Estimating the Rupture Risk of Large Abdominal Aortic Aneurysms

ObjectivesDetermining the rupture risk of large abdominal aortic aneurysms (AAA) through clinical studies remains elusive. We sought to employ computational methods on existing literature data and briefly report on stratified rupture risk of large AAAs. MethodsWe reviewed published English-language literature reporting on rupture risk of large AAAs. Analysis of rupture risk was performed on Microsoft Excel and Visual Basic scripting. Outcome of interest was annual rupture probabilities stratified by aneurysm size (range 5.0/5.5 - 10.0 cm in women/men) and patient sex. Uncertainty in rupture probabilities was considered through probability distributions. ResultsFor aneurysms sized 5.5 - 7.0 cm, estimated annual rupture probabilities in women were much higher than literature-reported estimates in men, ranging from 6.4% (95% confidence interval: 3.5% - 10.1%) to 54.5% (95% confidence interval: 39.3% - 69.3%). For aneurysms sized 7.5 cm, estimated annual rupture probabilities were 32.4% (95% confidence interval: 26.1% - 39.0%) in men and 64.8% (95% confidence interval: 51.3% - 77.1%) in women. For aneurysms sized 10.0 cm, estimated rupture probabilities increased to near-certainty at 96.6% (95% confidence interval: 94.0% - 98.5%) in men and 98.8% (95% confidence interval: 96.8% - 99.9%) in women. ConclusionComputational analysis of existing data is feasible to estimate stratified rupture probabilities of large AAAs, based on aneurysm size and patient sex. Further clinical studies are needed to obtain more precise estimates of rupture probabilities.