A Computerized Method for Measuring Computed Tomography Pulmonary Angiography Yield in the Emergency Department: Validation Study (Preprint)

Abstract

Background: Use of computed tomography pulmonary angiography (CTPA) in the assessment for pulmonary embolism (PE) has significantly increased over the past two decades. While this technology has improved the accuracy of radiologic testing for PE, CTPA also carries the risk of significant iatrogenic harm. Each CTPA carries a 14% risk of contrast induced nephropathy and a lifetime malignancy risk that can be as high as 2.76%. Appropriate use of CTPA can be estimated by monitoring CTPA yield, the percentage of tests positive for PE. This is the first study to propose and validate a computerized method for measuring CTPA yield in the ED.

Predictors of Overtesting in Pulmonary Embolism Diagnosis

“…As was previously validated, CTPA yield was calculated as the number of ED CTPA orders linked to an inpatient discharge diagnosis of PE divided by the total number CTPAs completed (18). Our validation study found 96.4% accuracy using this method which utilizes EHR reports and not billing data.…”

“…In the rare, but potentially growing, number of cases in which a patient is diagnosed with PE, but discharged directly from the ED, our methodology would lead us to interpret this situation as a negative CTPA, falsely decreasing CTPA yield. This was a rare occurrence however in our validation study (44). Additionally, in the rare case that a provider orders a CTPA as well as a CTA abdomen/pelvis to evaluate for both PE and aortic disease the study would be eliminated.…”