Adding access blood flow surveillance reduces thrombosis and improves arteriovenous fistula patency: a randomized controlled trial

Purpose

Stenosis is the main cause of arteriovenous fistula (AVF) failure. It is still unclear whether surveillance based on vascular access blood flow (Q_A) enhances AVF function and longevity.

Methods

We conducted a three-year follow-up randomized, controlled, multicenter, open-label trial to compare Q_A-based surveillance and pre-emptive repair of subclinical stenosis with standard monitoring/surveillance techniques in prevalent mature AVFs. AVFs were randomized to either the control group (surveillance based on classic alarm criteria; n = 104) or to the Q_A group (Q_A measured quarterly using Doppler ultrasound [M-Turbo^®] and ultrasound dilution [Transonic^®] added to classic surveillance; n = 103).

The criteria for intervention in the Q_A group were: 25% reduction in Q_A, Q_A<500 mL/min or significant stenosis with hemodynamic repercussion (peak systolic velocity [PSV] more than 400 cm/sc or PSV pre-stenosis/stenosis higher than 3).

Results

At the end of follow-up we observed a significant reduction in the thrombosis rate in the Q_A group (0.025 thrombosis/patient/year in the Q_A group vs. 0.086 thrombosis/patient/year in the control group [p = 0.007]). There was a significant improvement in the thrombosis-free patency rate (HR, 0.30; 95% CI, 0.11-0.82; p = 0.011) and in the secondary patency rate in the Q_A group (HR, 0.49; 95% CI, 0.26-0.93; p = 0.030), with no differences in the primary patency rate between the groups (HR, 0.98; 95% CI, 0.57-1.61; p = 0.935).

There was greater need for a central venous catheter and more hospitalizations associated with vascular access in the control group (p = 0.034/p = 0.029).

Total vascular access-related costs were higher in the control group (€227.194 vs. €133.807; p = 0.029).

Conclusions

Q_A-based surveillance combining Doppler ultrasound and ultrasound dilution reduces the frequency of thrombosis, is cost effective, and improves thrombosis free and secondary patency in autologous AVF.