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05 May 2010

A look at bypass surgery

Coronary bypass surgery have been considered a routine operation for more than 30 years. In South Africa, approximately 8 400 coronary bypass operations are performed per year.

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Coronary bypass surgery have been considered a routine operation for more than 30 years. It's a way to treat blocked heart arteries by using blood vessels from other parts of your body to reroute the blood around the clogged artery to re-establish good bloodflow to your heart muscle.

In South Africa, approximately 8 400 coronary bypass operations are performed per year, with the majority done in the private sector.

There's an alarming incidence of heart disease in South Africa: one in three men and one in four South African women will suffer a heart attack before their 60th birthday. Every year, more than 50 000 South Africans suffer heart attacks. Of these 50 000, 25% - about 12 000 people – die immediately. Only Scotland, Finland and Northern Ireland have a higher heart-disease mortality rate, according to data from the Heart and Stroke Foundation of South Africa.

How a patient with heart disease will present
A patient with heart disease (and blockage or narrowing of the coronary arteries) usually presents in one of three ways:

1. The patient may be completely symptom-free. His heart problem may only become apparent during a routine medical investigation or a medical investigation performed as prerequisite for an assurance policy. An exercise ECG may indicate that one or more coronary arteries may be blocked or nearly blocked. It is possible that the patient had already suffered a few "silent" heart attacks of which he may be unaware, but had been serious enough to cause damage to the heart muscle.

2. The patient tends to suffer from angina, especially when he is active. He treats this by putting his small anti-angina tablet under his tongue and the pain subsides. If and when the pain becomes more severe and the frequency increases, the risk of a heart attack increases.

3. The seemingly healthy patient suddenly suffers a heart attack. He may die immediately, or may survive the heart attack, depending on which coronary arteries are blocked, which part of the heart muscle is deprived of blood and oxygen, and what percentage of the heart muscle is left without blood supply. No heart attack will leave no trace of damage; all heart attacks result in some degree of damage to the heart muscle.

All three these cases require urgent and effective medical attention and treatment. The treatment – whether it is medication, the unblocking of a coronary artery by means of a stent, or coronary bypass surgery – is determined by the exact location of the blockage in the coronary artery and the extent of damage to the heart muscle.

Surgery or medication?
Three comprehensive studies have now shown that there is little difference between the survival rates of heart patients treated with bypass surgery versus heart patients treated with medication. There was no real statistical difference between the ten-year survival rates of patients treated with bypass surgery and patients treated with medication.

The biggest advantage of bypass surgery was pain relief.

The cost of surgical treatment seems to be lower than that of medical treatment, at least in South Africa. The total cost of a bypass operation is approximately R100 000, while the total cost of angina medication over a ten-year period exceeds this amount.

When can coronary bypass surgery save a life?
In most cases, coronary bypass surgery is performed to relieve pain and not to prolong life. However, in some instances, bypass surgery is essential and failure to undergo the surgery may be fatal.

In the following scenarios, bypass surgery is essential and lifesaving:

  • When the left main coronary artery is severely narrowed or blocked. Blockage of this artery will leave the left ventricle completely without blood supply and oxygen, resulting in a potentially fatal heart attack or severe damage to the left ventricle, the main pump of the heart.
  • If the patient has two or more blockages, of which one is located in the first few centimeters of the left anterior descending coronary artery. Blockage of this artery will also deprive the left ventricle of blood and oxygen, resulting in a potentially fatal heart attack or severe damage to the left ventricle, the main pump of the heart.
  • If the patient has two or more coronary artery lesions and the left ventricle – the heart’s main pump – is functioning poorly. The first signs and symptoms of heart failure may already be present. The patient may feel tired and out of breath, and his heart may pump faster, but weaker.
  • If the patient has debilitating angina, or chest pain, because several of the arteries that supply the heart muscle are narrowed. Chest pain is an important indicator for bypass surgery because it is a sign of poor oxygen delivery to the heart muscle. In some cases balloon angioplasty (stent) will bring relief.
  • If the patient has a blockage that cannot be opened by means of angioplasty or that has reappeared after angioplasty.

