AUC may influence some, not all, forms of cardiac imaging

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 - guidelines, directions, advice

Imaging appropriate use criteria (AUC) should  reduce the number of less-appropriate tests, however, researchers have found that in some cases, the gray area may hold greater sway in how frequently rarely appropriate tests are performed. They published their findings in the March 3 issue of the Journal of the American College of Cardiology.

While rates of transthoracic echocardiography (TTE) and CT angiography (CTA) have improved, the same cannot be said for stress imaging or transesophageal echocardiography (TEE), noted Ricardo Fonseca, MD, and colleagues from the Menzies Institute for Medical Research at the University of Tasmania in Hobart, Australia. The analysis incorporated data from 59 reports published between 2000 and 2012.

Imaging modalities with AUCs included in their research encompassed SPECT, cardiac MR (CMR), CTA, TTE, TEE and stress echo.

Looking at the literature, the research team wanted to know if there was evidence that tests were more appropriately used now compared with 10 years ago, stated co-author Thomas H. Marwick, MBBS, MPH, PHD, in an interview with Cardiovascular Business. “Generally speaking, it was—but not universally. Appropriate use is still lower than it should be for CT criteria. And in fact that has fallen a little bit. It’s also lower than it should be for some of the stress testing, such as nuclear stress or SPECT,” Marwick said. “It’s changed the most for echocardiography and it’s changed the least for CT and some of the stress testing approaches.”

Marwick noted that the reduction in imaging is related, to some extent, to radiology benefits managers and other processes in the U.S. that were influenced by AUCs and altered access. However, the number of gray area, “rarely appropriate” tests has increased. “You would think that as we become more facile with some of these appropriate use guidelines that, in fact, the numbers of the indeterminates would decrease.  I think it simply reflects that the evidence in some of these areas is not as strong as we would like it to be,” he said.

Also, when accurately measuring appropriateness, two confounders emerged: observer variability and appropriateness of imaging for nonactive problems vs. active problems. “The reliability of scoring is not very high,” Marwick said. “We looked at who was scoring the test for echocardiography, for example. Sometimes it’s stenographers, sometimes it’s nurses and often it’s doctors. The variability of those observers [themselves] differs. It was probably greatest for the clinicians, but it was very variable.

“If you look at the criteria—there’s over 100 of them for echocardiography—somebody might be appropriate in one area and rarely appropriate in another area. Different scorers will score those things differently.” This makes it possible that changes seen in appropriateness may not be related to AUCs at all.

Getting the right boxes checked the right way for the right reason requires enforcement of AUCs, Marwick said. And appropriate use studies, like this, are the acid test for successful reduction of less appropriate utilization of resources. “We don’t have this process [to identify appropriate vs. rarely appropriate use] in Australia at the moment and I used to work in the U.S., so I’m quite tuned into this.

“What my research group is interested in is trying to identify tests in the laboratory," he said. "If you give [clinicians] a series of boxes to tick and they know there’s somebody with a big stick standing behind them that’s going to hit them over the head if they tick the wrong box, then they’ll tick the right box,” Marwick said.