ASNC: CAC scoring may change patient management, not outcomes

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DENVER—Incorporating coronary artery calcium screening (CAC) into practice can change the diagnoses and management of coronary artery disease (CAD), however, it may still be too early to tell how it will impact patient outcomes, Tim M. Bateman, MD, co-director of cardiovascular radiologic imaging at Mid America Heart Institute, Saint Luke's Health System in Kansas City, said during a presentation Sept. 11 at the 16th annual American Society of Nuclear Cardiology (ASNC) scientific session.

“In patients undergoing a normal SPECT study, does the addition of CAC screening have a role?” Bateman asked. “What can we conclude from a normal SPECT scan when the CAC score is known?”

Typically, patients who undergo a SPECT exam are symptomatic and at an intermediate risk.

CAC scoring may be a promising tactic to detect CAD because it is performed with good accuracy and is reproducible. Additionally, the test can be performed on most contemporary scanners (those that use four slices or more), Bateman added. CAC scoring also emits a low radiation dose (less than 2 mSv), is inexpensive and risk-free. In fact, newer, hybrid scanners may even be able to perform CAC scoring without exposing the patient to the 2 mSv of radiation, Bateman said.

“But will knowing calcium artery screening score change patient management?” Bateman asked. Previous studies have shown that knowing a patient's CAC score can influence whether patients are administered the appropriate therapy, either statins or aspirin.

In fact, a previous study showed that when patients had a CAC score of zero, statin use was 45 percent. Meanwhile, when a patient's CAC score was more than 100, statin use was more than 85 percent.

“Management does change when patients have an elevated CAC score,” Batemen offered. “CAC scores can change the diagnosis, it can change prognosis and it can change management strategies, but does this matter? Will knowing CAC score change patient outcomes?” he asked.

While Batemen said that previous studies have shown that having a higher CAC score can change the diagnosis of no ischemia to better understanding whether CAD is present or not, it remains unknown as to whether knowing CAC scores will affect outcomes.

Batemen concluded that knowing CAC score can change the perception of long-term CAD risk in addition to changing the management strategy. However, more research will be necessary to understand whether knowing the CAC score improves outcomes.