In this short article, I am going to explain to you what a CT calcium score is, why you use them and what information it gives us. You can watch my video on this topic here.
Cardiovascular risk assessment, the basics
One of our jobs as a cardiologist is to assess your future risk of cardiovascular disease. We try to decide whether you’re low risk, medium risk, high risk, or very high risk. From there we can decide what treatments/lifestyle adjustments you need (if any) to prevent heart attack and stroke. One of the tools we first use is a risk calculator. There are many available, most being derived from large populations of people that have been highly characterized and that have been followed up for years to see who has heart attacks and strokes. With these calculators we input your data, cholesterol, blood pressure, family history, smoking history, medical history etc and the calculator then estimates your risk of future heart attack and stroke based on the population the calculator was derived from. They are a useful starting point to assess your risk , but they are a blunt tool that can often over and underestimate your risk. One group they often fail to stratify properly are those with a strong family history of coronary artery disease and stroke. Once we have this basic data we will then use other tools to refine your risk calculation, and one of these tools is a CT calcium score.
What is a CT calcium score?
It is a super simple and quick CT scan of the heart. There are no injections of contrast, and it is really really low radiation. All it does is it looks for calcium in the heart arteries. And what we know from studying big populations of people is that the more calcium you have in your arteries, the higher your risk of a heart attack. Conversely if you have a calcium score of zero, you have a very low risk of a heart attack. You are very unlikely to have significant coronary artery disease. This test gives you the ability to see the disease. If you have calcium in your heart arteries then you already have some coronary artery disease and are at higher risk of a heart attack. We calculate a calcium score and then compare your level to other people your age and sex.With this information we can further work out your risk. It doesn’t tell you how severe the blockages are and it doesn’t tell you how many blockages you have. For that you would need a coronary angiogram. All it does is it shows little specks of calcium in the arteries.
Why do we get calcium in the arteries?
As we develop artery disease (atherosclerosis) we start with fatty plaque and inflammatory cells. These plaques can rupture and heal, and in that process calcium is deposited in the wall of the vessel.Therefore, your calcium levels are a good approximation of the amount of arterial disease you have.
In summary, it is a simple, safe, non-invasive and cheap test that allows us to see the disease in your heart arteries, and from that we can help treat you to prevent it getting worse and reduce your chance of heart attacks and stroke.
Related article: How Much Does It Cost To See A Cardiologist In Singapore?
Dr Michael MacDonald is a heart doctor and cardiologist working in Singapore.