A non-invasive method in the assessment of surgically created arteriovenous fistulae for uraemia

Subcutaneous arteriovenous fistulae are constructed regularly for haemodialysis in uraemia. However there is little available data on fistula blood flow patterns. Twenty-eight radio-cephalic fistulae constructed for 18 patients were examined over a 3-month-period using range gated pulsed Doppler ultrasound. Contralateral arms were also examined. The parameters measured were mean arterial and venous diameter, mean volume flow and mean velocity flow. The values obtained from successful and failed fistulae were compared. There was no statistical difference between either arterial or venous diameter in the two groups. Mean velocity flow and mean volume flow in the successful group however did differ significantly from those that failed. Unless the values obtained at 48 h are significantly higher than the contralateral arm, then the fistula seems unlikely to succeed. It would also seem that a simple Doppler flow meter which gives reliable mean velocity flow values is sufficient for these investigations and may even be used preoperatively, resulting in fewer re-operations.