We thank doctors Zhou Feng, Ma Tiantian, and Zhu Dongming at our hospital for providing the assistance with ultrasound examination.

The MNTT was conducted according to the human research protocol approved by the ethics committee of the Affiliated Suzhou Science &#38; Technology Town Hospital of Nanjing Medical University (IRB2021029).
1. Preoperative evaluation
<ol>
	<li>Check the medical history: Ensure that the patients have no coagulation abnormalities, valvular heart disease, congestive heart failure, peripheral vascular disease, skin disease, history of central venous catheterization, history of pacemaker implantation, neck and chest trauma, or surgical diseases.</li>
	<li>Perform physical examination results: Ensure symmetrical blood pressure in both upper limbs, good arterial pulse, strong pulsation, negative Allen test11, good venous distensibility after binding the tourniquet, no edema or varicose veins in the upper limb, and no previous central or peripheral venous scars.</li>
	<li>Perform comprehensive assessment of the forearm vasculature of the patient&#39;s operative limb by color Doppler ultrasound.</li>
</ol>
2. Disinfection and anesthesia
<ol>
	<li>Place the patient in the supine position with external rotation and abduction of the operative upper limb.</li>
	<li>Perform routine iodophor disinfection, draping, and local infiltration anesthesia with 1% lidocaine.</li>
</ol>
3. Superficial fascia exposure
<ol>
	<li>Make a 4-cm skin incision (longitudinal incision) at a distance of &#60;2 cm between the radial artery and the cephalic vein of the forearm, and ensure it is relatively close to the cephalic vein.</li>
	<li>Separate the subcutaneous adipose tissue using curved hemostatic forceps to expose the superficial fascia. Look for the presence of the cephalic vein and its surrounding tissues below the superficial fascia (Figure 2a). Do not open the superficial fascia in this step and do not use the electric knife to stop the bleeding.</li>
</ol>
4. Preparation of the cephalic vein
<ol>
	<li>Ensure that below the exposed superficial fascia, the cephalic vein (including part of the vasa vasorum) and its surrounding adipose tissue could be clearly seen.Make two tunnels along the direction perpendicular to the cephalic vein. The tunnel openings should be located &#62;1 cm from both sides of the cephalic vein.</li>
	<li>Pull the cephalic vein close to the radial artery by two blue vessel loops passing through the tunnels at each end to facilitate surgical suturing (Figure 2b).</li>
</ol>
5. Preparation of the radial artery
<ol>
	<li>Cut the tissue layer by layer to expose the radial artery pedicle (including the radial artery and its accompanying veins on both sides) in the pulsating area of the radial artery that can be reached with the index finger. Ligate the small artery branches and pick out the radial artery pedicle with the hemostatic forceps. Dissect the radial artery pedicle for about 40-50 mm.</li>
	<li>Pass the two red vessel loops through each end of the radial artery pedicle. The radial artery could be pulled to be closer to the cephalic vein to facilitate the surgical suture (Figure 2c).</li>
</ol>
6. Opening the cephalic vein and the radial artery
<ol>
	<li>Place a vascular clamp along the tunnel at both ends of the cephalic vein to block the cephalic vein blood flow. Place a vascular clamp at each end of the pedicle to block arterial blood flow. 
	NOTE: Although vascular clamps were used to block blood flow, the intact tissue is preserved around the cephalic vein, which plays a better protective role for the vessels.</li>
	<li>Pull the red vessel loops to bring the radial artery pedicle closer to the cephalic vein, and an incision is made on the lateral wall corresponding to the radial artery and cephalic vein.</li>
	<li>Lift the superficial fascia at the cephalic vein gently with micro-forceps and cut the superficial fascia and the wall of the cephalic vein with a micro-scissor or sharp knife. The incision length should be about 8-10 mm. 
	NOTE: Do not touch or mobilize the vein outside this incision.</li>
	<li>Open the arterial sheath and the wall of the radial artery successively to make an 8-10-mm-long incision with a sharp knife and microscopic scissors, taking care not to twist the vessel. The incision is in the lateral wall of the artery. 
	NOTE: Do not touch or mobilize the artery outside this incision.</li>
	<li>Gently rinse the cephalic vein and radial artery with heparin saline solution (25 IU/mL) to remove any blood or blood clots.</li>
</ol>
7. Functional end-to-side anastomosis
<ol>
	<li>Use the 7.0 non-absorbable single-strand suture to establish vein-arterial anastomosis (side-to-side) with the Kunlin&#39;s technique (Figure 2d, e). Suture the posterior wall of the vessel first, and then suture the anterior wall of the vessel. Pull the vessels close to each other to reduce vascular tension.</li>
	<li>Open the blood flow and ligate the distal cephalic vein to form a functional end-to-side anastomosis (Figure 2f).</li>
	<li>Ensure that no obvious bleeding is detected in the surgical field and use a mattress suture for surgical incision.</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/62784/62784fig02.jpg" /> 
Figure 2. Surgical steps of the modified no-touch technique. a: Exposure of the cephalic vein with the surrounding tissue in situ. b: Placing the blue vessel loop. c: Exposure of the radial artery and its companion vein. d: A side-to-side anastomosis using the Kunlin&#39;s technique. e: Anastomosed the posterior wall of the vessel. f: The distal cephalic vein was ligated to form a functional end-to-side anastomosis. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/62784/62784fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<ol>
