Stents, the small tubes used in medical procedures to open blocked or narrowed arteries or veins, can be coated with medication or left uncoated. They can be made of fabric, plastic, or metal. Uncoated metal stents made of wire mesh are called "bare metal" stents. Stents that are coated with medication are called "drug-coated," or "drug-eluting," stents.
Another term used for coated stents is “covered,” while uncoated stents are termed “uncovered.” Both coated and uncoated wire mesh stents are used to treat specific diseases or body conditions. Clinical studies have determined that using drug-eluting stents to unblock arteries helped reduce the amount of reblocking more than using an uncoated metal stent did.
Each type of stent can be constructed in different shapes and sizes for a wide range of uses. For example, self-expanding stents used to treat cancers of the esophagus are shaped like small cylinders. They are made of flexible rows of cross-hatching, which allows the cylinder to be easily expanded or contracted. Self-expanding stents can be made of plastic or metal, and they may be drug-eluting to carry chemotherapy medication.
A relatively new type of uncoated wire mesh metal stent is covered with a titanium alloy, allowing the stent to be better tolerated by the body’s immune response system; this stent is called a “bioactive” stent. Another type of wire mesh stent, or vascular stent, can be coated with radioactive material for treatment of specific cancer sites. Both the uncoated metal stent and the drug-eluting stent can be used in practically any part of the body, including the chest, thorax, abdomen, esophagus, ureters, and other areas crucial for sustaining life processes. Peripheral stents used to unblock or dilate veins or arteries in the appendages can also be coated or uncoated.
A coronary stent is for heart disease treatment. The angioplasty procedure is one method used to unblock and/or dilate arteries in the heart or coronary system. Both wire mesh coated and uncoated metal stents have been used for angioplastic treatment. Sometimes, tears can develop in the aorta, and fabric stents have been used to repair these tears or to strengthen a weakened aortic lining.
A principal benefit of using stents, whether bare metal or drug-eluting, to treat heart disease is that they help prevent coronary arteries from becoming narrowed or blocked again, because the stents remain in place after an angioplasty procedure. This narrowing after arterial repair is known as restenosis. In contrast to a plain metal stent, a drug-eluting stent contains medication that helps to prevent blood clots that could again block a stented artery. Drug-coated stents also help to reduce the effects of reactions by the body to permanently placed stents.
