How useful is a cardiac calcium CT scan?

Being a radiologist, I rarely speak to patients, but I was asked to counsel Mrs. Patel (not her real name), who was worried about the risks of radiation from cardiac calcium CT scan. Because of her risk factors for atherosclerosis, her cardiologist wanted her to take statins for primary prevention, but she was reluctant to start statins. They eventually reached a truce. If she had even a speck of calcium in her coronary arteries, she would take statins. If her calcium score was zero, she wouldn’t. This type of shared decision making is the most frequent reason why cardiologists order calcium scans at my institution. A calcium scan is a nifty test, not because it improves outcomes — that’s a population-based consideration — but because it changes management, specifically when there is zero calcium. It does this by so lowering the patient’s risk profile that they no longer meet the risk threshold deemed by the American Heart Association, and endorsed by the U.S. Preventive Services Task Force, for starting statins for primary prevention. You can quibble about the threshold for recommending statins, but there is no quibbling that [a] zero-calcium scan often reclassifies risk bringing the person to a lower risk than previously thought. Zero calcium portends a happier future. In one study, of those who were eligible for statins because their estimated risk of cardiovascular events over ten years was greater than 7.5 percent, nearly half had zero calcium, which p...
Source: Kevin, M.D. - Medical Weblog - Category: Journals (General) Authors: Tags: Conditions Radiology Source Type: blogs