Effects of Nitinol Microstructural Purity on Localized and Uniform Corrosion Susceptibility

Nagaraja, Srinidhi; Sena, Grazziela; Stafford, Philip; Braeuner, Chris; Hempel, Philipp; Pelton, Alan R.; Ravi, Vilupanur A.

doi:10.1007/s40830-022-00366-1

Cited by 4 publications

(2 citation statements)

References 23 publications

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“…To assess general corrosion susceptibility and metal ion release, the FDA recommendations include testing per the American Standard of Testing and Materials (ASTM) F2129-08 (Standard Test Method for Conducting Cyclic Potentiodynamic Polarization Measurements to Determine the Corrosion Susceptibility of Small Implant Devices), the ASTM F3306-19 (Standard Test Method for Ion Release Evaluation of Medical Implants), and the ASTM G31-72(2004) (Standard Practice for Laboratory Immersion Corrosion Testing of Metals) . Various studies have investigated the corrosion resistance and metal ion release from nitinol stent-based devices. − Specifically, Sullivan et al studied the effect of oxide layer composition in nitinol stents manufactured by various processing methods and suggested strong correlations between the layer thickness and cumulative Ni release. Nagaraja et al tested generic heart valve frames manufactured with different vacuum arc remelting methods and surface finishes and showed that the localized and uniform corrosion performance is maintained in higher microstructural nitinol purity.…”

Section: Introductionmentioning

confidence: 99%

“…Various studies have investigated the corrosion resistance and metal ion release from nitinol stent-based devices. − Specifically, Sullivan et al studied the effect of oxide layer composition in nitinol stents manufactured by various processing methods and suggested strong correlations between the layer thickness and cumulative Ni release. Nagaraja et al tested generic heart valve frames manufactured with different vacuum arc remelting methods and surface finishes and showed that the localized and uniform corrosion performance is maintained in higher microstructural nitinol purity.…”

Section: Introductionmentioning

confidence: 99%

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A Predictive Toxicokinetic Model for Nickel Leaching from Vascular Stents

Giakoumi,

Stephanou,

Kokkinidou

et al. 2024

ACS Biomater. Sci. Eng.

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In vitro testing methods offer valuable insights into the corrosion vulnerability of metal implants and enable prompt comparison between devices. However, they fall short in predicting the extent of leaching and the biodistribution of implant byproducts under in vivo conditions. Physiologically based toxicokinetic (PBTK) models are capable of quantitatively establishing such correlations and therefore provide a powerful tool in advancing nonclinical methods to test medical implants and assess patient exposure to implant debris. In this study, we present a multicompartment PBTK model and a simulation engine for toxicological risk assessment of vascular stents. The mathematical model consists of a detailed set of constitutive equations that describe the transfer of nickel ions from the device to peri-implant tissue and circulation and the nickel mass exchange between blood and the various tissues/organs and excreta. Model parameterization was performed using (1) in-house-produced data from immersion testing to compute the device-specific diffusion parameters and (2) full-scale animal in situ implantation studies to extract the mammalian-specific biokinetic functions that characterize the timedependent biodistribution of the released ions. The PBTK model was put to the test using a simulation engine to estimate the concentration−time profiles, along with confidence intervals through probabilistic Monte Carlo, of nickel ions leaching from the implanted devices and determine if permissible exposure limits are exceeded. The model-derived output demonstrated prognostic conformity with reported experimental data, indicating that it may provide the basis for the broader use of modeling and simulation tools to guide the optimal design of implantable devices in compliance with exposure limits and other regulatory requirements.

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