Vascular access is essential for hemodialysis patients. The mature native arteriovenous fistula has been the preferred vascular access for hemodialysis, because it has greater longevity than synthetic grafts. However, once surgically created, fistulas often fail to develop (mature) into viable points of vascular access, requiring surgical or radiologic interventions before their use. Because maturation depends on vascular mechanics (e.g., distensibility and wall shear), we developed open-source ultrasound software to investigate these metrics clinically. We demonstrated in a single patient the ability of the software for consistent measurements from various locations within a cardiac cycle and between different cardiac cycles. We further assessed the ability of the software to identify changes in distensibility of a patient’s fistula from 1 to 6 weeks postoperation. The routine frame rates of clinical machines demonstrated high fidelity tracking within cardiac cycles (coefficient of variation [CV] = 2.4% ± 0.011) and between cardiac cycles (CV = 2.4% ± 0.004). The distensibility of the patient’s fistula from 1 to 6 weeks postoperation increased from 4% to 7% in the arterial inflow and from 3% to 4% in the postarterial anastomotic segment (PAAS). In contrast, the distensibility of the outflow vein decreased from 4% to 2%. These results corroborate that in addition to diameter changes, the mechanical properties of the vascular segments changed during fistula maturation. This demonstrates that our software-based approach may allow ultrasound-based mechanical measurements to become more accessible for wider clinical research.
From the *Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; †Innovative Medical Engineering and Technology, National Cancer Center, Goyang-si, Gyeonggi-do, Republic of Korea; ‡Veterans Affairs Ann Arbor Health System, Ann Arbor, Michigan; and §Internal Medicine, Ann Arbor, Michigan.
Submitted for consideration December 2016; accepted for publication in revised form April 2017.
Disclosures: The authors have no conflicts of interest to report.
This work was supported in part by NIH grant R21DK100753.
Correspondence: Dae Woo Park, Innovative Medical Engineering and Technology, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10408, Republic of Korea. Email: firstname.lastname@example.org.