A new fistula asks the heart to do more; a very high NT-proBNP may mark the hearts that can't keep up
In a small Sydney study, cardiac output rose as new fistulas matured, and patients whose output didn't rise by at least 15% had more than four times higher NT-proBNP. Exploratory and hypothesis-generating.
🎧 Listen: Weekly · Oct 20, from 19:24.
The question
An arteriovenous fistula is a shunt: it lowers systemic resistance and raises venous return, so the heart has to pump more. Can cardiac biomarkers tell us whose heart will cope?
What the study did
This prospective cohort at Prince of Wales Hospital in Sydney (February 2022 to December 2024) enrolled 59 adults with advanced CKD or on hemodialysis; 30 had a new fistula created. Cardiac output was measured by point-of-care echocardiography before (or within a day of) surgery and at maturation, and NT-proBNP and high-sensitivity troponin T were followed for about a year.
What they found
- Of the 30 new fistulas, 18 matured. Only 16 patients had paired cardiac output measurements; in them, output was higher at maturation. Group averages were about 5.4 liters a minute at baseline (22 patients) and 6.4 at maturation (18 patients).
- NT-proBNP was very high at baseline (median about 2,200 pg/mL) and did not rise consistently after fistula creation.
- In an exploratory analysis, patients whose cardiac output didn't rise by at least 15% had more than four times higher baseline NT-proBNP than those whose output did (geometric means about 6,700 vs 1,460 pg/mL), a difference that persisted through follow-up.
- Troponin T was elevated but stable. Both markers were lower after kidney transplantation (exploratory).
Why it matters
The authors suggest that a high NT-proBNP marks a heart with little reserve to respond to the shunt, and that combining hemodynamics and biomarkers may help with cardiovascular risk around fistula creation. Our take: a very high NT-proBNP before access surgery may be a nudge to look more closely at the heart, not a rule.
Caveats
The study was small and exploratory, with echocardiography in a subset only and attrition over time. Blood samples weren't drawn at a standard time relative to dialysis, heart failure was taken from chart diagnoses, and the 15% cutoff is arbitrary. It cannot show whether checking NT-proBNP should change who gets a fistula.
Funding and ties: supported by UNSW and Prince of Wales Hospital Foundation grants; the authors declare no relevant financial interests.
The source: Shah NA, Thomas R, Thomas SD, et al. The Proof is in the Peptide: Baseline NT-proBNP and Cardiac Output Responses at AVF Maturation in Hemodialysis Patients. Kidney Med. Published online October 13, 2026 (article in press). doi:10.1016/j.xkme.2026.101580 Read the original
🎧 Listen: Weekly · Oct 20, from 19:24.
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