Q: What is a drug-coated stent?Answer from Dr. Andrew Carter, director of interventional cardiology research for Providence Heart and Vascular Institute: Let me begin with the basics. A stent is a tiny, expandable steel-mesh tube that fits over an uninflated angioplasty balloon. Stents are used to open arteries that have been blocked by the build-up of cholesterol and scar tissue (atherosclerosis) and help restore normal blood flow to the heart muscle. In the United States this year, about one million patients will undergo a balloon angioplasty procedure. About 80 to 85 percent of these patients will receive a stent.
Stents are excellent in terms of their ability to open an artery and restore normal blood flow. We can successfully place stents and open the artery more than 95 percent of the time. However, there are limitations. In about 15 to 25 percent of stent patients, their body’s efforts to heal will cause a build-up of scar tissue, called restenosis, which clogs the stent. Restenosis causes a return of heart disease symptoms and a need for further treatment.
Source: Boston Scientific, Co.
A drug-eluting stent is placed inside a coronary artery that has been cleared of plaque or scar tissue. Once in place, the stent releases a medication that prevents scar tissue from reclogging the arteries.
Clinical studies at Providence and other institutions around the country have shown that stents coated with sirolimus, a drug traditionally used to prevent the rejection of transplanted organs, significantly reduce the risk of restenosis in some patients. The FDA recently approved the first drug-coated stent, called the CYPHER sirolimus eluting stent, for use in patients with blockages in coronary arteries of a certain size.
The CYPHER stent offers a significant advance for these patients. Additional research is necessary to determine whether drug-coated stents offer added benefit for other patients, including those in whom the bare metal stent or bypass surgery have already proven effective. Talk with your doctor if you have questions about whether this therapy is right for you.
Providence will remain involved with ongoing drug coated-stent research. We are presently participating in a study to compare the CYPHER stent to radiation therapy in patients who have experienced restenosis after receiving bare metal stents. We will be studying the CYPHER stent in patients with heart attacks. The Providence Heart and Vascular Institute will be one of 15 to 20 sites in the United States participating in a National Heart, Lung and Blood Insitute study that will compare the safety and efficacy of the CYPHER stent to open heart surgery in diabetic patients who need multiple stents or bypass surgery. In the future, clinical trials are anticipated to evaluate other new drug coated stents.
