Volume Flow Assessment to Optimize Angioplasty of Dysfunctional Dialysis Access. The VOLA II Multicenter Study

This is a prospective, multi-center, single-arm observational clinical trial investigating a new functional index of success of endovascular treatment of dysfunctional AVF assessed with intraprocedural percutaneous DUS. The study will include 100 consecutive patients undergoing fluoroscopically-guided percutaneous balloon angioplasty due to dysfunctional AVF. Exclusion criteria will be (i) patients with arteriovenous synthetic grafts. (ii) Immature AFVs not previously used for hemodialysis (at least once). Patients' demographical data, dialysis access history, and procedural details will be recorded. Intraprocedural volume flow measurements will be obtained just prior to the procedure and after final balloon dilation, before sheath removal. Clinical follow-up will be set at 6 months after the index procedure. All DUS measurements will be performed using the same imaging protocol. The study's primary endpoints will be (i) the quantification of angioplasty outcome using DUS volume flow analysis before sheath insertion and at the end of the procedure before sheath removal and (ii) to assess the correlation between volume flow at the end of the procedure and clinically driven re-intervention-free rate at defined as the rate of reintervention due to dysfunction recurrence of the treated AVF. Secondary endpoints will be (i) to assess the correlation between volume flow and clinical success defined as high-quality dialysis for a period of at least one month and (ii) identification of independent predictors of re-intervention-free rate.