A coronary stent is small metal coil used to help keep a blocked artery in the heart open and reduce the chance of it narrowing. It is commonly employed in angioplasty surgery, also known as percutaneous coronary intervention, which is performed in patients whose coronary arteries have become narrowed and blocked. Angioplasty can also be used during a heart to immediately open a blocked artery and reduce damage to the heart. Coronary stents vary in type according to purpose.
Drug-Eluting Stent
Drug-eluting stents, also called coated stents, contain drugs that are released slowly over time to help prevent arteries becoming re-blocked, a process known as restentosis. Arteries opened with drug-eluting stents become blocked up again in seven percent of cases compared to about 25 percent with bare-metal stents. An example of a drug used to coat stents is the antibiotic, rapamycin. However, results of research published in a 2010 issue of the "Journal of Biological Chemistry" showed that rapamycin may have detrimental effects as it can prevent tissue from growing over and protecting the stent. Without this protection a blood clot may develop in the months following angioplasty.
Bare Metal Stent
Bare metal stents provide support to help keep arteries open after angioplasty surgery. Although in 25 percent of cases, arteries become re-blocked after insertion of a bare-metal stent, research has suggested that bare metal stents may be safer than other types of stents such as drug-eluting stents. Data presented in 2007 at the Society for Cardiovascular Angiography and Interventions in Orlando, Florida, showed that patients who have angioplasty with bare-metal stents are less likely to develop life-threatening cardiac complications if they undergo later surgerical procedures, compared to those who have drug-eluting stents implanted.
Bioabsorbable Stent
Bioabsorbable stents provide a scaffold for the wall of the artery vessel wall when needed and then "disappear" or become absorbed into the vessel wall when they are no longer required. According to a 2006 article published in "The Journal of Invasive Cardiology," the main advantage of this type of stent is that the risk of blood clot formation is unlikely. The article's author, Dr. Waksman, adds that the low risk of blood clot formation means that patients implanted with a bioabsorbable stent do not need to undergo long-term anti-platelet therapy with drugs such as aspirin and a thienopyridine, as do patients who have been implanted with a bare-metal or drug-eluting stent.
References
- Mayo Clinic: Coronary angioplasty and stents
- Stent Plus: Bare Metal vs. Drug-Coated Stents
- Science Daily: Antibiotic Used on Drug-Eluting Stents May Lead to Advances in Heart Disease and Cancer Treatment
- Science Daily:Bare-Metal Stents Are Better For Some Heart Patients
- The Journal of Invasive Cardiology: Biodegradable Stents: They Do Their Job and Disappear
