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A3767 - Evaluation of CT Angiograms from the Hahnemann Emergency Room of CT Angiograms from the Hahnemann Emergency Room
Author Block: E. Randhawa1, M. Stephen2; 1Internal Medicine, Drexel University College of Medicine, Philadelphia, PA, United States, 2Pulmonary and Critical Care, Drexel University, Philadelphia, PA, United States.
Introduction: There are a high number of CT Angiograms (CTA) performed in the emergency department for suspicions of PE. Criteria such as PERC (Pulmonary Embolism Rule-out Criteria) and Wells score are used because of their negative predictive values. The implementations of these algorithms are inconsistent. As a result, many patients are unnecessarily exposed to the radiation and contrast of a CT scan. The purpose of this study is to assess the percentage of CTA which could have been avoided by the use of Wells score and PERC score in the Emergency Department. Methods: A retrospective chart review of 100 subjects who had a CTA for rule our pulmonary embolism in the Hahnemann University Hospital Emergency Room. Data was collected to calculate each subjects Wells and PERC score. The end point was if the CTA radiology read to see a PE diagnosis. Results: Of the 100 charts, 9 had a PE. 44 subjects were less than age of 50 and 55% were female. Of those with a PE, all 9 were PERC positive, 5 had D-dimers’ drawn and were all positive. The Wells scores for patients who had documented PE were one, five and three for low, moderate and high probability. The one subject with a low Wells score had their PE discovered incidentally. Out of the 91 subjects who did not have a PE, 20 were PERC negative of which 19 had a low Wells score. Of these 20 PERC negative, 17 had positive D-dimer, and 2 did not have a D-dimer drawn. Only 4 subjects of the 91 patients who ruled out for PE had a negative D-dimer. 37 subjects did not have a D-dimer drawn of which 21 were Low, 15 Moderate and 1 high Wells score. Conclusions: Of the total 100 subjects, 69 of 70 with a low Wells score and all 20 subjects who were PERC negative were not found to have a PE. Of the 91 who ruled out for PE by CTA, 20 were PERC negative. Of the remaining 71 who were PERC positive, fifty were low probability on Wells score. Combining the criteria of either PERC negative or low probability on Wells score yields a negative predictive value of 99% for ruling out pulmonary embolus. In this cohort, 70 CTA studies out of 100 would have been avoided using this criterion. D-dimer was frequently positive regardless of whether PE was shown on CTA.