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Access recirculation in a native fistula in spite of a seemingly adequate access flow
P Krisper1, M Aschauer, K Tiesenhausen
1Department of Internal Medicine, Division of Nephrology, the Department of Radiology, Division of MR Imaging, the Department of Surgery, and the Department of Physiology, University of Graz, Austria. peter.krisper@kfunigraz.ac.at
Summary
True access recirculation (AR) can occur even with high blood flow in native arteriovenous (AV) fistulas. A case study revealed a collateral loop causing AR, highlighting the need for regular monitoring of both access flow and recirculation.
Area of Science:
- Nephrology
- Vascular Surgery
- Radiology
Background:
- True access recirculation (AR) is typically absent in well-functioning shunts and associated with low access flow (Qa).
- High access flow rates are generally presumed to prevent AR, with known exceptions including intra-access strictures and reversed blood lines.
Observation:
- A case of true AR in a native arteriovenous (AV) fistula with correctly placed bloodlines was observed.
- Access blood flow (Qa) unexpectedly exceeded pump blood flow (Qb) nearly threefold in this fistula.
Findings:
- Magnetic resonance angiography revealed a collateral vessel forming a functional loop, which caused true AR in one branch.
- This collateral loop led to AR despite overall adequate blood flow through both fistula branches.
Implications:
- Seemingly adequate access flow does not always prevent AR in native AV fistulas.
- Regular monitoring of both access flow and recirculation is recommended for hemodialysis accesses.
- This case provides insight into the complex pathophysiology of native fistulae.