Report from ACC: Cardiologists slowly adopt appropriateness criteria

More than 13% of SPECT myocardial perfusion imaging exams are performed without clinical justification, and the appropriateness of another 14% is questionable, according to a pilot study that assesses physician referring practices and compliance with American College of Cardiology Appropriate Use Criteria.

The investigation suggests that cardiologists and other ordering physicians have been slow to adopt the criteria since their introduction by the ACC in 2004. It also found that supplemental training will lead to better referring physician compliance with the guidelines. The study was conducted jointly by the ACC, the American Society of Nuclear Cardiology, and UnitedHealthcare, a large health insurer based in Minnesota.

Findings were drawn from online technology combined with ACC Appropriate Use Criteria for SPECT myocardial perfusion imaging to track referral patterns at six cardiology imaging practices of varying sizes and location in the U.S. The study evaluated 6351 patients in 2008. Physicians completed a form for each patient and entered the data into a web-based tool. The computer-based algorithm was able to determine the appropriateness of the referrals for SPECT perfusion imaging in 93.4% of cases.

Results were presented March 31 at the 2009 ACC meeting in Orlando.

Dr. Robert C. Hendel, a clinical cardiologist at Midwest Heart Specialists in Winfield, IL, explained that the feasibility study is part of an effort by physicians to be proactive about imaging utilization, identifying when an imaging test is not needed and developing physician-centered tools to accomplish these goals. Hendel is a past president of the ASNC.

"We have criteria for using the right test for the right patient at the right time," he said.

Results indicate that cardiologists and other physicians complied with the ACC criteria for 66% of their referrals. For the remaining third, 13.4% of the SPECT studies were deemed inappropriate, and 13.9% were of uncertain appropriateness. Seven percent were rated as unclassified.

The most common instance of inappropriate testing was that done on asymptomatic, low-risk patients, accounting for 44.5% of all inappropriate SPECT myocardial perfusion imaging.

"If we could markedly reduce testing in low-risk patients, we could reduce imaging volume, radiation exposure, and unnecessary downstream tests and procedures by a large amount -- but we would be doing so selectively," Hendel said.

The cost implications for cutting the wasteful use of SPECT perfusion imaging are huge, he said.

Inappropriate testing varied widely, from 4% to 22%, among the imaging facilities. At the worst performing practice, inappropriate use of SPECT-MPI was reduced from 22% to 13% after physician education and feedback, Hendel said. Other practices maintained a consistently low rate of inappropriate use after training.

The investigators determined that cardiologists were less likely to order inappropriate SPECT perfusion than were primary care physicians. About one of four referrals for a perfusion study from noncardiologists from outside the participating cardiac imaging practices was considered inappropriate, compared with about 13% for cardiologists within the practice.

The study demonstrates the feasibility of measuring appropriateness of cardiac imaging, evaluating test ordering, and educating physicians about how to improve their performance, according to Hendel.

"This is all about quality, not about an indiscriminate reduction in value," he said.

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