	<li>Trerotola, S. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=KDOQI+clinical+practice+guideline+for+vascular+access+2019+update:+Kinder,+Gentler,+and+More+Important+Than+Ever.">KDOQI clinical practice guideline for vascular access 2019 update: Kinder, Gentler, and More Important Than Ever.</a> Journal of Vascular and Interventional Radiology. 31 (7), 1156-1157 (2020).</li><li>Schmidli, 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=Editor's+Choice+-+vascular+access:+2018+clinical+practice+guidelines+of+the+European+Society+for+Vascular+Surgery+(ESVS).">Editor's Choice - vascular access: 2018 clinical practice guidelines of the European Society for Vascular Surgery (ESVS).</a> European Journal of Vascular and Endovascular Surgery. 55 (6), 757-818 (2018).</li><li>Abreo, K., Buffington, M., Sachdeva, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angioplasty+to+promote+arteriovenous+fistula+maturation+and+maintenance.">Angioplasty to promote arteriovenous fistula maturation and maintenance.</a> Journal of Vascular Access. 19 (4), 337-340 (2018).</li><li>Souza, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+no-touch+preparation+technique:+Technical+notes.">A new no-touch preparation technique: Technical notes.</a> Scandinavian Journal of Thoracic and Cardiovascular Surgery. 30 (1), 41-44 (1996).</li><li>Souza, D. 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=High+early+patency+of+saphenous+vein+graft+for+coronary+artery+bypass+harvested+with+surrounding+tissue.">High early patency of saphenous vein graft for coronary artery bypass harvested with surrounding tissue.</a> Annals of Thoracic Surgery. 71 (3), 797-800 (2001).</li><li>Souza, D. S., Gomes, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+future+of+saphenous+vein+graft+for+coronary+artery.">The future of saphenous vein graft for coronary artery.</a> Revista Brasileira de Cirurgia Cardiovascular. 23 (3), (2008).</li><li>Souza, D. 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=Harvesting+the+saphenous+vein+with+surrounding+tissue+for+CABG+provides+long-term+graft+patency+comparable+to+the+left+internal+thoracic+artery:+results+of+a+randomized+longitudinal+trial.">Harvesting the saphenous vein with surrounding tissue for CABG provides long-term graft patency comparable to the left internal thoracic artery: results of a randomized longitudinal trial.</a> Journal of Thoracic and Cardiovascular Surgery. 132 (2), 373-378 (2006).</li><li>H&#246;rer, T. 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=No-touch+technique+for+radiocephalic+arteriovenous+fistula:+surgical+technique+and+preliminary+results.">No-touch technique for radiocephalic arteriovenous fistula: surgical technique and preliminary results.</a> Journal of Vascular Access. 17 (1), 6-12 (2016).</li><li>Sadaghianloo, N., 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=Radial+artery+deviation+and+reimplantation+inhibits+venous+juxta-anastomotic+stenosis+and+increases+primary+patency+of+radial-cephalic+fistulas+for+hemodialysis.">Radial artery deviation and reimplantation inhibits venous juxta-anastomotic stenosis and increases primary patency of radial-cephalic fistulas for hemodialysis.</a> Journal of Vascular Surgery. 64 (3), 698-706 (2016).</li><li>Xiaohe, 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=A+modified+no-touch+technique+for+anastomosis+to+create+a+radiocephalic+arteriovenous+fistula.">A modified no-touch technique for anastomosis to create a radiocephalic arteriovenous fistula.</a> Journal of Vascular Surgery Cases, Innovations and Techniques. 7 (4), 686-690 (2021).</li><li>Lok, C. 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=KDOQI+Clinical+Practice+Guideline+for+Vascular+Access:+2019+Update.">KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update.</a> American Journal of Kidney Diseases. 75 (4), 1 (2020).</li><li>Xiaohe, 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=Clinical+report+of+4+cases+of+autogenous+forearm+arteriovenous+fistula+constructed+by+modified+no-touch+technique.">Clinical report of 4 cases of autogenous forearm arteriovenous fistula constructed by modified no-touch technique.</a> Chinese Journal of Blood Purification. 10 (20), 693-695 (2021).</li><li>Allon, 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=Association+of+preexisting+arterial+intimal+hyperplasia+with+arteriovenous+fistula+outcomes.">Association of preexisting arterial intimal hyperplasia with arteriovenous fistula outcomes.</a> Clinical Journal of the American Society of Nephrology. 13 (9), 1358-1363 (2018).</li><li>Allon, 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=Vascular+calcification,+intimal+hyperplasia,+and+arteriovenous+fistula+maturation.">Vascular calcification, intimal hyperplasia, and arteriovenous fistula maturation.</a> American Journal of Kidney Diseases. 58 (3), 437-443 (2011).</li><li>Vazquez-Padron, R. I., 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=intimal+hyperplasia+and+arteriovenous+fistula+failure:+looking+beyond+size+differences.">intimal hyperplasia and arteriovenous fistula failure: looking beyond size differences.</a> Kidney360. 2 (8), 1360-1372 (2021).</li><li>Shenoy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+technique+determines+the+outcome+of+the+Brescia/Cimino+AVF.">Surgical technique determines the outcome of the Brescia/Cimino AVF.</a> Journal of Vascular Access. 18, 1-4 (2017).</li><li>Bai, H., 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=Artery+to+vein+configuration+of+arteriovenous+fistula+improves+hemodynamics+to+increase+maturation+and+patency.">Artery to vein configuration of arteriovenous fistula improves hemodynamics to increase maturation and patency.</a> Science Translational Medicine. 12 (557), (2020).</li></ol>

