What is Coronary Calcium Score?
The Coronary Artery Calcium, or CAC score, is a valuable test to estimate the future risk of a heart attack. I will discuss the pros and cons of this test and how it can be helpful or harmful if ordered and interpreted inappropriately.
 For decades, investigators have been trying to discover the “risk factors” that increase the likelihood of heart attack. Many risk factors have been identified through years of intensive and elegant research [1], including Smoking, Obesity, sedentary lifestyle, high cholesterol (known as hypercholesterolemia), high blood pressure (hypertension), positive family history of heart attack, menopause, inflammatory diseases like rheumatoid arthritis, and last but not least, Diabetes. Many studies have proven that we can significantly reduce the risk of heart attack by modifying these factors.
Despite these massive efforts and discoveries, still, many individuals suffer from a heart attack prematurely without having any or only a few of these risk factors. This fact suggests that our current risk calculators, developed based on “traditional risk factors,” are far from perfect. They can potentially miss many “preventable” cases of heart attack.
During the past 15 years, coronary calcium score has emerged as a reliable “predictive” test to further refine someone’s risk of future heart attack by identifying atherosclerosis.
Plaques are the main precursors of myocardial infarction. Atherosclerosis is an inflammatory process in the arterial wall that starts at a young age and is the primary driver of the “plaque” formation in the arterial wall. As we age, the process of calcification begins within the plaques. We can then identify the calcium in x-ray images, confirming the presence of an underlying plaque.
Figure 1: This CT scan, which belongs to a 60-year-old asymptomatic man, shows significant calcification of the LAD and RCA arteries. It implies that under this bulk of calcium, the process of “atherosclerosis” is progressing fast, which, if not controlled, can result in acute coronary syndromes (heart attack).Â
He was initially labelled as “low-risk” based on traditional risk factor calculations. But this mere new fact (high coronary calcium score) will change his previous “low risk” status to “high-risk.”
When should you consider checking your calcium score?
There has been significant debate as to what clinical situation a coronary calcium score should be considered. CAC Score is a preventive test and should not be used in symptomatic patients (if someone has chest pain or shortness of breath). It is another piece of the puzzle to shed more light on someone’s “future risk of a Heart Attack”.Â
Before considering a calcium score, it is crucial to calculate the patient’s baseline risk of a heart attack. Many online calculators like this online calculator from the American College of Cardiology can do this. It needs a few baseline information like the presence of Diabetes, Hypertension or high cholesterol levels. Smoking status, age and medications are other components. Based on this information, a 10-year risk estimate is generated. The patient will be categorised as low-risk, intermediate-risk, or high-risk for future heart attacks.Â
To illustrate how the CAC score check can be helpful, here I present a typical case.
CASE: A 55-year-old man presents to you after his close friend suffered a massive myocardial infarction. They have been colleagues and used to exercise regularly with weekly swimming, cycling, and running regularly and intensely. He does not smoke, eats healthy, and has no significant family history of ischaemic heart disease. His cholesterol is on the low side, and he has mild hypertension, which is well-controlled with a low-dose antihypertensive. He is not complaining of any symptoms indicative of angina. He insists that his friend had the same profile and was at low risk for myocardial infarction. In this scenario, a test that can add significant weight and information to stratify his risk for future IHD is a coronary calcium score. He performs a CAC score, which comes back as 300. A calcium score at this level will immediately move him from the low-risk category to the moderate-high-risk category. He will undoubtedly benefit from intensive reduction of his LDL to 1.4-1.6 mmol/L and the addition of Aspirin.
This case illustrates that coronary calcium score should only be considered in individuals with “low to intermediate" baseline risk. A high coronary calcium score can modify someone's low-risk status to high-risk, but a low or even zero calcium score does not change the status of a high-risk patient to low-risk. We should remember that A "high-risk" individual will remain "high risk" regardless of their calcium score. They should be on intensive therapy with Statins, Aspirin and encouraged to change their lifestyle rather than checking their calcium score.
