SPECT emerged as the winner in a head-to-head comparison of cost outcomes for patients evaluated for coronary artery disease (CAD) after a two-year follow-up. The cost of subsequent invasive procedures made rivals PET and coronary computed tomography angiography (CTA) more expensive.

The analysis was published March 18 in the Journal of the American College of Cardiology.

Mark A. Hlatky, MD, of Stanford University School of Medicine in Stanford, Calif., and other investigators in the SPARC (Study of Myocardial Profusion and Coronary Anatomy Imaging Roles in Coronary Artery Disease) study used SPARC registry data to evaluate economic outcomes in 1,703 participants evaluated for suspected CAD. The patients had enrolled in one of 41 study centers between 2006 and 2008 and were followed up to two years.

For their analysis, Hlatky and colleagues stratified patients by modality, with 565 under SPECT, 590 under CTA and 548 under PET. They looked at patient characteristics, outcomes and costs using the 2008 Medicare fee schedule for tests and procedures.

PET had the highest two-year costs at a mean of $6,647 followed by CTA at $4,909 and SPECT at $3,965. After adjusting for baseline clinical differences, they determined that patients in the CTA group had 15 percent higher costs and patients in the PET group had 22 percent higher costs than patients in the SPECT group. Adjusted analyses on survival found no significant differences between CTA and SPECT or between PET and SPECT.

Cost-effectiveness analyses suggested that SPECT offered lower costs and better survival than PET while CTA carried higher costs and no significant difference in mortality. But the researchers added that the cost-effectiveness analysis “had a wide range of uncertainty” because differences in clinical outcomes between the groups were small.  

“The significantly higher costs among patients undergoing CTA or PET were primarily due to higher rates of subsequent invasive cardiac procedures, because there was little difference in initial costs of testing,” Hlatky and colleagues wrote. “The higher costs among patients evaluated with CTA or PET do not appear to be explained by differences in baseline characteristics, because costs remained significantly higher even after multivariable adjustment.”