Jamal S. Rana, MD, PhD
Jamal S. Rana, MD, PhD, chief of cardiology at Kaiser Permanente Oakland Medical Center and immediate past president of the California Chapter of the American College of Cardiology. KaiserPermanente.org
When your doctor broaches the topic of taking a statin drug to lower your cardiovascular risk, you may wonder if it’s really necessary…especially after hearing that you are at only slightly elevated or intermediate risk. Fortunately, a screening tool called the coronary artery calcium (CAC) score can help “break the tie” in those ambiguous situations.
What is it? Over your lifetime, plaque accumulates in the arteries of your heart and then hardens, or calcifies. The more calcified plaque in your coronary arteries, the more likely you are to experience a heart attack. CAC screening is a computed tomography scan that measures the calcified plaque in those coronary arteries. This noninvasive test requires no contrast dye, takes only 15 minutes and, if needed, can be repeated after three to five years.
Who should get one? Not everybody. CAC is a screening test, not for anyone with chest pain or symptoms. If you are over 40 years old, your doctor will first use a ACC/AHA risk calculator to categorize your cardiovascular risk as low, intermediate or high based on your risk factors such as smoking and cholesterol level. Patients in the “intermediate” bucket typically are candidates for CAC screening. And if you have other “risk enhancers,” such as family history of early onset cardiovascular disease, South Asian ancestry or inflammatory conditions like rheumatoid arthritis, your doctor also might suggest a CAC test.
How are CAC results used? The results take the form of images and a score. A score of zero means that no calcified plaque is detected—although there still is a chance that you have noncalcified plaque that the test cannot detect. Unless there are other significant risk factors, such as diabetes or active smoking, you and your doctor may decide there’s no need for a statin at the present time or that the decision can be deferred until your next CAC in, perhaps, three to five years. This concept is what is now also known as the “power of zero.”
Scoring between 1 and 99 means that the scan showed some calcified plaque. In this case, there is no guesswork about the presence of disease. You’ll probably discuss the benefits of a statin and, even more important, lifestyle improvements. Patients often find the visual images of calcified plaque to be good motivators for diet and exercise changes.
A score of 100 or higher means a higher risk so there is a compelling case to start taking a statin.
Is the test dangerous? No. While it does rely on radiation, the amount is similar to that of a mammogram, which women in their 40s are now recommended to undergo biannually. Since the guidelines for CAC indicate screening only every three to five years, total radiation exposure is considerably less than with mammography.
Who pays for it? Your insurance or Medicare may or may not cover CAC, so plan to pay for it yourself. But CAC screening is relatively inexpensive—usually between $50 and $100.
