Abdominal Aortic Aneurysm Screening Study

This study was approved by the University of California, San Francisco (UCSF) Institutional Review Board (18–26351). Patients ≥ 55 years of age were recruited at the UCSF Vascular Surgery outpatient clinics and vascular laboratories between January 2019 and 2020. All patients who underwent screening or surveillance imaging for AAA during this time were reviewed for possible study participation based on the inclusion and exclusion criteria stated below [4 (link)]. Cases were defined as patients with a maximum infrarenal abdominal aorta diameter of ≥ 3 cm on US or computed tomography (CT). Controls, or patients without aneurysms, were defined as having a maximum infrarenal abdominal aorta diameter of < 3 cm on US or CT. Patients were excluded from participating if they had severe hepatic (Child-Pugh ≥ B) or renal (creatinine ≥ 2 mg/dL) dysfunction, a non-vascular inflammatory disease, a severe acute illness or surgery within 30 days, or were taking immunosuppressive medications or steroids (Table 1). The inclusion and exclusion criteria were selected with the goal of reducing the possible influence of acute and chronic diseases that may directly affect circulating miRNA patterns, with a focus on diseases associated with changes in systemic inflammation.