Prediction of Arteriovenous Fistula Clinical Maturation from Postoperative Ultrasound Measurements: Findings from the Hemodialysis Fistula Maturation Study

Abstract

Background: The utility of early postoperative ultrasound measurements in predicting arteriovenous fistula (AVF) clinical maturation is uncertain.

Methods: We investigated the relationships of ultrasound parameters with AVF clinical maturation in newly created AVF, measured at 1 day and 2 and 6 weeks, in 602 participants of a multicenter, observational cohort study. A backward elimination algorithm identified ultrasound measurements that independently predicted unassisted and overall AVF maturation. Candidate variables included AVF blood flow, diameter, and depth, upper arm arterial diameter, presence of stenosis, presence of accessory veins, seven case-mix factors (age, sex, black race, AVF location, diabetes, dialysis status, and body mass index), and clinical center. We evaluated the accuracy of the resulting models for clinical prediction.

Results: At each ultrasound measurement time, AVF blood flow, diameter, and depth each predicted in a statistically significant manner both unassisted and overall clinical maturation. Moreover, neither the remaining ultrasound parameters nor case-mix factors were associated with clinical AVF maturation after accounting for blood flow, diameter, and depth, although maturation probabilities differed among clinical centers before and after accounting for these parameters. The crossvalidated area under the receiver operating characteristic curve for models constructed using these three ultrasound parameters was 0.69, 0.74, and 0.79 at 1 day and 2 and 6 weeks, respectively, for unassisted AVF clinical maturation and 0.69, 0.71, and 0.76, respectively, for overall AVF maturation.

Conclusions: AVF blood flow, diameter, and depth moderately predicted unassisted and overall AVF clinical maturation. The other factors considered did not further improve AVF maturation prediction.

Keywords: Ultrasonography; access blood flow; arteriovenous fistula; clinical trial; dialysis access; hemodialysis.

Figure 1.

The figure displays how the probability of overall maturation increases at higher AVF blood flow and at higher vein diameter, but decreases at higher vein depth. A cubic spline in AVF blood flow was used to account for nonlinear association. The depicted levels of vein diameter and vein depth represent the 5th, 50th, and 95th percentiles.

Figure 2.

The cross-validated receiver operating characteristic curve displayed in the figure shows that the multivariable model based on 6-week AVF blood flow, diameter, and depth provides moderately accurate prediction of unassisted clinical maturation. The sensitivities and specificities of prediction of clinical maturation using the KDOQI and UAB criteria are also displayed. Crossvalidated areas under the receiver operating characteristic curves for prognostic models on the basis of only the three ultrasound parameters increased from 0.69 at 1 day to 0.74 and 0.79 at 2 and 6 weeks. KDOQI criteria: AVF blood flow ≥600 ml/min, vein diameter ≥0.6 cm, and vein depth ≤0.6 cm; UAB criteria: AVF blood flow ≥500 ml/min and vein diameter ≥0.4 cm.