A newly published Multi-Ethnic Study of Atherosclerosis (MESA) concludes that Coronary Artery Calcium (CAC) scores better at predicting the risk of cardiovascular disease (CVD) event in patients with type 2 than traditional scores. Coronary arterial calcification is part of the development of atherosclerosis, occurring almost exclusively in atherosclerotic arteries being absent in normal vessel walls. Atherosclerotic plaque proceeds through progressive stages where instability and rupture can be followed by calcification, providing stability to an unstable lesion. CAC is determined by electron-beam (EBCT) and multi-detector (MDCT) computed tomography, which is painless and noninvasive and is of approximately 10 minutes duration. It has a strong correlation with the total coronary atherosclerotic burden and is able to define CHD risk.

The American Heart Association considers coronary calcium scanning a reasonable option for people who have no symptoms of coronary heart disease but are at intermediate risk for the disease and are uncertain about whether to go on a statin and/or aspirin. Scores of 1 to 10 indicate arteries with a very mild buildup of calcium-containing plaque; scores of 11 to 100 signify mild buildup of this type of plaque , and scores of 101 to 400 indicate moderate calcium-containing plaque formation. People with higher calcium scores have a greater risk of heart attack and stroke over the next decade than those with lower scores.

The study was conducted in a MESA cohort consisting of 6,814 men and women (45–84 years) without known CVD. The primary end-point for the study was an incident coronary heart disease [CHD] event (myocardial infarction, resuscitated cardiac arrest, or CHD death). The secondary end-point was an incident atherosclerotic CVD event (CHD event and fatal or nonfatal stroke). More than a third (37%) of patients with diabetes, 45% of those with metabolic syndrome, and 55% of the other patients had a baseline CAC score of 0, and this was associated with a low 10-year risk of CHD events.

Among patients without evidence of CAC at baseline, the 10-year CHD event rates were just 2.3% in patients with metabolic syndrome and 3.7% in patients with diabetes. And this was independent of diabetes duration, insulin use, or glycemic control, even after adjusting for multiple confounders.

In short, people with CAC scores of 100 or higher might have a two- to threefold higher risk, versus those with no calcium buildup in their arteries. Meanwhile, the ‘warranty period’ of a CAC score of 0 can be extended to 10 years in those with metabolic syndrome or diabetes.

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