 

How is bypass surgery done?
Coronary bypass surgery generally takes between three and six hours. On average, between three and five coronary arteries are bypassed during the surgery, although it is not uncommon to have more. A patient will be in the intensive care unit for one or two days in uncomplicated cases. Most people stay in hospital for six to seven days in total.

Coronary bypass surgery may be performed by using one of three possible methods:

1. Conventional. This option is used in more than 90% of cases in South Africa. It involves an incision down the midline of the chest, through the breastbone. The surgeon opens the rib cage to expose the heart. During the operation, a heart-lung machine takes over the functions of the heart and lungs, and the surgeon operates on an unbeating heart.

Surgeons restore blood flow to deprived sections of the heart by creating detours around blocked coronary arteries with sections of a vein taken from the leg or with the internal mammary arteries from the chest wall (which are close enough to the heart that the upper end can remain attached to their original blood source and the lower open end is sewn onto the affected coronary artery, below the blockage).

2. Beating heart. To avoid an intense inflammatory reaction, a potential side effect of being on a heart-lung machine, some surgeons perform coronary bypass surgery on beating hearts. The inflammatory reaction follows because the body regards the blood returning from the machine as foreign tissue and react violently to reject it. During this surgery, the initial incisions are the same as for conventional surgery, but the heart is never connected to a heart lung machine.

Operating on a beating, moving heart is much more difficult, but patient recovery is quicker.

Choose only the best cardiac surgeon who is familiar with this procedure, when you consider this option.

3. Minimally invasive. This type of procedure uses small incisions and is only an option when one or two bypasses are needed. In some cases the surgeon will make three or four incisions or remove a portion of a rib in order to have a better view of the operating field.

Life after bypass surgery
While bypass surgery improves blood supply to the heart, it is not a cure for underlying coronary artery disease. After surgery, new blockages may be formed in the grafts or in arteries that were not bypassed. That's why it is important to combat this effect with dietary and lifestyle changes and with aggressive treatment of elevated cholesterol levels. You need to stop smoking if you’re a smoker, reduce cholesterol levels if they are elevated, maintain a healthy weight, control blood pressure, manage diabetes if you’re a diabetic and to exercise.

Success rate
The mean success rate for coronary bypass operations is 98%. The risk may be higher for patients with severe damage to the heart muscle and severe blockage of the arteries. Even in the hands of the most competent surgeon, about 2% of the patients will not survive the surgery.

Follow-up studies have shown that in many patients with poor heart muscle function – resulting from a heart attack – the poor function improves after bypass surgery. The improved blood supply stimulates the damaged heart muscle to contract with more force.

No surgery is without risk. Complications — such as arrhythmias, kidney failure, stroke and infections — may occur after heart surgery. Some people – especially those older than 70 years, those who have hypertension or lung disease or consume alcohol excessively - experience a decline in memory and intellectual functioning after coronary bypass surgery. But most people regain their memory and intellectual abilities within six to 12 months.

More coronary bypass operations are now performed on older patients, especially on those without other risk factors such as kidney problems, diabetes or hypertension.

What about stents and medication?
An increasing percentage of patients with coronary artery disease are now being treated with balloons and stents, and other non-surgical methods. Huge strides have been made over the past 15 years in balloon angioplasty and the risks are now lower than ever and the success rate higher. Stents are coated with medication to help control local inflammatory reactions and to reduce the risk of renarrowing.

In 10 percent to 20 percent of cases, the artery narrows again within six months at the spot where it was opened.

There is no doubt that medication and lifestyle changes can postpone the renarrowing of bypassed or openened arteries. According to three new studies, the incidence of heart attacks can be lowered by 40% with cholesterol lowering drugs.

- (The Heart and Stroke Foundation and Health24, updated June 2008)

 
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