title: Nitinol Stent Oversizing in Patients Undergoing Popliteal Artery Revascularization: A Finite Element Study.
abstract: Nitinol stent oversizing is frequently performed in peripheral arteries to ensure a desirable lumen gain. However, the clinical effect of mis-sizing remains controversial. The goal of this study was to provide a better understanding of the structural and hemodynamic effects of Nitinol stent oversizing. Five patient-specific numerical models of non-calcified popliteal arteries were developed to simulate the deployment of Nitinol stents with oversizing ratios ranging from 1.1 to 1.8. In addition to arterial biomechanics, computational fluid dynamics methods were adopted to simulate the physiological blood flow inside the stented arteries. Results showed that stent oversizing led to a limited increase in the acute lumen gain, albeit at the cost of a significant increase in arterial wall stresses. Furthermore, localized areas affected by low Wall Shear Stress increased with higher oversizing ratios. Stents were also negatively impacted by the procedure as their fatigue safety factors gradually decreased with oversizing. These adverse effects to both the artery walls and stents may create circumstances for restenosis. Although the ideal oversizing ratio is stent-specific, this study showed that Nitinol stent oversizing has a very small impact on the immediate lumen gain, which contradicts the clinical motivations of the procedure.
authors.affiliation: Institute for Surgical Technology & Biomechanics, University of Bern, Bern, Switzerland.
authors.forename: Can
authors.initials: C
authors.lastname: Gökgöl
authors.affiliation: Clinical and Interventional Angiology, Kantonsspital Aarau, Tellstrasse, Aarau, 5001, Switzerland. nicolas.diehm@ksa.ch.|University of Applied Sciences Furtwangen, Villingen-Schwenningen, Germany. nicolas.diehm@ksa.ch.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Diehm
authors.affiliation: Institute for Surgical Technology & Biomechanics, University of Bern, Bern, Switzerland.|Harvard-MIT Biomedical Engineering Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
authors.forename: Farhad Rikhtegar
authors.initials: FR
authors.lastname: Nezami
authors.affiliation: Institute for Surgical Technology & Biomechanics, University of Bern, Bern, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Büchler
mesh_terms: D000368:Aged; D000497:Alloys; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011150:Popliteal Artery / Q000503:physiopathology*; D012039:Regional Blood Flow; D015607:Stents; D013314:Stress, Mechanical
chemical_list: D000497:Alloys; C013616:nitinol
keywords: Acute lumen gain; Computational fluid dynamics (CFD) analysis; Curved arteries; Finite element analysis (FEA); Patient-specific arterial geometry; Popliteal arterial segment; Self-expanding Nitinol stents; Stent deployment; Stent oversizing