Numerical Assessment of Novel Helical/Spiral Grafts with Improved Hemodynamics for Distal Graft Anastomoses.

Foad Kabinejadian,Lina Badimon,Andres Ruiz-Soler,Mark A Slevin,Hwa Liang Leo,Amir Keshmiri,Michael Mcelroy,Josué Sznitman

doi:10.1371/journal.pone.0165892

Abstract

In the present work, numerical simulations were conducted for a typical end-to-side distal graft anastomosis to assess the effects of inducing secondary flow, which is believed to remove unfavourable flow environment. Simulations were carried out for four models, generated based on two main features of 'out-of-plane helicity' and 'spiral ridge' in the grafts as well as their combination. Following a qualitative comparison against in vitro data, various mean flow and hemodynamic parameters were compared and the results showed that helicity is significantly more effective in inducing swirling flow in comparison to a spiral ridge, while their combination could be even more effective. In addition, the induced swirling flow was generally found to be increasing the wall shear stress and reducing the flow stagnation and particle residence time within the anastomotic region and the host artery, which may be beneficial to the graft longevity and patency rates. Finally, a parametric study on the spiral ridge geometrical features was conducted, which showed that the ridge height and the number of spiral ridges have significant effects on inducing swirling flow, and revealed the potential of improving the efficiency of such designs.

Highlights

1.1 Graft AnastomosesAn anastomosis is a surgical connection between an autologous or prosthetic graft and veins or arteries inside the human body
Investigation of the hemodynamic parameters in the present study revealed that Time-Averaged WSS (TAWSS) increases on the arterial bed and around the anastomosis by adding the non-planar helicity
The present study shows that inducing swirling flow into the bypass grafts would lead to positive flow features and more favourable distribution of hemodynamic parameters in the graft, anastomotic region, and the host artery, which in turn, could possibly enhance the patency and longevity of the bypass graft

Summary

Introduction

An anastomosis is a surgical connection between an autologous or prosthetic graft and veins or arteries inside the human body. From a geometrical point of view, the graft anastomoses can be divided into three classes: (1) end-to-side, (2) end-to-end, and (3) side-to-side anastomosis. Vascular grafts can be categorised under the following two main applications: PLOS ONE | DOI:10.1371/journal.pone.0165892. Numerical Assessment of Novel Helical/Spiral Grafts for Distal Graft Anastomoses. 1. Arterial Bypass Grafts (ABGs): Examples of ABGs include Peripheral Vascular Disease (PVD) and Coronary Artery Disease (CAD). 2. Arterio-Venous Grafts (AVGs): AVGs are mainly used for creating an ‘access point’ for haemodialysis treatments for patients with renal diseases

Methods

Results

Discussion

Conclusion