February is American Heart Month -- a time for all of us to refocus on preventing cardiovascular disease. So, here's a pop quiz. Who is more likely to die from a heart attack or other cardiovascular-related event?
A. A person who is overweight, has high cholesterol, high blood pressure, and diabetes, and a Calcium Score of 0?
B. A person with no risk factors and a Calcium Score of over 400?
This is important to be aware of, since nearly 1 million American men and women have a heart attack every year.
As a creator of the Calcium Score (also called the Agatston Score), which many experts consider to be the best predictor of a future heart attack, I can tell you that the answer is B. Strikingly, it is estimated that nearly 50 percent of those who suffer fatal heart attacks don't even know they have risk factors.
Recently, a large and important study has found that even if you don't have any of the conventional risk factors for heart disease -- high blood pressure, high cholesterol, family history, prediabetes and diabetes, smoking, being overweight, high triglycerides, a sedentary lifestyle -- it doesn't necessarily mean you're home free.
The study, which was published in the journal Circulation Cardiovascular Imaging, looked at more than 44,000 individuals free of known coronary heart disease. Each person underwent a noninvasive computed tomography (CT) scan of the heart for coronary calcium and was then followed for a median of five5 years for whether or not they died of any cause (this is called "all-cause mortality" and is an appropriate end point to follow, because when one accounts for both cardiac and systemic forms of the disease, nearly three-fourths of all deaths have been related to atherosclerosis).
Those with no coronary calcium and no risk factors had the lowest death rate, whereas those with a Calcium Score of over 400 and three risk factors had the highest death rate. Not surprising. What's notable about this study, however, is that the individuals with no risk factors and a Calcium Score of more than 400 (people who are not generally candidates for aggressive prevention) had substantially higher death rates compared with individuals with three risk factors and the absence of coronary calcium ( approximately 17 vs. approximately 3 per 1,000 person-years).
What does this striking data mean? It suggests that people with coronary calcium (with and without other risk factors) are more likely to die, and that a selected group of patients without risk factors may benefit from further risk assessment and preventive therapies.
Here's what you need to know about the No. 1 predictor of a heart attack -- the Calcium Score.
What is a Calcium Score? A Calcium Score, derived from a CT scan of your heart, is the measure of the amount of calcium nestled in the walls of your coronary arteries (the arteries that feed your heart muscle). This number reflects the total amount of atherosclerotic plaque that has built up and it's an indicator of how all of your risk factors interact with each other to cause heart disease. The higher your Calcium Score for your age, the greater your risk of a heart attack or stroke. Today many preventive cardiologists like me are recommending that all asymptomatic men over age 45 and most postmenopausal women over age 55 who are at intermediate risk of a heart attack according to their Framingham Risk Score have a heart scan to determine their Calcium Score. But as the study above suggests, certain "low-risk" individuals should also be scanned, and it's important to do so earlier rather than later.
How do you know if you're one of these people? If there is heart disease in your family (siblings, parents, grandparents, uncles, aunts), you should be tested even if other risk factors are not present. The closer the relative (siblings are most important and then parents) and the earlier the heart disease occurred, the more important it is to get a Calcium Score.
What Do the Numbers Mean? A Calcium Score can range from 0 to several thousand. A score of 0 means you have no calcium deposits and little or no atherosclerotic plaque and a low risk of heart attack (if you're a nonsmoker) in the next two to five years. A score of 400 or more means you have a build up of plaque and it puts you at high risk of a heart attack within 10 years; a score of 1,000 plus means you have up to a 25 percent chance of having a heart attack within one year without appropriate aggressive medical treatment. There are no detectable differences in the predictive value of CAC scores among ethnic groups.
The significance of a given score also depends on your age. For instance, if you're 40 and have a score of 50, it indicates you are at high risk. If an 80-year-old has a score of 50, it indicates low risk, because the atherosclerotic process has proceeded very slowly, taking 30 more years to reach the same quantity of atherosclerosis. If your score is high for your age, then your doctor may advise adopting a heart-healthy diet along with other lifestyle changes, and often medications, to improve your risk profile. You may require a statin to lower cholesterol and/or a medication to lower your blood pressure. For those with prediabetes, diabetes, and metabolic syndrome, diet and exercise are essential to reduce the risk of heart attack.
What Does the Procedure Involve? A CT scan with a Calcium Score is a quick, easy, accurate, noninvasive, and painless procedure that takes just a few minutes. It does not require the use of dye. You lie down fully clothed on an examination table, the scanner passes over you for a minute or two, and it's over. If you have few or no calcium deposits, you don't have to repeat the heart scan for at least five years. If you do have signs of calcium buildup, the test can be repeated in three to five, depending on your other risk factors.
Is It Safe? The amount of radiation from a typical scan is about the same as what you'd get from a mammogram. The CT heart scan should not be confused with CT angiography, however, which involves injecting dye, is riskier (requiring a greater dose of radiation), and is more expensive. You should be aware that the CT angiogram, while a valuable test, has often been used inappropriately to find asymptomatic blockages that lead to unnecessary cardiac catherization followed by angioplasty or even bypass surgery.
Will My Insurance Pay? Today, you can get a CT scan for coronary calcium at most major medical centers for a cost ranging from $99 to $399. More and more insurance companies are getting on board with this screening test. Check with your insurance provider to see if it is covered.
The Bottom Line: As a country, we must change our approach to diagnosing heart disease. Heart attacks are preventable. Thousands of studies, including the impressive one mentioned above, now show the superiority of noninvasive imaging of atherosclerosis over the traditional method of measuring risk factors. To delay the use of this test on a more widespread basis is to sentence millions more people to early deaths from America's No. 1 killer.
Arthur Agatston, M.D., is the medical director of Wellness and Prevention for Baptist Health South Florida and a clinical professor of medicine at the FIU Herbert Wertheim College of Medicine. He is the author of the best-selling South Beach Diet book series, with more than 23 million copies in print worldwide. Dr. Agatston's latest book, The South Beach Diet Gluten Solution, will be published in April. Dr. Agatston can be found on the Web at SouthBeachDiet.com and EverydayHealth.com.
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