Supplementary Material for: Novel method to monitor arteriovenous fistula maturation: impact on catheter residence time.

Introduction
Arterio-venous fistula (AVF) maturation assessment is essential to reduce venous catheter residence. We introduced central venous oxygen saturation (ScvO2) and estimated upper-body blood flow (eUBBF) to monitor newly created fistula maturation and recorded catheter time in patients with and without ScvO2-based fistula maturation.
Methods
From 2017 to 2019 we conducted a multicenter quality improvement project (QIP) in hemodialysis patients with the explicit goal to shorten catheter residence time post-AVF creation through ScvO2-based maturation monitoring. In patients with a catheter as vascular access, we tracked ScvO2 and eUBBF pre- and post-AVF creation. The primary outcome was catheter residence time post-AVF creation. We compared catheter residence time post-AVF creation between QIP patients and controls. One control group comprised concurrent patients, a second control group comprised historic controls (2014-2016). We conducted Kaplan Meier analysis and constructed a Cox proportional hazards model with variables adjustment to assess time-to-catheter removal.
Results
The QIP group comprised 44 patients (59±17 years), the concurrent control group 48 patients (59±16 years), the historic control group 57 patients (58±15 years). Six months post-AVF creation, the fraction of non-censored patients with catheter in place was 21% in the QIP cohort, 67% in the concurrent control group, and 68% in the historic control group. In unadjusted and adjusted analysis, catheter residence time post-fistula creation was shorter in QIP patients compared to either control groups (P<0.001).
Conclusion
ScvO2-based assessment of fistula maturation is associated with shorter catheter residence post-AVF creation.