Drug-eluting stent

A drug-eluting stent (DES) is a peripheral or coronary stent (a scaffold) placed into narrowed, diseased peripheral or coronary arteries that slowly releases a drug to block cell proliferation. This prevents fibrosis that, together with clots (thrombi), could otherwise block the stented artery, a process called restenosis. The stent is usually placed within the peripheral or coronary artery by an interventional cardiologist or interventional radiologist during an angioplasty procedure. A drug-eluting stent (DES) is a peripheral or coronary stent (a scaffold) placed into narrowed, diseased peripheral or coronary arteries that slowly releases a drug to block cell proliferation. This prevents fibrosis that, together with clots (thrombi), could otherwise block the stented artery, a process called restenosis. The stent is usually placed within the peripheral or coronary artery by an interventional cardiologist or interventional radiologist 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 for the treatment of native coronary artery narrowings, having lower rates of major adverse cardiac events (usually defined as a composite clinical endpoint of death + myocardial infarction + repeat intervention because of restenosis). The first drug-eluting stents to be approved in Europe and the U.S. were coated with paclitaxel or an mTOR inhibitor, such as sirolimus. Clinical trials have shown the benefits of coronary stenting with bare-metal stents over other methods of angioplasty, including balloon angioplasty and atherectomy. Drug-eluting stents (DES) have also been extensively studied, and are generally superior to bare-metal stents with respect to occurrence of major adverse cardiac events (MACE, generally defined as death, myocardial infarction, or the need for a repeat revascularization procedure). Stents are indicated to improve the diameter of the coronary artery lumen, when narrowing (generally because of atherosclerosis) causes ischemia (reduced oxygen delivery to the muscle supplied by that artery). Drug-eluting stents also have been shown to be superior to bare-metal stents in reducing short-term complications of stenting in saphenous vein grafts; however, use in these bypass grafts is an example of an 'off-label' use of drug-eluting stents. That is, this application has not been sufficiently examined by the Food and Drug Administration for that agency to recommend the use. For 'on-label' applications, the FDA 'believes that coronary drug-eluting stents remain safe and effective when used for the FDA-approved indications. These devices have significantly reduced the need for a second surgery to treat restenosis for thousands of patients each year.' Some concern has been expressed about overzealous use of stents in general. Two studies found about half of patients received stents for unapproved reasons, with worse outcomes for the patients in both studies. More recent data suggest off-label use of both bare-metal stents and drug-eluting stents have increased risks. However, drug-eluting stents seemed to have similar or improved rates of death or MI compared with bare-metal stents, and consistently reduced need for target vessel revascularization. Overall, the data support the use of drug-eluting stents for off-label indications. Medical therapy for coronary artery disease has also improved since the 1970s, and for many kinds of patients may be as successful as stenting or surgery. For those requiring PCI or surgery, medical therapy and revascularization should be viewed as complementary rather than opposing strategies. Coronary artery bypass graft surgery is the best treatment for some patients. Differences between outcomes with stenting and with coronary artery bypass surgery (CABG) are a point of controversy. A recent study comparing the outcomes of all patients in New York state treated with CABG or percutaneous coronary intervention (PCI) demonstrated CABG was superior to PCI with DES in multiple vessel coronary artery disease . Patients treated with CABG had lower rates of death and of death or myocardial infarction than treatment with a drug-eluting stent. Patients undergoing CABG also had lower rates of repeat revascularization. Two major randomized controlled trials comparing CABG and DES are either completed or ongoing, and have published results - Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) and Future Revascularization Evaluation in Patients With Diabetes Mellitus—Optimal Management of Multivessel Disease (FREEDOM). The five-year follow-up results of SYNTAX showed, depending on the complexity of coronary vessel disease, PCI was either equally effective or inferior to CABG. Similarly, results from the FREEDOM trial published after five years showed CABG to be superior to PCI in reducing rates of death and myocardial infarction. Both trials found either increased or insignificantly different rates of stroke with CABG as compared to PCI. The registries of the nonrandomized patients screened for these trials may provide as much robust data regarding revascularization outcomes as the randomized analysis. Other studies, including the ARTS II registry, suggest drug-eluting stenting is not inferior to coronary bypass for treatment of multiple-vessel coronary disease. The ARTS II registry compared a cohort of patients treated with multiple-vessel stenting with DES, to the historical CABG cohort in the ARTS I trial (itself a randomized comparison between multiple-vessel bare-metal stenting vs. CABG.) At three-year follow-up, major adverse cardiac events were comparable between the ARTS II DES group and the ARTS I CABG group. Reintervention was lower in the ARTS I CABG group.In all comparison studies of stenting vs. bypass surgery, only a small minority of patients with multiple-vessel coronary disease have been eligible for inclusion in the studies, and for most patients, clinical judgement by experienced operators suggest one or the other approach is preferred.