Thermal processing and characterization of 316LVM cardiovascular stent

Article type: Research Article

Authors: Verma, Arpana | Choubey, Animesh^; | Raval, Ankur | Kothwala, Devesh

Affiliations: University of Arkansas, Fayetteville, AR 72701, USA | University of Texas Health Science Center at San Antonio, TX 78256, USA | Research and Development Division, Sahajanand Medical Technologies, Surat-395 003, India

Note: [] Corresponding author. Tel.: +1 210 262 1811; E-mail: choubey@uthscsa.edu.

Abstract: In the current investigation, annealing was employed as a means to improve the mechanical performance of 316LVM coronary stents. Two different temperatures (1000°C and 1150°C) were explored for the thermal processing of the device. Acid pickling was done as a pre-annealing step to remove the debris and slag material attached to the stent after laser cutting. Post annealing operation involved the electrochemical polishing of the device which was also a parameter for assessment of the feasibility of the annealing process. Microstructural characterization, balloon expandability and tensile testing of the stents were performed to characterize the properties after thermal treatment. A fine grained austenitic structure with marked improvement in the % elongation (>40%) could be achieved after annealing the stents at 1000°C. Balloon expandability tests of the stents annealed at 1000°C indicated that the device was implantable.

Keywords: Cardiovascular stent, acid pickling, annealing, electrochemical polishing

Journal: Bio-Medical Materials and Engineering, vol. 16, no. 6, pp. 381-395, 2006