Venous juxta-anastomotic stenosis is one of the main factors affecting the maturation of AVF5. It is known to be closely related to intimal hyperplasia13,14,15. However, prevention strategies for intimal hyperplasia are still limited. Modified surgical procedures16 such as RADAR have been shown to have less venous juxta-anastomotic stenosis, increased maturation and patency, and fewer secondary interventions9,17. However, the inflow artery stenosis was more prominent with RADAR.
Here, we extended the RADAR technique and avoided devascularization of the venous and arterial wall and did not sever the radial artery. The results showed a significant reduction in venous stenosis, and no arterial stenosis was observed. Spiral laminar flow was shown on the blood-flow spectrum of the cephalic vein 1.5-cm from the anastomosis. The blood flow of the brachial artery was &#62;600 mL/min. In the postoperative follow-up, we found that the patients did not have pain, ischemia, numbness, and other adverse problems in the distal forearm. These improved outcomes suggest that MNTT is likely the preferred surgical technique to perform AVF.
The first critical surgical step was exposure of the superficial fascia. The cephalic vein and its surrounding tissues below the superficial fascia could be seen clearly. Care should be taken not to damage the superficial fascia, and an electric knife should not be used to stop bleeding. The second critical surgical step was preparation of the radial artery. By bringing the cephalic vein and radial artery close together, we can achieve suturing. In the procedure of artery isolation, the arterial pedicle (artery and two veins) was dissected for 4-5 cm. The farther the distance between the artery and the vein, the longer the arterial pedicle needed to be dissected. In the 10 cases of RC-AVF that we completed with MNTT, the distance between the artery and the vein was up to 2 cm.
The advantages of this technique are listed here. The cephalic vein and radial artery were not skeletonized at the site of anastomosis. The aim of MNTT is primarily to avoid devascularization of the venous and arterial wall. The artery pedicle was not severed. MNTT is applicable to a wide range of patients (forearm and upper arm fistulas).
There are limitations associated with the technique. First, based on our experience, the operation cannot be performed if the distance between the cephalic vein and radial artery &#62;3 cm. Second, despite the protecting the perivascular tissue, anastomosis is still needed with a vascular clamp to block blood flow.
There is a wide range of surgical indications without severing the artery. In our experience, MNTT is suitable for snuffbox, forearm, and upper arm fistula surgery.
We confirmed that MNTT can be used to create RC-AVF, and the short-term follow-up outcomes were satisfactory. A larger sample size is still needed to evaluate the long-term efficiency and applicability of this technique.

