FDA Draft Guidance: Nitinol in Med Devices

New draft guidance offers considerations for using the unique alloy in patient contacting components. Labeling is key in limiting risks from allergic reaction. Comments are due June 17, 2019.

Nitinol is commonly used in cardiovascular devices such as stents, heart valves, guidewires, and vena cava filters.
Nitinol is commonly used in cardiovascular devices such as stents, heart valves, guidewires, and vena cava filters.

The FDA released newdraft guidancethis week,Technical Considerations for Non-Clinical Assessment of Medical Devices containing Nitinol.

Often employed for cardiovascular products, Nitinolis a nickel-titanium alloy commonly used in medical devices because of unique properties such aspseudoelasticity and shape memory behavior.

While nitinol enables many innovative designs, it requires special considerations due to its “thermomechanical behavior and processing sensitivity… when compared to conventional metals such as stainless steel, titanium, or cobalt-chrome alloys.”

The draft recommendations are separated into the various forms of patient exposure: limited, prolonged and permanent contact.Labeling is key in limiting risk for those who may be allergic to nickel or titanium.

Recommendations include providing FDA with:

  • The nitinol composition and a description of its specific properties (if it does not conform to a recognized consensus standard)

  • A flow chart to identify the manufacturing processes leading from your raw material to the final device sterilization, as well as a detailed description of surface processing steps and post-processing cleaning steps (when applicable)

  • Information on whether pseudoelastic (superelastic) or shape memory behavior is being employed

  • Phase transformation temperatures of your final finished form

The document also provides testing, corrosion and computational stress/strain analysis considerations.

Comments

Comments are accepted for 60 days from the document’s release, ending June 17, 2019 at the following link: https://www.regulations.gov/document?D=FDA-2019-D-1261-0001

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