Performing CT coronary artery calcium (CAC) screening of patients with risk factors for cardiovascular disease can identify individuals who might suffer future cardiac events and could result in lower costs for subsequent medical tests, according to a study published this week in the Journal of the American College of Cardiology.
The Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research (EISNER) study was designed to assess the procedural costs and resource consumption patterns following CAC screening of patients with cardiovascular risk factors who were followed for four years. The study was conducted at multiple centers in the U.S.; the principal investigator was Dr. Daniel S. Berman of Cedars-Sinai Medical Center in Los Angeles (JACC, Vol. 54:14, pp. 1258-1267).
The EISNER team studied 1,361 individuals between May 2001 and June 2005. Participants had no symptoms or prior history of cardiovascular disease, but had at least one risk factor. Patients were scanned with an electron beam CT scanner (Imatron C-150 or e-Speed, GE Healthcare, Chalfont St. Giles, U.K.) or a multislice CT scanner (Somatom Volume Zoom, Siemens Healthcare, Malvern, PA). CAC scores were generated with semiautomated commercial software (NetraMD, ScImage, Los Altos, CA).
Shaw and colleagues then followed the patients over the next four years, analyzing follow-up imaging procedures that were required and noting any invasive therapeutic interventions. They also tracked clinical outcomes and costs.
The researchers found that individuals with low CAC scores had lower rates of follow-up testing, while those with higher scores, particularly CAC scores of 400 or greater, had higher rates. Individuals with higher CAC scores also saw higher follow-up costs. The table below shows the results by CAC score.
Follow-up procedures and costs by CAC score
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The researchers also found that CAC screening did not lead to increased use of invasive coronary angiography, which has been indicated as a possible consequence of increased use of the technique. One year after CAC testing, coronary angiography was used in less than 1% of subjects with CAC scores at or below 1,000 and in only 19.4% of individuals with CAC scores greater than 1,000.
In financial disclosures, several of the authors reported receiving funding support from GE Healthcare.
Related Reading
Coronary CTA beats calcium scoring for short-term prognosis, August 14, 2009
Coronary artery calcium independently predicts risk in CAD patients, July 29, 2009
Zero calcium means good outcomes, even with undetected plaques, July 23, 2009
CTA predicts coronary plaque instability, June 30, 2009
Absence of coronary calcium predicts excellent 10-year survival: study, June 18, 2009
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