A retrospective application of the pulmonary embolism rule out criteria (PERC) of the American College of Physicians would reduce the number of CTPAS by 6% without a false negative in an Irish hospital.

Abstract

Internationally, the number of computerised tomographic pulmonary angiographies (CTPAs) being performed to rule out pulmonary embolism (PE) has caused some concern. This study was performed to assess if the application of Pulmonary Embolism Rule-out Criteria (PERC) in an Irish Emergency Department (ED) would have helped to safely reduce the number of D-dimer assays and computed tomographic pulmonary angiographies (CTPAs) ordered. The PERC was retrospectively calculated in all patients who underwent CTPA for possible PE. It was then established if the application of the PERC as per the American College of Physicians' (ACP) guidelines would have safely ruled out the need for further imaging. Of the 529 patients who underwent CTPA in the study, 63 patients (12%) had PE on CTPA. Had the PERC criteria been applied, no patient who had a PE would have been missed. In this study, PERC had 100% sensitivity and 14% specificity. Application of the PERC rule, as per the ACP guidelines, would have reduced the number of CTPAs performed by 32 (6%) without missing any patient with a proven pulmonary embolus.