Radio-cephalic autologous arteriovenous fistula (RC-AVF) have been regarded as the primary and best choice for vascular access in hemodialysis patients1,2. However, the early failure to mature continues to be a major problem with RC-AVF creation3. Different surgical methods have different degrees of vascular injury and affect the maturation of RC-AVF. In 1996, Souza4 first proposed the use of a no-touch technique (NTT) to separate the great saphenous vein in coronary artery bypass grafting and achieved good results5,6,7. Horer et al.8 was the first to use NTT to construct RC-AVF. At the 1-year follow-up, primary patency was 54% and secondary patency was 80%. Sadaghianloo et al.9 further extended the concept of no-touch technology and proposed the radial artery deviation and reimplantation (RADAR) technique. This technique is associated with less juxta-anastomotic stenosis. However, the inflow artery stenosis was more prominent with RADAR. We speculate that this may be related to the severance of the radial artery and skeletonization of the distal tip of the artery.
To further reduce the injury to veins and arteries during the operation, we proposed a new modified no-touch technique (MNTT), which significantly improved the patency rate and the fistula maturation10. The aim of this technique was to primarily avoid both devascularization of the venous and arterial wall and severing of the radial artery. After the skin and subcutaneous tissue were incised, the cephalic vein and its surrounding adipose tissue were seen below the superficial fascia. An 8-10-mm-long incision was made in the superficial fascia and cephalic vein wall, and the radial artery pedicle (including the radial artery and its accompanying veins) was isolated 40-50 mm. The artery pedicle was not severed, and the radial artery pedicle was raised to approach the cephalic vein. An 8-10-mm-long incision was made in the artery. The anastomosis was performed side-to-side and the distal vein was ligated to form a functional end-to-side anastomosis (Figure 1).
We evaluated blood vessels by Doppler ultrasound before the surgeries of 10 cases: there was no stenosis in the radial artery and cephalic vein with radial artery diameter&#8805;1.6 mm and cephalic vein diameter&#8805;2 mm. Echocardiography showed left ventricular score &#62;60%, and the patient had no surgical contraindications. A distance of &#60;2 cm between the artery and vein was identified as the proposed anastomosis site.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62784/62784fig01.jpg" /> 
Figure 1. Schematic diagram of anastomosis types in AVFs12. a: Conventional surgery for an AVF. b: AVF created using the NTT. c: AVF created using the MNTT and a functional end-to-side anastomosis. AVF: arteriovenous fistula; NTT: no-touch technique. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/62784/62784fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table><tbody><tr><td>Curved hemostatic forceps</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZH131R/RN</td><td></td></tr><tr><td>Dissecting Forceps</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZDO25R/RN</td><td></td></tr><tr><td>Electrotome</td><td>Changzhou Yanling Electronic Equipment Co., Ltd.</td><td>TY21205812</td><td></td></tr><tr><td>Eyelld Retractor</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>Z014602T</td><td></td></tr><tr><td>Lidocaine</td><td>Hebei Tiancheng Pharmaceutical Co., Ltd.</td><td>1B200612104</td><td></td></tr><tr><td>Halsey needleholder</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZM208R/RN</td><td></td></tr><tr><td>Micro forceops</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZD275RN/T</td><td></td></tr><tr><td>Micro needle holder forceps</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZF2618RB/T</td><td></td></tr><tr><td>Micro scissors</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZF022T</td><td></td></tr><tr><td>Micro vessel knife</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZF1549RN</td><td></td></tr><tr><td>Non-absorbable suture 3-0</td><td>Ethicon,LLC</td><td>SA84G</td><td></td></tr><tr><td>Poly propylene 7-0</td><td>Ethicon,LLC</td><td>PDB601</td><td></td></tr><tr><td>Sharp blade</td><td>Suzhou Medical Products Factory Co., Ltd.</td><td>TY21232001</td><td></td></tr><tr><td>scalpel handle</td><td>Shanghai Medical Instrument (Group) Co., Ltd. Surgical Instruments Factory</td><td>J11030</td><td></td></tr><tr><td>Syringe with needle (5ml)</td><td>BD medical devices (Shanghai) Co., Ltd</td><td>2006116</td><td></td></tr><tr><td>Triangle needle</td><td>Hangzhou Huawei medical supplies Co., Ltd</td><td>7X17</td><td></td></tr><tr><td>Vessel clamp</td><td>Xinhua Surgical Instrument Co., Ltd.</td><td>ZF220RN</td><td></td></tr><tr><td>Vessel loop</td><td>Shenzhen Yiman Technology Co., Ltd</td><td>EM-SR1</td><td></td></tr></tbody></table>

creating radio-cephalic arteriovenous fistula in the forearm with a modified no-touch technique

Autologous arteriovenous fistula (AVF) is the primary and best option to obtain vascular access for hemodialysis treatment; other options are arteriovenous graft (AVG) and central venous catheterization (CVC). The implementation of radio-cephalic autologous arteriovenous fistula (RC-AVF) in the forearm was preferred among patients with superior vascular conditions. However, there is a high rate of early fistula failure. The chosen surgical method is understood to have an effect on the maturation of the fistula. New surgical procedures such as radial artery deviation and reimplantation (RADAR) have been significantly improved for juxta-anastomotic stenosis. Nevertheless, new problems such as stenosis of arteries and narrowing of surgical indication were also found. In this report, we presented a modified no-touch technique (MNTT) to create an RC-AVF, in which the venous and arterial wall avoid devascularization and the radial artery does not sever.

