# The Role of Guideline’s Threshold Vascular Diameters in Long-Term Radio-Cephalic Arteriovenous Fistula Failure

## TL;DR

This study finds that following vascular diameter guidelines helps create functional arteriovenous fistulas, but other factors also affect long-term success.

## Contribution

The study identifies the cephalic vein diameter as an independent predictor of long-term RC-AVF failure.

## Key findings

- Non-guideline-compliant RC-AVF had smaller arterial and venous diameters and higher failure rates.
- A threshold of 2.75 mm for the radial artery and 2.52 mm for the cephalic vein was identified.
- Only the cephalic vein diameter remained an independent predictor of long-term success after adjustments.

## Abstract

Background/Objectives: According to the guidelines established by the European Society of Vascular Surgery (ESVS), a minimum 2 mm diameter is advised for both the radial artery (RA) and cephalic vein (CV) to perform a radio-cephalic arteriovenous fistula (RC-AVF). However, studies have suggested that larger vein diameters, over 2.5 or 3 mm, or even smaller vessel diameters, above 1.6 mm, can yield satisfactory outcomes in both the medium and long term. This study aims to analyze how preoperative vascular mapping influences the long-term RC-AVF failure, considering adherence to guidelines. Methods: This retrospective, monocentric, and observational study enrolled 110 patients with ESKD who were admitted, between 2018 and 2024, to the Vascular Surgery Department at the Emergency County Hospital of Târgu Mureș for the creation of an RC-AVF. Demographic characteristics, comorbidities, preoperative vascular mapping data, and laboratory data were meticulously collected from the hospital’s electronic databases. Patients enrolled in the current study were categorized into two groups based on their adherence to guideline recommendations. Results: Patients whose RC-AVF was created outside guideline recommendations demonstrated smaller arterial (p < 0.001) and venous (p < 0.001) diameters. Additionally, a higher percentage of these patients were on hemodialysis via CVC at the time of RC-AVF creation (p = 0.041), as well as a higher incidence of 6-week AVF maturation failure (p = 0.012) and long-term AVF failure (p = 0.016). In ROC Curve analysis, a threshold of 2.75 mm was established for the RA (AUC: 0.647, p = 0.005) and 2.52 mm for the CV (AUC: 0.677, p = 0.001). Additionally, patients whose RC-AVF procedures adhered to guideline recommendations had a significantly lower risk of long-term RC-AVF failure (HR: 0.44, p = 0.012). This association lost significance after adjusting for cardiovascular risk factors and the presence of CVC at admission (HR: 0.69, p = 0.328). After full adjustment, only the CV remained an independent predictor of long-term successful RC-AVF (HR: 0.68, p = 0.026). In contrast, RA lost significance after adjusting for cardiovascular risk factors and the presence of CVC at admission (HR: 0.71, p = 0.086). Conclusions: In conclusion, this study reveals that only the diameter of the CV is correlated with the long-term failure of RC-AVF, independent of age, gender, diabetes, hypertension, active smoking, and the presence of a CVC at the time of AVF creation. Therefore, while adhering to the threshold diameters of the AR and CV, as recommended by the ESVS guidelines, facilitates the creation of a functional RC-AVF, we assert that additional cofactors, such as demographic data, usual cardiovascular risk factors, or CVC presence, must also be considered to achieve optimal long-term AVF.