Bedside 3D ultrasound fistula maturation assessment by non-expert sonographers provides equivalent accuracy to formal duplex sonography: A prospective clinical trial.

Background: EchoSure is an automated point-of-care 3D ultrasound (3DUS) designed to be used by dialysis technicians without advanced ultrasound training. The EchoMark/EchoSure System is a two-part system comprised of a bioresorbable implant, EchoMark, and a diagnostic ultrasound imaging platform, EchoSure. EchoSure was designed to enable any healthcare personnel in a dialysis clinic setting to obtain non-invasive, direct measurements of flow and vessel parameters that are critical quantifications used in the assessment of AVF maturation and readiness for hemodialysis cannulation.

Objective: In this pilot feasibility study, we sought to explore whether use of an automated 3DUS could enable fistula assessment by non-experts and obtain measurement accuracy comparable to expert sonographer Duplex.

Method: This was a 20 subject prospective multicenter trial conducted at four sites in the United States. All subjects had an EchoMark implanted under their AVF during the fistula creation procedure. Subjects were evaluated at 2-weeks post-op with EchoSure and Duplex, followed by monthly assessments until either the 4-month visit or until radiographic maturation was achieved, whichever was longer. Beyond monthly ultrasound assessments, clinical follow-up continued every 6 months between months 6 and 24.

Result: Technical success of EchoMark implantation was demonstrated in 100% of subjects. Technical success of EchoSure was 99% across all scans. The mean percent difference in flow rate measurements between EchoSure and Duplex was -9.2% with a standard deviation of 38.1% compared to a mean percent difference of -15.7% with a standard deviation of 35.5% between Duplex measurements taken at the cannulation zone and brachial artery. Pearson correlation between EchoSure and Duplex was 0.708 versus 0.716 for the two Duplex measurements. Radiographic maturation was achieved in 70% of study subjects by 30 days and continued to rise to 90% through 90 days and 95% through 180 days after baseline.

Conclusion: This study demonstrates the feasibility and accuracy of an automated 3D ultrasound system for assessment of maturation at the dialysis bedside by non sonographers.