Drug eluting coronary artery stents

Atherosclerosis is the primary cause of coronary heart disease, which is characterized by a narrowing (stenosis) of the arteries that supply blood to tissues of the heart. Over the past decade, the use of "Bare metallic stents" during Percutaneous Transluminal Coronary Angioplasty (PTCA) has become a common practice for treating the coronary arterial stenosis. However, the restenosis is common problem in patients receiving stents. Recently, Drug-Eluting Stents (DES) with synthetic polymer coatings which act as drug reservoirs and elute drugs over a period of several weeks or months have emerged to tackle restenosis. The polymer coatings on these stents contain various drugs like immunosuppressive drugs, anti-neoplastic drugs, anti-inflammatory drugs, migration inhibitor drugs and enhanced healing drugs that inhibit thrombus formation, inflammation or cellular proliferation which in turn prevent restenosis. Different methods like dip coating, dip spin coating, ultrasonic spray coating and ink-jet coating help to coat stent uniformly. Drug from the stent can be released by diffusion, dissolution or ion exchange mechanism. There are some disadvantages of the polymer coated stents and hence they are being superseded by completely bioabsorbable stents. Such stents are heading for clinical trials and may hit the market soon. This review gives a glimpse over DES and the future prospects of DES.