Abstract: TH-PO765

Influence of Arterial Dilatation on Fistula Maturation with Adequate Blood Flow: Supports Concept That Arterial Elasticity Has Key Role

Session Information

Category: Dialysis

  • 603 Hemodialysis: Vascular Access

Authors

  • Paulson, William D., Augusta University, Augusta, Georgia, United States
  • Bastola, Sulav, Charu Polyclinic and Diagnostic Center, Kathmandu, Nepal
  • Jones, Steven A., Louisiana Tech University, Ruston, Louisiana, United States
Background

Fistula maturation success is strongly dependent on adequate dilatation of the inflow artery and outflow vein. The Rule of 6s emphasizes an adequate vein luminal diameter is needed to allow successful cannulation. However, poor arterial elasticity is associated with maturation failure, probably because of failure of the inflow artery to dilate adequately. We further explored this issue by applying a mathematical model of the fistula in which the outflow vein dilates but the artery dilates minimally or not at all.

Methods

Mathematical model was a brachiocephalic fistula that included cephalic vein anastomosed end to side to the brachial artery; ulnar artery; palmar arch; and vein that drains the hand and connects to the cephalic vein. We set mean arterial pressure = 93 mmHg, central venous pressure = 5 mmHg. We predicted fistula blood flow at dilated vein luminal diameters ranging from 4 to 8 mm, and arterial diameters ranging from 2 to 6 mm. We also evaluated influence of stenosis at arteriovenous anastomosis on blood flow.

Results

A fistula with an arterial diameter of 2 mm is predicted to have a blood flow ranging from only 232 to 241 ml/min despite widely accepted adequate venous diameters ranging from 4 to 8 mm. Even arterial dilatation to 3 mm diameter will provide only marginal blood flows ranging from 581 to 665 ml/min. Flows in the range of 1,000 ml/min or more require an arterial diameter of at least approximately 4 mm. Development of stenosis at the arteriovenous anastomosis will significantly impair flow and thereby require even larger arterial diameters if blood flow is to be adequate.

Conclusion

These results support the concept that dilatation of the inflow artery is a key step in fistula maturation. Arterial properties are as important as venous in assessing suitability of vessels for fistula formation. Poor arterial elasticity may result in a high resistance fistula circuit despite adequate dilatation of the outflow vein. An arterial diameter of 2 mm is widely accepted as a minimally acceptable preoperative diameter, but such an artery cannot support adequate blood flow unless it is able to dilate.

 Fistula blood flow (ml/min) at inflow artery luminal diameters ranging from 2 to 6 mm
Vein diameter2 mm3 mm4 mm5 mm6 mm
4 mm23258197112211352
6 mm240652134420972715
8 mm241665144524933626

Funding

  • Clinical Revenue Support