Coronary Artery Calcium Score Conversion Assessed
Study finds conversion from normal to abnormal score occurs at low frequency before four years
FRIDAY, March 12 (HealthDay News) -- Individuals with a coronary calcium (CAC) score of zero likely do not require frequent repeat scanning, as conversion to a score above zero is uncommon before four years, suggesting that a zero score has a four-year "warranty period," according to research published in the March 16 issue of the Journal of the American College of Cardiology.
James K. Min, M.D., of the Weill Medical College of Cornell University in New York City, and colleagues analyzed data from 422 participants with a CAC score of zero and a group of 621 participants with a baseline CAC score greater than zero.
The researchers found that, of the subjects with a zero score, 106 developed CAC, with a mean time to conversion of 4.1 years. Rates of conversion were nonlinear, and conversion incidence was highest in the fifth year. Progression to CAC greater than zero was associated with diabetes, age and smoking. However, no clinical factor appeared to call for earlier repeat scanning. In individuals with a baseline score above zero, coronary artery disease risk factors didn't predict CAC progression.
"It seems reasonable to repeat CAC scanning at a four-year interval in patients whose CAC = 0 [has] resulted in withholding drug therapy that might have been implemented on the basis of their Framingham risk score. The nonlinear conversion is reassuring and supports a four-year rather than a shorter interval," writes the author of an accompanying editorial.
Three co-authors reported financial relationships with GE Healthcare and/or Siemens, and the editorial author reported a financial relationship with Philips Medical Systems.