#1487 Preoperative ultrasound vascular mapping as a predictor of arteriovenous fistula survival: a prospective cohort study
Authors: Cantalejo Leyre García , Paez Cristina Noboa , Suárez Gabriel Manuel González , Ribas Ana Merino , Alemany Nadia Martín , Carcasi Mara Lisbet Cabana , Devia Claudia Marcela Castillo , Baptista Yanel Adriana Acosta , Jean Álvarez Saltos Jehimy , Soler Laura Boix , Martínez Jordi Calabia 
Published: May 2024

Abstract

Background and Aims
The morbidity and mortality of hemodialysis (HD) patients is directly related to the vascular access (VA) type. The arteriovenous fistula (AVF) is considered the VA of choice. When compared to the use of catheter, the use of AVF encompasses a lower infectious complications rate and a higher survival rate. The use of catheter has been independently associated with an increased risk of morbidity and mortality, especially during the first year of treatment.
It is essential that HD programs maintain a high incidence and prevalence of AVF as a VA. For that reason, a multidisciplinary management is mandatory, with the collaboration of nephrologists, vascular surgeons, radiologists, and nurses. All patients who have an indication of AVF should have a prior ultrasound vascular mapping performed by the nephrologist to determine the most appropriate type of AVF.
According to guidelines, there are several factors that increase the risk of AVF failure including advanced age, history of smoking, diabetes mellitus and peripheral vascular disease, among others.
Therefore, the aim of this study is to determine the benefits of performing a preoperative ultrasound vascular mapping in terms of AVF survival. The secondary objective is to associate some risk factors to a higher rate of AVF failure.

Method
We conducted a prospective cohort study between January 2020 and December 2023. The viability of AVF was compared between AVF resulting from a preoperative ultrasound vascular mapping and those AVF without previous mapping.
A multivariate analysis was performed with the entire population to determine the factors related to AVF survival.

Results
This study analyzed a total of 136 AVF, both native and prosthetic. Our population included 106 patients, mostly men (69.79%), with a median age of 68 years old (IR: 56-76), and history of smoking in a 39.10%, of diabetes in a 42.43%, and of peripheral vascular disease in a 17.54%. A preoperative ultrasound vascular mapping was previously performed in 107 AVF (78.7%). A total of 93 AVF were functional (68.4%).
Regarding the analyzed risk factors of AVF failure (including advanced age and history of smoking, diabetes mellitus and peripheral vascular disease, and elbow/wrist AVF), we observed that advanced age and elbow AVF were related to higher survival of the AVF (p = 0.048 and p = 0.01 respectively).
In the multivariate analysis we observed that advanced age and elbow AVF were independent predictors of AVF survival (p = 0.038 and p = 0.001, respectively).
When comparing the cohorts, in the AVFs were the preoperative vascular ultrasound was performed, 78 AVF were functional (72.9%). In the AVFs were no mapping was performed, 15 AVF were functional (51.7%). This difference was statistically significant (p = 0.03). This implies a 21.2% increase in the probability of AVF survival when performing our AVF mapping.

Conclusions
The performance of a preoperative ultrasound vascular mapping by the nephrologist in our population has been associated to a significant increase in AVF survival. For that reason, we consider that it is an indispensable tool for the creation and monitoring of VA.
When analyzing risk factors classically associated to AVF failure, we found that advanced age and elbow AVF were independent predictors of higher AVF survival. Other risk factors, such as history of diabetes mellitus, smoking, and peripheral arterial disease, were not significantly related to AVF failure in our population.