What is the ideal age to check coronary calcium score?
Coronary Calcium test should be considered in individuals between 45-70 years of age. This does not mean those below 45 or above 70 cannot have the test, but the interpretation of the results should be guarded. Under 40, there has not been enough time for the lipid-rich plaques to calcify, and we can miss them on imaging as we can only see them if they are already calcified. For example, a young patient with familial hypercholesterolemia could have many “coronary plaques” at 30. Still, their CAC score could be zero, as no calcium has yet formed in the plaques. This can be misleading and result in “false reassurance”. However, a high calcium score in a young patient is highly concerning and should be taken seriously. It indicates that they already have formed coronary plaques with an increased risk of future IHD.
Above 70, nearly everyone has calcification of the coronary arteries. An elevated calcium score in the elderly, unless “significantly” elevated, does not necessarily indicate “high risk”. However, a low or0 calcium score in this age group can be extremely reassuring.
Therefore rather than concentrating on the “absolute” number of the calcium score, you should see where you stand compared to the people your age. By incorporating the “age factor” in our calculations, we reach a “percentile”, which is much more accurate in risk assessment compared to the “absolute” number. The MESA CAC score calculator is an excellent tool in this regard.
How should we interpret a calcium score of 0?
Coronary calcium score should always be interpreted in the context of other risk factors and never solely. As a calcium score of 0 in a low-risk patient is highly reassuring, the same score in someone who smokes and has high cholesterol or diabetes, is much less predictive of the risk. Any other diseases (risk factors) should be treated diligently, regardless of the coronary calcium score. Even with a calcium score of 0, patients should be counselled regarding smoking, treated for hypercholesterolemia, hypertension, and diabetes and encouraged to exercise regularly and eat healthily.Â
To show the importance of this point, I have briefly discussed two cases of “severe coronary artery disease despite a calcium score of zero” in a separate post. Hopefully, these cases will explain why we can’t call a calcium score of zero, “normal”, without considering the patient’s age and other risk factors.Â
How should a high calcium score be interpreted?
We know that Coronary calcium score must be interpreted according to age. A calcium score of 20 in a 70-year-old is considered low and excellent but significantly elevated for a 40-year-old. Many online charts show the risk according to the calcium score. However, interpreting the calcium score results is not as simple as looking at a chart and coming up with an answer. Many factors are involved in this process, and each result should be interpreted individually according to the patients, age, risk factors and likely complaints.
A calcium score above 300-400 is significantly elevated at any age. These patients require tighter control of their risk factors and more intense medical therapy, which should include Statins and Aspirin. Knowing their “high” risk motivates patients to be physically more active and follow a healthy diet. However, a high calcium score must never initiate the process of looking for “blockages” in coronary arteries or end up in angioplasty if the patient is “truly” asymptomatic.
Should the calcium score test be repeated in future?
Generally, if the calcium score is high, there is no need to repeat the test. A high score means the patient’s risk of ischemic heart disease is elevated, and they need intensive treatment of their risk factors and lifestyle modifications, and there is no need to repeat the test. A high-risk patient will remain high-risk, regardless of the future CAC scores.Â
Select patients with a calcium score of 0, especially younger individuals, could consider repeating the test in 5 years, particularly if they have a few risk factors like high cholesterol or blood pressure and decide against medical therapy.
Is a calcium score test required for someone already on a statin?
The answer generally is no, but it depends on the case. A CAC test is not required if the patient is taking their medicine regularly and their LDL is around 2 mmol/L (77 mg/dl). However, if they are taking statin sparingly, and LDL is way above 2 mmol/L, we can consider a CAC test to guide the therapy. A more lenient approach towards medical therapy can be taken if the score is 0 or very low and vice versa. In the following video, I present a real case and show how Coronary Calcium Score can change someone’s cardiovascular risk profile and how it can be helpful or harmful.
Coronary Calcium Score video:
Frequently asked questions:
To learn more about the cost of a CAC score and how it is done, check this Coronary Calcium Score WebStory.
