CORONARY CALCIUM SCORING TEST: Should you have one?
For decades physicians have been searching for the ideal, non-invasive test to diagnose coronary artery disease early enough to prevent a heart attack. The ultimate test, of course, is cardiac catheterization, but it’s invasive and requires the patient to be put to sleep, wires and catheters to be threaded into the heart and coronary arteries, and dye to be injected into the heart. All this carries with it major risks, among those plaque rupture and death.
So if a simpler, less invasive, reliable test with low radiation exposure could be devised, it would be a welcome blessing. CORONARY ARTERY CALCIUM SCORING has been proposed as that test, but disagreement about its accuracy and usefulness continues. A major debate about whether this is the diagnostic gem for which doctors have been looking, persists. Opinions, however, vary widely.
Coronary Artery Calcium Scoring has been done for nearly twenty years but has yet to “catch on” as something everyone should have. The test does just what it’s name implies—it detects calcium in the walls of the coronary arteries and quantifies it in a number called the Agatston Calcium Score.
Using a specialized form of non-invasive computerized tomography (CT scanning), the heart is scanned and calcium build up in the coronary arteries is measured. The amount of calcium is reported as a number from 0 to 400. This is the Agatston score. The higher the calcium score number, the greater the amount and concentration of calcium in the coronary arteries.
It is a generally-accepted fact that calcium builds up in the arteriosclerotic plaques found in the arterial vascular system. The coronary arteries, which supply blood to the heart muscle, are no different. Coronary artery plaques form over time after a traumatic injury to the inner lining of the artery (the intima). In an attempt to heal the injury, the lining attracts cells (platelets), protein (fibrin), and cholesterol that together, over months and years, form a hardened area of “scar,” (a plaque). Calcium circulates in the blood and is deposited in the plaque.
Older, larger plaques contain larger amounts of calcium, and are thus detectable by the CT scanner. Theoretically, calcium build up in the arteries should be a direct indicator of coronary artery disease, and the calcium score should guide the physician where to look for plaques that block blood circulation.
It does, but with significant limitations. Unfortunately, there is not a direct correlation between the presence of calcium in the coronaries and the presence of plaques that affect blood flow. Even if you have a high calcium score, it doesn’t mean you have severe coronary disease. One can have “a high score and not have signs of heart disease.” It is true, however, that “the higher your calcium score, the higher your risk for a heart attack.”
In reality, the calcium score is not diagnostic of coronary disease. It’s value lies in that it tells you that you are more likely to develop coronary disease or have an event such as a heart attack or stroke over the next 5-10 years. It’s a “wake up call” that should be heeded and serves as a strong incentive to “clean up your act,” especially if your score is over 100. It warns you to lose weight, exercise, watch your intake of cholesterol, stop smoking, and control your blood sugar and blood pressure.
The results of a heart scan should not be used as the only predictor of your overall health and risk of heart disease. It’s just not reliable enough to base a diagnosis of coronary artery disease solely on it. Exercise stress tests are more reliable and reproducible. Cardiac catheterization with coronary angiography is the definitive diagnostic test.
There are, in fact, some situations, or people, where coronary calcium scoring should not be done.
Calcium Score Heart Scans are NOT recommended for the following:
- Men under age 40
- Women under age 50
- People who have very low risk of heart disease—no family history of heart attack at a young age.
- People who have known high risk factors— heavy smokers, those with diabetes, or very high cholesterol
- People with symptoms or a diagnosis of coronary artery disease.
- People who have already had an abnormal calcium heart scan.
Coronary Artery Calcium Screening is not meant to be used as a “mass screening tool,” and is not intended to be the “Mammogram of the heart.” There are just too many situations where the detection of calcium does not correlate to significant coronary disease. Regardless of ethnicity, the higher the calcium score, the greater is the chance of finding coronary disease. Coronary artery calcium scoring is “strongly associated with the 10-year risk of arteriosclerotic disease in patients with high cholesterol.” But other more specific, more reliable and informative tests need to be done to confirm the presence of significant plaque disease.
Dr. G’s Opinion: The major problem with Coronary Calcium Scoring tests is the very high rate of false positives. A large percentage of patients with high calcium scores DO NOT have coronary disease that poses a risk to them. In my practice I had many patients who had high calcium scores (one man in the 300’s), but none of them was found to have significant coronary disease after stress testing and, in one case, cardiac catheterization. I did not actively recommend this test, but also didn’t discourage patients from having it if they wanted. I saw so many false positives that I became cynical about it.
Should you have one? Well, maybe, but only if you don’t have any of the disqualifying criteria I listed above. You just have to be prepared to have additional diagnostic tests in case it is abnormal. But don’t call the undertaker yet. There’s a good chance you’re really ok.
References: https://www.uofmhealth.org/health-library
Arnson Y, et al. Comparison of the Coronary Artery Calcium Score and Number of Calcified Coronary Plaques for predicting Patient Mortality Risk AmJCardiol 2017 Dec 15;120(12):2154-2159.
Bos D, Leening MJG Leveraging the Coronary calcium scan beyond the coronary calcium score. Eur Radiol 2018 Jul;28(7):3082-3087.
Sharma D, et al The additive prognostic value of coronary calcium score to single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI)-real world data from a single center. J Nucl Cardiol 2019 Dec 3.
Cainzos-Achirica M, et al. Coronary artery calcium score: the “Mammogram” of the heart? Curr Cardiol Rep 2018 Jul 10;20(9):70.
