Midterm changes in aortic aneurysm morphology after endovascular repair

Purpose: To study midterm changes in aortic aneurysm morphology after endov ascular aneurysm repair. Methods: Of 94 patients with abdominal aortic aneurysms (AAAs) treated with endografts between November 1993 and August 1998, 84 were available for fo llow-up. Patients were evaluated preoperatively by spiral computed tomograp hy (CT) and aortography; in followup, spiral CT scanning was performed at 1 , 3, and 6 months and semiannually thereafter. Measurements of the aneurysm neck diameter, maximum aneurysm diameter, and the distance from the lowerm ost renal artery to the aortic bifurcation were made preoperatively and in follow-up. Results: Mean follow-up was 17.5 +/- 1.1 months; 56 (67%) patients were fol lowed for 1 year and 28 (33%) for greater than or equal to 2 years. There w as a median 2-mm increase (interquartile range [IQR] 0 to 3) in neck diamet er at 18 months. However, a greater than or equal to 3-mm increase was seen in 18 (46%) of 39 patients examined at 18 months (median 4 mm, IQR 3 to 4, p = 0.0001). The maximum AAA diameter decreased by 9 mm (IQR 4 to 16, p = 0.0003) at 24 months, but after 18 months, no further interval decrease was seen. Aneurysms with a persistent endoleak showed either increasing or unc hanged AAA diameters. There was no change in the renal artery to bifurcatio n distance. Conclusions: The infrarenal aortic neck appears to dilate after AAA endogra fting, but only in a subset of patients. Shrinkage of aneurysms after succe ssful stent-grafting seems to stop after 18 months, implying that the only indication of late failure in the absence of endoleak might be aneurysm enl argement. Graft-related endoleaks are often associated with an increase in aneurysm diameter.