CEUS-guided PTA on stenotic AVF: Morphological and functional point of view

Background: Stenosis represents the main cause of hemodialysis fistula malfunction. The ultrasound-guided angioplasty with ecographic contrast (CEUS) could provide further advantages to the classical ultrasound guided method improving the morphological characterization of the stenosis and providing quantitative data with the creation of time intensity curves (TIC) collecting functional data comparable between pre and post procedure. Methods: A total of 10 CEUS-guided angioplasties were performed on malfunctioning fistulas. The sonographic contrast medium was injected into the vascular tree trough the introducer. Morphological and functional data nature were collected. Were generated TIC curves, obtained by positioning a ROI in correspondence with the post-stenotic tract of the efferent vein. The data collected, regarding the peak intensity reached by the signal (PI) and the time to reach the peak signal intensity (TTP), were compared in the pre and post-procedural phase with flow of vascular access (Qa) and resistance indices (RI). Results: Statistically significant correlation ( p < 0.05) was observed between Qa and TTP ( r = 0.77; p = 0.009), RI and TTP ( r = 0.71; p = 0.02), Qa and PI ( r = 0.86; p = 0.0012), and between RI and PI ( r = 0.88; p < 0.001). Conclusion: In addition to the advantages associated with the use of ultrasound contrast medium in improving the visualization and characterization of the stenosis by facilitating the PTA procedure, the functional data deriving from the quantitative analysis provide new parameters for evaluating the success of the procedure which could also be used as predictive markers of stenosis recurrence together with the classical ones.