CT angiography helps screen asymptomatic patients

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Coronary CT angiography (CCTA) may be justified in asymptomatic patients with a high risk of coronary artery disease (CAD) and might even oust coronary calcium scoring as the best option for screening these patients.

Recommendations call for using coronary calcium scoring with CT to detect calcifying plaque in low- to intermediate-risk asymptomatic patients, but CT angiography also can find noncalcifying plaques, wrote a research team from Innsbruck Medical University in Austria recently in Open Heart. New CT technologies have reduced radiation to patients, putting CCTA on equal footing with coronary calcium scoring for exposure. They reasoned that CCTA might offer diagnostic benefits beyond the recommended approach.

They enrolled 711 asymptomatic patients referred for CCTA between 2005 and 2012. Patients had to have a high “a priori” risk of CAD, which could be either a high lifetime cardiovascular risk or a low lifetime risk with a borderline or nonspecific stress test result. They examined patients using coronary calcium scoring and CCTA.

To assess coronary atherosclerosis regardless of stenosis, they quantified coronary plaque using segment involvement score as the measure. They also calculated a noncalicified segment involvement score.

Their primary endpoint was major adverse cardiac events, which included STEMI, NSTEMI and cardiac death. Follow-up was a mean 2.65 years.

The prevalence of CAD was 71.3 percent based on CCTA findings. Of those patients, 15.6 percent had plaques without stenosis; 23.9 percent had mild stenosis; 10.7 percent had intermediate stenosis and 21.5 percent had high-grade stenosis.

A total of 43 percent of patients had a zero coronary calcium score. Of those, they discovered noncalcified plaques in 32 percent. “Our study revealed that zero CCS [coronary calcium score] does not exclude CAD,” they wrote.

The findings supports the use of CCTA over coronary calcium scoring for screening asymptomatic patients for CAD, especially high-risk patients, they proposed. “CTA provides the advantage of detecting non-calcifying plaque (representing early stages of atherosclerosis), coronary plaque load assessment and stenosis quantification for risk stratification,” they wrote.