What are the technical steps to performing a revision using distal inflow for vascular access?

Technical Steps for Revision Using Distal Inflow (RUDI) Procedure

Revision Using Distal Inflow (RUDI) is an effective surgical technique for treating dialysis access-associated steal syndrome (DASS) and pathologic high flow in arteriovenous fistulas by relocating the arterial inflow to a more distal artery while preserving the existing access. 1, 2

Indications for RUDI

• RUDI is primarily indicated for patients with dialysis access-associated steal syndrome (DASS) or pathologic high flow (>2 L/min) in brachial artery-based arteriovenous fistulas 3
• RUDI is particularly beneficial for patients with upper arm fistulas who have developed hand ischemia or cardiac symptoms due to excessive flow 1, 4
• RUDI is considered when other interventions such as banding have failed or are not suitable 3

Preoperative Assessment

• Perform diagnostic fistulography to evaluate the entire arterial inflow from the aortic arch to the palmar arch, with and without occlusion of the AV access 1
• Assess hemodynamic parameters including access flow volume measurements and digital pressures 4
• Identify suitable distal arterial inflow sources (typically proximal radial or ulnar artery) 2
• Evaluate venous outflow and potential conduit options (autologous vein preferred) 5

Technical Steps of the RUDI Procedure

1. Access and Exposure:

   • Position the patient supine with the affected arm extended on an arm board 6
   • The procedure can be performed under local or general anesthesia depending on patient factors 6
   • Expose the existing arteriovenous fistula at the anastomosis site 2

2. Fistula Ligation and Preparation:

   • Ligate the fistula at its origin from the brachial artery 2
   • Mobilize the venous outflow component of the fistula sufficiently to allow for reanastomosis 6
   • Expose the selected distal inflow artery (proximal radial or ulnar artery) 2, 3

3. Conduit Preparation:

   • Harvest an autologous vein conduit, typically from the great saphenous vein 5
   • Alternatively, use a venous collateral from the existing fistula if suitable 6
   • Prepare the conduit by reversing it, ligating side branches, and sizing it appropriately 5

4. Creation of New Anastomosis:

   • Perform an end-to-side anastomosis between the conduit and the selected distal artery (proximal radial or ulnar) 2
   • Create a tunnel for the conduit in a subcutaneous position 5
   • Complete the procedure with an end-to-end anastomosis joining the conduit to the venous outflow portion of the original fistula 5, 2

5. Verification and Closure:

   • Confirm adequate flow through the revised access 3
   • Verify resolution of steal symptoms by checking distal pulses and perfusion 2
   • Close the incisions in layers with attention to hemostasis 6

Post-Procedure Management

• Monitor the access for patency and function 3
• Assess for symptom resolution (pain, pallor, sensorimotor dysfunction) 2
• Allow appropriate maturation time before cannulation, typically 4-6 weeks 7
• Perform follow-up duplex ultrasound to evaluate flow characteristics 4

Expected Outcomes and Monitoring

• Mean flow reduction of approximately 1200 mL/min can be expected after RUDI 3
• Complete resolution of ischemic symptoms occurs in approximately 69% of patients, with partial improvement in the remaining 31% 3
• One-year primary assisted patency rates of approximately 74% 3
• Monitor for potential recurrence of high flow, which may occur due to persistent brachial artery dilatation 4

Advantages of RUDI Over Other Techniques

• RUDI preserves the existing access while treating steal syndrome 2
• Unlike DRIL (Distal Revascularization-Interval Ligation), RUDI places the fistula at risk rather than the native arterial supply 2
• RUDI effectively decreases the radius of the inflow vessel and lengthens the fistula, both of which reduce flow 2
• The procedure can often be performed under local anesthesia, reducing surgical risk 6

RUDI represents an effective surgical option for treating dialysis access-associated steal syndrome while preserving the functionality of the existing access, with good technical success rates and symptom resolution.