A doctor may recommend measuring your coronary artery calcium (CAC) if you’re at risk of coronary artery disease or another heart condition but have no symptoms.
A CAC procedure is a CT scan that takes only minutes and shows the amount of calcium in the coronary arteries. It’s a low-cost and noninvasive way to measure your heart health.
The amount of calcium in your arteries can affect how much oxygen and blood your heart receives. Your CAC score can indicate your risk of a heart attack. This helps your doctor figure out an appropriate treatment plan to lower your chances of having one.
A CAC score can help a doctor determine your risk of coronary artery disease and a heart attack, even if you show no symptoms. A doctor can use your score to create a treatment plan to help you manage your heart health.
Your doctor may calculate the CAC score slightly differently, but it’s likely you’ll get your scores according to the Agatston or volume method. Some recent studies suggest these scores should be calculated differently, but the Agatston and volume methods are still the most used scoring systems and have been used for three decades.
The Agatston scoring method computes the amount of calcium in your heart. It examines where the calcium is located, how much there is, and the number and size of the calcium lesions. The score can also factor in your age, gender, and other factors.
The advantages of these scoring methods are:
- They are simple and quick to calculate.
- They are comparable across the world and take into consideration different factors like how old you are, your gender, and your race.
- They have been used for decades and are considered reliable.
What is a healthy cardiac calcium score?
A healthy CAC score is 0, meaning you have no plaque in your arteries and are at low risk of a heart attack. The higher your CAC score, the more you are at risk of heart attack.
- Scores from 1 to 100 indicate a low or medium risk of a heart attack.
- Scores between 100 and 300 indicate more calcium in your arteries and a higher risk of heart attack.
- Scores above 300 suggest you are at a high risk of a heart attack and require prompt treatment.
| CAC scores | Results from test | Risk level for heart attack | Treatment/follow-up required | Notes |
| 0 | No plaque | Low risk | No treatment required | |
| 1–100 | Small amount of plaque | Medium risk | May require lifestyle changes, some medical treatments | Your doctor may divide this category as 1–10 (low risk) and 11–100 (moderate risk). |
| 100–300 | Some plaque may be blocking your arteries | Medium to high risk | May require further testing and medical treatments along with lifestyle changes | |
| More than 300 | A very high chance that calcium is blocking your arteries | High risk | Requires immediate follow-up testing and treatment | The higher your score in this measurement, the more severe your risk is for a heart attack. |
You will need to speak with a doctor to get a CAC test. The procedure will expose you to a small amount of radiation, so a doctor will determine whether the test is necessary. You do not need to have symptoms to get this procedure.
Your doctor may suggest a CAC test if you:
- have a family history of heart conditions
- are middle-aged or older
- have high blood pressure
- have high cholesterol
- have diabetes
- take certain medications
- have overweight
- do not get regular exercise
- smoke tobacco
The CAC test is a CT scan that takes around 10 minutes. A trained technician will conduct the CAC.
You can wear comfortable clothes to the procedure, but you may be asked to change into a gown to assure you are not wearing any metal.
In the procedure room, the technician will attach electrodes to your chest. These will monitor your heart rate during the CAC. The technician will help position you flat on a table that will roll into a circular machine. This machine adjusts your position as it takes X-rays of your heart. The technician may direct you to hold your breath for several seconds at a time to get the right image.
After the procedure, a radiologist reads the X-rays and provides your doctor with an analysis.
The CAC procedure is quick and does not require a lot of preparation. You should not ingest caffeine the day of the procedure, but there is not much more you need to do unless directed by your doctor.
A CAC test is useful if you’re at risk of coronary artery disease but show no symptoms. Other tests for coronary artery disease may be more appropriate if you have symptoms or risk factors. Your doctor may also order additional tests depending on your CAC score.
Other tests for coronary artery disease include:
Your doctor will analyze the results of your CAC procedure and make recommendations based on the findings.
Some treatment plans for coronary artery disease include:
- getting regular exercise
- eating a nutritious, balanced diet that avoids excessive salt, fat, and sugar
- trying to quit or reduce your alcohol intake
- trying to stop smoking if you smoke (this can be difficult, but your doctor can help you create a plan that works for you)
- taking medications like statins
Your doctor may also recommend follow-up tests, procedures, or regular appointments to monitor your symptoms and reduce your risk of heart attack.
Some procedures for coronary artery disease include:
- angioplasty
- bypass graft surgery
- enhanced external counterpulsation
A CAC test can determine the severity of blockage in your heart’s arteries, even if you have no symptoms. This can indicate your risk of coronary artery disease and heart attack.
Treatments for coronary artery disease include lifestyle changes, medications, and additional procedures in some cases.
