Incidence and Outcomes of High-Output Heart Failure in Patients with Arteriovenous Fistula: A Single-Center Retrospective Cohort Study

<b>Background</b>: Arteriovenous fistula (AVF) in patients with end-stage renal disease (ESRD) can lead to high-output heart failure (HOHF). There is limited data on the incidence and outcomes of HOHF in patients with AVF. <b>Objective</b>: The main goal of our study was to determine the incidence and prevalence of HOHF [diagnosed via right heart catheterization (RHC)] in chronic kidney disease (CKD)/ESRD patients with AVF. We also aimed to evaluate the clinical determinants of the development of HOHF in this group. <b>Methods</b>: We conducted a retrospective cohort study at the University of Kansas Medical Center from January 2011 to December 2023. Patients with CKD/ESRD with AVF who underwent RHC after AVF creation were included in the study. HOHF was defined as a cardiac index (CI) ≥ 4.0 L/min/m², measured either with the Fick or the Thermodilution method. Bivariate and multivariable regression analyses were performed to identify independent predictors of HOHF in this population. <b>Results</b>: Out of 84 patients with AVF, 34 patients met established inclusion and exclusion criteria. Ten out of thirty-four patients (29.4%) developed HOHF. Hemoglobin (Hb) was significantly lower in the HOHF group than the non-HOHF group (10.16 vs. 11.52 g/dL; <i>p</i> = 0.02). Patients with HOHF had significantly elevated CI when compared with the non-HOHF group (CI Fick: 4.54 vs. 2.91 L/min/m², <i>p</i> < 0.001). Similar mortality was observed in the HOHF and non-HOHF groups. After multivariant regression analysis, Hb was an independent predictor of HOHF (HR 0.86, 95% CI: 0.76-0.98, <i>p</i> =< 0.01). <b>Conclusions</b>: HOHF is common in patients with AVF; nearly 1/3 (29.4%) of the patients developed HOHF, confirmed with RHC. Low Hb was found to be an independent predictor of HOHF. Further larger studies are needed to confirm these findings and establish an early detection protocol to detect and treat this condition.