Reperfusion via Common Carotid Artery Repair in Mice

The ischemic stroke is a major cause of adult long-term disability and death worldwide. The current treatments available are limited, with only tissue plasminogen activator (tPA) as an approved drug treatment to target ischemic strokes. Current research in the field of ischemic stroke focuses on better understanding the pathophysiology of stroke, to develop and investigate novel pharmaceutical targets. Reliable experimental stroke models are crucial for the progression of potential treatments. The middle cerebral artery occlusion (MCAO) model is clinically relevant and the most frequently used surgical model of ischemic stroke in rodents. However, the outcomes of this model, such as lesion volume, are associated with high levels of variability, particularly in mice. The alternative MCAO model described here allows the reperfusion of the common carotid artery (CCA) and the increased perfusion of the middle cerebral artery (MCA) territory, using a tissue pad with fibrinogen-based sealant to repair the vessel, and the improved welfare of the mice by avoiding external carotid artery (ECA) ligation. This reduces the reliance on the Circle of Willis, which is known to be highly anatomically variable in mice. Representative data show that using this alternative surgical approach decreases the variability in lesion volumes between the traditional MCAO approach and the alternative approach described here.

Intraluminal filament occlusion of the middle cerebral artery is the most frequently used in vivo model of experimental stroke in rodents. An alternative surgical approach to allow common carotid artery repair is performed here, which allows the reperfusion of the common carotid artery and a full reperfusion to the middle cerebral artery territory.

Oclusão de artéria Cerebral média, permitindo a reperfusão através de reparação de artéria carótida comum em ratos

The ischemic stroke is a major cause of adult long-term disability and death worldwide. The current treatments available are limited, with only tissue ...

A Rat Carotid Artery Pressure-Controlled Segmental Balloon Injury with Periadventitial Therapeutic Application

Cardiovascular disease remains the leading cause of death and disability worldwide, in part due to atherosclerosis. Atherosclerotic plaque narrows the luminal surface area in arteries thereby reducing adequate blood flow to organs and distal tissues. Clinically, revascularization procedures such as balloon angioplasty with or without stent placement aim to restore blood flow. Although these procedures reestablish blood flow by reducing plaque burden, they damage the vessel wall, which initiates the arterial healing response. The prolonged healing response causes arterial restenosis, or re-narrowing, ultimately limiting the long-term success of these revascularization procedures. Therefore, preclinical animal models are integral for analyzing the pathophysiological mechanisms driving restenosis, and provide the opportunity to test novel therapeutic strategies. Murine models are cheaper and easier to operate on than large animal models. Balloon or wire injury are the two commonly accepted injury modalities used in murine models. Balloon injury models in particular mimic the clinical angioplasty procedure and cause adequate damage to the artery for the development of restenosis. Herein we describe the surgical details for performing and histologically analyzing the modified, pressure-controlled rat carotid artery balloon injury model. Additionally, this protocol highlights how local periadventitial application of therapeutics can be used to inhibit neointimal hyperplasia. Lastly, we present light sheet fluorescence microscopy as a novel approach for imaging and visualizing the arterial injury in three-dimensions.

The rat carotid artery balloon injury mimics the clinical angioplasty procedure performed to restore blood flow in atherosclerotic vessels. This model induces the arterial injury response by distending the arterial wall, and denuding the intimal layer of endothelial cells, ultimately causing remodeling and an intimal hyperplastic response.

Uma lesão de balão segmental controlada por pressão da artéria de rato com aplicação terapêutica periadventicional

Cardiovascular disease remains the leading cause of death and disability worldwide, in part due to atherosclerosis. Atherosclerotic plaque narrows the ...

Bandagem Aórtica Ascendente para Estudo da Insuficiência Cardíaca Induzida por Sobrecarga de Pressão

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.

Autor em destaque: Desenvolvimento de um modelo minimamente invasivo de animais de grande porte para pesquisa cardiovascular confiável e reprodutível 

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

Modelo Minimamente Invasivo de Estenose Aórtica em Suínos

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