Although arterio-venous grafts (AVGs) represent the second choice as permanent vascular access forhemodialysis, this solution is still affected by a relevant failure rate due to graft thrombosis, and devel-opment of neointimal hyperplasia (IH) at the distal vein. As a key role in these processes has been attrib-uted to the abnormal hemodynamics establishing in the distal vein, the optimization of AVGs designaimed at minimizing flow disturbances would reduce AVG hemodynamic-related risks. In this studywe used computational fluid dynamics to investigate the impact of alternative AVG designs on the reduc-tion of IH and thrombosis risk at the distal venous anastomosis. The performance of the newly designedAVGs was compared to that of commercially available devices. In detail, a total of eight AVG models inclosed-loop configuration were constructed: two models resemble the commercially available straightconventional and helical-shaped AVGs; six models are characterized by the insertion of a flow divider(FD), straight or helical shaped, differently positioned inside the graft. Unfavorable hemodynamic condi-tions were analyzed by assessing the exposure to disturbed shear at the distal vein. Bulk flow was inves-tigated in terms of helical blood flow features, potential thrombosis risk, and pressure drop over the graft.Findings from this study clearly show that using a helically-shaped FD located at the venous side of thegraft could induce beneficial helical flow patterns that, minimizing flow disturbances, reduce the IH-related risk of failure at the distal vein, with a clinically irrelevant increase in thrombosis risk and pres-sure drop over the graft.

Hemodialysis arterio-venous graft design reducing the hemodynamic risk of vascular access dysfunction / De Nisco, Giuseppe; Gallo, Diego; Siciliano, Katia; Tasso, Paola; Lodi Rizzini, Maurizio; Mazzi, Valentina; Calò, Karol; Antonucci, Marta; Morbiducci, Umberto. - In: JOURNAL OF BIOMECHANICS. - ISSN 0021-9290. - STAMPA. - 100:(2020), pp. 1-11. [10.1016/j.jbiomech.2019.109591]

Hemodialysis arterio-venous graft design reducing the hemodynamic risk of vascular access dysfunction

De Nisco, Giuseppe;Gallo, Diego;Siciliano, Katia;Tasso, Paola;Lodi Rizzini, Maurizio;Mazzi, Valentina;Calò, Karol;Morbiducci, Umberto
2020

Abstract

Although arterio-venous grafts (AVGs) represent the second choice as permanent vascular access forhemodialysis, this solution is still affected by a relevant failure rate due to graft thrombosis, and devel-opment of neointimal hyperplasia (IH) at the distal vein. As a key role in these processes has been attrib-uted to the abnormal hemodynamics establishing in the distal vein, the optimization of AVGs designaimed at minimizing flow disturbances would reduce AVG hemodynamic-related risks. In this studywe used computational fluid dynamics to investigate the impact of alternative AVG designs on the reduc-tion of IH and thrombosis risk at the distal venous anastomosis. The performance of the newly designedAVGs was compared to that of commercially available devices. In detail, a total of eight AVG models inclosed-loop configuration were constructed: two models resemble the commercially available straightconventional and helical-shaped AVGs; six models are characterized by the insertion of a flow divider(FD), straight or helical shaped, differently positioned inside the graft. Unfavorable hemodynamic condi-tions were analyzed by assessing the exposure to disturbed shear at the distal vein. Bulk flow was inves-tigated in terms of helical blood flow features, potential thrombosis risk, and pressure drop over the graft.Findings from this study clearly show that using a helically-shaped FD located at the venous side of thegraft could induce beneficial helical flow patterns that, minimizing flow disturbances, reduce the IH-related risk of failure at the distal vein, with a clinically irrelevant increase in thrombosis risk and pres-sure drop over the graft.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2786276