A thin film nitinol heart valve.
In order to create a less thrombogenic heart valve with improved longevity, a prosthetic heart valve was developed using thin film nitinol (NiTi). A "butterfly" valve was constructed using a single, elliptical piece of thin film NiTi and a scaffold made from Teflon tubing and NiTi wire. Flow tests and pressure readings across the valve were performed in vitro in a pulsatile flow loop. Bio-corrosion experiments were conducted on untreated and passivated thin film nitinol. To determine the material's in vivo biocompatibility, thin film nitinol was implanted in pigs using stents covered with thin film NiTi. Flow rates and pressure tracings across the valve were comparable to those through a commercially available 19 mm Perimount Edwards tissue valve. No signs of corrosion were present on thin film nitinol samples after immersion in Hank's solution for one month. Finally, organ and tissue samples explanted from four pigs at 2, 3, 4, and 6 weeks after thin film NiTi implantation appeared without disease, and the thin film nitinol itself was without thrombus formation. Although long term testing is still necessary, thin film NiTi may be very well suited for use in artificial heart valves.
Stepan
Lenka L
LL
Biomedical Engineering Department, University of California at Los Angeles, Room 32-135, Engineering IV, Los Angeles, CA 90095, USA. lenka@seas.ucla.edu
Levi
Daniel S
DS
Carman
Gregory P
GP
D000497:Alloys / Q000032:analysis / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D003343:Corrosion; D019544:Equipment Failure Analysis; D006350:Heart Valve Prosthesis; D008422:Materials Testing; D008567:Membranes, Artificial; D011474:Prosthesis Design; D011673:Pulsatile Flow / Q000502:physiology*; D013552:Swine
D000497:Alloys; D001672:Biocompatible Materials; D008567:Membranes, Artificial; C013616:nitinol