A systematic review of anatomic predictors of abdominal aortic aneurysm remodeling after endovascular repair

Objective: The long-term outcomes after endovascular abdominal aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs) have been inferior to those after open surgical repair with regard to reinterventions and late mortality. AAA sac remodeling after EVAR has been associated with endoleaks, reinterventions, and mortality. Therefore, knowledge of the predictors of AAA sac remodeling could indirectly give insight into the long-term EVAR outcomes. In the present review, we aimed to provide an overview of the evidence for anatomic predictors of positive and negative AAA sac remodeling after EVAR. Methods: A systematic literature review and analysis were conducted in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) and Cochrane guidelines. The PubMed and Scopus databases were searched using terms of AAA sac growth, shrinkage, and remodeling. Eligible studies were identified, and only those studies that had included currently used endografts were included. Results: A total of 19 studies that had reported on a total of 27 anatomic parameters of the aortoiliac anatomy were included. Only 4 parameters had been investigated by more than five studies, 7 parameters were investigated by three to five studies, 7 parameters were investigated by two studies, and 9 parameters were investigated by one study. For the presence of neck thrombus, three of four studies had reported similar results, indicating that the presence of neck thrombus might predict for less AAA sac shrinkage. AAA thrombus, the total AAA volume, the flow-lumen volume, aortic calcification, and the number of hostile neck parameters were only investigated by two to three studies. However, these parameters seemed promising for the prediction of sac remodeling. For hostile neck anatomy, neck length, infrarenal neck angulation, and patency of the inferior mesenteric artery, no significant association with any category of AAA sac remodeling was found. Conclusions: The present review demonstrates neck thrombus, AAA thrombus, number of hostile neck parameters, total AAA volume, AAA flow-lumen volume, and aortic calcification as important anatomic features that are likely to play a role in AAA remodeling after endovascular repair and should be further explored using advanced imaging techniques. We also found that strong, consistent evidence regarding the anatomic predictors of AAA sac remodeling after EVAR is lacking. Therefore, further research with large patient groups for a broad range of predictors of AAA sac change after EVAR is needed to complement the current gap in the evidence

Predictors of Abdominal Aortic Aneurysm Shrinkage after Endovascular Repair

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

Predictors of Abdominal Aortic Aneurysm Shrinkage after Endovascular Repair

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 radiomic