What is Coronary artery calcium scoring?
This tests costs approximately $150 to $200 in Brisbane and takes just a few minutes at a radiology or cardiology facility. Your GP Can refer you directly for the test.
The test is an indirect measure of the amount of atheroma of the coronary arteries – in other words, it indirectly measures the amount of plaque (furring) inside the coronary vessels. The plaque becomes calcified and so the amount of calcium in the coronary vessels is a measure of the amount of plaque in the coronary vessels.
There is a radiation dose involved of 1 to 2 mSV which is the same as the background radiation that we experience over the course of 1 year. It is not a huge dose but is worth knowing about.
Who might benefit from Coronary Artery Calcium Scoring?
The test provides information about the risk of a future cardiovascular event such as a heart attack.
The test is is not appropriate for people with symptoms of heart disease who will need diagnostic testing. People with symptoms such as Angina will need a workup with tests such as a stress echocardiogram or nuclear medicine scan. These diagnostic tests ‘look for’ areas of the heart where there is inadequate blood supply in the coronary arteries (flow -limiting areas).
Coronary artery calcium scoring is helps to refine the risk of future coronary artery disease. The ultimate purpose is to identify people at high risk would would benefit from knowing about their high risk. Those at higher risk will need to consider lifestyle factors, as well as medication for high cholesterol or high Blood Pressure.
The traditional way to establish risk of heart disease is by checking for:
- Family History of cardiovascular disease
- Blood sugar
- Cholesterol Profile
- Body Mass index
- Smoking Status
This data is entered into an algorithm to produce an overall ‘risk score.’ This risk score is useful but fairly coarse. However, the risk can be made more accurate with the use of Coronary Artery Calcium Scoring.
The test is also useful in people with Diabetes when a score of under 10 is a good result. A score over 10 suggests the need for intervention and considering a statin medication.
Coronary Artery calcium scoring measures the total amount of atheroma (plaques). Most heart attacks are caused by thrombus forming on plaques. In other words, it would appear that CT artery calcium scoring is better than the other tests at identifying which patients are at greater risk of a heart attack. Given that the test is over more than 3 times cheaper than the other tests, this is good news!
The test is particularly useful for people whose risk of heart disease is not definitely high … not definitely low, but in the middle.
How do I interpret the calcium score?
The score is given from 0 to over 1000. The score is expected to go up with increasing age.
A score of 100 gives an ‘arterial age’ of 73. In other words, a score of 100 is normal for a 73 year old but not a 50 year old.
So what really matters is the score in relation to your age, and this is given in the form of a ‘risk centile’ in %. You should consider statin medication if the risk is over 75%.