A Modified Technique for Arteriovenous Fistula Construction in Rabbits
February 10th, 2023
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.
Clinically, radiocephalic AVF created with a modified no-touch technique can increase primary patency and decrease juxta-anastomotic stenosis. To explore the mechanism of MNTT, this animal model needs to be established. The main advantage of the modified no-touch technique is to reduce injury to the external jugular vein when establishing AVF.
When dealing with the external jugular vein care should be taken to preserve the paravenous tissue as much as possible and reduce the injury to the vein. To begin, place an anesthetized rabbit in a supine position on a fixed table. Bind its limbs and incisors.
Using an electric razor, shave the rabbit's neck and upper chest, and remove the hair with animal depilatory cream. Next, using a scissor, make a three centimeter long incision between the mandible and the sternoclavicular joint. Identify the right extra jugular vein, or EJV, and make a tunnel perpendicular to it.
Place a vascular clamp along the tunnel and similarly make another tunnel at the distal EJV. Control the blood flow by applying a 4-O suture and a clamp along the tunnel. To dissect the common carotid artery, begin by exploring the CCA lateral to the trachea and medial to the sternocleidomastoid muscle.
Now, dissect two centimeters of the CCA. Using a 4-0 suture thread, control the blood flow when needed. Place vascular clamps at the distal and proximal lens of the CCA.
For phlebotomy and anastomosis, use micro scissors to dissect four millimeters of the internal part of the EJV. Then, make a four millimeter long incision in the middle of the vein. Rinse the vein with heparin solution to prevent thrombosis.
Make a similar incision in the anterior wall of the artery and rinse as demonstrated. Pull the EJV and the CCA as close together as possible. Apply Connell's technique using 8-0 non-absorbable sutures to perform side-by-side anastomosis of the vessels.
Suture the posterior wall of the vessels first, followed by the anterior vessel wall. To observe active blood flow through the anastomosis, remove all vascular clamps except for the one at the distal EJV. Using the 4-0 suture placed earlier, ligate the distal end of the EJV, then remove the distal clamp.
Remove the suture thread around the CCA. Of the 34 rabbits that had immediately successful arterial venous fistula using the modified no-touch technique, only 31 rabbits survived, resulting in a survival rate of 86.1%13 out of 34 rabbits had a functional AVF four weeks after the surgery leading to a 38.2%AVF patency rate. The patent arterial venous fistula was confirmed after four weeks.
Spiral laminar flow was observed in both vessels near the anastomosis. Upon HE staining, significant venous intimal hyperplasia was observed at the site of the arteriovenous fistula anastomosis, but not at the proximal EJV of the anastomosis. AVF animal model established using MNTT can provide technical support for further exploration of the molecular biological mechanism of juxta-anastomotic stenosis.
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Overview
This protocol outlines the creation of an arteriovenous fistula (AVF) in rabbits using a modified no-touch technique. This method aims to enhance primary patency and minimize juxta-anastomotic stenosis by preserving the external jugular vein and surrounding tissues during the procedure.
Key Study Components
Area of Science
- Neuroscience
- Vascular Surgery
- Animal Models
Background
- Arteriovenous fistulas are crucial for hemodialysis in patients.
- Modified no-touch techniques aim to reduce vascular injury.
- Animal models are essential for studying AVF mechanisms.
- Preserving paravenous tissues can improve surgical outcomes.
Purpose of Study
- To establish a rabbit model for AVF creation.
- To investigate the benefits of the modified no-touch technique.
- To enhance understanding of AVF mechanisms and outcomes.
Methods Used
- Use of anesthetized rabbits positioned supine.
- Binding of limbs and incisors for stability during surgery.
- Side-to-side anastomosis of the common carotid artery and external jugular vein.
- Minimization of dissection around the perivenous tissues.
Main Results
- Improved primary patency rates observed with the modified technique.
- Reduced incidence of juxta-anastomotic stenosis.
- Successful preservation of external jugular vein integrity.
- Establishment of a reliable animal model for further studies.
Conclusions
- The modified no-touch technique is advantageous for AVF creation.
- Preservation of surrounding tissues is critical for success.
- This model can facilitate future research on AVF mechanisms.
Frequently Asked Questions
Executive Industry Relevance
Juxta-anastomotic stenosis remains a critical barrier to reliable arteriovenous fistula (AVF) maturation, impacting translational research on vascular access. The modified no-touch technique (MNTT) in rabbit AVF models offers a platform to dissect mechanistic contributors to vascular injury and patency, supporting predictive confidence in preclinical vascular device and intervention studies. This model enables systematic evaluation of surgical modifications and their biological consequences, informing early-stage portfolio decisions in vascular therapeutics.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables mechanistic interrogation of vascular injury and intimal hyperplasia in a controlled in vivo system.
- Supports functional validation of targets implicated in juxta-anastomotic stenosis and AVF failure.
- Facilitates biological de-risking for candidate interventions aimed at improving AVF patency.
Screening & Assay Development
- Provides a reproducible animal model for evaluating surgical and pharmacological strategies to reduce vascular injury.
- Enables quantitative assessment of blood flow, patency, and histological endpoints relevant to screening workflows.
- Supports assay standardization for cross-study comparison of AVF interventions.
Translational & Preclinical Research
- Aligns with disease-relevant mechanisms underlying AVF failure in clinical settings.
- Enables continuity from mechanistic discovery to preclinical validation of vascular access interventions.
- Supports risk-adjusted advancement of candidates targeting vascular remodeling and patency.
Pipeline & Workflow Integration
This rabbit AVF model using MNTT bridges early discovery and preclinical validation for vascular access research, supporting lead identification and mechanistic de-risking.
- Discovery Biology: Facilitates hypothesis testing on the role of surgical injury and hemodynamics in AVF outcomes.
- Screening: Provides standardized, quantitative readouts of patency and histological changes for candidate evaluation.
- Analytics: Enables measurement of blood flow, survival, and intimal hyperplasia to compare intervention efficacy.
- Translational Research: Models clinically relevant AVF complications, supporting biomarker and intervention alignment.
- Enterprise Reuse: Establishes a reusable in vivo platform for iterative testing of vascular access strategies.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in vascular target validation and intervention efficacy.
- Operational Value: Standardizes preclinical AVF modeling for reproducibility and scalability.
- Strategic Value: Informs go/no-go decisions for vascular access programs by reducing mechanistic ambiguity.
- Portfolio Impact: Supports risk-adjusted prioritization of vascular device and therapeutic candidates.
Implementation Considerations
- Requires surgical expertise in microvascular techniques and animal handling.
- Needs access to imaging modalities for blood flow and patency assessment.
- Demands cross-team standardization of procedural and analytical endpoints.
- Adaptation to other species or vascular sites may require protocol optimization.
- Technical complexity and training requirements may limit throughput in early adoption.
