VOLume flow assistance for optimizing outcomes of dysfunctional autologous arteriovenous fistula Angioplasty: the VOLA Pilot Study

Objectives To investigate the feasibility of VF-assisted angioplasty (VFA) in dysfunctional AVF using sequential intraprocedural duplex ultrasound (DUS), to utilize intraprocedural VF as a quantifiable, functional endpoint in endovascular treatment. Methods This prospective study included 20 consecutive patients (23 lesions; 16 men; mean age 67 ± 16 years) with dysfunctional AVF undergoing fluoroscopically guided balloon angioplasty between June 2019 and May 2020. Primary endpoints were quantification of outcome using sequential DUS VF analysis following each dilation, 6-month target lesion re-intervention (TLR)-free rate, standard technical success, procedural success (achievement of a postprocedural VF value equal (or 10% less) or superior to the baseline steady-state access), and correlation between procedural success and TLR-free rate. Secondary endpoints included 6-month lesion late lumen loss (LLL), correlation between balloon diameter used and intraprocedural VF values, and correlation between VF and LLL at 6 months follow-up. Results Mean VF increase was 168.5% ± 102.5% (range: 24.24–493.33%). Procedural success was 80% (16/20 cases). VFA improved procedural success by 20% (4/20 cases) compared to standard assessment (< 30% residual stenosis and palpable thrill). TLR-free rate was 78.3% and 67.3% at 6 and 12 months. Significantly less TLR was noted in cases of procedural success (82.4% vs. 66.7% 6 months; p = 0.041). Unweighted linear regression showed a significant positive relationship between diameter of balloon and VF (146.9 ± 42.3 mL/min VF gain per mm of balloon diameter; p = 0.001, R2 = 0.23) and a significant negative relationship between LLL and VF decline at follow-up (102.0 ± 34.6 mL/min loss per mm of LLL; p = 0.01, R2 = 0.35). Optimal VF cutoff value and percentile increase to predict access failure were 720 mL/min (sensitivity 58.3%, specificity 71.4%) and 153% (sensitivity 66.7%, specificity 85.7%), respectively. Conclusion Intraprocedural VF assessment could be used to optimize AVF angioplasty. Key Points • A newly proposed functional endpoint of angioplasty in dysfunctional dialysis fistula was evaluated and angioplasty outcome was quantified using volume flow (VF) assessment with sequential intraprocedural DUS. • Intraprocedural VF assessment improved immediate procedural success; increased balloon diameter was correlated with VF gain and late lumen loss with VF decline. • Intraprocedural VF values ≥ to baseline steady-state values were correlated with less re-interventions.