Volume Flow-guided Angioplasty of Dysfunctional Dialysis Access (VOLA)

VOLume Flow-guided Angioplasty of Dysfunctional Autologous Arteriovenous Fistula. The VOLA Pilot Study

This is a pilot study investigating a new concept of intra-procedural percutaneous duplex ultrasound (DUS) volume flow-guided balloon angioplasty for the quantification and optimization of endovascular treatment outcomes of dysfunctional autologous arteriovenous fistulae (AVF).

This is a prospective, single-center, single-arm clinical trial introducing a new functional index of clinical success of endovascular treatment and investigating the feasibility of volume flow-guided balloon angioplasty of dysfunctional AVF assessed with intraprocedural percutaneous DUS. The study will include consecutive patients undergoing fluoroscopically-guided percutaneous balloon angioplasty due to dysfunctional AVF in the investigator's center. Exclusion criteria will be: (i) not available volume flow values at the time of AVF maturation, (ii) patients with arteriovenous synthetic grafts. 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 each balloon dilation. Volume flow measurements will be correlated with digital subtraction angiography quantitative vessel analysis (QVA) performed by an independent investigator blinded to the volume flow analysis outcomes. Follow up DUS imaging including volume-flow assessment will be set at 24h, 6, and 12 months after the index procedure, while fistulograms with QVA analysis will be performed at 6 and 12 months. All DUS measurements will be performed using the same imaging protocol and the same operator. The study's primary endpoints will be (i) the quantification of angioplasty outcome using sequential DUS volume flow analysis following each balloon catheter dilation and (ii) to assess the correlation between volume flow and clinical success defined as high-quality dialysis for a period of at least one month. Secondary endpoints will be (i) re-intervention-free interval defined as the time interval between endovascular treatment and reintervention due to dysfunction recurrence of the treated AVF and (ii) correlation between volume flow and QVA measurements.

Percutaneous transluminal angioplasty, Volume-flow measurment, Autologous arteriovenous fistula, Dialysis access

The study will include consecutive patients undergoing fluoroscopically-guided percutaneous balloon angioplasty due to dysfunctional AVF. Intraprocedural volume flow measurements will be obtained just prior to the procedure and after each balloon dilation. Volume flow measurements will be correlated with digital subtraction angiography quantitative vessel analysis (QVA) performed by an independent investigator blinded to the volume flow analysis outcomes. Follow up DUS imaging including volume-flow assessment will be set at 24h, 6, and 12 months, while fistulograms with QVA analysis will be performed at 6 and 12 months.

Volume flow measurements using DUS will be obtained at the end of each balloon dilation, at 24 hours, 6 months, and one year after index procedure.

The quantification of angioplasty outcomes will be performed using sequential DUS volume flow analysis

The investigators will use ROC analysis to define a cut off value of volume flow increase (ml per minute) at the end of the procedure to predict clinical success.

The time interval between endovascular treatment and reintervention due to dysfunction recurrence of the treated AVF

Comparison of Duplex Ultrasound volume flow values with digital subtraction angiography QVA measurements.

To assess wheather a significant volume flow decrease of >50% measured by Duplex ultrasound indicates an analougously significant late lumen loss (mm) of the target lesion measured with QVA analysis of digital subtracted venography

Inclusion Criteria: Consecutive patients undergoing fluoroscopically-guided percutaneous balloon angioplasty due to dysfunctional AVF Signed consent form Agree to the imaging protocol Exclusion Criteria: not available volume flow values at the time of AVF maturation patients with arteriovenous synthetic grafts.

The investigators plan to make individual participant data (IPD) available to other researchers upon request.