Radiology: CT angiography proves cost-effective in chest pain diagnosis strategy
A coronary CT angiography-only approach -- when factoring in a $20,000 threshold level for cost per correct diagnosis and $50,000 per quality-adjusted life-year (QALY) -- is the most cost-effective diagnostic strategy for the evaluation of patients presenting with stable chest pain without known coronary artery disease (CAD) with intermediate CAD prevalence, according to a decision analysis study published in the March issue of Radiology.

In a prospective, multicenter study, James K. Min, MD, from the departments of medicine and radiology at Weill Medical College of Cornell University in Ithaca, N.Y., and the New York Presbyterian Hospital in New York City, and colleagues evaluated patients who had chest pain without known CAD in the ACCURACY-eligible population (Assessment by Coronary CT Angiography (CCTA) of Individuals Undergoing Invasive Coronary Angiography).

The authors sought to determine the incremental costs per correct diagnosis and per QALYs saved for noninvasive imaging strategies that do or do not incorporate coronary CT angiography (CCTA).

“Although noninvasive testing of individuals who are suspected of having CAD has been performed by using functional ischemia testing with myocardial perfusion SPECT, 64-section CCTA has emerged as a promising modality for diagnosis and prognosis in these individuals,” wrote Min and colleagues.

A decision analysis was performed in which five diagnostic pathways were compared. First, the researchers compared CCTA, followed by invasive coronary angiography for positive or equivocal findings to only CCTA. Next, they compared CCTA, followed by invasive coronary angiography for positive findings and myocardial perfusion SPECT for equivocal findings. Myocardial perfusion SPECT was then tested, followed by invasive coronary angiography for positive or equivocal findings to myocardial perfusion SPECT-only results. Finally, myocardial perfusion SPECT, followed by invasive coronary angiography for positive findings and CCTA for equivocal findings was compared to myocardial perfusion SPECT first and invasive coronary angiography.

The authors utilized a 55-year-old man with 30 percent risk of obstructive CAD as their base case for near-term cost per correct diagnosis. They found that the most cost-effective diagnostic strategy was a CCTA-only method, which resulted in an incremental cost-effectiveness ratio of $20,429 and resulted in 986.3 correct diagnoses per 1000 patients and QALY relative to the least expensive CCTA-first strategy, which resulted in a ICER of $17,516 but did not result in the same number of correct diagnoses (982.1 per 1000 patients) as CCTA-only.

The authors also found that myocardial perfusion SPECT-only and myocardial perfusion SPECT-first strategies were more costly and less effective than both CCTA strategies.

“The results of the ACCURACY prospective multicenter study demonstrated high sensitivity for detection and high negative predictive value for exclusion of obstructive CAD, confirming the findings of numerous prior single-center studies,” wrote the authors.

The study's findings may result in practice pattern changes in the evaluation of CCTA for chest pain syndrome in intermediate-risk individuals, concluded Min and colleagues.