Coronary CT angiography (CCTA), when used as a decision-making test, may lead cardiac surgeons to overestimate coronary artery disease (CAD) severity similar to rates reported for cardiologists and radiologists, according to a study published in the September issue of Academic Radiology.

The test could lead to more invasive treatment choices if used in treatment planning, and cardiac surgeons may be more confident basing decisions on catheter coronary angiogram (CCA) results, explained authors Aine M. Kelly, MD, MS, University of Michigan Hospitals, Ann Arbor, and colleagues.

“These may be important limitations in the application of CCTA in clinical practice and may reflect the maturation of CCTA use in practice, diffusion of the technology and/or a reflection of the technology itself,” wrote the authors.

Currently, CCA is the reference standard for diagnosing CAD, though it costs more than CCTA and is more invasive. CCTA could provide needed information on the coronary arteries and aorta during pre-coronary artery bypass graft (CABG) planning and may replace CCA in patients with a low risk for CAD, but it’s not clear that cardiac surgeons can confidently make valid diagnostic and treatment decisions from CCTA alone.

To assess the impact of CCTA on cardiac surgeons’ treatment decisions, Kelly and colleagues conducted a retrospective cohort study featuring 30 chest pain patients from their institution. Three cardiac surgeons reviewed de-identified CCA and CCTA images from the same patient several weeks apart, and then answered questions on their level of confidence in decision-making.

Results indicated that the surgeons tended to report more severe disease with CCTA, and treatment decisions differed based on CCTA compared with CCA in 40 percent to 60 percent of patients, depending on the individual surgeon. There was a tendency toward more invasive treatments—angioplasty, stent insertion or CABG—when making decisions using CCTA, according to the authors.

The surgeons reported higher confidence levels using CCA, and while surgeon familiarity may impact the decision to order a test, the level of confidence was significantly lower regardless of a surgeons’ years of clinical experience when making decisions based on CCTA. The authors noted that technical issues with CCTA, including limitations viewing distal landing zones for graft anastomosis, may negatively affect confidence.

“Surgeons' confidence with CCTA may remain low until its use is routinely introduced into surgical training and they become just as familiar with it, as they are for CCA,” wrote Kelly and colleagues.

Despite CCTA’s advantages with regard to invasiveness and cost compared with CCA, low surgeon confidence for management of CAD patients requiring CABG will decrease overall CCTA use, according to the authors. “Until cardiac surgeons and other consumers of diagnostic imaging become more familiar and confident with CCTA technology, this may limit the appropriate utilization of CCTA in clinical practice.”