The effect of immediate postoperative increase in blood flow velocity in predicting maturation of arteriovenous fistula for dialysis

Background
Doppler ultrasonography is the main imaging modality for hemodialysis arteriovenous fistula (AVF) as it is safe, accurate, and noninvasive. Published literature related to the utility of early postoperative ultrasound in predicting AVF maturation is scarce. With the KDOQI guidelines recommending an AVF first catheter last approach, the quest to increase AVF maturation is of utmost importance. This study aims at measuring blood flow immediately postoperatively and assessing its predictive role in AVF maturation.
Methods
We correlated the ultrasound parameters with maturation in newly created AVFs measured preoperatively, immediately postoperatively, 6 weeks, and 3, 6, and12 months postoperatively. Both demographics and vascular parameters were compared between the group of patients whose AVFs successfully maturated and those whose AVFs did not. Primary endpoint was AVF maturation; secondary endpoints included patency, functional success, and predictive value of increased vein blood flow on fistula patency.
Results
A total of 50 procedures were performed; the mean age was 52.12 years (±6.58). The overall technical success rate was 86% (43) and 39 (90.7%) of them were functionally mature according to KDOQI guidelines for maturation. Primary patency was 93.02%, 92.7%, and 88.89%; and the primary-assisted patency was 97.7%, 95.12%, and 91.67% at 3, 6, and 12 months, respectively. Receiver-operated curve (ROC) showed a cutoff value of 322.8 ml/min increase in blood flow above which the AVF is more likely to become mature. Binary logistic regression showed that arterial depth greater than 3.92 mm, arterial flow velocity greater than 88 ml/min, preoperative average vein diameter of greater than 2.5 mm, arterial flow velocity of greater than 73 ml/min immediately postoperatively, and average vein diameter of greater than 3.94 mm immediately postoperatively were significant predictors of successful maturation at 6 weeks postoperatively ( values 0.001, <0.0001, <0.0001, <0.0001, and <0.0001, respectively).
Conclusion
Immediately postoperative flow measurement is a reliable parameter that can be used to predict successful fistula maturation, especially if flow velocities exceed 326.15 ml/min.