Introducción:

Different first-generation methods exist for the detection of stenosis.

Objective:

To determine the accuracy of first-generation methods in detecting stenosis in native arteriovenous fistulas.

Material and Method:

Retrospective observational study. Sample: Patients with functioning native arteriovenous fistulas. First-generation methods include physical examination, manual tests, pulse increase test and arm elevation test, indirect methods, Kt/V, and arteriovenous fistula recirculation. The diagnosis of stenosis was confirmed by Doppler ultrasound. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of first-generation methods based on Doppler ultrasound were calculated.

Results:

Sample 39 patients, 79.48% male. Ultrasound detected 19 stenoses, nonsignificant. Physical examination: sensitivity 31.5%, specificity 80%, PPV 60%, NPV 55.1%, accuracy 56.4%. Pulse rise test: sensitivity 5.2%, specificity 90%, PPV 33.3%, NPV 50%, accuracy 48.7%. Arm elevation test: sensitivity 52.6%, specificity 70%, PPV 62.5%, NPV 60.8%, accuracy 61.5%. Indirect methods: sensitivity 15.7%, specificity 55%, PPV 25%, NPV 40.7%, accuracy 35.9%. Kt/V: sensitivity 10.5%, specificity 75%, PPV 28.5%, NPV 46.8%, accuracy 43.5%. AVF recirculation: sensitivity 10.5%, specificity 100%, PPV 100%, NPV 54.1%, accuracy 56.4%.

Conclusions:

All first-generation methods have high specificity and low sensitivity. The degree of stenosis (significant or non-significant) could influence the sensitivity of the physical examination but not the specificity. The arm elevation test is the most accurate first-generation method of detecting stenosis.