The Study: A superb study concerning the cardiac calcium score was published in December 2007 in the Archives of Internal Medicine. It looked at about 3600 women aged 45 to 84 who were considered to be at low risk of heart disease (less than 10% chance in the next decade) according to the Framingham Risk Score. That score is based upon the person’s age, gender, total cholesterol, HDL cholesterol, systolic blood pressure, and cigarette smoking. All the women also had a cardiac calcium score obtained through a CT scan that measures the accumulation of calcium in the coronary arteries in the heart. Calcium only infiltrates damaged areas of the blood vessel wall, and is believed to be a good proxy for the presence of noncalcified cholesterol deposits (soft plaque) as well. The purpose of this X-ray test is to see if we can identify people who are at higher risk of heart disease than we would expect based upon the the typically measured risk factors just mentioned.
The Results: The women were followed for almost four years. Two-thirds showed no cardiac calcium, 22% had a small amount, 6% had a moderate amount, and 4% had a substantial amount (a calcium score over 300). Relatively few cardiac events occurred (these were low-risk women). But 7 of 24 events (about 30%) occurred in the small group (4%) of women who had calcium scores over 300, a rate about 22 times higher than the women who had no coronary calcification. Women with lesser amounts of cardiac calcium (0-100 or 100-300) had somewhat increased rates (about fivefold) of heart problems, but not nearly so striking. In effect, the calcium score identified a small subgroup of women who were thought to be at low risk of active heart disease, but who in fact were at moderate to high danger over an extremely relevant time period of well under a decade.
What Does This Mean? This study is one of the first to show that the cardiac calcium score truly provides early warning of serious heart disease and can be more accurate that the basic risk evaluation using blood pressure and cholesterol values. It means we can identify women (and men) who should be offered aggressive risk management (including medication for cholesterol, blood pressure and diabetes control) rather than just prodded to improve their life style.
As a practical matter, I have been recommending the cardiac calcium score for about three years and have encountered several handfuls of women and men who had unexpectedly high scores and with whom we adopted a much more intensive therapeutic approach. This study strongly supports that strategy.
The full article follows for those who would like to read it. Cardiac Calcium Scores in “Low Risk” Women
