Numerical Modeling of Nitinol Stent Oversizing in Arteries with Clinically Relevant Levels of Peripheral Arterial Disease: The Influence of Plaque Type on the Outcomes of Endovascular Therapy

摘要

Oversizing of the Nitinol stents in the femoro-popliteal arterial tract is commonly performed by clinicians and further encouraged by stent manufacturers. However, in spite of the procedure's supposed benefits of strong wall apposition and increased luminal gain, its effects on the mechanical behavior of arteries with peripheral arterial disease are not fully clear. In this study, finite element (FE) analyses of endovascular revascularization of an idealized artery with 70% stenosis and three different plaque types have been performed to examine the influence of Nitinol stent oversizing on the arterial stresses and acute lumen gain. The analyses included the simulation of balloon angioplasty to model plaque failure, followed by stent implantation, in which four different oversizing ratios were investigated. Results showed that balloon angioplasty was crucial in determining the stress levels of the artery prior to stent implantation and heavily affected the outcome of endovascular therapy. For all plaque types, Nitinol stent oversizing was found to produce a marginal lumen gain in contrast to a significant increase in arterial stresses. For the arteries with lightly and moderately calcified plaques, oversizing was found to be non-critical; whereas for the arteries with heavily calcified plaques, the procedure should be avoided due to a risk of tissue failure.