Combined functional and anatomical diagnostic endpoints for assessing arteriovenous fistula dysfunction

Area of Science:

• Nephrology
• Vascular Surgery
• Biomedical Engineering

Background:

• Arteriovenous fistulas (AVFs) are crucial for hemodialysis, but maturation failure and thrombosis cause significant morbidity and mortality.
• Stenosis, resulting from adverse AVF remodeling, is a primary cause of AVF failure, necessitating early detection for timely intervention.
• Current surveillance strategies aim to supplement clinical evaluation for earlier stenosis diagnosis in AVFs.

Purpose of the Study:

• To review the advantages and limitations of current functional and anatomical diagnostic endpoints for arteriovenous fistula stenosis.
• To highlight the shortcomings of existing surveillance strategies based solely on blood flow (Qa) or venous access pressure ratio (VAPR).
• To discuss the potential of novel hemodynamic endpoints that integrate both flow and pressure for improved stenosis detection.

Main Methods:

• Review of existing literature on surveillance strategies and diagnostic endpoints for arteriovenous fistula stenosis.
• Analysis of functional hemodynamic endpoints, including blood flow (Qa) and venous access pressure ratio (VAPR).
• Discussion of anatomical assessment methods and their limitations in diagnosing AVF stenosis.

Main Results:

• Current methods like Qa and VAPR have limitations in consistently detecting stenosis in AVFs, particularly outflow lesions.
• AVFs can maintain adequate blood flow despite significant stenosis, limiting the efficacy of flow-based surveillance.
• VAPR, developed for grafts, shows limited accuracy in diagnosing outflow stenosis in AVFs.

Conclusions:

• Existing hemodynamic surveillance endpoints for AVFs are not consistently accurate due to the complex nature of these accesses.
• New diagnostic endpoints combining pressure and flow measurements demonstrate superior predictive value for stenosis severity.
• Further research and validation of combined hemodynamic endpoints are crucial for improving AVF surveillance and patient outcomes.