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

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

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

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

Page 2: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 3: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Diagram of Angioplasty Procedure

Page 4: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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

Page 5: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Restenosis of Balloon Angioplasty

Page 6: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 7: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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

Page 8: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 9: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Early Palmaz-Schatz stent

Page 10: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Stenting Diagram

Page 11: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 12: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 13: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Diagram of Reoccurring Restenosis

Page 14: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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)

Page 15: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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%

Page 16: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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

Page 17: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Cypher stent which uses Sirolimus

Page 18: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 19: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

Taxus Stent which uses Paclitaxel

Page 20: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.

Page 21: Angioplasty’s Fight against Restenosis: Drug Eluting Stents & Bare Metal Stents

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.