Heart failure with preserved / high cardiac output is a well-known syndrome in patients with high-flow arteriovenous fistula (AVF). However, the threshold for classifying an AVF as high-flow is currently undefined. Cardio-fistular recirculation (CFR) is often used as a criterion, with values greater than 25-30% considered cardiotoxic and associated with adverse outcomes. Additionally, CFR is one of the few easily modifiable risk factors through surgical reduction of AVF volume blood flow (Qa).

The study aimed to evaluate the extent of involution of heart structural and functional changes following Qa reduction in patients with heart failure and CFR > 25%.

Inclusion Criteria:

• Signed informed consent
• age > 18 years
• CKD 5D
• Native arteriovenous fistula or vascular graft
• Heart failure with preserved CO (NYHA I-IV )
• Cardio-fistula recirculation ≥ 25%
• eKt/V > 1.2
• Absence of arrhythmias (except grade I AV block)
• Absence of valvular disease (except mitral regurgitation I-II)
• Arteriovenous fistula blood flow reduction surgery

Exclusion Criteria:

• Death
• Kidney transplantation
• Conversion of vascular access to central venous catheter
• Withdrawal of informed consent

Adult patients receiving maintenance hemodialysis treatment

Upon reasonable request.