Value of doppler ultrasonography in the study of hemodialysis peripheral vascular access dysfunction.

OBJECTIVE The main objectives of this study were to evaluate the sensitivity and specificity of duplex Doppler ultrasonography in the study of hemodialysis peripheral vascular access dysfunction and to analyze the resistance index and flow in the afferent artery. MATERIAL AND METHODS We prospectively studied 178 patients with 178 peripheral vascular accesses that were dysfunctional in at least three consecutive hemodialysis sessions. Patients underwent duplex Doppler ultrasonography and clinical and laboratory follow-up for three months (provided angiography findings were negative). We calculated the sensitivity, specificity, predictive values, and coefficients of probability. We studied the morphology of the afferent artery, the arteriovenous anastomosis, and the efferent vein, and we measured the resistance index and the flow of the afferent artery, the diameter of the anastomosis, and the flow and peak systolic velocity in the efferent vein. RESULTS The final sample consisted of 159 patients. The sensitivity, specificity, positive and negative predictive values, and positive and negative coefficients of probability were 0,98 (95% CI: 0,88-1.00), 0,74 (95% CI: 0,66-0,81), 0,96, 0,82, 3.7, and 0,03, respectively. The resistance index was less than 0,5 in 78.5% of the peripheral vascular accesses with normal function and greater than 0,5 in 86.1% of the dysfunctional peripheral vascular accesses. We found aneurysms in 19 of the native peripheral vascular accesses and pseudoaneurysms in 7 of the prosthetic grafts. Inverted flow was seen in 57 peripheral vascular accesses. CONCLUSION Duplex Doppler ultrasonography is an efficacious method for detecting and characterizing stenosis and thrombosis in peripheral vascular accesses, and it provides information about the morphology and hemodynamics.