#858 The efficacy of preoperative ultrasound mapping prior to arteriovenous fistula creation: a meta-analysis and systematic review
Authors: Baciga Federica , Fiorini Fulvio , Granata Antonio , Lentini Paolo Luca Maria , Shakkour Meilad , Esposito Pasquale , Pertica Nicoletta , Ortalda Vittorio , Gambaro Giovanni , Mantovani Alessandro , Battaglia Yuri 
Published: May 2024

Abstract

Background and Aims
Current literature presents conflicting evidence regarding the benefits of Color Doppler Ultrasound (DUS) in the preoperative vascular mapping of arteriovenous fistula (AVF) for haemodialysis. Thus, we conducted a systematic review and meta-analysis of RCTs to evaluate differences in primary AVF failure between patients randomly assigned to routine preoperatory DUS and those randomly assigned to physical examination assessment alone or combined with DUS when physical examination provides limited information.

Method
We systematically searched PubMed, Google Scholar, Web of Science, and Scopus databases from their inception to November 30, 2023. The accessible text search terms were: “fistula” AND “arteriovenous” AND “dialysis” OR “haemodialysis” AND “Doppler” OR “ultrasound” OR “ultrasonography” AND “preoperative” OR “perioperative” OR “mapping”. No language restriction was applied. We also reviewed references from original papers and review articles to identify additional suitable studies not covered by our original database searches. Exclusion criteria were: (1) meeting abstracts, case reports, reviews, practice guidelines, case-control or cross-sectional or longitudinal studies; (2) RCTs that did not report any estimates of the outcomes of interest; (3) RCTs conducted in the paediatric population (&lt;18 years of age). Two authors independently extracted data from eligible RCTs. Disagreements at this level were resolved by consensus and a third author if needed. The outcome was categorized into three groups: primary AVF failure within 48 hours, within six weeks or 40 months from the vascular procedure. AVF Failure was defined as intraoperative inadequate vessels, incomplete surgical procedure, absence of thrill, thrombosis detection, AVF unsuitability for cannulation at 90 days, inability to achieve Qb 200-300 ml/min at six months, or lack of maturation at 40 months. Statistical analysis was performed using STATA 17.0 software with the metanalysis package and R (version 4.2.2.) for all statistical analyses. This study was performed according to the updated Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement.

Results
We included 6 RCTs involving 802 patients. Fig. 1 summarizes the results of the literature search and study selection. Table 1 shows the main clinical characteristics of RCTs. Compared to controls, the use of routine preoperative DUS was associated with a reduction in the risk of AVF failure within 48 hours [5 RCTs; OR 0.27, confidence interval 95% 0.16-0.45 for the common effect model (CEM); OR 0.27, CI 95% 0.16-0.46 for the random effects model (REM), no heterogeneity (I2 = 0%)]; within six weeks [2 RCTs (OR 0.33, CI: 95% 0.18-0.61 for CEM, and OR 0.34, CI 95% 0.18-0.63 for REM with I2 = 0%]; and within 40 months [4 RCTs, OR 0.51, CI 95% 0.35-0.75 for CEM; and OR 0.51, CI 95% 0.35-0.76 for the REM, with I2 = 0%] from surgical intervention (Figs 2–4).

Conclusion
Routine use of DUS in preoperative vascular mapping improves the survival AVF in the immediate to 40 months post-surgery, compared to relying solely on physical examination or using DUS only in cases of insufficient physical examination.