Patient Factors Impacting Dialysis Patency: A Tool to Guide Decision Making for Creation of Lower Extremity Arteriovenous Access

Background

Lower extremity access remains a last resort for many patients needing dialysis access. We sought to identify patient factors impacting lower extremity arteriovenous fistula (AVF) and arteriovenous graft (AVG) patency and create a clinical tool to help guide decision-making in these complex patients.

Methods

All patients in the Vascular Quality Initiative dialysis module undergoing lower extremity access creation from 2011 to 2023 were separated into 2 cohorts based off whether the access was AVF or AVG and retrospectively analyzed. Univariate Kaplan–Meier and multivariable regression analyses were conducted with outcomes being overall survival and primary/secondary patency. Significant factors were standardized and scaled to create scores for loss of secondary patency. The model was then internally validated and imported into a clinical calculator to generate a score that was predictive of loss of patency (the Dialysis Patency Estimation score).

Results

In addition, 1,213 patients underwent creation of lower extremity access from 2011 to 2023 with 151 (12.45%) AVF and 1,062 (87.5%) AVG. One-year primary patency was 52.18% and secondary patency was 77.56% No difference was seen with primary patency based on access type (AVF 60.5%/AVG 50.9%, P = 0.068); however, AVG had worse secondary patency (AVF 88.6%/AVG 74.3%, P = 0.013). Factors increasing loss of secondary patency included: length of stay, age, body mass index, peripheral vascular disease, diabetes, and prior AVF/AVG. These factors were standardized and scaled to create a scoring system of 0 to 100 to predict loss of secondary patency at 1 year, with a score of >56 being near 100% risk. This scoring system was separated into 4 groups to predict risk of loss of patency (0–40 = low risk, 41–50 = medium low risk, 51–55 = medium high risk, and 56–100 = high risk).

Conclusion

Lower extremity AVG has inferior patency compared to AVF, but are more commonly placed. We have created a risk stratification score to determine which patients may benefit from a lower extremity AVG.