Hemodynamics of distal revascularization-interval ligation

Area of Science:

• Vascular Surgery
• Hemodynamics
• Dialysis Access

Background:

• Distal revascularization-interval ligation (DRIL) is a common surgical technique to address steal phenomenon after arteriovenous fistula (AVF) creation.
• The precise mechanism by which DRIL improves distal perfusion remains incompletely understood, despite its empirical effectiveness.
• Understanding the hemodynamic changes post-DRIL is crucial for optimizing AVF outcomes in patients with steal syndrome.

Purpose of the Study:

• To investigate the hemodynamic alterations responsible for the effectiveness of DRIL in symptomatic patients with upper arm autologous AVFs.
• To elucidate the pressure and flow dynamics at critical arterial segments before and after DRIL intervention.

Main Methods:

• Intravascular pressure and flow measurements were performed in nine symptomatic patients before and after DRIL.
• Measurements were taken at the proximal brachial artery (PROX) and the arteriovenous (AV) anastomosis.
• Flow dynamics distal to the AV anastomosis were assessed with and without fistula occlusion.

Main Results:

• DRIL did not significantly alter pressures at the PROX and AV ANAST sites.
• However, pressure at the flow split point (distal brachial artery) increased significantly post-DRIL (from 47 +/- 38 mmHg to 104 +/- 24 mmHg).
• Post-DRIL, distal flow to the hand became antegrade (51 +/- 39 mL/min) and pressure increased significantly (104 +/- 27 mmHg).

Conclusions:

• DRIL enhances hand perfusion by increasing pressure at the flow split point, promoting antegrade flow to the distal limb.
• This hemodynamic effect is attributed to increased resistance created by the interposed arterial segment, functionally similar to fistula banding.
• DRIL represents a physiologically acceptable method to increase fistula resistance and improve distal perfusion.