Identifying Patients at High Risk for Post-EVAR Aneurysm Sac Growth.

Purpose: Post-EVAR (endovascular aneurysm repair) aneurysm sac growth can be seen as therapy failure as it is a risk factor for post-EVAR aneurysm rupture. This study sought to identify preoperative patient predictors for developing post-EVAR aneurysm sac growth.

Material and methods: A systematic review was conducted to select potential predictive preoperative factors for post-EVAR sac growth (including a total of 34.886 patients), which were evaluated by a retrospective single-center analysis of patients undergoing EVAR between 2009 and 2019 (N=247) with pre-EVAR computed tomography scans and at least 1 year follow-up. The primary study outcome was post-EVAR abdominal aortic aneurysm (AAA) sac enlargement (≥5 mm diameter increase). Multivariate Cox regression and Kaplan-Meier survival curves were constructed.

Results: Potential correlative factors for post-EVAR sac growth included in the cohort analysis were age, sex, anticoagulants, antiplatelets, renal insufficiency, anemia, low thrombocyte count, pulmonary comorbidities, aneurysm diameter, neck diameter, neck angle, neck length, configuration of intraluminal thrombus, common iliac artery diameter, the number of patent lumbar arteries, and a patent inferior mesenteric artery. Multivariate analysis showed that infrarenal neck angulation (hazard ratio, 1.014; confidence interval (CI), 1.001-1.026; p=0.034) and the number of patent lumbar arteries (hazard ratio, 1.340; CI, 1.131-1.588; p<0.001) were associated with post-EVAR growth. Difference in estimated freedom from post-EVAR sac growth for patients with ≥4 patent lumbar arteries versus <4 patent lumbar arteries became clear after 2 years: 88.5% versus 100%, respectively (p<0.001). Of note, 31% of the patients (n=51) with ≥4 patent lumbar arteries (n=167) developed post-EVAR sac growth. In our cohort, the median maximum AAA diameter was 57 mm (interquartile range [IQR] = 54-62) and the median postoperative follow-up time was 54 months (IQR = 34-79). In all, 23% (n=57) of the patients suffered from post-EVAR growth. The median time for post-EVAR growth was 37 months (IQR = 24-63). In 46 of the 57 post-EVAR growth cases (81%), an endoleak was observed; 2.4% (n=6) of the patients suffered from post-EVAR rupture. The total mortality in the cohort was 24% (n=60); 4% (n=10) was AAA related.

Conclusions: This study showed that having 4 or more patent lumbar arteries is an important predictive factor for postoperative sac growth in patients undergoing EVAR.

Clinical impact: This study strongly suggests that having 4 or more patent lumbar arteries should be included in preoperative counseling for EVAR, in conjunction to the instructions for use (IFU).