Tuesday, September 7th, 2010
Angioplasty and Restenosis: A Patient's Guide
John B. Bedotto, M.D., F.A.C.C.
Percutaneous Coronary Intervention (PCI) is a safe and effective method to open blocked coronary arteries. Since introduced by Andreas Guentzig twenty-five years ago, PCI techniques and devices have steadily improved. Angioplasty, Atherectomy and Stent placement are PCI procedures that may be recommended by your cardiologist as alternatives to coronary bypass surgery. PCI is now performed more frequently than bypass surgery and an estimated one million procedures are performed each year. PCI techniques are now successful in well over ninety (90%) percent of cases with complication rates below five (5%) percent.
Angioplasty and Atherectomy
The technique of angioplasty involves placing a catheter into an artery located in the groin or arm. The catheter is then guided through the artery toward the heart and placed into a coronary (heart) artery. A tiny guide wire is next steered across the blockage (plaque) in the coronary artery. The guide wire serves as a rail to deliver a catheter which is used to unblock the obstructed coronary artery. This may be a balloon catheter which is opened to flatten the plaque or a mechanical device which cuts and/or removes the plaque from the artery. When the plaque is cut from the artery it is called Atherectomy.
Stents
Stents are small metal devices mounted on a balloon catheter. Stents are usually made of stainless steel and are deployed by inflating a balloon catheter which pushes the stent into the wall of the artery. The stent serves as a scaffolding to help keep the artery open. To date, stents are the only method which effectively helps prevent restenosis (recurring blockage) of the artery.
Restenosis
Any technique which disrupts the integrity of the blood vessel wall causes new tissue growth as part of the healing process. This new tissue growth consists of healthy cells which smooth over the injured area caused by the mechanical action of the angioplasty catheter. Overgrowth of this tissue may be thick enough to obstruct blood flow and cause the artery to become blocked by this scar tissue. This occurs in about one-third of arteries treated by PCI techniques and is called restenosis.
When scar tissue forms inside a stent it is called in-stent restenosis. In-stent restenosis is found to occur six months after placement of the stent and almost never occurs after the stent has been in place for twelve months. Standard un-coated stents have reduced restenosis rates to about 25% or less. The Federal Drug Administration (FDA) recently approved drug eluting stents. This type of stent slowly releases medication into the blood vessel wall which inhibits the restenosis process. Studies have shown that when drug eluting stents are used restenosis rates are below ten (10%) percent.
Restenosis usually produces symptoms such as chest pain triggered by exertion or stress that are very similar to those symptoms that initially brought the patient to the cardiologist. These symptoms should not be ignored. Diabetics may have more subtle symptoms or no symptoms at all when restenosis occurs. For this reason, it is important for patients to follow-up with their cardiologist after any PCI procedure. If symptoms recur stress testing or a nuclear stress test may be recommended by your cardiologist to detect restenosis.
Treating Restenosis
Multiple medications, drugs, vitamins, etc., have been tried unsuccessfully to prevent restenosis. If you develop symptoms or your stress tests suggest that restenosis has occurred your cardiologist may recommend a repeat catheterization. If restenosis is demonstrated at the time of catheterization, repeat angioplasty or possibly bypass surgery may be recommeded. If a stent was not implanted during the initial procedure a stent procedure may be performed.
There are a variety of methods to treat in-stent restenosis. Treatment may include the use of a radioactive source that is delivered to the blockage by a coronary catheter. This source delivers radioactive energy locally for a short period of time and is then removed. This procedure is called brachytherapy and it requires coordinated treatment by your cardiologist and a radiation oncologist.
After Your PCI Procedure
After your percutaneous coronary intervention (angioplasty, atherectomy, stent placement) it is important to follow an active, healthy lifestyle. This includes a diet low in fat, smoking cessation, blood pressure control and diabetes control. Medications to lower your cholesterol and thin your blood are often used following the procedure. Blood thinners including aspirin and Plavix are always used after a stent procedure. You will be asked to follow-up with your cardiologist closely for the first six (6) months after any percutaneous coronary intervention.
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