This work was supported by US National Institute of Health (NIH) Grant R01-HL128406; the United States Department of Veterans Affairs Biomedical Laboratory Research and Development Program Merit Review Award I01-BX002336; as well as with the resources and the use of facilities at the VA Connecticut Healthcare System, West Haven, CT.

All experiments were performed with approval from the Yale University Institutional Animal Care and Use Committee (IACUC).
1. Anesthesia and pre-operative procedures
<ol>
	<li>Sterilize all surgical instruments and materials by autoclaving. Turn on the thermal support device to be certain it is warm (40&#8211;42 &#176;C).</li>
	<li>Place a 9&#8211;11-week old C57BL/6 mouse into an acrylic induction chamber and anesthetize it with vaporized 2.5% isoflurane and 0.8 L/min oxygen. Anesthesia ind...

<ol>
	<li>Dember, L. 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=Effect+of+clopidogrel+on+early+failure+of+arteriovenous+fistulas+for+hemodialysis:+a+randomized+controlled+trial.">Effect of clopidogrel on early failure of arteriovenous fistulas for hemodialysis: a randomized controlled trial.</a> JAMA. 299 (18), 2164-2171 (2008).</li><li>Dixon, B. 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B., Arici, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arteriovenous+Fistulas+and+Their+Characteristic+Sites+of+Stenosis.">Arteriovenous Fistulas and Their Characteristic Sites of Stenosis.</a> AJR: American Journal of Roentgenology. 205 (4), 726-734 (2015).</li><li>Kian, K., Asif, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cephalic+arch+stenosis.">Cephalic arch stenosis.</a> Semin Dial. 21 (1), 78-82 (2008).</li><li>Agarwal, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Central+vein+stenosis.">Central vein stenosis.</a> American Journal of Kidney Diseases. 61 (6), 1001-1015 (2013).</li><li>Glanz, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axillary+and+subclavian+vein+stenosis:+percutaneous+angioplasty.">Axillary and subclavian vein stenosis: percutaneous angioplasty.</a> Radiology. 168 (2), 371-373 (1988).</li><li>Yamamoto, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mouse+aortocaval+fistula+recapitulates+human+arteriovenous+fistula+maturation.">The mouse aortocaval fistula recapitulates human arteriovenous fistula maturation.</a> American Journal of Physiology: Heart and Circulatory Physiology. 305 (12), H1718-H1725 (2013).</li><li>North American Symptomatic Carotid Endarterectomy Trial. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods,+patient+characteristics,+and+progress.">Methods, patient characteristics, and progress.</a> Stroke. 22 (6), 711-720 (1991).</li><li>Kuwahara, G., 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=CD44+Promotes+Inflammation+and+Extracellular+Matrix+Production+During+Arteriovenous+Fistula+Maturation.">CD44 Promotes Inflammation and Extracellular Matrix Production During Arteriovenous Fistula Maturation.</a> Arteriosclerosis, Thrombosis, and Vascular Biology. 37 (6), 1147-1156 (2017).</li><li>Protack, C. 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=Eph-B4+regulates+adaptive+venous+remodeling+to+improve+arteriovenous+fistula+patency.">Eph-B4 regulates adaptive venous remodeling to improve arteriovenous fistula patency.</a> Scientific Reports. 7 (1), 15386 (2017).</li><li>Payne, H., Brill, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stenosis+of+the+Inferior+Vena+Cava:+A+Murine+Model+of+Deep+Vein+Thrombosis.">Stenosis of the Inferior Vena Cava: A Murine Model of Deep Vein Thrombosis.</a> J Vis Exp. (130), (2017).</li><li>Nam, 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=Partial+carotid+ligation+is+a+model+of+acutely+induced+disturbed+flow,+leading+to+rapid+endothelial+dysfunction+and+atherosclerosis.">Partial carotid ligation is a model of acutely induced disturbed flow, leading to rapid endothelial dysfunction and atherosclerosis.</a> American Journal of Physiology: Heart and Circulatory Physiology. 297 (4), H1535-H1543 (2009).</li><li>Ene-Iordache, B., Remuzzi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disturbed+flow+in+radial-cephalic+arteriovenous+fistulae+for+haemodialysis:+low+and+oscillating+shear+stress+locates+the+sites+of+stenosis.">Disturbed flow in radial-cephalic arteriovenous fistulae for haemodialysis: low and oscillating shear stress locates the sites of stenosis.</a> Nephrology, Dialysis, Transplantation. 27 (1), 358-368 (2012).</li><li>Yamamoto, K., 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=Disturbed+shear+stress+reduces+Klf2+expression+in+arterial-venous+fistulae+in+vivo.">Disturbed shear stress reduces Klf2 expression in arterial-venous fistulae in vivo.</a> Physiological reports. 3, (2015).</li><li>Remuzzi, A., Ene-Iordache, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+paradigms+for+dialysis+vascular+access:+upstream+hemodynamics+and+vascular+remodeling+in+dialysis+access+stenosis.">Novel paradigms for dialysis vascular access: upstream hemodynamics and vascular remodeling in dialysis access stenosis.</a> Clinical Journal of the American Society of Nephrology. 8 (12), 2186-2193 (2013).</li></ol>

