| Popis: |
Background International guidelines recommended screening for AVF stenosis using various non-invasive methods. The previous studies have reported conflicting results. This study aims to evaluate the utility of the different non-invasive AVF flow measurements for detecting AVF stenosis. Methods We evaluated 23 HD patients with the clinical suspicion for AVF stenosis based on physical examination or high venous pressures during. Patients underwent all three non-invasive measurements including ultrasound dilution, urea dilution, and Doppler ultrasonography. Fistulography was performed to confirm the degree of AVF stenosis in all patients. Results Fistulography revealed AVF stenosis in eighteen patients, twelve of whom had severe stenosis (greater than 50% stenosis). About the location of the stenotic lesions, eight were at the inflow site, six at the outflow site, and four at both sites. In those AVFs with severe stenosis, median access flows were 625 mL/min by ultrasound dilution method, 615 mL/min by urea dilution method, and 590 mL/min by Doppler ultrasonography. Receiver operating characteristic (ROC) curve analysis showed that Doppler ultrasonography had a high discriminative ability and the averaged areas under the curves were 0.933 (95% confidence interval [CI], 0.81 to 0.99) for stenosis and 0.929 (95% CI, 0.82 to 0.99) for severe stenosis. The sensitivity of each method for prediction of access stenosis was 73%, 73%, 80% by using the ultrasound dilution, urea dilution, and Doppler ultrasonography methods, respectively. The specificity of each method was 40%, 80%, and 100% respectively. Physical examination showed 80% sensitivity and 80% specificity for detecting AVF stenosis. The combination of non-invasive access flow measurement with physical examination increased the sensitivity for detection of AVF stenosis to 80%, 93%, and 93% respectively. Conclusions Doppler ultrasound combine with physical examination, was more accurate than other non-invasive methods for detection of AVF stenosis. |
