Treatment Options for Coronary Artery Disease (CAD)
There are two treatments your cardiologist may use to relieve blockages caused by CAD: bypass surgery or balloon angioplasty. Angioplasty is far less invasive than bypass surgery and is the procedure of choice among cardiologists for many patients. In the early 1990s, physicians began using a technology called a stent to improve the success rates of angioplasty. A stent is a small metal tube, which the physician inserts into the artery to prop it open. Stents have been effective at reducing elastic recoil (the tendency of elastic tissues to return to their original position), which can result in the early re-blockage of an artery.
Since the development of stents, a large obstacle for physicians has been preventing the artery from re-clogging in the stent (a process known as in-stent restenosis). Restenosis still occurs in approximately 10 to 30 percent of patients who receive bare metal stents.
When a stent is implanted in an artery, the body reacts naturally to heal itself. To accomplish this, the vessel produces a layer of new cells which will eventually cover the stent. While this covering of the stent is a natural healing response, the layer can become too thick. This leads to a narrowing of the vessel, and reduced blood flow. The reblockage of the vessel is called restenosis ("stenosis" is the medical term for a blockage of your artery, so "restenosis" means "re-blockage.")
Drug-eluting stents, introduced in 2003, have been shown to dramatically reduce the rates of restenosis and repeat procedures. This new technology represents a huge step forward for cardiovascular medicine.
How the Technology Operates
A stent is a small mesh tube which props open the artery, reducing the likelihood that the artery will narrow again. The stent is made of a metal such as stainless steel. Stents do not rust, as they are made from a non-corroding metal.
A drug-eluting stent has all the structural features of a conventional stent. The major difference between the two is that a drug-eluting stent has a coating of a polymer (a chemical compound) which emits a restenosis-fighting drug. The polymer coating on the stent provides for consistent and even distribution of the drug from the stent.
The Boston Scientific drug-eluting stent is called the TAXUS™ Express²™ Paclitaxel-Eluting Coronary Stent System. The TAXUS stent uses a drug known as paclitaxel, which has been widely tested and is used in treating other kinds of disease. Paclitaxel interferes with the ability of the vessel cells to divide and multiply, therefore reducing restenosis. Other drug-eluting stents may use different medications.
During the Procedure
The procedure for implanting a drug-eluting stent is much like the procedure for implanting a conventional stent. In both cases, the physician will insert an introducer sheath into your groin, arm, or wrist to gain access to the artery. A balloon-tipped catheter will be threaded through the sheath, into your bloodstream, and to the affected portion of your coronary artery. The balloon is inflated to compress the plaque against the wall of the artery. This is called "pre-dilatation." After the artery has been widened, a second catheter is then inserted with a stent wrapped around the balloon. When the balloon inflates, the stent expands and is imbedded in your arterial wall. The artery will heal around the stent, holding it firmly in place. The special polymer coating on the stent will release an anti-restenosis medication directly into the artery in small, controlled quantities.
The procedure will be performed under local anesthetic, so that you can respond to your physician's directions and notify him or her of any pain you experience during the procedure. You may experience tightness or discomfort in your chest while the catheter is being guided to the lesion and the balloon is expanded. If you feel any pain, tell your physician immediately. The procedure should take less than two hours. Following the procedure, your doctor will prescribe one or more medications to prevent the formation of blood clots. On average, your hospital stay may last one to three days before you are discharged.
For more information about how to prepare for the procedure or what to expect during the recovery process, talk to your cardiologist.
Reasons for Undergoing the Procedure
Recent clinical trials suggest that drug-eluting stents may rapidly become the most important and helpful adjunct to angioplasty on the market. The improved long-term success rates made possible by drug-eluting stents are truly remarkable. In a recent clinical trial, the rate of repeat procedures to the target lesion 9 months after the stent implant was reduced from 11.3% with a bare metal stent to only 3.0% with a drug-eluting stent. 1 year after the stent implant, the rate of repeat procedures to the target lesion was 14.7% with a bare metal stent and only 4.2% with the drug-eluting stent.¹
¹ TAXUS IV Clinical Trial (data on file)
Who Can Have This Procedure
The use of a drug-eluting stent is frequently an excellent option to improve vessel diameter and reduce restenosis in patients who have simple coronary lesions. It is contraindicated in patients with a known sensitivity to the drug, in patients who cannot take the recommended anti-platelet therapy following the procedure, and if the physician decides that the blockage will not allow complete inflation of the angioplasty balloon or proper placement of the stent. Your physician will make the decision for the most appropriate treatment for your condition. As with any medical procedure you are considering, you should talk to your doctor about potential complications and alternative treatments available to you.
It is important that this information is provided for INFORMATIONAL PURPOSES ONLY and must never be considered medical advice or diagnosis.
Always consult with your physician if you have any concerns regarding your medical situation.
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