Since January 2021, we have applied the MNTT technique in 10 patients to construct AVF. Seven of the 10 patients have been under dialysis.
None of the patients had fever or infection after surgery. Physical examination of the cephalic-vein at weeks 4 and 8 showed significant dilation. Fistula can be palpable tremor with loud murmur. Doppler ultrasonography showed obvious dilation of the cephalic vein and radial artery. The blood flow spectrum of the cephalic vein 1.5 cm away from the anastomosis showed spiral laminar flow (Figure 3). The fistula constructed by MNTT can be punctured repeatedly with two needles. Blood flow of the brachial artery was &#62;600 mL/min (Table 1). Four hours of hemodialysis was successfully completed. None of the patients had any current vascular access-related complications.
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/62784/62784fig03.jpg" /> 
Figure 3. Postoperative ultrasound results. a: Juxta-anastomotic region. b: Spiral laminar flow was shown at the outflow tract vein and radial artery. c: Cephalic vein. d: Blood flow of cephalic vein (5 cm from the anastomosis). e: Blood flow of radial artery (1.5 cm from the anastomosis). f: Blood flow of brachial artery (elbow fossa). <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/62784/62784fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Table 1: Ultrasound results of the patient 4 and 8 weeks after RC-AVF surgery <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/62784/table1.zip" target="_blank">Please click here to download this Table.</a>

Watch this Scientific Journal Video about Creating Radio-cephalic Arteriovenous Fistula in the Forearm with a Modified No-Touch Technique at JoVE.com

Creating Radio-cephalic Arteriovenous Fistula in the Forearm with a Modified No-Touch Technique

We present a modified no-touch technique (MNTT) to create a radio-cephalic arteriovenous fistula (RC-AVF) in which the venous and arterial wall avoid devascularization and the radial artery does not sever.

Autologous arteriovenous fistula (AVF) is the primary and best option to obtain vascular access for hemodialysis treatment; other options are ...

creating-radio-cephalic-arteriovenous-fistula-forearm-with-modified

Universidad San Sebastian

Research

JoVE Journal

Medicine

7.2K Views.  Nanjing Medical University. We present a modified no-touch technique (MNTT) to create a radio-cephalic arteriovenous fistula (RC-AVF) in which the venous and arterial wall avoid devascularization and the radial artery does not sever.

Video: Creating Radio-cephalic Arteriovenous Fistula in the Forearm with a Modified No-Touch Technique

Technical Aspects of the Mouse Aortocaval Fistula

Technical aspects of creating an arteriovenous fistula in the mouse are discussed. Under general anesthesia, an abdominal incision is made, and the aorta and inferior vena cava (IVC) are exposed. The proximal infrarenal aorta and the distal aorta are dissected for clamp placement and needle puncture, respectively. Special attention is paid to avoid dissection between the aorta and the IVC. After clamping the aorta, a 25 G needle is used to puncture both walls of the aorta into the IVC. The surrounding connective tissue is used for hemostatic compression. Successful creation of the AVF will show pulsatile arterial blood flow in the IVC. Further confirmation of successful AVF can be achieved by post-operative Doppler ultrasound.

The goal is to produce an arteriovenous fistula that is simple and reproducible. This method does not use sutures or glue adhesive. Therefore the samples can be used with the least amount of foreign materials for analysis.

Technical aspects of creating an arteriovenous fistula in the mouse are discussed. Under general anesthesia, an abdominal incision is made, and the aorta ...

A Novel Murine Model of Arteriovenous Fistula Failure: The Surgical Procedure in Detail

The arteriovenous fistula (AVF) still suffers from a high number of failures caused by insufficient remodeling and intimal hyperplasia from which the exact pathophysiology remains unknown. In order to unravel the pathophysiology a murine model of AVF-failure was developed in which the configuration of the anastomosis resembles the preferred situation in the clinical setting. A model was described in which an AVF is created by connecting the venous end of the branch of the external jugular vein to the side of the common carotid artery using interrupted sutures. At a histological level, we observed progressive stenotic intimal lesions in the venous outflow tract that is also seen in failed human AVFs. Although this procedure can be technically challenging due to the small dimensions of the animal, we were able to achieve a surgical success rate of 97% after sufficient training. The key advantage of a murine model is the availability of transgenic animals. In view of the different proposed mechanisms that are responsible for AVF failure, disabling genes that might play a role in vascular remodeling can help us to unravel the complex pathophysiology of AVF failure.

