In a Preliminary Simulation Data, Stent with Thinnest Strut Beta Crystalline Titanium Gold Alloy (β-Ti-Au) Outperforms Typical Implants

Adam Au^1, and Sahil Verma²

¹School of Medicine, Florida International University Herbert Wertheim College of Medicine, Miami, Florida, USA

²University of Miami, PRISM and Foote Fellow Program, Coral Gables, Florida, USA

Cite this paper:
Adam Au and Sahil Verma. In a Preliminary Simulation Data, Stent with Thinnest Strut Beta Crystalline Titanium Gold Alloy (β-Ti-Au) Outperforms Typical Implants. American Journal of Biomedical Research. 2018; 6(2):46-52. doi: 10.12691/ajbr-6-2-3

Abstract

Background: Large volume of data support the overall safety of coronary stents for cardiovascular disease. Yet, one cannot lose sight of their shortcomings such as restenosis; hence stents continue to evolve in lattices, materials, and drugs. Studies outlining the successful use of titanium gold alloy stents to counter these issues are lacking. Methods: In this analysis we obtained available historical manufacturing records on routinely used stents to compare to two revolutionary titanium-gold alloy stents. By using a 3D CAD finite element analysis space, each stent type was tested for flexibility, rigidity, and radial forces. Except for lengths and diameter, each type was held to their own strut geometry and thickness. Our analysis focused on using Von Mises Stress and resulting deformation or expansion. Our assessments were performed by using discrete changes and Pearson’s chi-squared statistics to obtain significance of our findings. Three lengths: 15mm,27.5mm and 40mm were tested for each type. Comparisons were obtained from the mean percentage length or diameter (3.5mm) changes. Results: β-Ti-Au alloy in our hexagonal mesh was significantly more expansive (78.29 percent gain in diameter under 7 atm. than Orsiro Hybrid (the baseline). p < 0.001. The best performance in vertical crush testing was obtained from our second original structure, titanium – gold alloy stent 1 (0.8 percent vs control). Nobori was the most longitudinally flexible in that testing category but was closely matched by beta titanium – gold alloy (1.97 percent vs 2.19 percent) with promus PREMIER’s performance serving as the zero-reference point. In radial strength testing, our opened and closed titanium-gold structures first and second designs respectively came second and third to Orsiro (10.03 percent >9.09 percent >7.80 percent). Maximum changes in displacements, 0.19 and 0.25. Both values were significant. (95% CI 0.11-0.27, 0.17-2.33). Conclusion: Routine use of Titanium in coronary stents has been hindered by its low density, elastic modulus and strength; contrary these results suggest that by mixing titanium with gold and on the right structure the alloy can be constructed with a thin strut for percutaneous coronary intervention.

Keywords:
beta crystalline titanium gold alloy (β-Ti-Au) coronary artery disease cardiac catheterization percutaneous coronary intervention coronary stents drug-eluting stents atherosclerotic heart disease cardiovascular disease interventional cardiology nitinol titanium cobalt chromium stent technology myocardial infarction

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References:

[1]	O'Brien B, Zafar H2, Ibrahim A, Zafar J, Sharif F. Coronary Stent Materials and Coatings: A. Technology and Performance Update. Ann Biomed Eng. 2016 Feb; 44(2): 523-35.
[2]	Gregory D. Curfman, et al. Drug-Eluting Coronary Stents - Promise and Uncertainty. NEW Engl J Med 2007; 356:1059-1060.
[3]	Shuichi Yoneda. Comparison of Stent Performance Between ZES and EES. Circulation. 2018;134: A13902.
[4]	“Nitinol Technical Properties”. http://jmmedical.com/resources/221/Nitinol-Technical-Properties.html Accessed April 12, 2018.
[5]	Stoeckel, Pelton, Duerig, Self‐Expanding Nitinol Stents, Material and Design Considerations. European Raiology. 2003. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.542.9850&rep=rep1&type=pdf. Retrieved 7/29/18.
[6]	Stent platforms and materials. Journal of American College of Cardiology. JACC 1996; 27: 53.
[7]	Technical Data, Physical and Chemical Properties of Cobalt Chromium. Medical Devices Certification Data. http://www.3trpd.co.uk/wp-content/uploads/2013/03/cobalt-chrome-alloy-co28-cr6mo-2012.pdf Retrieved 6/28/2018.
[8]	Bagheri S, Yasemi M, Safaie-Qamsari E, Rashidiani J, Abkar M, Hassani M, Mirhosseini SA, Kooshki H. Using gold nanoparticles in diagnosis and treatment of melanoma cancer. Artif Cells Nanomed Biotechnol. 2018 Jan 26:1-10.
[9]	Kubota T, Kuroda S, Morihiro T, Tazawa H, Kagawa S, Fujiwara T. [Novel HER2-Targeted Therapy Combined with Gold Nanoparticles. Gan To Kagaku Ryoho. 2016 Oct; 43(10): 1237-1239.
[10]	P. PONCIN, J. PROFT. Stent Tubing: Understanding the Desired Attributes. Materials & Processes for Medical Devices Conference 8-10 September 2003.
[11]	Trina Roy, Abhijit Chandra. Computational Modeling and Analysis of Latest Commercially Available Coronary Stents During Deployment, Science Direct. Procedia Materials Science 5(2014) 2310-2319.
[12]	Hongxia Li, Tianshuang Qui, Bao Zhu, Jinying Wu, and Xichheng Wang. Design Optimization of Coronary Stents Based On Finite Element Models. The Scientific World Journal. Volume 2013 Article ID 630243.
[13]	U.S. Food and Drug Administration. Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems - Guidance for Industry and FDA Staff. April 18, 2010.
[14]	Kastrati A, Mehilli J, Dirschinger J, et. Al. Intracoronary Stenting and Angiographic Results Strut Thickness Effect on Restenosis Outcome (ISAR-STEREO) Trial]. Vestn Rentgenol Radiol. 2012 Mar-Apr; (2): 52-60.
[15]	John A. Ormiston, Mark W.I. Webster, Peter N. Ruygrok. Stent Strut Thickness and Restenosis. Mar 2018Circulation. 2018; 105: e12.
[16]	Harold L. Dauerman. The Magic of Disappearing Stents. Journal of the American College of Cardiology Oct 2011, 58 (15) 1589-1591.