A drug-eluting stent (DES) is a coronary stent (a scaffold) placed into narrowed, diseased coronary arteries that slowly releases a drug to block cell proliferation. This prevents fibrosis that, together with clots (thrombus), could otherwise block the stented artery, a process called restenosis.
The stent is usually placed within the coronary artery by an Interventional cardiologist during an angioplasty procedure.
Drug-eluting stents in current clinical use were approved by the FDA after clinical trials showed they were statistically superior to bare-metal stents (BMS) for the treatment of native coronary artery narrowings, having lower rates of major adverse cardiac events (MACE) (usually defined as a composite clinical endpoint of death + myocardial infarction + repeat intervention because of restenosis).
The first procedure to treat blocked coronary arteries was coronary artery bypass graft surgery (CABG), wherein a section of vein or artery from elsewhere in the body is used to bypass the diseased segment of coronary artery. In 1977, Andreas Grüntzig introduced percutaneous transluminal coronary angioplasty (PTCA), also called balloon angioplasty, in which a catheter was introduced through a peripheral artery and a balloon expanded to dilate the narrowed segment of artery.
As equipment and techniques improved, the use of PTCA rapidly increased, and by the mid-1980s, PTCA and CABG were being performed at equivalent rates. Balloon angioplasty was generally effective and safe, but restenosis was frequent, occurring in ~30–40% of cases, usually within the first year after dilation. In ~3% of balloon angioplasty cases, failure of the dilation and acute or threatened closure of the coronary artery (often because of dissection) prompted emergency CABG. In 1986, Puel and Sigwart implanted the first coronary stent in a human patient. . As currently used in clinical practice, "drug-eluting" stents refers to metal stents which elute a drug designed to limit the growth of neointimal scar tissue, thus reducing the likelihood of stent restenosis.
The first successful trials were of sirolimus-eluting stents. A clinical trial in 2002 led to approval of the sirolimus-eluting Cypher stent in Europe in 2002. After a larger pivotal trial (one designed for the purpose of achieving FDA approval), published in 2003, the device received FDA approval and was released in the U.S. in 2003.
The Xience V everolimus eluting stent was approved by the FDA in July 2008 and has been available in Europe and other international markets since late 2006. It is an investigational device in Japan.
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