Coronary Artery Stents

The balloon is used to expand the stent. The stent presses against the narrowed vessel wall holding the vessel open. This makes a wider channel to improve blood flow to the heart muscle. This may be followed by repeat balloon inflations with the stent delivery system or with a different angioplasty balloon to achieve the result desired by your doctor. Once the balloon has been deflated and withdrawn, the stent stays in place permanently, holding the coronary artery open. The inner lining of the artery grows over the surface of the stent making the stent a permanent part of your artery.

Unfortunately, 30-50% of patients undergoing balloon angioplasty will experience narrowing of the artery within the treated area (restenosis) within the first 6 months. This narrowing can be caused by many factors including vessel shrinkage and formation of tissue ingrowths in the treated area. Coronary artery angioplasty with stent placement has proven to reduce restenosis compared to balloon angioplasty alone. Still, in about one third of the patients who are treated with coronary angioplasty and stent placement narrowings can reoccur within 6 months of the procedure. This is primarily due to increased tissue ingrowths within the stented area.

Drug Eluting Stents (DES)

A drug eluting stent is a coronary artery stent that has been coated with a drug and a polymer to deliver the drug locally to the diseased area. The drug is designed to reduce tissue ingrowths and therefore reduce the need for re-intervention due to restenosis in the stented area over time (in-stent restenosis).

When Coronary Stent  Should Not be Used (Contraindicated)

1. If you have a known hypersensitivity (allergy) to its costituents.
2. If you cannot take aspirin or blood thinning medications (also called antiplatelet or anticoagulant therapy).
3. If the physician decides that the blockage will not allow complete inflation of the angioplasty balloon or proper placement of the stent.

Potential adverse events associated with the implantation of a coronary stent in native coronary arteries are:

1. Abrupt closure (sudden blockage of the artery)
2. Acute myocardial infarction (heart attack)
3. Allergic reaction or hypersensitivity to contrast dye and drug reactions to antiplatelet drugs or contrast dye
4. Aneurysm (a sac-like protrusion from a blood vessel, resulting from a weakening of the vessel wall)
5. Arterial perforation (puncture of the coronary artery) and injury to the coronary artery
6. Arterial rupture (rupture of the coronary artery)
7. Arteriovenous fistula (connection between an artery and an adjacent vein)
8. Atrial and ventricular arrhythmias (irregular heart beats in the upper and lower chambers of the heart), including bradycardia (slowing of heart rate), tachycardia (increased heart rate) and fibrillation (rapid irregular contraction of the heart muscle)
9. Bleeding complications, which may require transfusion
10. Cardiogenic shock (shock from heart failure)
11. Cardiac tamponade (compression of the heart due to accumulation of blood around the heart)
12. Coronary artery spasm (spasm of the coronary artery causing the artery to narrow)
13. Coronary artery or stent embolism (air, fatty deposits, fragments of blood clots, or parts of the stent going downstream and blocking the arteries or the stent)
14. Coronary artery or stent thrombosis (fat or fragments of blood clots blocking the arteries or the stent)
15. Death
16. Distal emboli (air, tissue or thrombotic)
17. Emergency or non-emergency coronary artery bypass graft surgery
18. Heart, lung and kidney failure
19. Hypotension (decreased blood pressure) / Hypertension (increased blood pressure)
20. Infection and pain at insertion site

Your Coronary Stent Procedure

Preparing for Your Procedure:

• In the days prior to your treatment, make sure you:
• Take all of your prescribed medicines
• Tell your doctor if you are taking any other medication
• Tell your doctor if, for any reason, you cannot take aspirin and/or Plavix
• Make sure your doctor knows about any allergies you have
• Refrain from eating and drinking after midnight on the night before your treatment

You may be given a mild sedative to help you relax, but you will not be put to sleep. There are two reasons for this. First, most people find they can cope quite well with any discomfort from the procedure. Secondly, your doctor may need to ask you to take a deep breath while X-rays are being taken to improve the quality of the pictures.

The procedure usually lasts for about 90 minutes, during which time your doctor will ask you to remain very still. For the most part, you will be comfortable but you may feel some pressure or chest pain when the balloon is inflated. This is normal and will quickly fade when the balloon is deflated again.

Steps of  Stent Placement Procedure:

Your procedure will be performed in a cardiac catheterization laboratory (cath lab). This room may be similar to the one where you had your diagnostic angiogram . You will lie on the X-ray table, and an X-ray camera will move over your chest during the procedure. The staff will monitor your heart by attaching several small, sticky patches to your chest and using a specialized ECG recorder and monitor.

The groin is the most common site for catheter introduction and requires a small incision to be made on the inside of your upper thigh. The area will be shaved and cleaned with an antiseptic and you will be given a local anesthetic to numb the area. This incision will allow an introducer sheath (short tube) to be inserted into your femoral artery. Your doctor will then insert a guiding catheter (long, flexible tube) into the introducer sheath and advance it to where the coronary arteries branch off to the heart. A fine guide wire is then advanced through the guiding catheter to the narrowing in the coronary artery. This helps carry all the necessary catheters required during the stenting procedure.

Additional options for catheter introduction are the arm / brachial approach (incision is made on the inside of your elbow) and the transradial approach (incision is made on the inside of your wrist).

After the catheters are inserted, your doctor will inject a contrast dye through the guiding catheter into your artery to view the narrowing. Your doctor will watch the injection on an X-ray monitor, much like a TV screen. While these X-rays are being taken, your doctor may ask you to take a deep breath and hold it for a few seconds. You may also be asked to cough after the X-ray picture is completed to help speed the removal of the contrast dye from the arteries.

Using the guiding catheter, a balloon catheter is positioned in the narrowing in the coronary artery and the balloon is then inflated. This compresses the plaque and widens the coronary artery. This procedure is called pre-dilatation. The stent mounted on a balloon catheter is delivered to the narrowing in the coronary artery by a delivery catheter. The balloon is then inflated and this expands the stent pressing it against the coronary artery wall. Your doctor may choose to expand the stent further by using another balloon so that the stent can make better contact with the artery wall. This is known as post-dilatation. Once in place, the stent will remain as a permanent implant in your coronary artery.

Recovery:

Immediately after the procedure, you will be returned to a special observation unit, where your heart rhythm, blood pressure and puncture site will be monitored closely.

During the stenting procedure, you will have been given a blood thinning medication (antiplatelet and/or anticoagulant medication). The effects of the medication will take a few hours to wear off.

Once you are back in the observation room, you may be asked to drink lots of fluids to flush the contrast dye out of your system as quickly as possible.

Due to the puncture site in your groin, you will have to stay in bed for several hours after the procedure, keeping the relevant leg straight and the insertion site immobile.

You may need to stay in the hospital for 1 to 2 days and then you will be discharged into the care of your doctor. Make sure you contact your doctor or the hospital immediately if you experience any discomfort, pain or bleeding once you get home.

Taking Your Medications is Essential. Your cardiologist may prescribe a number of medications including antiplatelet and anticoagulant medicines such as Plavix, or Ticlid and/or aspirin - to thin the blood and prevent blood clots from forming and potentially adhering to the surface of the stent. It is very important that you take your recommended medication dosage exactly as prescribed for the entire duration. It is extremely important to follow your medication regimen. If you stop taking these medications earlier than instructed by your cardiologist, you increase your risk for a serious blood clot, which often leads to a heart attack and death. Be sure not to miss any doses.