The Proof is in the Peptide: Baseline NT-proBNP and Cardiac Output Responses at AVF Maturation in Hemodialysis Patients

Rationale & Objective Arteriovenous fistula (AVF) creation increases venous return and may augment cardiac output (CO), but prospective data integrating peri-access hemodynamics with cardiac biomarkers in people with kidney failure are limited. Study Design Prospective longitudinal cohort study. Setting & Participants Fifty-nine adults with advanced CKD or kidney failure receiving or approaching hemodialysis at a tertiary Australian centre were enrolled across three prespecified clinical groups; primary longitudinal analyses focused on participants undergoing new AVF creation (n=30). Exposure(s) or Predictor(s) AVF creation and CO augmentation phenotype, defined as a ≥15% increase in POCUS-derived CO from baseline to AVF maturation. Outcome(s) Serial NT-proBNP and hs-cTnT concentrations; POCUS-derived CO at baseline and AVF maturation. Analytical Approach Biomarkers were analyzed using log-transformed linear mixed-effects models accounting for repeated measures. Post-transplant observations were prespecified exploratory analyses. Results Among participants with paired hemodynamic measurements (n=16), CO was higher at AVF maturation than at baseline (P=0.03). NT-proBNP concentrations were markedly elevated but did not consistently increase after AVF creation (P=0.09). NT-proBNP was higher in participants without CO augmentation than in those with CO augmentation (geometric mean 6,716 pg/mL [95% CI, 2,418-18,654] vs 1,456 pg/mL [95% CI, 593-3,577]; P=0.03), and this difference persisted across post-AVF follow-up (P=0.04). Hs-cTnT did not change after AVF creation (P=0.63). NT-proBNP and hs-cTnT were lower after kidney transplantation (P=0.004 and P=0.002, respectively). Limitations Modest sample size, subset-only POCUS measurements, attrition, clinically timed biomarker sampling without dialysis-phase standardisation, pragmatic HF ascertainment, and exploratory transplant analyses. Conclusions AVF maturation was associated with measurable CO augmentation in a POCUS subset. Higher NT-proBNP was associated with attenuated CO augmentation, supporting further study of integrated hemodynamic-biomarker phenotyping for cardiovascular risk stratification around AVF creation.