Gaps in preoperative surveillance and rupture of abdominal aortic aneurysms among Medicare beneficiaries

Objective Screening and surveillance are recommended in the management of small abdominal aortic aneurysms (AAAs). Gaps in surveillance after early diagnosis may lead to unrecognized AAA growth, rupture, and death. This study investigates the frequency and predictors of rupture of previously diagnosed AAAs. Methods Data were extracted from Medicare claims for patients who underwent AAA repair between 2006 and 2009. Relevant preoperative abdominal imaging exams were tabulated up to 5 years prior to AAA repair. Repair for ruptured AAAs was compared with repair for intact AAAs for those with an early diagnosis of an AAA, defined as having received imaging at least 6 months prior to surgery. Gaps in surveillance were defined as no image within 1 year of surgery or no imaging for more than a 2-year time span after the initial image. Logistic regression was used to examine independent predictors of rupture despite early diagnosis. Results A total of 9298 patients had repair after early diagnosis, with rupture occurring in 441 (4.7%). Those with ruptured AAAs were older (80.2 ± 6.9 vs 77.6 ± 6.2 years; P <.001), received fewer images prior to repair (5.7 ± 4.1 vs 6.5 ± 3.5; P =.001), were less likely to be treated in a high-volume hospital (45.4% vs 59.5%; P <.001), and were more likely to have had gaps in surveillance (47.4% vs 11.8%; P <.001) compared with those receiving repair for intact AAAs. After adjusting for medical comorbidities, gaps in surveillance remained the largest predictor of rupture in a multivariate analysis (odds ratio, 5.82; 95% confidence interval, 4.64-7.31; P <.001). Conclusions Despite previous diagnosis of AAA, many patients experience rupture prior to repair. Improved mechanisms for surveillance are needed to prevent rupture and ensure timely repair for patients with AAAs.