The murine AVF model has been used to study the basic mechanisms and molecular events leading to AVF maturation13,14. In this study, we modified an established murine AVF model to create a novel murine aortocaval fistula model with an IVC stenosis in the outflow tract of the fistula. Our ligation model is similar to several previously described murine models that use vascular ligation. A murine model of deep vein thrombosis was created using partial IVC ligation ...

Arteriovenous fistulae (AVF) are the most common accesses for hemodialysis, with superior patency and reduced infection compared to other accesses such as grafts or central venous catheters. However, up to 60% of AVF fail to mature1,2,3; a recent systematic review reported that primary patency rates at 1 year were only 60%4. Stenosis along the venous outflow predominantly causes failure of AVF maturation5,6. There are certain characteristic locations prone to stenosis proximal to the fistula: the juxtaanastomotic swing segment for the radiocephalic fistula, the cephalic arch region for the brachiocephalic fistula and the central vein for the fistula with previously placed ipsilateral subclavian or internal jugular vein catheters7,8.
Central venous stenosis is often asymptomatic in patients without an AVF, but can cause ipsilateral extremity edema by venous hypertension as well as failure of fistula maturation when challenged by fistula flow9. The pathophysiology of central venous stenosis is most likely related to inflammation and the activated coagulation cascade after device placement. Furthermore, constant movement of the catheter tip as well as increased flow from the fistula can alter shear stress, resulting in platelet deposition and venous wall thickening10. To understand the basic mechanisms underlying AVF failure caused by central venous stenosis, an animal model mimicking central venous stenosis with an AVF is required.
We have established a murine aortocaval fistula model that is easy to perform and master and recapitulates the clinical course of human AVF.11 We applied the concepts and technique of several previously established murine models to create a novel murine AVF model with venous stenosis. We introduce a murine aortocaval fistula model with an IVC stenosis in the outflow fistula that can be used for the study of central venous stenosis.

