Explanation

It refers to the placement of an internal stem in the diseased segment on the basis of balloon dilation to support the vessels in the stenosis and occlusion segment, reduce the elasticity retraction and remodeling of the vessels, and maintain smooth blood flow in the lumen. Some internal stem also have the function of preventing restenosis, which are mainly divided into coronary stem, cerebral and renal artery stem, and major artery stem. They are made of metal or macromolecule materials and can be kept in human blood vessels for a short time or temporarily. At present, materials commonly used to make stem include tantalum, medical steel and nickel titanium alloy. The types of stem can be divided into self expanding and balloon expanding according to the way of unfolding in the blood vessel. The former, such as Z-shaped stem and mesh shaped stem, can expand itself in the blood vessel. The latter has no elasticity of its own and adheres to the blood vessel by means of balloon expansion to a certain diameter. Stem can be divided into bare type, coated type and film covered type according to surface treatment. The exposed surface is only polished: the coating type is coated with substances such as heparin and titanium oxide on the metal surface; Film covered type means that the surface of the metal stem is covered with degradation or non degradation polymer film. According to the function, it can be divided into simple support stem and therapeutic stem therapeutic stem, including stem or radioactive stem coated with drugs on the surface of stem or coated with therapeutic materials outside stem.

Classification