RESUMO
AIMS: The aims of this study is to correlate colour duplex ultrasonography (US) with contrast fistulography for the detection of functional stenoses in the autogenous AVF (arterio-venous fistula) circuit. METHODOLOGY: Colour duplex US scans of 93 dialysis patients with dysfunctional AVF were compared with fistulograms performed within 6 weeks of the US. The AVF circuit was divided into six zones: inflow artery; anastomosis; distal vein; mid vein; proximal vein; and central vein. Colour duplex US and fistulogram images/reports were independently re-reported for stenoses in each fistula zone by two trained clinicians blinded to the outcomes. For each fistula, only zones examined by both modalities were included in the study. Kappa analysis of the results was performed to assess the accuracy of colour duplex US in the dysfunctional AVF circuit. RESULTS: Most AVF studied were radio-cephalic (59%) or brachio-cephalic (22%). Stenoses identified within the AV circuit in order of frequency were: distal vein (41), mid vein (23), arterial (12), proximal vein (7) and anastomosis (3). The interval between US and fistulogram studies was 33 + or - 29 days. Congruence of results between US and fistulograms ranged from 85% to 96%, depending on the zone examined. Kappa analysis of this US versus fistulogram data was also moderate to good, ranging from 0.72 and 0.91. CONCLUSIONS: Colour duplex US provides an accurate diagnostic assessment of a dysfunctional autogneous AVF, and is an important planning tool for subsequent open or endovascular intervention. It is particularly accurate in the peri-anastomotic area of the fistula which harbours the majority of fistula problems.
