The following is a summary of “Optimal flow volume measurements in forearm versus arm arteriovenous fistulas,” published in the March 2023 issue of Nephrology by Yii, et al.

Arteriovenous (AV) access flow must be at its best for hemodialysis to be effective. Although the National Kidney Foundation recommends a functional flow volume (Qa) essential threshold of 600 ml/min, this may not apply to all AV fistulas (AVF) or AV grafts (AVG) due to their various designs. Therefore, to determine whether there is considerable flow-related AV dysfunction, they assessed the Qa measurement obtained from ultrasound in the input brachial artery to autologous AVF in the forearm radiocephalic and arm brachiocephalic/basilic configurations.

A total of 511 duplex ultrasound (DUS) scans were analyzed in 193 patients. The study assessed whether there were therapeutic interventions or thrombosis of AVF within 3 months of the scan. Receiver operating characteristic (ROC) curves were used to determine the optimal threshold Qa in the brachial artery supplying the AVF.

Out of the 511 scans, 155 scans were assigned to the intervention group, indicating AVF requiring intervention or thrombosis within 3 months. ROC curve analysis showed an area under the curve (AUC) of 0.90 (CI: 0.88-0.93) for all AVF, with an optimal threshold Qa of 686 ml/min. In forearm AVF, the threshold Qa was 589 ml/min, while in arm AVF, the threshold Qa was 877 ml/min. There was a statistically significant difference between forearm and arm Qa.

The study concluded that a forearm AVF with a Qa threshold of 589 ml/min and an arm AVF with a Qa threshold of 877 ml/min are predictive indicators of the need for intervention or thrombosis due to flow-limiting stenosis. 

The findings highlighted the distinct Qa thresholds for different AVF configurations.