Here we present a murine model of arteriovenous fistula (AVF) failure in which a clinically relevant anastomotic configuration is incorporated. This model can be used to study the pathophysiology and to test possible therapeutic interventions.

The arteriovenous fistula (AVF) still suffers from a high number of failures caused by insufficient remodeling and intimal hyperplasia from which the ...

Fabrication of Engineered Vascular Flaps Using 3D Printing Technologies

Engineering implantable, functional, thick tissues requires designing a hierarchical vascular network. 3D bioprinting is a technology used to create tissues by adding layer upon layer of printable biomaterials, termed bioinks, and cells in an orderly and automatic manner, which allows for creating highly intricate structures that traditional tissue engineering techniques cannot achieve. Thus, 3D bioprinting is an appealing in vitro approach to mimic the native vasculature complex structure, ranging from millimetric vessels to microvascular networks. 
Advances in 3D bioprinting in granular hydrogels enabled the high-resolution extrusion of low-viscosity extracellular matrix-based bioinks. This work presents a combined 3D bioprinting and sacrificial mold-based 3D printing approach for fabricating engineered vascularized tissue flaps. 3D bioprinting of endothelial and support cells using recombinant collagen-methacrylate bioink within a gelatin support bath is utilized for the fabrication of a self-assembled capillary network. This printed microvasculature is assembled around a mesoscale vessel-like porous scaffold, fabricated using a sacrificial 3D printed mold, and is seeded with endothelial cells. 
This assembly induces the endothelium of the mesoscale vessel to anastomose with the surrounding capillary network, establishing a hierarchical vascular network within an engineered tissue flap. The engineered flap is then directly implanted by surgical anastomosis to a rat femoral artery using a cuff technique. The described methods can be expanded for the fabrication of various vascularized tissue flaps for use in reconstruction surgery and vascularization studies.

Engineered flaps require an incorporated functional vascular network. In this protocol, we present a method of fabricating a 3D printed tissue flap containing a hierarchical vascular network and its direct microsurgical anastomoses to rat femoral artery.

Engineering implantable, functional, thick tissues requires designing a hierarchical vascular network. 3D bioprinting is a technology used to create ...

Bioengineering

Procurement and Perfusion-Decellularization of Porcine Vascularized Flaps in a Customized Perfusion Bioreactor

Large volume soft tissue defects lead to functional deficits and can greatly impact the patient&#39;s quality of life. Although surgical reconstruction can be performed using autologous free flap transfer or vascularized composite allotransplantation (VCA), such methods also have disadvantages. Issues such as donor site morbidity and tissue availability limit autologous free flap transfer, while immunosuppression is a significant limitation of VCA. Engineered tissues in reconstructive surgery using decellularization/recellularization methods represent a possible solution. Decellularized tissues are generated using methods that remove native cellular material while preserving the underlying extracellular matrix (ECM) microarchitecture. These acellular scaffolds can then be subsequently recellularized with recipient-specific cells.
This protocol details the procurement and decellularization methods used to achieve acellular scaffolds in a pig model. In addition, it also provides a description of the perfusion bioreactor design and setup. The flaps include the porcine omentum, tensor fascia lata, and the radial forearm. Decellularization is performed via ex vivo perfusion of low concentration sodium dodecyl sulfate (SDS) detergent followed by DNase enzyme treatment and peracetic acid sterilization in a customized perfusion bioreactor.
Successful tissue decellularization is characterized by a white-opaque appearance of flaps macroscopically. Acellular flaps show the absence of nuclei on histological staining and a significant reduction in DNA content. This protocol can be used efficiently to generate decellularized soft tissue scaffolds with preserved ECM and vascular microarchitecture. Such scaffolds can be used in subsequent recellularization studies and have the potential for clinical translation in reconstructive surgery.

The protocol describes the surgical procurement and subsequent decellularization of vascularized porcine flaps by the perfusion of sodium dodecyl sulfate detergent through the flap vasculature in a customized perfusion bioreactor.

Large volume soft tissue defects lead to functional deficits and can greatly impact the patient&#39;s quality of life. Although surgical reconstruction ...

