Stenting for Left Subclavian Artery Stenosis before and after Coronary Artery Bypass Grafting Using the Internal Mammary Artery: A Report of Three Cases.

SUMMARY: Stenosis of the subclavian artery proximal to the origin of the internal mammary artery (IMA) used for coronary artery bypass grafting may produce flow reversal (steal syndrome) and cause myocardial ischemia. We present three cases of subclavian artery stenosis proximal to the IMA before and after CABG. The first case developed symptomatic myocardial ischemia resulting from a variant of coronary-subclavian steal syndrome. The second case had asymptomatic subclavian artery stenosis proximal to the IMA used for CABG. In the third case we planned to perform CABG using the left IMA to treat cardiac ischemia. All of the patients were successfully treated by stent placement without the use of a protection device. In the first and second cases, cardiac ischemia did not appear during balloon inflation of the subclavian artery and no embolic complication occurred. In the third case, CABG was performed six months after stenting. Subclavian artery stenting is a valid alternative to surgical treatment to restore the flow to the IMA before or after CABG.

The super-elastic Japanese NiTi alloy wire for use in orthodontics. Part III. Studies on the Japanese NiTi alloy coil springs.

Closed and open Japanese nickel titanium (NiTi) alloy coil springs were fabricated from the Japanese NiTi alloy wire. The closed coil springs were subjected to a tensile test and the open coil springs were subjected to a compression test to evaluate the mechanical properties. At the same time, a test with the commercially available steel coil springs also was done. It was clearly established that the Japanese NiTi alloy coil springs exhibited superior springback and super-elastic properties similar to the properties of the Japanese NiTi alloy arch wires. In addition, it was shown that the load value of super-elastic activity can be effectively controlled by changing the diameter of the wire, the size of lumen, the martensite transformation temperature, and the pitch of the open coil spring. The most important characteristic of the Japanese NiTi alloy coil springs is the ability to exert a very long range of constant light, continuous force. It is possible to use this coil selectively to obtain optimal tooth movement.

The super-elastic property of the Japanese NiTi alloy wire for use in orthodontics.

A new Japanese nickel-titanium (NiTi) alloy wire was developed by the Furukawa Electric Co., Ltd. of Japan. This wire was subjected to uniaxial tensile testing and a specially designed three-point bending test to determine the wire stiffness, and to evaluate spring-back, shape memory, and super-elasticity. The Japanese NiTi wire exhibited an unusual property termed "super-elasticity," which no other orthodontic wire has shown. This phenomenon was researched thoroughly. The wire delivered a constant force over an extended portion of the deactivation range. Among all the wires compared, Japanese NiTi alloy wire was the least likely to undergo permanent deformation during activation. The new alloy exhibited a specific stress-strain curve unlike those of the other tested materials. Stress remained nearly constant despite the strain change within a specific range. This unique feature is the manifestation of so-called super-elasticity. Heat treatment enabled the load magnitude at which super-elasticity is reflected to be influenced and controlled by both temperature and time. A unique and useful process was also developed so that an arch wire delivering various magnitudes of force for a given activation could be fabricated from the wire of the same diameter. The clinical application of wires of this new alloy should be more likely to generate a physiologic tooth movement because of the relatively constant force delivered for a long period of time during the deactivation of the wire. Japanese NiTi alloy should be considered an important material addition to clinical orthodontic metallurgy.