At any age, 0 is the ideal and normal calcium score. A score of 0 means no “calcified” plaque exists in the coronary arteries. However, it is imperative to note that if you have “non-calcified” plaques, the score would still be 0, but falsely reassuring. This is a big caveat of the calcium scoring test, which should be kept in mind.
Calcium score indicates the future risk of a heart attack. If elevated, instead of focusing on that number, you should focus on the ways to reduce the overall risk of cardiovascular disease. These include smoking cessation, exercise, a healthy diet and statin therapy, depending on the score and cholesterol levels. After initiating statins and starting exercise, your score might increase. This is not a “bad thing” and means that plaques are hardening and becoming more stable with a reduced risk of a heart attack. In this video, Coronary Calcium Score: how to interpret, I have explained further in detail.
No. An Echocardiogram is a test to check the heart chambers and valves and does not show coronary arteries or their calcification.Â
No. A stress test or stress echocardiogram is a test to check your exercise tolerance and can help identify coronary artery narrowing or blockages. Like echocardiograms, we use ultrasound waves for this test, which cannot identify coronary calcifications. The stress test is an entirely different type of investigation and can’t be compared to a coronary calcium score test. They have very different indications and implications.
Most places that do CT Coronary Angiogram (CTCA) routinely include calcium scores in the final report. However, some places do not report calcium scores in the final CTCA report unless specifically requested. Ask your doctor to request a calcium score as well if you have a CT Coronary Angiogram. Visit the article CT Coronary Angiogram vs. CT Calcium Score: Differences, Limitations, and Indications to learn more about the difference between CTCA and CAC Score scans.
This question requires a blog post as there is great debate in this regard. Suffice it to say that I order CTCA in patients with chest pain or abnormalities on their stress echocardiogram. CT Coronary Angiogram is a “diagnostic” test. However, coronary calcium score is a test we order in people who don’t have complaints and is a “predictive” test.
The coronary artery calcium score is only one piece of overall risk factor puzzle. Like any other test in medicine, it has pros and cons, can be helpful or harmful and should be used judiciously. It clarifies someone’s risk for future ischaemic heart disease and should never be interpreted solely without having the whole picture in mind. It should never be used to investigate chest pain and should not be ordered in high risk patients.
References:
- DeGoma EM, Knowles JW, Angeli F, Budoff MJ, Rader DJ. The evolution and refinement of traditional risk factors for cardiovascular disease. Cardiol Rev. 2012;20(3):118-129.Â
- Maureen M et al. Noninvasive Evaluation With Multislice Computed Tomography in Suspected Acute Coronary Syndrome: Plaque Morphology on Multislice Computed Tomography Versus Coronary Calcium Score. J Am Coll Cardiol. 2008 Jul, 52 (3) 216–222
hi I have recently been told i have a calcium score of 448 at 42 years old,, showing heavy burden of coronary artery atheroma but no significant stenosis, but a high Burdon of non obstructive atheroma, not really sure what all this means and should i be significantly worried
Hi Peter
“Non-obstructive atheroma” essentially indicates that the coronary arteries remain open at the moment, but they are at a heightened risk of becoming blocked. It’s similar to a vital mountain road where vehicles can move unimpeded, but large unstable rocks at the summit may tumble down and obstruct the path at any time. The rational approach would be to secure these unstable rocks to prevent blockage and closures.
You have a substantial amount of calcium located on the arterial wall, which doesn’t obstruct blood flow, but the risk of blockage is significant. To stabilize these plaques and minimize the risk of coronary obstruction, also known as a heart attack, we suggest using statins and aspirin (though this is debatable), maintaining a healthy lifestyle, engaging in regular exercise and physical activity, achieving a healthy BMI, and avoiding tobacco use.
