A coronary artery calcium scan is a CT scan that looks for calcium deposits in the arteries that supply the heart. It is noninvasive and is often promoted commercially – for roughly $300 per scan – as a way to screen for the buildup of plaque in arteries, a condition called atherosclerosis. Calcium often – though not always – builds up in plaque the longer it sits in artery walls. Thus a high score on a calcium scan can indicate long-lasting plaque and – perhaps – elevated risk of heart attacks or sudden death.
But calcium scans may not be a good idea, or prove terribly useful, for most people. For one thing, the scans expose a patient to significant radiation – equivalent to roughly 50 chest X-rays – said Dr. Warren Manning, chief of noninvasive cardiac imaging at Beth Israel Deaconess Medical Center.
For another, it’s not clear what to do with the results from a calcium scan. If you have diabetes, high cholesterol, high blood pressure, or a family history of heart disease, you already know – or should know – that you are at increased risk of heart problems and should lower these risk factors. So, a calcium scan provides little additional information, Manning said.
Moreover, even a high score doesn’t necessarily mean that the calcified plaque in your arteries is obstructing blood flow, said Dr. Adolph Hutter, a cardiologist at Massachusetts General Hospital.
“The vast majority of people with high calcium tests don’t have obstructions and they do fine long-term. So you’d have to test lots and lots of people to prevent one heart attack or sudden death,” said Manning.
And if you get a low calcium score, a sign of little or no calcification of plaques, that’s not very useful, either, because it could be wrong, or it could be right but lull you into believing you do not have to exercise and watch your diet, cholesterol, and blood pressure levels. “You can still be at risk even if your calcium test is negative,” Hutter said.
Some doctors believe that knowing your calcium score may motivate you to live a heart-healthy lifestyle, but studies suggest that patients are motivated for only a few months. Besides, we should all be living that way anyway. So, save your money and skip the calcium scan unless your doctor specifically recommends it.