Abstract 17206: Screening for Aortic Aneurysm Using Non-contrast Computed Tomography is Invalid Even in a High-risk Population: Asian Perspectives
Background: Efficacy of non-contrast computed tomography (CT) for screening of thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) is not well established. We studied prevalence of aortic aneurysm using non-contrast CT in a population of high incidence of cardiovascular disease at a tertiary referral hospital in Korea.
Methods: We prospectively enrolled consecutive 542 elderly male hypertensive patients (≥ 65 years old) without history of TAA or AAA from June 2012 to April 2013. After excluding 30 patients with suboptimal CT image, 512 patients comprised the study population. Maximal diameters of ascending and descending thoracic aorta and abdominal aorta were measured using non-contrast CT. Maximal diameter of aortic arch was reassured in sagittal plane using reconstructed images in patients with the aortic arch of 40 mm or over from the transverse plane.
Results: Mean diameters of maximal ascending thoracic aorta, descending thoracic and abdominal aorta were 38.5±4.0 mm, 28.5±3.0 mm, and 23.0±5.5 mm, respectively. TAA of 50 mm or greater and AAA of 40 mm or greater, which implies increased annual rupture risk, were seen only in a small portion of the patients (7 patients [1.3%] with TAA and 9 patients [1.6%] with AAA). One patient (0.2%) showed aortic arch of the diameter over 50 mm with AAA of the diameter over 40mm. Mean radiation dose to patients receiving CT for whole aorta was 7.0±5.3 mSv. Screening of 4302 and 1330 subjects is required to prevent 1 rupture of TAA and AAA respectively, when calculated on the basis of the previous reports of annual rupture risk, even though the current study was performed in a high-risk population.
Conclusion: The prevalence of clinically significant aortic aneurysm was considerably low, even in a high-risk population among Asian. Therefore, screening for whole aorta using non-contrast CT should be carefully applied due to the low prevalence of the disease and from the view point of cost-effectiveness and radiation hazard in Asian population.
- © 2013 by American Heart Association, Inc.