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.

Selecting important predictors for arteriovenous fistula maturation in older hemodialysis patients by using random survival forests

“…A prediction model including AVF blood flow, diameter, and depth at 1 day and 2 and 6 weeks after AVF placement achieved C statistics of 0.69, 0.74, and 0.79, respectively, for unassisted maturation and 0.69, 0.71, and 0.76, respectively, for overall AVF maturation. Patient's case‐mix factors including age, gender, race, dialysis status, diabetes, BMI, and AVF location (forearm versus upper arm) were not associated with unassisted or overall AVF maturation . We highly recommend future studies to further evaluate these parameters for possibilities to include ultrasound evaluation as a routine clinical practice.…”

“…A larger proportion of matured AVF were abandoned in females (21%) than in males (16% with unassisted or overall AVF maturation. 11 We highly recommend future studies to further evaluate these parameters for possibilities to include ultrasound evaluation as a routine clinical practice.…”

AIUM Practice Parameter for the Performance of Vascular Ultrasound Examinations for Postoperative Assessment of Hemodialysis Access

“…A prospective study of 602 fistulas suggested that low blood flow and a small venous diameter at 2 weeks are predictive of AVFs that may not develop optimally at 6 weeks . A follow‐up evaluation of the 602 AVFs showed that measurement of the AVF blood flow rate, AVF diameter, and distance of the anterior AVF vein wall from the skin was moderately predictive of AVF maturation . A separate study showed an increased risk of failure to mature if blood flow was less than 413 mL/min at 2 weeks after fistula creation …”

“…If no stenosis is identified, thresholds for the AVF vein diameter and blood flow and AVF depth from the skin may suggest whether the AVF is adequately mature for hemodialysis . An AVF with a venous diameter of at least 0.4 to 0.6 cm and blood flow of at least 500 to 600 mL/min predicts that an AVF has a high likelihood of supporting successful hemodialysis .…”

Strategies to improve vascular access outcomes in haemodialysis patients

“…Results from the Haemodialysis Fistula Maturation (HFM) study are expected to advance our understanding of anatomical, biological and clinical characteristics, as well as processes of care associated with enhanced AVF usability254 . This study has recruited 602 patients undergoing single-stage AVF surgery in the US and already provided information on clinical and post-operative processes of care predictors of AVF maturation255,256 . Assessment of pre-operative vessel characteristics, anaesthetic (e.g.…”