<table>
	<tbody>
		<tr>
			<td>20-60 Mhz scan head</td>
			<td>VisualSonics Inc.</td>
			<td>RMV-704</td>
			<td></td>
		</tr>
		<tr>
			<td>8-0 Sterile Micro Suture, 6mm (140 &#181;), 3/8 Circle, TAP Point Needle</td>
			<td>AROSuture</td>
			<td>T06A08N14-13</td>
			<td>polyamide monofilament sutures</td>
		</tr>
		<tr>
			<td>Induction Chamber, 2 Liter 
			3.75&#34;W x 9.00&#34;D x 3.75&#34;H</td>
			<td>VetEquip</td>
			<td>941444</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflo, Isoflurane liquid</td>
			<td>Zoetis</td>
			<td>26675-46-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Mice, C57BL/6J</td>
			<td>The Jackson Laboratory</td>
			<td>664</td>
			<td></td>
		</tr>
		<tr>
			<td>Pet Bed Microwave Heating Pad</td>
			<td>Snuggle Safe</td>
			<td>6250</td>
			<td></td>
		</tr>
		<tr>
			<td>PrecisionGlide Needle 25G</td>
			<td>BD</td>
			<td>305122</td>
			<td></td>
		</tr>
		<tr>
			<td>Surflo I.V. Catheter 22G</td>
			<td>Terumo</td>
			<td>SR-OX2225CA</td>
			<td>0.85mm outer diameter</td>
		</tr>
		<tr>
			<td>Vascular clamp</td>
			<td>Roboz Surgical Instrument</td>
			<td>RS-5424</td>
			<td></td>
		</tr>
		<tr>
			<td>Vevo770 High Resolution Imaging System</td>
			<td>VisualSonics Inc.</td>
			<td>770</td>
			<td></td>
		</tr>
	</tbody>
</table>

murine model of central venous stenosis using aortocaval fistula with an outflow stenosis

Central venous stenosis is an important entity contributing to arteriovenous fistula (AVF) failure. A murine AVF model was modified to create a partial ligation of the inferior vena cava (IVC) in the outflow of the fistula, mimicking central venous stenosis. Technical aspects of this model are introduced. The aorta and IVC are exposed, following an abdominal incision. The infra-renal aorta and IVC are dissected for proximal clamping, and the distal aorta is exposed for puncture. The IVC at the midpoint between the left renal vein and the aortic bifurcation is carefully dissected to place an 8-0 suture beneath the IVC. After clamping the aorta and IVC, an AVF is created by puncturing the infra-renal aorta through both walls into the IVC with a 25 G needle, followed by ligating a 22 G intra-venous (IV) catheter and IVC together. The catheter is then removed, creating a reproducible venous stenosis without occlusion. The aorta and IVC are unclamped after confirming primary hemostasis. This novel model of central vein stenosis is easy to perform, reproducible, and will facilitate studies on AVF failure.

Male mice underwent the operation mentioned above to create both an AVF and an IVC stenosis. Control mice underwent only laparotomy and dissection of the tissues surrounding the IVC, e.g., a sham procedure, or only creation of an IVC stenosis without simultaneous creation of an AVF.
The IVC was observed with Doppler ultrasound on day 7 after the surgical procedure (Figure 2). The fistula and stenosi...

Watch this Scientific Journal Video about Murine Model of Central Venous Stenosis using Aortocaval Fistula with an Outflow Stenosis at JoVE.com

Murine Model of Central Venous Stenosis using Aortocaval Fistula with an Outflow Stenosis

An aortocaval fistula was created by puncturing the murine infra-renal aorta through both walls into the inferior vena cava and was followed by creation of a stenosis in its outflow via partial ligation of the inferior vena cava. This reproducible model can be used to study central venous stenosis.

Central venous stenosis is an important entity contributing to arteriovenous fistula (AVF) failure. A murine AVF model was modified to create a partial ...

