Incidence and Predictors of Repeated Computed Tomographic Pulmonary Angiography in Emergency Department Patients
Received 23 April 2008; received in revised form 30 June 2008 and 5 August 2008; accepted 14 August 2008. published online 06 October 2008.
Refers to article:
Chest Computed Tomography in the Emergency Department for Suspected Pulmonary Embolism: It's Time to Practice What We Preach
, 22 January 2009
Gregory Piazza, Samuel Z. Goldhaber
Annals of Emergency Medicine
July 2009 (Vol. 54, Issue 1, Pages 49-52) Full Text |
Full-Text PDF (138 KB)
Study objective
Use of contrast-enhanced computed tomography (CT) of the pulmonary arteries to evaluate for pulmonary embolism has increased, raising concern about radiation and contrast toxicity. We sought to measure the frequency of repeat CT pulmonary angiography in emergency department (ED) patients.
Methods
This was a prospective, longitudinal follow-up of ED patients who underwent first-time CT pulmonary angiography as part of a research protocol for diagnosis of pulmonary embolism in 2001 to 2002. Two authors (DMB and MCK) searched electronic medical record databases to measure the frequency of repeated CT scans performed within 5 years. Primary outcome was greater than or equal to 1 repeated CT pulmonary angiography examination. Radiologist-written interpretations of CT pulmonary angiography were categorized by 2 observers (DMB and JAK). Cox regression was used to estimate hazard ratios for 24 clinical variables.
Results
A cohort of 675 ED patients was observed for a median of 1,989 days: 226 of 675 (33%) had at least 1 additional CT pulmonary angiography scan, and 60 died with no repeated CT pulmonary angiography, leading to a mortality-adjusted frequency of repeated CT pulmonary angiography scanning of 226 of 615, or 37%. Seventy-three percent of the cohort had 1 or more subsequent CT scans of any body part, and 31 patients (5%) had 5 or more repeated CT pulmonary angiography scans. The pulmonary embolism (positive) prevalence was 57 of 675 (8.4%; 95% confidence interval [CI] 6.5% to 10.8%) on the first CT pulmonary angiography versus 8 of 226 (3.5%; 95% CI 1.5% to 6.9%) on the second CT pulmonary angiography scan. Hazard ratios indicated that respiratory rate, active malignancy, previous coronary artery disease, and previous or new diagnosis of venous thromboembolism were positively associated with repeated CT pulmonary angiography scanning.
Conclusion
At least one third of ED patients who undergo CT pulmonary angiography scanning will have a second CT pulmonary angiography result that will be negative for pulmonary embolism. New methods are needed to exclude pulmonary embolism recurrence without use of ionizing radiation.
aDepartment of Emergency Medicine, Carolinas Medical Center, Charlotte, NC
bDepartment of Emergency Medicine, Northwestern Memorial Hospital, Feinberg School of Medicine, Chicago, IL
Address for reprints: Jeffrey A. Kline, MD, Emergency Medicine Research, Department of Emergency Medicine, Carolinas Medical Center, PO Box 32861, Charlotte, NC 28323-2861; 704-355-7092, fax 704-355-7047
Author contributions: JAK conceived the work, obtained funding, supervised the project, performed database queries, contributed to the primary analyses, and wrote the article. DMC performed the statistical and graphic analyses and edited the article. DMB, MCK, and MS performed database queries, data entry, and assisted with article production. JAK takes responsibility for the paper as a whole.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. JAK is inventor on US patent numbers 6,575,918; 6,881,193; 7,104,964. JAK owns stock in a company involved in developing a medical device referenced herein.
Publication date: Available online October 5, 2008.
ABSTRACT