Recent studies demonstrate that patients with a shrinking abdominal aortic aneurysm (AAA), one-year after endovascular repair (EVAR), have better long-term outcomes than patients with a stable AAA. It is not known what factors determine whether an AAA will shrink or not. In this study, a range of parameters was investigated to identify their use in differentiating patients that will develop a shrinking AAA from those with a stable AAA one-year after EVAR. Hundred-seventy-four patients (67 shrinking AAA, 107 stable AAA) who underwent elective, infrarenal EVAR were enrolled between 2011-2018. Long-term survival was significantly better in patients with a shrinking AAA, compared to those with a stable AAA (p = 0.038). Larger preoperative maximum AAA diameter was associated with an increased likelihood of developing AAA shrinkage one-year after EVAR-whereas older age and larger preoperative infrarenal β angle were associated with a reduced likelihood of AAA shrinkage. However, this multivariate logistic regression model was only able to correctly identify 66.7% of patients with AAA shrinkage from the total cohort. This is not sufficient for implementation in clinical care, and therefore future research is recommended to dive deeper into AAA anatomy, and explore potential predictors using artificial intelligence and radiomics.
Keywords: AAA; EVAR; prediction; regression; remodeling; shrinkage.