Transvenous Embolization of Carotid Cavernous Fistula through Inferior Petrosal Sinus with Detachable Coils and Ethylene Vinyl Alcohol Copolymer

Carotid cavernous fistula (CCF) is a rare disease caused by abnormal communications between the internal carotid artery (direct fistula) or meningeal branches of the external carotid artery (indirect fistula) and the cavernous sinus (CS). Trauma is the most common cause of CCF. The clinical presentation of CCF is closely related to the venous drainage pattern. Orbital and neuro-ophthalmological symptoms are the most common clinical presentation of CCF with drainage through the superior ophthalmic vein (SOV). Endovascular embolization by arterial or venous approaches is the most common management of CCF. Transvenous embolization using detachable coils and ethylene-vinyl alcohol copolymer (EVOH) is an alternative method for the treatment of CCF. Endovascular embolization offers different options to treat CCF by minimally invasive approach decreasing morbidity and residual fistulas. The purpose of this article is to report our treatment experiences via the inferior petrosal sinus (IPS), and immediate-term outcomes of endovascular embolization of CCF by using detachable coils and EVOH.

The purpose of the article is to present our experience in endovascular treatment via the inferior petrosal sinus of the carotid cavernous fistula with detachable coils and ethylene-vinyl alcohol copolymer.

Carotid cavernous fistula (CCF) is a rare disease caused by abnormal communications between the internal carotid artery (direct fistula) or meningeal ...

A Modified Cuff Technique for Mouse Cervical Heterotopic Heart Transplantation Model

Cardiac allograft rejection limits the long-term survival of patients after heart transplantation. A mouse heart transplantation model is ideal for investigating the mechanism of cardiac allograft rejection in preclinical studies because of their high homology with human genes. This understanding would help develop unique approaches to improving patients&#39; long-term survival treated with cardiac allografts. In a mouse model, abdominal donor heart implantation is commonly performed with an end-to-end&#160;anastomosis to the recipient&#39;s aorta and inferior vena cava using stitches. In this model, the donor&#39;s heart is implanted by end-to-end anastomosis to the recipient&#39;s carotid artery and jugular vein by the modified-Cuff technique. The transplantation surgery is performed without stitching and thus may increase the survival of the recipient since there is no interference with the blood supply and venous reflux of the lower body. This mouse model would help investigate the mechanisms underlying the immunological and pathological (acute/chronic) rejection of cardiac allografts.

In the present protocol, a mouse heart transplantation model is used for investigating the mechanism of cardiac allograft rejection. In this heterotopic heart transplantation model, operation efficiency is improved, and the survival of cardiac grafts is ensured by a cervical end-to-end anastomosis of heart implantation using a modified Cuff technique.

Cardiac allograft rejection limits the long-term survival of patients after heart transplantation. A mouse heart transplantation model is ideal for ...

A Murine Model of Hemodialysis Access-Related Hand Dysfunction

Chronic kidney disease is a major public health problem, and the prevalence of end-stage renal disease (ESRD) requiring chronic renal replacement therapies such as hemodialysis continues to increase. Autogenous arteriovenous fistula (AVF) placement remains a primary vascular access option for ESRD patients. Unfortunately, approximately half of the hemodialysis patients experience dialysis access-related hand dysfunction (ARHD), ranging from subtle paresthesia to digital gangrene. Notably, the underlying biologic drivers responsible for ARHD are poorly understood, and no adequate animal model exists to elucidate the mechanisms and/or develop novel therapeutics for the prevention/treatment of ARHD. Herein, we describe a new mouse model in which an AVF is created between the left common iliac artery and vein, thereby facilitating the assessment of limb pathophysiology. The microsurgery includes vessel isolation, longitudinal venotomy, creation of arteriovenous anastomosis, and venous reconstruction. Sham surgeries include all the critical steps except for AVF creation. Iliac AVF placement results in clinically relevant alterations in central hemodynamics, peripheral ischemia, and impairments in hindlimb neuromotor performance. This novel preclinical AVF model provides a useful platform that recapitulates common neuromotor perturbations reported by hemodialysis patients, allowing researchers to investigate the mechanisms of ARHD pathophysiology and test potential therapeutics.

This protocol details the surgical steps of murine common iliac arteriovenous fistula creation. We developed this model to study hemodialysis access-related limb pathophysiology.

Chronic kidney disease is a major public health problem, and the prevalence of end-stage renal disease (ESRD) requiring chronic renal replacement ...