Hi,
My husband is 41 and has a cac score of 58. He is otherwise healthy. The nurse at cardiology office said that was a perfect score, but I’m thinking she is wrong. He has minimal calcification in LAD. Would really appreciate another opinion. Thanks in advance
Hi Katie
Calcium scores must be evaluated alongside other risk factors, such as lifestyle choices, family history, and laboratory tests, to ensure a comprehensive understanding of the results. Relying solely on the calcium score without considering the broader context can be misleading. He falls within the 90th percentile for their age group when utilising the MESA calculator. This indicates that his calcium score is higher than 90% of men in their demographic, implying that the score is notably elevated.
Iam a 66 year old woman with a CAC score of 225 with the split mainly in the right oronary and left descending. My primary care doctor order this test due high cholesterol/high blood serum. He had taken me off cholesterol med 7 months ago and of course will be putting back on it. My question is,
should I see a cardiologist at this point?
Hi Bonnie
If you exercise regularly, are taking statins with an LDL-cholesterol at or below 70 mg/dl (1.8 mmol/L), and have no symptoms such as chest pain or shortness of breath on exertion, it is not necessary to urgently see a Cardiologist. However, your primary doctor is the most appropriate person to make a decision on this matter.
Hello Dr. I will be 44 in a month, 5,11.5 and 250 lbs. I just found out my calcium score was 446. I was beyond shocked, especially when I saw how few my age have scores even half that value. I am a little terrified. It feels like I have just been given a death sentence or at least told I won’t the next decade, let alone see my 70s and 80s. I don’t even know, if I shoud do any physical activity, like tennis, running, and calisthenics. I feel like I should have a defibrillator with me at all times a wearing a heart rate monitor. Anyway, I guess I am asking if i can still live a long time with a heart such as mine? Can I still be active in exercise and competitive sport? Im seeing my cardiologist in a few days, to talk about the result, but I am really panicking now. I cant stop crying actually.
Hi Dayne
I am sorry to hear that. I hope you have already seen your Cardiologist and are feeling better. It’s important to remember that there’s no need to panic about these results. Your Cardiologist will likely perform a functional test, such as a stress echocardiogram or Nuclear scan, to determine if there are any severe blockages. If not, you should be able to participate in any exercise you like. However, this is a wake-up call for you to focus on a healthy lifestyle, and your Cardiologist may recommend statin therapy. In cases like yours, I always check for Lp(a) levels in the blood as well. Fortunately, a defibrillator is not necessary for you.
Can you explain why you would look Lp(a) levels? What levels might reassure or be concerning? And when evaluating Lp (a) levels, what others lipid profile levels would be of interest in relationship to Lp (a)? Any ratios related to Lp(a)? Thank you for such an informative video and thoughtful responses in your comments section, learned from these too!
Thank you, Penny, and I’m pleased to know that the information provided is helpful. I am currently working on completing an article about Lp(a) and a corresponding video that will be uploaded to my YouTube channel. Subscribers will receive automatic notifications. Lp(a) has gained considerable interest and warrants a dedicated section for discussion.
Hi Dr.
I am 57 and my CAC score was 1009 with most of that in my LAD. It is just one test, but should I be worried? I have the data, but have not yet spoken with my cardiologist. I workout every day, have high cholesterol, and have been eating healthier and doing more cardio as a result.
Hi Stephen
A calcium score of 1009 is severely elevated, and the chance of “obstructive” coronary artery disease is high in this range. It is extremely important to note that a high calcium score should NOT automatically lead to angioplasty (Stenting of the arteries). Unfortunately, there have been many cases that patients with such scores have been directly referred for invasive coronary angiogram without any prior functional testing like stress echocardiogram or Myocardial Perfusion Scan (nuclear testing), depending on the local expertise and preference. I recommend seeing a Cardiologist with that score, even if you are asymptomatic BUT be wary of unnecessary angioplasty.
Thanks Doc! My cardiologist has scheduled a nuclear stress test and a lipid panel. I take Warfarin for a prosthetic, mechanical aortic valve, which I think has contributed to the calcium buildup. My doc wants me to take a statin, but I am wary of treating what may be the side effect of one drug with another drug that also has its own side effects. I will if I have to, but not until after my lipid panel.
