Key result
Access flow best identifies AVF dysfunction, whereas access recirculation marks late-stage failure.
Why the study?
Access flow (QACC), access recirculation (AR), and normalized venous intra-access pressure (vPIA/MAP) are used to detect vascular access dysfunction, but their comparative diagnostic value is unclear.
Which measure (QACC, AR, or vPIA/MAP) best detects vascular access dysfunction in AVFs and PTFE grafts?
Observational (n=172)
Which measure (QACC, AR, or vPIA/MAP) best detects vascular access dysfunction in AVFs and PTFE grafts?
Access flow (QACC) is superior to access recirculation and venous pressure for detecting access dysfunction in arteriovenous fistulas.
QACC may enable earlier AVF dysfunction detection than recirculation; hypothesis-generating and requires prospective validation before practice change.
Access flow (QACC) is a major determinant of patency. Access recirculation (AR > 2%), normalized venous intra-access pressure (vPIA/MAP), and QACC are used to detect access dysfunction. We compared these three measures of access function (ultrasound dilution to measure AR and QACC). A total of 779 measurements were performed on 58 arteriovenous fistulas (AVFs) and 114 polytetrafluoroethylene (PTFE) grafts (1–8/access) over 13 months, and the access parameters at the beginning of each period were related to access events within that period. Pump blood flow averaged >420 ml/min. AR occurred uncommonly (3.8%), and in half the cases, resulted from technical error by staff. In accesses that thrombosed or underwent intervention for stenosis, AR was present in only 3 of 11 AVFs and 8 of 57 PTFE accesses. When AR was present in grafts, QACC averaged 270 ± 23, and access thrombosis followed unless intervention occurred. In grafts, vPIA/MAP averaged 0.34 ± 0.01 in those remaining patent, 0.52 ± 0.08 in those that had undergone intervention, and 0.54 ± 0.04 in those that had thrombosed. QACC averaged 1,121 ± 26,605 ± 45, and 550 ± 65 ml/min, respectively, in the three groups. By contrast, QACC differed significantly in patent AVFs (1,053 ± 35) compared with failing AVFs (363 ± 48), but vPIA/MAP did not. AR is thus a late manifestation of access failure. QACC is the best diagnostic test of access dysfunction in AVFs. Interpretation of vPIA/MAP in grafts is enhanced by periodic QACC measurements.
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Besarab et al. (1997) conducted an observational in Vascular access dysfunction (n=172). Access flow (QACC), access recirculation (AR), and normalized venous intra-access pressure (vPIA/MAP) was evaluated on Access thrombosis or intervention for stenosis. Access flow (QACC) was the best diagnostic test for access dysfunction in AVFs (1,053 vs 363 ml/min in patent vs failing), while access recirculation was a late manifestation of failure.
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