Central venous stenosis can cause both aortocaval fistula, or AVF, primary failure of maturation, as well as later failure in a working fistula. This technique uses a modified version of an established murine AVF model that recapitulates the clinical course of human AVF and is easily mastered through several critical steps. Before beginning the procedure, confirm a lack of response to toe pinch in a nine-to 11-week-old, C57-Black/6 mouse and place the mouse in the supine position in the surgical area.Apply ointment to the animal's eyes, and remove the fur from the ventral side of the neck to the lower abdomen. Then cleanse and disinfect the surgical site with three sequential 10%povidone-iodine and 70%isopropanol scrubs, and place a surgical drape over the animal. For clamp and puncture site exposure, place the mouse under a dissecting microscope and, using sterile technique and a scalpel, make a skin-deep, midline, abdominal incision from the lower liver edge to just above the pubis.Cut through the musculature with scissors to open the abdominal cavity, and insert a retractor into the abdomen. Move the bowels to the right side, and wrap them in a saline-soaked gauze. Move the bladder and the seminal vesicles to the caudal side of the animal, and use a microneedle holder to dissect the mesentery between the rectum and the retroperitoneum to secure a full view of the aorta and inferior vena cava, or IVC.Then use the microneedle holder to dissect the infrarenal aorta and IVC en bloc from the lateral and dorsal surrounding retroperitoneal tissues to cross-clamp the tissues together, and dissect the surrounding tissues to expose the aortic puncture site at approximately three-quarters of the distance from the left renal vein to the aortic bifurcation. For isolation of the IVC, dissect between the infrarenal IVC and the aorta immediately distal to the left renal vein and extend the dissection distally to halfway between the left renal vein and the aortic bifurcation for post-operative infrarenal IVC observation. Make a window to separate the IVC from the aorta, and dissect the IVC from the surrounding tissue.Then carefully place an 8-0 polyamide monofilament suture beneath the IVC and the aorta before pulling the suture end through the window to position the suture beneath the IVC only. To create the AVF, first bend a 25-gauge needle to a 45-to 60-degree angle four millimeters from the needle tip and clamp the infrarenal aorta and IVC with a microsurgical clip. Grasping the connective tissue surrounding the bifurcation, rotate the aorta medially and caudally to expose the puncture site of the aorta stretched slightly to the ventral side, and use the 25-gauge needle to puncture through the aorta into the IVC.When the tissue has been pierced, release the aorta and pull up from the left side of the aorta to cover the puncture site with the surrounding tissue. Then remove the needle, and press the puncture site gently with a cotton-tipped swab for hemostasis. For IVC stenosis creation, place the tip of a 22-gauge intravenous catheter longitudinally onto the IVC and ligate the catheter to the IVC with an 8-0 suture.When the suture has been placed, remove the catheter and confirm primary hemostasis before unclamping the aorta and the IVC. Cover the puncture site for another minute to ensure hemostasis, and return the organs to their abdominal cavity before closing the abdomen with 6-0 sutures. Then place the mouse into an individual bedding-free cage on a thermal support device with monitoring until full recovery, and use Doppler ultrasound to confirm the patency of the fistula.On day seven after the surgical procedure, the fistula and stenosis areas of the IVC are easily detected in the longitudinal view. In mice bearing a stenosis without an AVF, the stenosis segment exhibits a venous waveform with more spectral broadening than sham-operated mice but without much pulsatility. In mice having an AVF as well as a stenosis, the stenosis segment shows a pulsatile waveform in addition to spectral broadening, and the time-averaged maximum velocity of the flow at the stenosis in mice having an AVF with stenosis is significantly higher than in mice with stenosis alone.The mean IVC diameter at the stenosis in mice with stenosis alone is similar to that observed in mice with an AVF and stenosis. In addition, using either the upstream or downstream segment as a reference, the percent stenosis is significantly greater in mice having an AVF in addition to a stenosis. When you ligate the IV catheter and the IVC together, it is important to tie them tightly to create a reproducible stenosis.The application of this procedure to murine venous graft implantation model could answer how to overcome the occlusion of venous graft stenosis.

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7.2K Views.  Yale University. La stenosi venosa centrale può causare sia fistola aortocavale, sia AVF, insufficienza primaria di maturazione, così come un successivo fallimento in una fistola funzionante. Questa tecnica utilizza una versione modificata di un modello AVF murino stabilito che riassume il decorso clinico dell'AVF umano ed è facilmente padroneggiabile attraverso diversi passaggi critici. Prima di iniziare la procedura, confermare la mancanza di risposta al dito del dito in un topo C57-Black/6 di nove-11 se...