What is the best predictor of a heart attack?

Written by Dr Harold Gunatillake-health writer

There are many health nuts, who seems to eliminate risk factors to prevent a heart event, by eating the right foods (low carbs, low saturated and low trans-fat containing foods, low salt, etc.), exercising daily, keeping their weights within BMI calculations, controlling their lipid levels in the blood (LDL cholesterol), checking blood pressures to maintain within normal range and so on. But can we predict in such healthy absolute situations you could avoid a cardiac event?

A good example is the death of former Australian Ironman Dean Mercer who suddenly died of a cardiac arrest at such young age of 47.

There are many who believe by keeping the cholesterol numbers in your blood as low normal as possible, are quite complacent about not getting a heart attack. But the stats show that 60 percent of the people who have had heart attacks the cholesterol levels have been even below normal. There are many situations that even with high cholesterol levels you may not suffer from a heart attack. In fact, studies have been done among old people in nursing homes, when half the inmates were given statin to control cholesterol levels and the other half not given statins with no control of cholesterol levels, and 10 year studies have revealed that the incidence of heart attacks and death were higher in those who had statin during that period. It is presumed, that in old age cholesterol acts as an antioxidant and it is best not to reduce by giving medication.

Most people check their blood pressure regularly which may prevent from getting atherosclerotic diseases, stroke or heart failure, but still, can you predict in such a situation one would not get a heart attack.

Recently, Sydney cardiologist Dr. Ross Walker on ABC radio interview said that common health checks for blood pressure and cholesterol were not the best predictors of heart attack. He seems to think rightly that to predict whether you would get a heart attack is to do a scan for coronary calcium levels, which is a far more accurate predictor of heart disease.

It is also known as the coronary artery calcium (CAC) scoring, and this test was pioneered by Dr Ross Walker in the late 1990s in conjunction with the Sydney Adventist Hospital.

In a way doing your annual lipid assay (LDL cholesterol and others) on your blood is a waste of time. It is much better to consume a diet that does not raise cholesterol  numbers in your blood. It is not the cholesterol in food that raises the serum cholesterol numbers, but it seems that saturated and trans-fat foods when eaten, through the liver manufacturing cycles that increase the blood cholesterol levels. Not consuming carbs containing high starch levels like the root veggies, beverages and treats with added sugar, and eating dark green veggies like the salad leaves, spinach, and cruciferous veggies and so on would keep your fat in your body under control.

People over the age of 50 should have a coronary calcium score as required if the initial score is above average.

According to Dr Ross Walker, it is the best predictive test for heart disease risk. Coronary CT scan-overview: It is also called a heart scan. It is a specialized X-ray test that provides pictures of your heart that can enable your doctor to detect and measure calcium- containing plaque in the arteries.

Plaques are found in the inner layers of the arteries: they eventually grow and restrict or block the flow of blood to the muscles of the heart. With time these plaques get calcified (calcium deposits). These calcified spots can be counted and given a score. The resultant CAC score is used to grade according to the risk of heart attack.

If the coronary calcium scans show a progressive increase in calcium scoring on regular check-ups, such individuals need closer supervision, and education to reduce all risk factors that may be responsible. Stress could be one of the worst factors that you need to get rid of or reduce.

The Cardiac Society of Australia and New Zealand describes the test as a ‘robust’ way to estimate future risk of cardiac events.

There is one problem- each coronary scan is equivalent of 50 chest x-rays per scan and such exposers, and the sub-committee of the Australian Health Ministers’ Advisory Council responsible for new and emerging technologies caution that calcium scoring for predicting heart disease “is of unproven clinical benefit or utility”

Our advice

Every Sri Lankan person at the age of 60 should have a CT scan of the heart, at least once.

If you come from a family with a history of heart disease, it is advisable to have a test once in 5 years. Meanwhile, strict adherence to a sensible diet, keeping the weight in control, daily exercising will prevent further calcium deposition in the plaques, and further growth of the plaques may be minimised.

If the initial CAC score is 0- further scans would be a waste of time.
If CAC score is 1-100 –healthy diet and lifestyle would be advised. No further scans
required.

If the score 101-400 and over- Daily aspirin and statins are recommended

The cost of this test costs between $100- $400

Conclusions: In addition to your ‘Fact check’ done annually, where the results do not
indicate any prediction of an impending heart attack, it is advised to get a heart scan
at least once, after the age of 60. The CAC score will assist your cardiologist in
further management of your heart condition.

Heart scan machines are available in Colombo in some private hospitals.