Medicare beneficiaries who underwent coronary CT angiography (CCTA) in nonacute settings had a higher likelihood of undergoing subsequent invasive cardiac procedures and have increased coronary artery disease (CAD) spending compared with patients who underwent stress testing, according to a study published March 7 in the Journal of the American Medical Association. In response, several researchers submitted letters supporting and challenging the author’s findings.
For the study, Jacqueline Baras Shreibati, MD, of Stanford University School of Medicine in Stanford, Calif., and colleagues compared utilization and spending rates associated with stress testing and CCTA noninvasive cardiac testing in a Medicare population.
The authors evaluated claims data from a random sample of 2005-2008 Medicare fee-for-service beneficiaries who were 66 years or older, had no claims for CAD in the previous year and received non-emergent, noninvasive testing for CAD; 282,830 patients were identified.
Shreibati et al assessed cardiac catheterization, revascularization, acute MI, all-cause mortality and total and CAD-related Medicare spending over 180 days of follow-up. Of the cohort, patients had a median age of 73.6, 46 percent were men and 89 percent were white.
Myocardial perfusion scintigraphy (MPS) imaging was the most frequently used diagnostic test (46.8 percent), followed by stress echo (28.5 percent), ECG (21.6 percent) and CCTA (3.1 percent).
The researchers found patients who underwent CCTA had lower mean spending compared with patients who underwent MPS, $10,894 vs. $11,616, respectively. However, these patients had a higher mean spending when compared with patients who underwent stress echo or exercise ECG, $8,636 and $7,467, respectively.
It was also noted that 7.4 percent of patients underwent additional noninvasive testing, 11.1 percent underwent cardiac catheterization, 4.6 percent underwent coronary revascularization (3.1 percent underwent PCI and 1.6 percent underwent CABG), 0.37 percent were hospitalized for acute MI and 1.1 percent died. Also, it was found that additional noninvasive testing was performed more often after CCTA compared with MPS.
“Patients who underwent CCTA were nearly twice as likely to undergo subsequent cardiac catheterization as patients who underwent MPS and roughly 2.5 times as likely to undergo coronary revascularization,” the authors wrote.
CCTA was linked to higher total healthcare spending, which the authors found to be mostly attributed to payments for any CAD claims. The authors found that patients undergoing CCTA had "nearly 50 percent higher CAD-related expenditures than patients undergoing MPS. There was lower spending associated with stress echo and exercise electrocardiography when compared to MPS. CCTA also was associated with a lower rate of all-cause mortality and a lower likelihood of hospitalization for acute MI.
“This higher use of invasive procedures after CCTA appears to have led in turn to substantially higher spending for medical care at 180 days,” the authors wrote.
While the authors said that a normal CCTA result may reduce the need for further testing, they said that an inconclusive or positive CCTA could lead to additional functional testing, invasive angiography, or both.
“The net effect of CCTA on subsequent cardiac testing is therefore uncertain and may either increase or decrease use of such testing, depending on the patient population and the practice patterns of physicians,” Shreibati wrote.
“The increased use of invasive procedures and the higher spending on care after CCTA documented in this study suggest that clinicians and policy makers should critically evaluate the use of CCTA in clinical practice, based on studies of subsequent outcomes,” the authors summed.
In a research letter, Joseph A. Ladapo, MD, PhD, of the New York University School of Medicine in New York City, and Pamela Douglas, MD, of the Duke University Medical Center in Durham, N.C., wrote that Shreibati and colleagues “placed too little emphasis on the potential for an unmeasured difference in sensitivity between the two approaches [stress testing and CCTA].”
“Because patients with positive stress test results are more likely to undergo follow-up cardiac catheterization, the sensitivity and specificity derived from a population selected for angiographic confirmation are overestimated