UDT monitoring increased the rate of angioplasty procedures and thereby shortened primary unassisted patency, but did not decrease the thrombosis rate or improve cumulative fistula patency.

Conclusion:A monitoring strategy for autogenous arterial venous fistulas using an ultrasound dilution technique (UDT) with prophylactic angioplasty of detected stenoses does not decrease thrombosis rates or improve fistula patency.Summary: It is widely believed that regular access monitoring to detect access stenoses and subsequent prophylactic treatment before thrombosis will result in overall improved fistula patency. It has, however, been previously determined that early correction of graft stenoses before thrombosis did not improve overall graft patency for dialysis access (Kidney Int 2004; 66:390-8). Because the situation may be different for native arteriovenous fistulas, the authors chose to study their dialysis access monitoring technique for influence on access thrombosis and failure.Monthly access monitoring of arteriovenous fistulas using UDT was instituted at the authors' institution in 1999. They used a sequential observational trial design to assess the influence of this strategy on overall fistula patency. Group 1, a historic control group treated primarily before 1999, had 146 arteriovenous fistulas (50.7% upper arm) and was followed up for 259 access years. The group 2 patients had 76 arteriovenous fistulas (60.5% in the upper arm) and were followed up with UDT monitoring for 123 access years. Referral to angiography and possible angioplasty was based on clinical criteria for group 1 and a combination of clinical criteria and UDT flow-monitoring in group 2. Group 2 patients (monitored group) had a sevenfold increase in angioplasty procedures (0.67 vs 0.99 per access year); however, no improvement was noted in overall thrombosis rate or cumulative fistula patency.Comment: Vascular laboratory monitoring for development of stenoses in dialysis access grafts and fistula appears to be unnecessary. This study and the one referenced do not justify sequential monitoring of dialysis access fistulas or grafts, at least with the monitoring techniques used.