Author + information
- Received June 15, 2009
- Revision received August 17, 2009
- Accepted August 24, 2009
- Published online March 16, 2010.
- James K. Min, MD*,* (, )
- Fay Y. Lin, MD*,
- David S. Gidseg, MD*,
- Jonathan W. Weinsaft, MD*,
- Daniel S. Berman, MD†,
- Leslee J. Shaw, PhD‡,
- Alan Rozanski, MD§ and
- Tracy Q. Callister, MD∥
- ↵*Reprint requests and correspondence:
Dr. James K. Min, Department of Medicine, Weill Medical College of Cornell University, New York Presbyterian Hospital, 520 East 70th Street, K415, New York, New York 10021
Objectives This study identified the incidence and predictors of conversion of a normal to abnormal coronary artery calcium (CAC) scan during serial CAC scanning over 5 years.
Background Although a normal CAC scan signifies absence of significant atherosclerosis and is used to identify individuals at low clinical risk, the “warranty period” of a normal CAC scan relative to its ability to predict sustained absence of coronary atherosclerosis remains unknown.
Methods We assessed frequency of and time to progression, as well as proportional increase of CAC in 422 individuals with normal CAC scan (CAC = 0) undergoing annual CAC scanning for 5 years. Results were compared with those of a referent cohort of 621 individuals with baseline CAC scan (CAC >0).
Results A total of 106 (25.1%) patients with CAC = 0 developed CAC during follow-up at a mean time to conversion of 4.1 ± 0.9 years. Incidence of conversion to CAC >0 was nonlinear and was highest in the fifth year. In multivariable analysis, progression to CAC >0 was associated with age, diabetes, and smoking (p < 0.01 for all). Among the 621 individuals with baseline CAC >0, only the presence of CAC itself, rather than CAD risk factors, was predictive of CAC progression. Among propensity score-matched individuals with CAC >0 versus CAC = 0, baseline CAC >0 emerged as the strongest predictor of CAC progression (hazard ratio [HR]: 12.50, 95% confidence interval [CI]: 9.31 to 16.77), followed by diabetes (HR: 2.07, 95% CI: 1.47 to 2.90) and smoking (HR: 1.29, 95% CI: 1.02 to 1.63, p < 0.05 for all).
Conclusions Among individuals with CAC = 0, conversion to CAC >0 is nonlinear and occurs at low frequency before 4 years. No clinical factor seems to mandate earlier repeat CAC scanning.
Dr. Min has received research support from and is on the Speakers' Bureau and medical advisory board of GE Healthcare. Dr. Berman has received grant support from GE Healthcareand Siemens. Dr. Callister is on the Speakers' Bureau of GE Healthcare.
- Received June 15, 2009.
- Revision received August 17, 2009.
- Accepted August 24, 2009.
- American College of Cardiology Foundation