Peninsula Cardiology

Coronary Angiography Stenting

Coronary Angioplasty

Coronary angioplasty is a treatment to widen narrowed sections of the coronary arteries. It does not involve major heart surgery but involves the use of a catheter which is inserted into coronary arteries via the large blood vessels.

Understanding the arteries of the heart

The heart is mainly made of special muscle. The muscle pumps blood into arteries (blood vessels) which take the blood to every part of the body.

Like any other muscle, the heart muscle needs a good blood supply. The coronary arteries take blood to the heart muscle. The coronary arteries are the first arteries to branch off the aorta. The aorta is the large artery which takes blood from the left ventricle of the heart to the body.

What is angina and what causes it?

Angina is a pain that comes from the heart. The usual cause of angina is narrowing of one or more of your coronary arteries. This reduces the blood supply to a part(s) of your heart muscle. The blood supply may be enough when you are resting. However, your heart muscle needs more blood and oxygen when it works harder. For example, when you walk fast or climb stairs, your heart rate increases to deliver the extra blood. If the extra blood that your heart needs during exertion cannot get past the narrowed arteries, the heart 'complains' with pain.

The narrowing of the arteries is caused by atheroma. Atheroma is like fatty patches or 'plaques' which develop within the inside lining of arteries. (This is similar to water pipes which get 'furred up' with scale.) Plaques of atheroma may gradually form over a number of years in one or more places in the coronary arteries. In time, these can become bigger and cause enough narrowing of one or more of the arteries to cause symptoms. (The diagram shows three narrowed sections as an example. But, atheroma can develop in any section of the coronary arteries.)

What is coronary angioplasty?

Coronary angioplasty is a procedure where a narrowed section of a coronary artery is widened by using a balloon and a stent attached to a catheter. A catheter is a thin, flexible tube which is inserted into a coronary artery. The balloon at the tip of the catheter is blown up at the narrowed section of artery to force it wider. A 'stent' (a small tube) is left in place to keep the artery widened.

How is coronary angioplasty done?

You lie on a couch in a catheterisation room. An x-ray machine is mounted above the couch. A 'guide' catheter is inserted through a wide needle or small cut in the skin into a blood vessel in the groin or arm. Local anaesthetic is injected into the skin above the blood vessel. So, it should not hurt when the catheter is passed into the blood vessel. The doctor gently pushes the catheter up the blood vessel towards the heart. Low dose x-rays are used to monitor the progress of the catheter tip which is gently manipulated into the correct position. You may be able to see the progress of the catheter on the x-ray monitor.

The tip of the catheter is pushed inside a coronary artery down to where there is narrowed section caused by atheroma. A second thinner 'balloon catheter' is then passed down the 'guide' catheter. There is a balloon and a stent at the tip of the balloon catheter. The balloon is blown up for 30-60 seconds. This squashes the atheroma and widens the narrowed artery. When the balloon is blown up it stops the blood flow. So, you may get an angina-like pain for a short time. But, this soon goes as soon as the balloon is let down.

Usually, a stent is left in the widened section. A stent is like a wire mesh tube which gives support to the artery and helps to keep the artery widened. The 'collapsed' stent covers the balloon and is opened as the balloon is blown up.

The procedure may be repeated for one or more other narrowed sections within the coronary arteries.

You cannot feel the catheter inside the blood vessels. You may feel an occasional 'missed' or 'extra' heartbeat during the procedure. This is normal and of little concern. During the procedure your heartbeat is monitored by electrodes placed on your chest which provide a tracing on an ECG machine (electrocardiograph). Sometimes a sedative is given before the test if you are anxious.

Does everybody get a stent?

Almost everybody gets a stent after ballooning of the stent. Rarely a stent is not placed if arteries are very small or hardened and a stent can be placed there.

How do I prepare for a coronary angioplasty?

You should get instructions from your local hospital about what you need to do. The sort of instructions may include:

• If you take warfarin (a 'blood thinning' drug), you will need to stop this for 2-3 days before the test. (To prevent excessive bleeding from the site of the catheter insertion.)
• DO NOT STOP ASPIRIN AND/OR CLOPIDOGREL (ISCOVER OR PLAVIX)!!!!
• If you take insulin or drugs for diabetes, the timing of when to take these on the day of the test may need to be clarified.
• You may be asked to stop eating and drinking for a few hours before the procedure.
• You may be asked to shave both groins before the procedure.
• You will have to sign a consent form at some point before the test to confirm that you understand the procedure, understand the possible complications (see below), and agree to the procedure being done.

How long does coronary angioplasty take?

If just one section of artery is widened the procedure usually takes about 30 minutes. But if several sections are to be widened it takes longer. You will need to say in hospital overnight for 'observation' following the procedure.

How successful is coronary angioplasty?

Most procedures are successful at relieving angina. However, coronary angioplasty cannot be used for all people with angina. This is because in many cases there are too many narrowed sections in the coronary arteries. Or, the sections which are narrowed are too long or too narrow for this procedure.

After an angioplasty

You should avoid any heavy activities such as lifting for about a week until the small wound where the catheter was inserted has healed. You should not drive a car for a week after having an angioplasty. If you have a commercial or heavy vehicle licence, you should check with VIC ROADS about driving a bus or truck.

Are there any possible risks, complications or side-effects?

One common problem is that a bruise may form under the skin where the catheter was inserted (usually the groin). This is not serious, but it may be sore for a few days.

Failure of the procedure

Sometimes it is not possible to stretch the narrowed artery. This occurs in about 1 in 500 cases where this procedure is tried. An alternative treatment such for angina (coronary artery bypass grafting) may then be an option. But most people feel that it was worth trying an angioplasty first as, unlike bypass grafting, it does not involve major surgery.

Risks of the procedure

In vast majority of cases, there are no serious problems. However, you have to accept the risk that in some cases problems do arise.

• The small wound where the catheter is inserted sometimes becomes infected. Tell your GP if the wound becomes red and tender. A short course of antibiotics will usually deal with this if it occurs.
• Rarely, some people have an allergic reaction to the dye which is used to show up the coronary arteries on x-ray. This is used to help get the catheter into the correct position.
• Serious complications are rare, but do sometimes occur. The risk is mainly in people who already have serious heart disease. Potential serious complications are:
  • The procedure sometimes causes the artery to completely block off. This occurs in less 1 in 100 cases. If this occurs you may be taken for an urgent coronary artery bypass graft operation (which is usually successful).
  • A heart attack during the procedure. This occurs in less than 1 in 100 cases.
  • The catheter may damage a coronary artery. This is rare, and occurs in less than 1 in 200 cases. If this occurs, the artery may be repaired by emergency heart surgery.
  • A stroke is another rare complication.
  • Rarely, some people die during this procedure as a consequence of one of these serious complications.
  • Groin bleeding – usually just bruiing

Long term complications

In some cases, the atheroma 'grows back' within the stent over the next few months and years. This may narrow the artery again and angina pains may return again. It is difficult to give figures as to how often this occurs, If it does, then the procedure can be repeated, or other treatments for angina can be considered such as coronary artery bypass grafting. Drug eluting stents rarely re-narrow (see below). Bare metal stents have up to a 30% chance of renarrowing.

Different Kinds of Stents

1) Bare metal stents $700-$1,000

2) Drug eluting stents $3,000-$4,000

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.

The CYPHER SELECT stent has Sirolimus on it which prevents re-narrowing

Almost all private patients will get a drug eluting stent. Government policy significantly limits the use of this technology in public patients due to cost.