A Modified Technique for Arteriovenous Fistula Construction in Rabbits

Juxta-anastomotic stenosis is a challenging problem that often causes non-maturation and decreases the patency of an arteriovenous fistula (AVF). Injury to the veins and arteries during the operation and hemodynamic changes can lead to intimal hyperplasia, leading to juxta-anastomotic stenosis. To reduce injury to the veins and arteries during the operation, this study proposes a new modified no-touch technique (MNTT) for AVF construction that can decrease the rate of juxta-anastomotic stenosis and improve the AVF patency. To unravel the hemodynamic changes and mechanisms of the MNTT, this study presented an AVF procedure using this technique. Although this procedure is technically challenging, 94.4% procedural success was achieved after adequate training. Ultimately, 13 out of 34 rabbits had a functional AVF 4 weeks after the surgery, leading to a 38.2% AVF patency rate. However, at 4 weeks, the survival rate was 86.1%. Ultrasonography showed active blood flow through AVF anastomosis. Furthermore, the spiral laminar flow was observed in the vein and artery near the anastomosis, suggesting that this technique may improve the hemodynamics of the AVF. On histological observation, significant venous intimal hyperplasia was observed at the AVF anastomosis, whereas no significant intimal hyperplasia was observed at the proximal external jugular vein (EJV) of the anastomosis. This technique will improve the understanding of the mechanisms underlying the use of MNTT for AVF construction and provide technical support for the further optimization of the surgical approach in AVF construction.

The present protocol proposes the creation of an arteriovenous fistula in rabbits using a modified no-touch technique. The technique involves the side-to-side anastomosis of the common carotid artery and external jugular vein without the dissection of the perivenous tissues or cutting off the artery.

Juxta-anastomotic stenosis is a challenging problem that often causes non-maturation and decreases the patency of an arteriovenous fistula (AVF). Injury ...

Reduction of Radiation Exposure during Endovascular Treatment of Peripheral Arterial Disease Combining Fiber Optic RealShape Technology and Intravascular Ultrasound

Vascular surgeons and interventional radiologists face chronic exposure to low-dose radiation during endovascular procedures, which may impact their health in the long term due to their stochastic effects. The presented case shows the feasibility and efficacy of combining Fiber Optic RealShape (FORS) technology and intravascular ultrasound (IVUS) to reduce operator exposure during the endovascular treatment of obstructive peripheral arterial disease (PAD). 
FORS technology enables real-time, three-dimensional visualization of the full shape of guidewires and catheters, embedded with optical fibers that use laser light instead of fluoroscopy. Hereby, radiation exposure is reduced, and spatial perception is improved while navigating during endovascular procedures. IVUS has the capacity to optimally define vessel dimensions. Combining FORS and IVUS in a patient with iliac in-stent restenosis, as shown in this case report, enables passage of the stenosis and pre- and post-percutaneous transluminal angioplasty (PTA) plaque assessment (diameter improvement and morphology), with a minimum dose of radiation and zero contrast agent. The aim of this article is to describe the method of combining FORS and IVUS stepwise, to show the potential of merging both techniques in view of reducing radiation exposure and improving navigation tasks and treatment success during the endovascular procedure for the treatment of PAD.

Described here is a stepwise method of combining Fiber Optic RealShape technology and intravascular ultrasound to show the potential of merging both techniques, in view of the reduction of radiation exposure and improvement of navigation tasks and treatment success during an endovascular procedure for the treatment of peripheral arterial disease.

Vascular surgeons and interventional radiologists face chronic exposure to low-dose radiation during endovascular procedures, which may impact their ...

Modified Arteriovenous Fistula Surgery to Establish the RV Volume Overload Mouse Model

Establishment and Confirmation of a Postnatal Right Ventricular Volume Overload Mouse Model

Right ventricular (RV) volume overload (VO) is common in children with congenital heart disease. In view of distinct developmental stages,the RV myocardium may respond differently to VO in children compared to adults. The present study aims to establish a postnatal RV VO model in mice using a modified abdominal arteriovenous fistula. To confirm the creation of VO and the following morphological and hemodynamic changes of the RV, abdominal ultrasound, echocardiography, and histochemical staining were performed for 3 months. As a result, the procedure in postnatal mice showed an acceptable survival and fistula success rate. In VO mice, the RV cavity was enlarged with a thickened free wall, and the stroke volume was increased by about 30%-40% within 2 months after surgery. Thereafter, the RV systolic pressure increased, corresponding pulmonary valve regurgitation was observed, and small pulmonary artery remodeling appeared. In conclusion, modified arteriovenous fistula (AVF) surgery is feasible to establish the RV VO model in postnatal mice. Considering the probability of fistula closure and elevated pulmonary artery resistance, abdominal ultrasound and echocardiography must be performed to confirm the model status before application.

Author Spotlight: Establishment and Confirmation of a Postnatal Right Ventricular Volume Overload Mouse Model  

This protocol presents the establishment and confirmation of a postnatal right ventricular volume overload (VO) model in mice with abdominal arteriovenous fistula (AVF), which can be applied to investigate how VO contributes to postnatal heart development.