Objectives: Extravascular supported radiocephalic arteriovenous fistulas (ES-RCAVF) have demonstrated improved maturation rates for patients. However, ES has not been designed for snuffbox AVFs (SB-AVFs), which may still be a preferred option due to the more distal anatomical location. The aim of this study was to assess the comparative benefits of ES-RCAVF vs SB-AVF and explore the demographic/comorbidity implications on access type selection.
Methods: Data for primary RCAVFs created in patients from November 2017 until April 2024 at a single center was retrospectively analyzed. Selection of access type (ES-RCAVF or SB-AVF) was based on assessment of vessel size and quality. ES-RCAVFs and SB-AVFs were compared for maturation and cannulation rates, tunneled catheter removal rates, and 5-year secondary patency. A multivariate analysis was conducted incorporating age, sex, end-stage kidney disease (ESKD), diabetes, and vessel diameter to examine the influence of AVF type on outcomes. Secondary analyses explored patient factors that demonstrated a significant impact on outcomes by access-type.
Results: A total of 394 patients undergoing primary RCAVF creation were included; 50.3% were on hemodialysis at the time of access creation. ES-RCAVF patients (n=246) included significantly more female, elderly, and diabetic patients than SB-AVF (n=148). ES-RCAVFs reported higher rates of 4-week maturation (81.9% vs 69.7%), total maturation (93.6% vs 85.5%), 6-month unassisted cannulation (72.7% vs 62.7%), 6-month total cannulation (82.6% vs 71.6%) and catheter removal rates (62.9% vs 56.9%). Secondary patency trended to be higher for ES-RCAVF vs SB-AVF over the 5-year follow-up (Figure 1). In the multivariate analysis, ES-RCAVF was a significant factor associated with higher secondary patency rates (Table 1). We identified older age and diabetes as significant factors associated with lower maturation rates, while female gender stood alone as a significant factor negatively associated with all metrics except for secondary patency (Table 1). In a sub-group analysis of younger ( < 65 years), non-diabetic, and male patients, ES-RCAVF still reported comparatively higher rates of maturation and cannulation, than SB-AVF. However, the group of < 65 years old, non-diabetic, and female patients reported equivalent outcomes for both access-types.
Conclusions: ES-RCAVFs were associated with improved maturation/cannulation rates with higher long-term patency than SB-AVFs. However, younger, non-diabetic, and female patients reported equivalent outcomes for both access types suggesting these factors should be considered when choosing SB-AVF.
