Will your dialysis vessel mature successfully? This score can tell you
For many patients with end-stage chronic kidney disease, dialysis is an important treatment, and the most common form is hemodialysis. The physician usually creates an arteriovenous fistula (AVF) in the patient’s arm by surgery so that blood can circulate smoothly through the dialysis machine. By surgically connecting an artery to a vein, the vein becomes thicker and carries more blood flow, ready for the needling required during dialysis.
However, a successful operation does not mean the AVF can be used right away, because the access needs a period of “maturation” before it can truly be used for dialysis. Not every successfully created AVF matures well. If an AVF does not achieve the expected result, the patient may face the risk and inconvenience of another operation.
To improve this, is there any way to predict how well a dialysis vessel will mature, so that needling for dialysis can proceed smoothly?
A study from Singapore developed an innovative “risk score model” that can predict the likelihood of AVF maturation before surgery, offering an important reference for clinical practice.
The AVF risk score: a key to improving fistula success
This study was published in June 2025 in the Journal of Vascular Surgery. The research team analyzed data from several hundred patients in depth to identify the key factors that influence AVF maturation. Based on these factors, the team developed two different prediction models:
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Model 1: predicts whether the fistula can be “started for needling” (first use) within three months after surgery
Definition of “started for needling”: vessel diameter of 5.5 mm or more, vessel depth of less than 6 mm, and brachial artery blood flow of more than 500 mL per minute.
Commencement of Cannulation:
diameter >= 5.5mm
depth < 6mm
brachial artery volume flow > 500 ml/min
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Below is the scoring form for Model 1. It contains six variables: age, sex, daily functional status, peripheral artery disease, the location of the access, and whether that arm has previously undergone dialysis access surgery. Adding up the score for each variable according to the individual case gives a total score.
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The total score can then be used with the table below to estimate the probability of successful cannulation within three months.
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Here is an example given in the paper:
Figure from “‘Risk score for the prediction of arteriovenous fistula maturation” (J Vasc Surg 2025;81:1485-94.)
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Model 2: predicts whether “functional maturation” (stable use) will be reached
Definition of “functional maturation”: the native dialysis AV fistula can be used steadily and continuously, and any dialysis catheter has been removed.
Functional maturation:
Hemodialysis sustained by the AVF only and removal of any CVC
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Below is the scoring form for Model 2, which contains eight variables: age, sex, daily functional status, BMI, the location of the access, and whether the same arm has previously had dialysis access surgery. It also takes into account the average diameter of the vein sutured at surgery and whether the sutured artery shows calcification. Adding up the score for each variable in the individual case gives a total score.
The total score can be used with the table below to estimate the probability of the vessel maturing within three months.
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Here is an example of Model 2 from the paper.
Figure from “‘Risk score for the prediction of arteriovenous fistula maturation” (J Vasc Surg 2025;81:1485-94.)
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Both models performed well in testing and predicted outcomes with fairly good accuracy. The researchers used 474 AVF cases from the National University Hospital in Singapore between 2015 and 2020 as training data, and 220 cases from 2021 to 2022 for external validation. Both models reached a satisfactory level of performance, with C-statistics of 0.72 and 0.74 respectively. In both internal and external validation, the C-statistics of the two models were about 0.7.
A prediction model like this gives the operating surgeon an important reference. Before surgery, the tool can be used to estimate a patient’s chance of success, which not only predicts the outcome of the operation but also identifies potential risk factors at an early stage. It allows the physician to make more precise clinical decisions and tailor the treatment plan to each patient. It also helps patients fully understand their treatment, prepare mentally in advance, and approach it with a more positive attitude.
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