Corrosion, Surface Characterization, and Nickel Leaching in Cardiovascular Metallic Implants

FDA will be holding a a public workshop on "Cardiovascular Metallic Implants: Corrosion, Surface Characterization, and Nickel Leaching" on March 8 and 9, 2012, from 9 a.m. to 5:30 p.m. EST at the FDA White Oak Campus, 10903 New Hampshire Ave., building 31, room 1503, Silver Spring, MD 20993. The public workshop will also be viewable online via Webcast. The workshop will provide a forum for FDA, cardiovascular device manufacturers, test houses, and academia to discuss corrosion, surface characterization, and nickel leach testing, as well as to collect comments and input regarding when these assessments should be considered.

FDA notes that while most cardiovascular implants are made of metals and may be susceptible to corrosion, it is unclear whether the current corrosion-testing paradigm is predictive of in vivo corrosion outcomes or whether more-suitable assessments to predict corrosion failure may be available. In addition, the use of nitinol in cardiovascular implants has increased because of its superelastic properties. However, corrosion of implant devices made of nitinol and other nickel-containing metal alloys such as stainless steel and MP35N results in the release of nickel ions, which may lead to various toxicity modes. Furthermore, the release of nickel ions and corrosion characteristics are dependent on the surface finishing that nitinol and other nickel-containing alloys undergoes.

By collecting information from a preworkshop work assignment and holding discussions with workshop participants, FDA will be able to better determine what assessments can be considered for cardiovascular implants made of commonly used metallic alloys. This information, in turn, is expected to serve as the foundation for a future guidance document.

The workshop will discuss the various methods used for corrosion assessments, surface characterization techniques, and nickel leach testing for evaluating the suitability of metallic cardiovascular implant devices. In addition, it will highlight the limitations of each of these tests to predict actual in vivo performance, discuss the need and utility of each test, and explore potential testing paradigms such as when certain tests should be considered and how to establish acceptance criteria for each test.

Participants in the workshop will include both lead participants and audience members. Lead participants will include representatives from organizations involved in corrosion testing, surface characterization, or nickel leach testing and experts involved in toxicological assessments of nickel.