SS19 - Longitudinal Outcomes of Forearm Versus Upper Arm Arteriovenous Fistulas and the Impact of Hospital Volume: A Pooled Analysis of Prospective Multicenter Clinical Trials

Objectives: National guidelines generally recommend forearm arteriovenous fistulas (AVFs) over upper arm AVFs as the initial vascular access for hemodialysis if consistent with the end-stage kidney disease (ESKD) Life-Plan, but comparative outcomes are underexplored. Our objective was to utilize high-quality, prospective clinical trial data to compare longitudinal outcomes of forearm versus upper arm AVFs in patients with advanced kidney disease.

Methods: Using prospective multicenter data from three clinical studies (Hemodialysis Fistula Maturation [HFM] Study; PATENCY-1 [clinicaltrial.gov NCT02110901]; and PATENCY-2 [clinicaltrial.gov NCT02414841]), we conducted a pooled cohort study of 1,516 patients who underwent upper extremity AVF creation for hemodialysis access between 2014 and 2019. Demographic factors, comorbidities, procedural details, and 3 years of longitudinal follow up were captured. Outcomes included primary, primary-assisted, and secondary patency rates at 3 years, as well as adjudicated successful AVF use. Forearm versus upper arm AVF outcomes were compared using multivariable Cox regression and logistic regression models. Subgroup analyses included outcomes stratified by site volume using model interaction terms.

Results: We included 1,059 forearm AVFs and 457 upper arm AVFs; mean (SD) age was 56.2 (13.4) years; 25.2% were female; and 52.2% were on dialysis at the time of access creation. The overall primary, primary-assisted, and secondary patency rates at 3 years were 26.2% (95% CI 23.6% to 29.1%), 57.6% (54.6% to 60.9%), and 66.5% (63.6% to 69.5%), respectively, with no significant differences between forearm and upper arm AVFs (Figure 1). Successful AVF use at 6 months was also similar between forearm (60.2%) and upper arm AVFs (66.9%) (OR 0.94, 95% CI [0.65-1.34], p=0.72). Subgroup analyses showed that compared to upper arm AVFs, patients who received forearm AVFs at low volume sites (≤30 access creations per year) were at higher risk for loss of primary (HR 1.21, 95% CI [0.87-1.69], p =0.05), primary-assisted (HR 2.03, 95% CI [1.21-3.41], p< 0.001), and secondary patency (HR 2.53, 95% CI [1.33-4.83], p < 0.001) (Figure 2). Patients receiving forearm AVFs at low volume sites also had lower AVF use at 6 months (OR 0.47, 95% CI [0.19-1.16], p value of interaction =0.04).

Conclusions: Forearm AVFs have similar overall longitudinal patency and usability to upper arm AVFs. However, patients who received forearm AVFs at low volume sites had worse outcomes. Future investigations confirming this volume–outcome relationship may improve outcomes for forearm arteriovenous fistulas., which serve as a critical lifeline for patients with advanced kidney disease, in alignment with the ESKD Life-Plan.