Follow-Up of Aneurysm Neck Diameter after Endovascular Repair of Abdominal Aortic Aneurysms

Abstract

We assessed aneurysm neck diameter change after endovascular abdominal aortic aneurysm repair (EVAR) and its relationship to stent-graft diameter. Ninety-eight patients with abdominal aortic aneurysm who underwent EVAR were studied with multislice computed tomography following a standardized protocol. A preoperative study and immediate postoperative, 6-month, 1-year, and 2-year follow-up studies were performed. The aneurysm neck was measured from adventitia to adventitia, 6 mm below the lowermost renal artery, in planar images performed perpendicular to the vessel axis (real axial section). Baseline and follow-up neck diameters were compared with stent-graft diameters. For statistical analysis, a one-way analysis of variance with repeated measures was used. Pearson's correlation coefficient was used to examine the correlation between the change in neck diameter and stent-graft diameter. The average neck diameter was 22.38 mm (range 16-32.5) on the preoperative study and 23.35 mm (17-33.9) on the immediate postoperative, 24.35 mm (18.2-34.5) on the 6-month, 24.36 mm (18-34.5) on the 1-year, and 24.39 mm (17.8-35.7) on the 2-year follow-up. The mean device diameter was 24.08 mm (20-32). A significant increase in average neck diameter was found between the preoperative, immediate postoperative control, and 6-month control. There was no significant increase in the average neck diameter between the 6-month, 1-year, and 2-year follow-up. Baseline mean stent-graft oversizing was 1.7 mm, which decreased to -0.31 mm at latest follow-up. Dilation of the neck did not significantly exceed the endograft diameter in 83 cases (87.36%). An enlargement of the infrarenal aneurysm neck occurred during the first 6 months after EVAR. No significant variation in neck diameter occurred between the 6-month and 2-year follow-up visits. In the majority of cases, dilation of the aneurysm neck does not significantly exceed stent-graft diameter and, therefore, is possibly related to the presence of the endograft.