Post-EVAR aneurysm sac shrinkage is prognostically favorable, but does not justify withholding follow-up.

BACKGROUND: One of the main drawbacks of endovascular aortic aneurysm repair (EVAR) compared to open aortic surgery is the possibility of developing endoleaks and secondary aneurysm rupture, requiring frequent imaging follow-up. This study aims to identify prognostic factors that could be incorporated in follow-up protocols, which might lead to better personalized, lower cost and safe EVAR follow-up. METHODS: A retrospective study was performed including all patients who underwent elective EVAR from January 2000 to December 2015. Follow-up data were gathered by reviewing medical files for radiographic imaging. Linear and logistic regressions were used to assess predictive factors for aneurysm shrinkage. RESULTS: In 361 patients, aneurysm sac shrinkage of 10 millimeter or more was measured in 152 (42.1%) patients. Patients with ≥10mm aneurysm shrinkage had fewer endoleaks (4.3% vs 24.6%, p<0.0001) and fewer re-interventions for endoleak (3.0% vs 10.1%, p=0.007). Aneurysm sac shrinkage was correlated with the absence of endoleak development (OR 0.36, 95%CI 0.19-0.66, p=0.001). In patients who had achieved ≥10mm shrinkage of the aneurysm sac, no further significant growth was seen, compared to 38 (15.3%) patients who did not attain size reduction (p<0.001). CONCLUSIONS: Once patients achieve ≥10mm aneurysm sac shrinkage, they are less prone to developing subsequent aneurysm growth and have significantly lower risk of requiring surgery for endoleaks. However, a small number of patients remain at risk of requiring endoleak surgery after aneurysm shrinkage. Therefore, we would not recommend ceasing life-long imaging follow-up after significant aneurysm sac shrinkage, though it might be safe to increase the interval of follow-up.