A drug-eluting stent is a tiny mesh tube placed into an artery to hold the structure open after an angioplasty procedure. This tube is coated with a time-release medication that helps to prevent the artery from becoming reblocked by limiting the growth of scar tissue. The stent stays in the artery permanently; it acts to keep the artery open, improve blood flow to the heart muscle and relieve chest pain. The drug-eluting stent can often prevent the need for coronary artery bypass surgery.
Angioplasty is a procedure to restore blood flow through narrow or blocked arteries. The concept of the stent grew out of balloon angioplasty procedures performed in the early 1980s. These procedures were successfully used to open blocked coronary arteries. The artery walls frequently were weakened, however, and occasionally the artery would collapse after the procedure. In addition, the arteries would often close up after surgery, a phenomenon known as restenosis.
The first stents were bare-metal stents, consisting of a metal mesh that is inflated with a high-pressure balloon to ensure that it presses tightly against the arterial walls. Once placed, the stent acts as a scaffolding to prop the artery open. Bare-metal stents, which contain no medication, were more effective than other methods of angioplasty, but problems with artery closure remained. The drug-eluting stent, which releases drugs to prevent restenosis, was then developed and has proven even more effective at preventing death, heart attack or the need for a repeat procedure.
A drug-eluting stent consists of a mesh framework, a polymer coating that holds the drug and releases it into the arterial wall and a drug to inhibit cell growth and suppress inflammation. The mesh scaffolding is usually metal, generally stainless steel or a cobalt chrome alloy coated with gold or platinum, although plastic and fabric are sometimes used. Fabric stents are more commonly known as stent grafts and are used in large arteries. Drugs that are commonly used in drug-eluting stents include sirolimus, paclitaxel and everolimus.
Coronary stent placement carries some risks, including bleeding, allergic reaction and heart attack. Some evidence suggests that drug-eluting stents put patients at risk for the formation of a clot in the stent. Alternative treatment options for heart disease include drug therapies, lifestyle changes and coronary artery bypass surgery.