Length measurements of the aorta after endovascular abdominal aortic aneurysm repair

Abstract

Background: successful endovascular repair of abdominal aortic aneurysms (AAA) generally leads to a decrease in aneurysm size. Theoretically, this may lead to foreshortening of the excluded segment. If so, vertically rigid endografts may dislocate over time and cover renal or hypogastric arteries. Aim: to assess length changes of the infrarenal aorta after endovascular AAA exclusion. Patients and methods: forty-four consecutive patients were scheduled for the EndoVascular Technologies® endograft, a vertically non-rigid prosthesis which would potentially accommodate longitudinal changes. Twenty-four patients had completed at least 6 months of follow-up. In 18/24 patients a decrease in size was established by aneurysm volume measurements at 6 months' follow-up. Helical computer tomography (CT) angiograms were processed on a workstation. Aortic lengths were measured along the central lumen line from the lower renal artery orifice to the native aortic bifurcation. The computer tomography angiogram (CTA) reconstruction thickness of 2 mm yields at least a 4-mm error for each length measurement. Results: in the shrinking aneurysm group, the median length change was 0 mm (range -9 mm to +4 mm) at 6 months' follow-up (n = 18) and also 0 mm (range -7 mm to +4 mm) at 12 months' follow-up (n = 10). In 16/18 patients, length changes remained within the measurement error range of 4 mm. Conclusion: in this group of shrinking aneurysms after endovascular AAA repair, foreshortening of the excluded aortic segment appears not to be a clinically significant problem.