Screening Chest Computed Tomography is Indicated in All Patients with Abdominal Aortic Aneurysm

Background: This study quantifies the prevalence of thoracic aortic aneurysm (TAA) in patients with known abdominal aortic aneurysm (AAA). Methods: A retrospective review of patients with a diagnosis of AAA from January 2007 to December 2017 within Beaumont Health was undertaken. Radiology reports of abdominal ultrasound, computed tomography (CT), and magnetic resonance imaging were reviewed to identify patients with AAA. Of these, patients with a chest CT scan performed within 180 days before or after abdominal imaging were reviewed for diagnosis of TAA. AAA was defined as aortic diameter >= 30 mm, and TAA was defined as aortic diameter >= 40 mm. Results: The cohort included 218 patients with a chest CT scan performed within 180 days of initial diagnosis of AAA. The mean age at diagnosis of AAA was 74 years; 82 (37.6%) were women. There were no differences between men and women in the prevalence of diabetes mellitus, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, tobacco use, and family history of aortic aneurysm. Forty concomitant AAAs and TAAs were detected, for an overall prevalence of 18.3%, with no significant difference between men and women (15% vs. 24%, P = 0.07). Women were diagnosed with AAA at an older age than men (76 vs. 73 years, P = 0.01) and had lower body mass index (23 vs. 26, P = 0.01), smaller maximum AAA diameter (36.5 vs. 40 mm, P = 0.03), and larger TAA (47 vs. 41 mm, P = 0.01). TAAs were classified by location: 47.5% (19/40), ascending; 32.5% (13/40), descending; and 20% (8/40), ascending and descending. Six patients had thoracoabdominal aortic aneurysms: 2 patients with extent II, 2 with extent III, and 2 with extent V. These patients were included in the overall analysis; excluding them resulted in a rate of concomitant AAA/TAA of 16%. No significant differences were noted in comorbidities or AAA size between the TAA/AAA and AAA only groups. Conclusions: TAAs appear to occur concomitantly with AAAs with significant frequency. Women appear to have larger TAA diameter than men, despite smaller sized AAA at diagnosis. These data support creating guidelines for obtaining a screening chest CT scan in all patients diagnosed with an AAA.