Substitution-rate based screening model to assess stenosis progression in experimental stenotic arteriovenous grafts

Article type: Research Article

Authors: Kan, Chung-Dann^{a; *} | Chen, Wei-Ling^b | Lin, Chia-Hung^{c; *} | Wu, Ming-Jui^d | Mai, Yi-Chen^e

Affiliations: [a] Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan | [b] Department of Engineering and Maintenance, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan | [c] Department of Electrical Engineering, Kao-Yuan University, Kaohsiung, Taiwan | [d] Department of Internal Medicine, Kaohsiung Veterans General Hospital, Tainan Branch, Tainan, Taiwan | [e] Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan

Correspondence: [*] Corresponding authors: Chung-Dann Kan, Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan. E-mail: [email protected],DepartmentofElectricalEngineering,Kao-YuanUniversity,Kaohsiung82151,Taiwan.E-mail:[email protected].

Abstract: An arteriovenous graft (AVG) has a higher patency rate in stenosis progression at the venous anastomosis site, which causes coexisting inflow and outflow stenoses. This leads to increases in blood pressure, flow velocity, and flow resistance, resulting in hemodialysis (HD) vascular access dysfunction from early clots and thrombosis to the progression of coexisting stenoses. To prevent vascular access complications such as inflow or outflow stenoses, this study proposes a novel examination method in an experimental AVG system using a substitution-rate based screening model. In our practical measurements, we found that inflow and outflow channeled through a narrowed access indicated both pressure and resistance differences as the degree of stenosis (DOS) gradually increased. A substitution-rate matrix was conducted to replace bilateral pressure variations, while a transition probability matrix was calculated. Differences in transition probabilities were then used to distinguish between normal conditions and flow instabilities using the distance estimation method. The joint probability decayed from < 0.81 to 0.00 could be specified to identify the progression in stenosis levels from a DOS% = 50.0–95.0%. Average joint probabilities were found to be inversely related with the DOS using a non-linear regression (R>2 0.90). Hence, the joint probability could be specified as a critical threshold, < 0.81, to identify the severity stenosis level, DOS% ⩾ 70%, in the assessment of coexisting inflow and outflow stenoses. Experimental results suggest that the proposed model is superior to hemodynamic analysis and traditional intelligent method, and can be used for dysfunction screening during HD treatment.

Keywords: Arteriovenous graft, patency rate, substitution rate, transition probability matrix

DOI: 10.3233/THC-160474

Journal: Technology and Health Care, vol. 25, no. 5, pp. 887-902, 2017