ABSTRACT
This article describes the development of a Nitinol tracheal stent (HCPA NiTi-stent) and its application in a feline animal model. Straight-annealed, bright-polished Nitinol wire (55.8%Ni-44.2%Ti) was weaved around a 40-mm-long metal fixture with 8-mm diameter. The prototypes were submitted to different times of shape-setting heat treatment (530 degrees C), which resulted in stents of different colors and caused some variation in length and diameter. The prototypes were then submitted to compression testing, and the most resistant pieces, requiring the greatest force to achieve a 25% reduction in diameter and presenting the least variation in length and diameter (dark blue, 9 min of heat treatment), were submitted to fatigue testing. After that, only dark blue stents were manufactured and implanted in felines. No migration, tracheal stenosis, or any other type of damage were observed after 40 weeks. The integrity of the tracheal wall in contact with the stent was confirmed by macro and microscopic analyses. The development and in vivo testing of the HCPA NiTi-stent were successful.
