CHICAGO—Due to changes in CPT coding and fee schedules that have reduced reimbursement for stress tests and coronary CT angiography (CCTA) in the 2009 through 2011 Medicare fee schedules, triage strategies that begin with stress EKG or stress echocardiography and progress to CCTA (if the stress test is positive) represent the least expensive options, and are more cost-effective relative to strategies that utilize myocardial perfusion scintigraphy, according to a study presented Nov. 30 at the 97th annual meeting of the Radiological Society of North America (RSNA).

“A few years ago at RSNA, we presented a decision tree analysis that assessed diagnostic accuracy, cost and radiation dose with different work-ups for suspected coronary disease,” the study’s lead author Ethan J. Halpern, MD, a diagnostic radiologist at Thomas Jefferson University Hospitals in Philadelphia, explained in an interview. The study was later published in Academic Radiology. 

For this study, the researchers employed a decision analytic model to evaluate diagnostic accuracy and imaging costs for the diagnosis of coronary artery disease (CAD), and to evaluate how changes in the fee schedule might impact the cost-effectiveness of different work-up strategies.

The decision model utilizes stress testing (stress ECG, stress echocardiography or stress myocardial perfusion scintigraphy [MPS]) and CCTA for evaluation of suspected CAD. All possible combinations of stress tests and CCTA were evaluated. Patients with a positive stress/CCTA evaluation underwent cardiac catheterization. Values of sensitivity and specificity for stress tests and CCTA from the published literature were entered into the decision tree. Costs were evaluated as a function of CAD prevalence based upon Medicare fee schedules from 2009, 2010 and 2011.

The researchers found that the combination of CCTA with any stress study results in a decreased false-positive rate relative to a stress study alone. The false-positive rate is minimized when CCTA is combined with stress echocardiography. “For diagnostic value, if the suspicion of coronary disease is below 20 percent, you’re probably best to go with the stress echo first, but if the suspicion of the disease is between 20 and 50 percent, you’re best to start with CT,” Halpern said. 

Also, the reimbursement for CCTA was reduced each year from 2009 to 2011, with an overall reduction of 39 percent. Specifically, Halpern said that the global Medicare reimbursement dropped from approximately $680 in 2009 to less than $400 in 2011. Reimbursement for other stress studies was reduced by 7 to 12 percent over the same two-year period. Halpern reported that the stress test followed by CCTA results in lower imaging costs as compared to stress testing alone for any disease prevalence below 60 to 70 percent.

“Imaging costs are minimized by a strategy that employs stress ECG followed by CCTA,” the researchers concluded. “MPS alone is the most expensive diagnostic option for evaluation of CAD, and has become increasingly more expensive as compared to other options based upon changing reimbursement from 2009 to 2011.” 

Thus, Halpern said that the evaluation of coronary disease may be optimized by an appropriate combination of stress testing and CCTA to reduce imaging costs and unnecessary cardiac catheterizations.