The overuse of CTA in the Emergency Department and the over-diagnosis of pulmonary emboli of non-physiologic significance has been demonstrated as a significant societal harm. In response to this, the National Quality Forum has been looking at developing a quality measure aimed at reducing CTA use in the Emergency Department.
The NQF estimated 7 to 25% of CTAs in the ED might be unnecessary. From Jeff Kline's shop at Carolinas, they prospectively gathered data on all their potential pulmonary emboli and attempted to determine which scans were "inappropriate." For their purposes, a scan was "inappropriate" if it was a low-risk patient with a negative D-dimer assay, or it was a low-risk patient without D-dimer testing. 11% were D-dimer negative and 22% were low-risk without D-dimer testing performed, which sums to 32% potentially avoidable imaging.
Of the 1,205 "potentially avoidable" scans, there were 58 positives. The clinical significance of these potential misses is uncertain. Whether this represents an acceptable miss rate for a quality measure in a liability prone environment is another matter entirely.
"Evaluation of Pulmonary Embolism in the Emergency Department and Consistency With a National Quality Measure"