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Radiographic monitoring of incidental abdominal aortic aneurysms: a retrospective population-based cohort


Background — An abdominal aortic aneurysm (AAA) that is identified when the abdomen is imaged for some other reason is known as an incidental AAA. No population-based studies have assessed the management of incidental AAAs. The objective of this study was to measure the completeness of radiographic monitoring of incidental AAAs by means of a population-based analysis.

Method — Linked a cohort of patients with incidental AAA (defined as a previously unidentified aortic enlargement exceeding 30 mm in diameter found in an imaging study performed for another reason) to various population-based databases. Followed the patients to elective repair or rupture of the aneurysm, death or March 31, 2009. Used evidence-based monitoring guidelines to calculate the proportion of observation time during which each incidental AAA was incompletely monitored, and used negative binomial regression to determine the association of patient-related factors with this outcome.

Results — For the period between January 1996 and September 2008, 191 patients were identified with incidental AAA (mean diameter 37.6 mm, 95% confidence interval [CI] 36.6–38.6 mm; median follow-up 4.4 [range 0.6–12.7] years). Fifty-six of these patients (29.3%) had no radiographic monitoring of the aneurysm. Overall, patients spent one-fifth of their time with incomplete monitoring of the AAA (median 19.4%, interquartile range 0.3%–44.0%). Factors independently associated with incomplete monitoring included older age (relative rate [change in proportion of time with incomplete monitoring] [RR] 1.27, 95% CI 1.10–1.47, per decade), larger size (RR 1.65, 95% CI 1.38–2.01, per 10 mm increase) and detection of the aneurysm while the patient was in hospital or the emergency department (RR 1.34, 95% CI 1.00–1.79). Comorbidities were not associated with monitoring.

Interpretation — Radiographic monitoring of incidental AAAs was incomplete, and almost one-third of patients underwent no monitoring at all. Incomplete monitoring did not appear to be related to patients' comorbidity.



van Walraven C, Wong J, Morant K, Jennings A, Austin PC, Forster AJ. Open Med. 2011; 5(2):e67-76. Epub 2011 Apr 12.

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