Publications by authors named "Riona Ni Ghriallais"

Purpose: To quantify the deformation behavior of the diseased femoropopliteal segment and assess the change to deformation behavior due to various stent placements.

Methods: The length and curvature changes of 6 femoropopliteal segments (the right and left superficial femoral and popliteal arteries) from 3 cadavers were measured in 3-dimensional space based on rotational angiography image data in straight leg and flexed hip/knee (50°/90°) positions before and after placement of nitinol stents of varying type (EverFlex, Misago, and BioMimics 3D) and length (60, 100, and 200 mm) in different locations along the arteries. Three-dimensional centerline data were extracted for the measurements.

View Article and Find Full Text PDF

Physiological loads that act on the femoropopliteal artery, in combination with stenting, can lead to uncharacteristic deformations of the stented vessel. The overall goal of this study was to investigate the effect of stent length and stent location on the deformation characteristics of the superficial femoral artery (SFA) using an anatomically accurate, three-dimensional finite element model of the leg. For a range of different stent lengths and locations, the deformation characteristics (length change, curvature change, and axial twist) that result from physiological loading of the SFA along with the mechanical behavior of the vessel tissue are investigated.

View Article and Find Full Text PDF

During knee flexion, the muscles of the upper leg impose various loads on the underlying femoropopliteal artery resulting in radial compression, bending, torsion, axial extension and axial compression. Measuring the dynamic force environment of the femoropopliteal artery and quantifying its resulting deformation characteristics is an essential input to peripheral device design. The goal of this study was to create an anatomically accurate, three dimensional finite element model capable of capturing the loading conditions and deformation characteristics of the femoropopliteal artery during knee flexion.

View Article and Find Full Text PDF

Haemodynamic forces have a synergistic effect on endothelial cell (EC) morphology, proliferation, differentiation and biochemical expression profiles. Alterations to haemodynamic force levels have been observed at curved regions and bifurcations of arteries but also around struts of stented arteries, and are also known to be associated with various vascular pathologies. Therefore, curvature in combination with stenting might create a pro-atherosclerotic environment compared with stenting in a straight vessel, but this has never been investigated.

View Article and Find Full Text PDF

Computational simulations using finite element analysis are a tool commonly used to analyse stent designs, deployment geometries and interactions between stent struts and arterial tissue. Such studies require large computational models and efforts are often made to simplify models in order to reduce computational time while maintaining reasonable accuracy. The objective of the study is focused on computational modelling and specifically aims to investigate how different methods of modelling stent-artery interactions can affect the results, computational time taken and computational size of the model.

View Article and Find Full Text PDF