BTW, this is a fantastic thing you are doing here!
Thank you, Stephen.
I highly recommend following your Cardiologist’s recommendations and starting a statin, even if your cholesterol level is in the normal range. Statins have other properties that help prevent a heart attack. They reduce the amount of fatty deposits in the arteries and stop the further build-up of such deposits. Statins also make existing deposits less likely to break off and cause a blood clot. Clots are the main culprits in heart attacks and strokes.
A blood clot can cause a heart attack or stroke.
I am 72 and have FH from my Father. I had my first Calcium Test in 2017, and last year had a 2nd CAC test plus a Heart Exercise Stress Test. All returned – ZERO (in fact the cardio specialist asked why I was there)!. I have never taken any statins and will not do any until a test suggests I should consider it. Seems that no-one has done any research that makes sense under these circumstances. I eat well and exercise often and I personally feel that the high cholesterol reading is just that my body is fine with it. Whilst it doesn’t yet put the cholesterol it where it isn’t wanted – I should not risk any affects from the statins.
Hi Valerie
You probably have high cholesterol; hence you did all those tests. Not knowing how high your LDL is, having a calcium score of zero at 72, is very reassuring. However, as I have mentioned in previous replies, the calcium score is only “one” small part of the decision-making process, and other significant risk factors should guide the decision. I’m assuming your Cardiologist has performed a calcium score to see how hard she should try to convince you to start Statin if it is high, or leave it, if it returns zero.
I’m 60, my CAC score is 36. My doctor recommended going on a statin. According to this online calculator https://www.calciumscorecalculator.com/ , I’m 32nd percentile for a white male like me. If I’m “better” than 62% of white guys, I can’t see going on a statin. Do you argee?
CAC score is only a tiny part of the equation and cannot (or should not) be used as the only factor to decide whether to start a Statin. For example, if you are a healthy, athletic 60-year-old with no other risk factor (like diabetes, smoking, hypertension, strong family history or high cholesterol), I would be pretty lenient regarding the initiation of Statin in your case. A truly “individualised” care that makes it impossible to have a blanket rule.
I am 64, my score is 919 and percentile is 92. Guess it is pretty high: no symptoms, daily vigorous exercise. Are the units used are all the same around the world?
Yes, same everywhere. A calcium score of 919 is considered “significantly” elevated.
Thanks, clear and logical explaination.
My score went from a zero to 32 in a span of 4 years. as a 60 year old male, should I be concerned?
Hi Matt, we should never look at “one single test” and try to estimate someone’s risk of heart attack. Coronary Calcium Score is only one part of the whole puzzle and should be interpreted along with many other risk factors as I have explained in this post. (How to reduce the risk of a sudden heart attack). If you have no other risk factor, a calcium score of 32 at 60, is quite acceptable but you need to discuss with your care provider.
very informative. Thanks
Thank you
Thank you. Very informative!
Glad it was useful.
This discussion and particularly the video was excellent. I have a family history of heart disease. Starting with my primary physician and the through screening programs offered by a local hospital I’ve had regular vascular, CT scans and calcium scores.
The results were interpreted for me by my primary physician, but frankly I never really understood what she was telling me. Your video was extremely helpful in understanding how plaque develops.
Have you made, or do you know of other videos related not the issues that I should understand related to “intervention” options that – base on my family history – will likely be needed at some point?
Thanks, Scott
I should say that Calcium scores and especially CT Coronary angiograms, do not need to be repeated often. With the current medications that we have available these days, most coronary artery diseases could be managed medically, with no interventions required. Interventions (like stents or bypass surgery) are largely recommended for people who have “symptoms” like chest pain. They do not necessarily “prevent a heart attack” but can improve symptoms. However, what will prevent a heart attack, is tight management of risk factors (with the addition of statins and Aspirin if needed) and a healthy lifestyle. Here you can read about Heart Attack Prevention.
Great review of the subject and video, thank you