Atherosclerosis is a condition in which arteries become hardened and may become narrowed due to the deposition of cholesterol-rich plaques, which may initiate clot formation that can obstruct the flow of blood.
The treatment will depend on the problems experienced by the patient. If he/she has no symptoms, but is found to have a raised blood cholesterol, then steps will be taken to correct this.
If the cholesterol level is not too high, lifestyle changes (correct diet, sufficient exercise, smoking cessation) may be enough to manage the condition. However, this MUST be checked by follow-up blood tests. The patient must also be made aware that the improvement will only remain while the lifestyle changes remain, and that as soon as old habits are resumed, the cholesterol levels will return to what they were before.
If blood levels are too high, then medication of various sorts may be used. These work in different ways to help the body get rid of excess stored cholesterol, prevent the recycling of existing cholesterol (thereby gradually reducing the total cholesterol present in the body) and by reducing the amount of cholesterol manufactured.
If incomplete blockage of arteries result in problematic angina pectoris or placing the heart at risk of severe damage (e.g. left mainstem coronary disease), the diseased arteries may be bypassed surgically and a "detour" inserted to carry adequate blood to the organ or the arteries may be opened with a stent. Blockages in the arteries to the brain (carotid arteries) may be also be opened by bypass surgery or a stent in order to prevent strokes.
Medication vs surgery
This decision is best made by a cardiologist and is based on clinical and investigational findings.
If your symptoms are relatively mild ,they may improve with lifestyle changes which definitely have a significant impact in the long term. The drugs for angina pectoris are designed to either reduce your heart’s demand for oxygen, or to allow your blood vessels to relax and widen so that more blood can be supplied.
If you smoke, you must stop immediately. You should also look carefully at your diet – preferably with the help of a dietician – and cut down on fats, lose weight and do supervised exercise.
But some people are not helped by these relatively simple measures. The next step is to perform coronary angiography to assess the arteries and to decide about angioplasty (catheterisation to relieve the obstructed region and possibly to place a stent to sustain patency) or surgery to bypass a diseased region with one of the less needed arteries in the chest, forearm or a vein from the leg.
Angioplasty means blood-vessel repair. For many people this offers a safe and relatively easy way to deal with blocked arteries.
Coronary angioplasty is done under local anaesthesia and is generally no more than mildly uncomfortable. The different procedures take between 30 minutes to two hours and often only require one day in hospital.
The procedure is called percutaneous transluminal coronary angioplasty (PTCA). This means a procedure which goes through the skin, inside a coronary blood vessel, to repair that blood vessel.
A hollow tube called a catheter is inserted into an artery in the groin. The area will have been numbed first with local anaesthetic. The cardiologist is able to watch the position of the catheter using X-ray images on a television screen. The catheter is guided through your arteries until it arrives at the blocked artery in your heart.
A thinner catheter is then inserted through the first catheter. This has a miniature, deflated balloon at its tip. This is carefully threaded through the blockage. Once in position, the balloon is inflated. This widens the artery and improves the flow of blood through the area. The balloon is then deflated and removed.
Stents after PTCA
In around 80% of patients, a stent is also used after PTCA. This improves the outcome of the whole procedure, making sure that the formerly blocked artery remains open. Before stents were developed there was a chance that the blocked artery would narrow again – called restenosis.
A stent is a mechanical device which is used to keep a hollow tube open.
A coronary stent is a device which can be used in the arteries of the heart when one or more have been narrowed by a build up of plaque. A stent can be inserted after the narrowed area has been opened up using PTCA. The stent is then inserted to prevent the artery from narrowing again.
A coronary stent looks like a coiled spring. It is inserted into the artery using a catheter.
A stent is intended to remain in place permanently to keep the artery open. It is inserted under high pressure and over time actually becomes incorporated into the wall of the artery, so there is no danger of it moving later.
Bare metal stents may, however, also become obstructed with clot or growing cells. This is why drugs such as clopidogrel are prescribed for a long period after placing of a stent or a drug-eluting stent is used to suppress this process.
But there are risks involved in the use of drug-eluting stents: the potent anticlotting medication prescirbed to the patient after insertion of an drug-eluting stent may lead to uncontrolled bleeding, particularly if the patient is involved in a road accident or suffers severe physical trauma.
Take special care to get the patient to an emergency unit as soon as possible.
What about bypass surgery?
It used to be the case that the only option available to surgically deal with blocked coronary arteries was coronary artery bypass surgery. However, these newer techniques have replaced this in around half the people with blocked coronary arteries.
A bypass is a major operation. An artery from your chest wall or a vein from your leg, is attached (grafted) to the blocked part of your coronary artery. This then redirects the flow of blood around the blockage, allowing your heart muscle to receive enough blood and so oxygen.
The cost is generally higher than angioplasty, and it requires a fairly long stay in hospital.
However, for some people with blockage of many of the arteries of their heart, it remains the only option.
What are the advantages of angioplasty?
For many people, coronary angioplasty is as effective as bypass surgery in reducing chest pain and improving your ability to live a normal life. However, it has not yet been proved that either angioplasty or for that matter, bypass surgery, actually prolong life except in some specific circumstances. In spite of this, the technique is so much more effective than drugs in relieving symptoms, that it is preferred in many cases.
Angioplasty offers around a 98% immediate success rate.
Recovery from the procedure is quick, relatively pain free and much less expensive than bypass surgery.
What are the disadvantages of angioplasty?
In around 10 to 15% of people, the artery opened with PTCA re-narrows within six months. It is more likely to narrow again if the blockage was very long or was in a very small artery. The good news is that angioplasty can be repeated, but in some patients bypass surgery will be recommended if this occurs. S
ome cardiologists tend to add one stents after till the patient’s medical aid will no longer pay for any more stents. Some patients end up with 13 stents. This is medically unacceptable.
The chances of suffering a heart attack or needing an emergency bypass during coronary angioplasty are less than 2%. The risk of dying during the procedure is much less than one percent.
New research shows that the initial higher success rate of angioplasty evaporates after about two years - after two years the survival rates are no better than with bypass surgery.
Is angioplasty for you?
When you have chest pain and problems with daily life which are not being adequately treated with medication, you will normally be sent to see a cardiologist. He or she will then assess the different treatment options open to you.
You will have a coronary angiogram, which is a technique in which a dye is injected into the arteries of your heart. This allows the cardiologist to see exactly where and how severe blockages in your arteries are.
Around half the people who have blocked coronary arteries are offered angioplasty. The rest are better treated with bypass surgery. Diabetic patients often do better with coronary artery bypass grafting and there are instances when technical difficulties make bypass surgery the better option.
Even relatively mild angina which is controlled by medication can be relieved by angioplasty. It is a question of weighing up the risks, benefits and costs of this procedure rather than remaining on medication and altering your lifestyle.
Remember that lifestyle changes must be made even after angioplasty or bypass surgery. In particular, you must never smoke again.
Reviewed by Prof David Marais, head of UCT’s and Groote Schuur Hospital’s Lipid Clinic, September 2010.