1. Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

2. Balloon Angioplasty minimally invasive treatment to open blocked arteries. Within this procedure, a balloon catheter is employed to enlarge a narrowed vessel lumen stenosis. have shown increased coronary arterial lumen diameter, increased coronary blood flow, and decreased chest pain.

3. Diagram of Angioplasty Procedure

4. What is Restenosis? the re-narrowing of a coronary artery after dilation Coronary Angioplasty has been performed. six months after the procedure restenosis typically affects between 25% to 45% of patients within results in a repeat procedure. Restenosis is also considered an exaggeration of “vascular healing” and “remodeling” that probably occurs to some degree in all cases

5. Restenosis of Balloon Angioplasty

6. Fighting Restenosis Prior to the mid 1990’s, balloon angioplasty was the primary treatment of arteriosclerosis In the mid 1980's, radiologists and cardiologists worked on solutions to reduce restenosis rates; rotational polishers, tiny shavers, and lasers, to be delivered via catheters.

7. Bare Metal Stents are small expandable metal tubular structures that support the vessel wall and maintain blood flow through the opened vessel (5). In 2001, 84% of the 1,000,000 percutaneous coronary interventions were treated with stents. Of those million, 20% or 200,000 patients develop in-stent restenosis

8. History of the Bare Metal Stent The first stent was inserted into a human coronary artery by European researchers in 1986, in France, by Julio Palmaz and Richard Schatz. Julio Palmaz and Richard Schatz, lead to the first stents to be approved in the United States in 1994 The first company to produce a coronary artery stent was Cordis, a Johnson & Johnson company, in 1994.

9. Early Palmaz-Schatz stent

10. Stenting Diagram

11. Neointimal Hyperplasia is an abnormal increase in the number of cells causing a thickening of the intima of a blood vessel. caused by platelets that are attracted by the damaged tissue caused by the placement of a stent. tissue grows through the openings in the stent and eventually narrows the lumen of the vessel, therefore, reducing myocardial blood flow. This restenosis leads to a repeat procedure.

12. Restenosis of Bare Metal Stents Prevalent in 10 to 30% of patients who receive bare metal stents. usually eliminate abrupt closures, but typically result in a restenosis rate of 25% six months after being placed. The majority of restenosis occurring after a bare metal stent is placed usually occurs within 30 days.

13. Diagram of Reoccurring Restenosis

14. Drug Eluting Stents The invention of the drug-eluting stent came into the angiographic procedures in 2002. The three major elements of drug-eluting stents are: Stent Drug The mechanism for controlling drug release (usually a polymer to protect and control release)

15. Two Main Types of Drug Eluting Stents 1.Cordis CYPHER sirolimus-eluting stent (April of 2003) 2.Boston Scientific TAXUS paclitaxel-eluting stent system (March of 2004) Both stents have shown benefits toward reducing restenosis rates up to 9%

16. Cordis CYPHER Sirolimus-eluting stent Sirolimus is a drug used to help prevent the body from rejecting organ and bone marrow transplants. it helps to limit normal tissue overgrowth (restenosis) following coronary stent implantation. The polymer allows the drug to be released over 30 days which decreased restenosis effects. Since the FDA approval it is estimated that almost 450,000 of these stents have been implanted in 300,000 U.S. patients

17. Cypher stent which uses Sirolimus

18. Boston Scientific TAXUS Paclitaxel-eluting stent The drug Paclitaxel is an antineoplastic agent that inhibits cell migration and proliferation coated with a polymer chemical compound called Transulte (also known as SIBS). The Boston Corporation : Taxus I-VI studies. These clinical trials have shown that paclitaxel- eluting stents reduce restenosis and the need for revascularization with a neutral effect on mortality and myocardial infarction risk.

19. Taxus Stent which uses Paclitaxel

20. Controversy Arises with the use of Drug-Eluting Stents Drug eluting vs. Bare metal stent. Research shows that the revascularization rate for bare metal stents is only 12 to 14 percent. It is said that the financial impact is not with the patient, but it is the hospital taking the biggest loss. (stage the procedure, ethical or not) Drug eluting stents are about 2,000 dollars more than bare metal stents. (decrease $ for repeated procedures and decrease in surgery) An Economical Analysis (Cincinnati network of hospitals) – 3 million dollars in costs to the provider or to the hospital for every 1000 treated patients.

21. The Future of Angioplasty and Restenosis It is estimated that 800,000 to 900,000 individuals in the United States undergo some kind of percutaneous coronary intervention annually. Most of the procedures involve stenting. Drug eluting stent research seems to be at the tip of the ice berg. As studies progress, it will be clearer to health care providers of the details and benefits of the use drug eluting stents or bare metal stents.