#1335 Distal radio-cephalic arteriovenous fistula survival: comorbid conditions and long-term surveillance in hemodialysis
Authors: Vigueras María Rosa , Sirvent Ana Esther , Enriquez Ricardo , Nájera Celia Jiménez , Pérez Antonio Pérez , Abad Juan Mariano Pérez , Merino Guadalupe Ruiz , Torroglosa Francisco José Montiel , Medina Jose García , García Andrés Alonso , Fernández Gonzalo Martínez , Muñoz Alberto Andreu 
Published: May 2024

Abstract

Background and Aims
With a low incidence of infection and distal ischemia, the distal radio-cephalic arteriovenous fistula (dRCF) is the reference access for hemodialysis (HD). Smaller venous diameter and obesity have been associated with poor distal arteriovenous fistula (AVF) outcomes in some studies. On the other hand, HD patients often suffer from multiple co-morbidities, resulting in an increased number of complications. The impact of all these factors on vascular access survival has not been entirely characterized.
We evaluated long-term follow-up demographic and clinical data from a cohort of patients in relation to primary and secondary dRCF survival.

Method
The study included prevalent patients who had been receiving hemodialysis for at least 6 months at the same reference hospital. From 2008 to 2023, we retrospectively collected dRCF for HD performed by a single reference surgical team. All dRCF could be confirmed to be clinically useful for dialysis (i.e., functional patency). Socio-demographic data were collected. Our medical team (nephrologist and radiologist) periodically performs a physical examination and duplex ultrasound to identify physical signs of possible complications, understand the underlying cause and plan treatment in advance. The time to first repair is termed primary AVF survival, while secondary survival is the time after first repair. Primary and secondary survival analysis was performed using the Kaplan-Meier method.

Results
Of 253 prevalent patients receiving HD, 82.2% had an AVF. The mean HD vintage was 61 ± 50 months. HD was started on a planned basis in 61.4% of cases, with AVF being the initial access in 71.7% of cases. We included 145 dRCFs for HD. dRCF was the unique AVF that was placed in 74.5% of the patients. Mean age 69.5 ± 14.5 (years), women 31%, mean BMI 27.3 ± 6.08 kg/m2, non-smokers 46.9%, obesity 37.9%, diabetes mellitus 44.8%, ischemic cardiopathy 20%, peripheric vasculopathy 15.9%. Diabetic nephropathy was the most common cause of chronic kidney disease in our population, accounting for 44.8% of cases. dRCF primary failure was 11.11%, 40% of these patients were over 80 years of age. The dRCF was left-sided in 82.2%. dRCF median survival was 64.5 ± 50.4 months; survival rates at 12, 36 and 60 months were 92%, 67% and 41%, respectively. Primary and secondary dRCF median survival was 33 ± 39 months and 50 ± 45 months, respectively. Primary and secondary survival rates at 12, 36 and 60 months were 60%, 32% and 17% and 84%, 53% and 33%, respectively. With a median survival of 62 ± 44 months, 29.7% of the dRCF did not undergo repair either before or during dialysis. The dRCF requiring percutaneous intervention and/or surgical reanastomosis before dialysis was 16.7%. Factors identified as being associated with lower primary survival were obesity and peripheral vasculopathy (p=0.01 and p=0.001, respectively), as shown in Figs. 1 and 2. The percentage of salvage procedures (percutaneous, surgical or both) in obese was 78,2%; 76,7% involved surgical repair, most of which were lipectomies, superficializations with or without transposition. Although not statistically significant (p=0.056), dRCF secondary survival is decreased in diabetic patients (Fig. 3). No statistical impact was found between age, sex, smoking, or ischemic cardiopathy and either primary or secondary survival.

Conclusion
Our obese patients on HD are a special population with an increased need for surgical reintervention of dRCF, which impacts primary but not secondary survival. Primary dRCF survival is lower in patients with peripheral vascular disease compared to other comorbidities; however, this vasculopathy is not associated with worse secondary dRCF survival with active follow-up. It is likely that individualized and careful long-term active surveillance was a key aspect in improving the functional patency of dRCF in our patients with multiple comorbidities. Undoubtedly, these issues deserve further prospective investigation.