The role of vessel geometry and material properties on the mechanics of stenting in the coronary and peripheral arteries

Abstract

There have been notably higher rates of restenosis with stents used to restore blood flow to many stenosed peripheral arteries compared with their coronary counterparts. The mechanical environment of arteries such as the femoral and popliteal (and the stent fracture that this can cause) has previously been identified as a contributing factor to the relatively low success rates for this procedure. The aim of this study was to investigate how other factors, namely the differences in geometries and mechanical properties of the arteries and the stents used in them, might influence the outcome in these different arteries. Finite element models of the stents and arteries were created, and the results compared in terms of stresses induced in the arteries, the lumen gain, and the deformation of the stent due to pulsatile loading. It was found that deploying a Nitinol stent in a peripheral artery induced lower stresses in the vessel wall than expanding a stainless steel stent in a coronary artery, although the lumen gain was also lower. The predicted strain amplitude induced in Nitinol stents by the cardiac cycle was below the value required to cause fatigue failure. This study does not provide any evidence to suggest that differences in the geometry and material properties between peripheral and coronary arteries, or the types of stent used to restore vessel patency, are the dominate factors responsible for the higher rates of restenosis observed in peripheral arteries.

Quantification of Popliteal Artery Deformation During Leg Flexion in Subjects With Peripheral Artery Disease: A Pilot Study

“…Since the stents undergo rigorous FE simulations during development, these measurements can be applied as boundary conditions to realistically model the deformation of calcified arteries, even without explicitly modeling the calcification. To our knowledge, the measurements used in the previous FE simulations are all based on cadaveric [20][21][22] or healthy arteries 12 Several limitations of the present study need to be discussed. First, due to size constraints of the angiographic imaging system, we could not consider the entire length of the FPAS, but concentrated on its distal part.…”

Sequential Structural and Fluid Dynamics Analysis of Balloon-Expandable Coronary Stents: A Multivariable Statistical Analysis

“…Though limiting, this approach is not uncommon in the literature and many recent numerical studies have investigated stainless steel coronary stent designs. 14,19,20,25,[28][29][30][31]43,57,58,[64][65][66]69,70,73,80,89,91,92 Furthermore, one of the primary aims of this study was to assess the predictive nature of the numerical approach. This required that the relative performance of at least two of the investigated stents had been evaluated in large-scale clinical trials.…”

“…These computational methods of analysis employ sophisticated numerical techniques, such as the finite element and finite volume methods, to obtain approximate numerical solutions to complex physical problems. To date, a large number of studies have carried out computational structural (CS) analyses 1,4,5,14,15,19,[25][26][27][28][29]37,44,53,54,57,59,[62][63][64]72,73,78,80,85,87,[90][91][92] and computational fluid dynamics (CFD) analyses 3,8,9,12,30,31,33,42,[47][48][49][50][51]65,66,69,[74][75][76]83,89 ...…”

An anisotropic inelastic constitutive model to describe stress softening and permanent deformation in arterial tissue

“…Without considering such phenomena it will not be possible to develop models to accurately predict lumen gain during clinical procedures such as angioplasty and stenting (Early and Kelly, 2011;Early and Kelly, 2010;Early et al, 2009;Pericevic et al, 2009). In this study an anisotropic inelastic constitutive model is formulated to describe stress softening and permanent set for arterial tissue.…”