Jitse H M Paping, Ruth M.A. Bulder, Elizabeth Lancaster, Robert W. Chang, Hein Putter, Jaap F. Hamming, J. Lindeman
BACKGROUND: Abdominal aortic aneurysm (AAA) management is currently dictated by the 55 mm intervention threshold. While it has been suggested that this intervention threshold is too conservative, the rupture risk of AAAs larger than 55 mm is discussed differently. This scoping review aims to critically summarize and review the available evidence with respect to the rupture risk of larger AAA. METHODS: A quantitative and qualitative evaluation of the available literature on the rupture risk of larger AAAs. RESULTS: The search strategy identified 20 original papers. Qualitative evaluation indicated a high degree of heterogeneity. It was further concluded that all, but one paper most likely overestimated the risk of rupture rate because they ignored interference caused by competing risks. Only the most recent and by far largest study applied the required competing risk analysis. It is estimated that the annual rupture rates for AAAs sized 55-59 mm or 60-69 mm equal 1.02% (95% confidence interval: 0.59-1.68%), respectively and 2.36% (1.32-3.89%) for men, and 1.44% (0.40-3.88)% and 6.84% (3.19-12.39)% for women, respectively. CONCLUSION: Except for one study, reports on the diameter-rupture risk relationship fail to address the common presence of competing risks for AAA rupture and therefore overestimate the rupture risk. The rupture risk of larger AAA may be lower than commonly assumed.