Appropriateness and utilization of cardiac CT: Implications for development of future criteria

Background: The cardiac CT (CCT) appropriateness criteria (AC) were jointly published by multiple societies to ensure effective utilization of CCT. We sought to determine how these criteria apply to CCT scans performed at a tertiary-care hospital. Methods and Results: Data were collected from medical records and interviews of 267 consecutive patients referred for CCT. Two physicians designated exam indication as appropriate, inappropriate, or uncertain as per AC, or "not known" if not listed in AC. CCT exam indication was appropriate in 47%, inappropriate in 9%, uncertain in 15%, and not known in 29%. The most common appropriate indication was evaluation of CAD in symptomatic patients with equivocal stress test, whereas the most common inappropriate referral was evaluation of asymptomatic patients with low pretest probability of CAD. Most exams (69%) were for evaluation of CAD, with the remaining exams performed to evaluate other elements of cardiac structure or function. Exams for these non-CAD indications were more likely to be appropriate and less likely to have an undetermined (uncertain or not known) level of appropriateness than those for CAD indications. There was no difference in exam appropriateness whether ordered by cardiologists or internists, but providers who completed training >25 years ago ordered fewer appropriate and more inappropriate exams than younger providers. Conclusions: In applying the AC to a large academic medical center, few CCT exams were inappropriate; however, many patients referred for CCT, particularly for evaluation of CAD, had an indication for which the level of appropriateness remained undetermined. Given the rapid adoption of CCT, these results emphasize the need to refine current criteria for appropriate utilization.