Numerical evaluation and experimental validation of vascular access stenosis estimation

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Device Monitoring

Background:

• Vascular access dysfunction is a common complication in hemodialysis patients.
• Regular monitoring of vascular access is essential for patient care.
• Identifying reliable indicators of stenosis is critical for preventing access failure.

Purpose of the Study:

• To identify acoustic parameters and hemodynamic factors related to vascular access stenosis.
• To evaluate the correlation between acoustic signals (bruit) and hemodynamic changes.
• To develop a feasible index for real-time assessment of arteriovenous graft (AVG) dysfunction.

Main Methods:

• Utilized an in-vitro experimental circulation system to simulate hemodialysis vascular access.
• Created various degrees of stenosis (DOS) within the access to mimic patient conditions.
• Employed computational fluid dynamics (CFD) to simulate pressure, velocity, and flow distributions.
• Recorded acoustic bruit generated by fluid fluctuations in different stenosis severities.

Main Results:

• Acoustic bruit was recorded and correlated with fluid fluctuations caused by varying stenosis.
• A significant positive linear regression was observed between time constants and the degree of stenosis (DOS).
• The proposed parameter showed feasibility as an index for evaluating AVG dysfunction risk.

Conclusions:

• Acoustic parameters, specifically bruit characteristics, can indicate vascular access stenosis.
• The study established a correlation between acoustic signals and hemodynamic parameters.
• The developed parameter offers a promising tool for on-line, real-time monitoring of AVG dysfunction risk.