Grant: Operating Grant

An abdominal aortic aneurysm (AAA) is a dilatation of the aorta more than 50% of its original diameter. AAAs can rupture, with a case-fatality rate of approximately 75%. Rupture risk increases as maximum aneurysm diameter increases. Regular monitoring of AAAs is required to determine if and when their diameter exceeds 5.5 cm, at which time surgical repair is recommended. AAAs are identified in ~5% of abdominal imaging studies and frequently are incidental findings. The probability that incidental AAAs receive ongoing monitoring and their outcomes is unknown. This study will include a random sample of more than a thousand patients at the Ottawa Hospital with an incidental AAA identified at abdominal imaging (with computed tomography, magnetic resonance imaging, or ultrasound) between 1996 and 2008. Imaging reports will be reviewed to confirm the incidental status of the AAA and to determine its size. This dataset will be linked to population-based administrative datasets to determine which patients underwent appropriate monitoring with subsequent abdominal imaging. Factors influencing appropriate monitoring will be explored. Outcomes (elective AAA repair; admission to hospital for ruptured AAA; and all-cause mortality) will be compared between those with and without appropriate monitoring. This study will determine whether interventions are necessary to ensure that incidental AAAs are properly monitored.