NATURAL-HISTORY OF THE RESIDUAL INFRARENAL AORTA AFTER INFRARENAL ABDOMINAL AORTIC-ANEURYSM REPAIR

Purpose: We determined the natural history of the residual native infr arenal aortic segment after conventional abdominal aortic aneurysm (AA A) repair. Methods: For the retrospective arteriographic case series, 800 hundred translumbar aortograms (TLAs) were obtained for 272 patien ts, before and after conventional AAA repair. The main outcome measure s were changes in the aortographic diameter and the length of the infr arenal aortic segment, corrected and uncorrected for magnification by normalization to the first lumbar vertebral body height. Results: The mean follow-up time from the preoperative TLA to the most recent post operative TLA was 42 months (range, 1 to 257 months). Vertebral body h eight did not change (p = 0.35). The length of the native infrarenal a orta cephalad to the proximal anastomosis increased a mean of 3 mm, fr om 23 to 26 mm (p = 0.001). However, in 115 patients (43%), this aorti c segment elongated more than 5 mm, and in 63 patients (24%), it elong ated more than 10 mm. The native residual infrarenal aorta above the p roximal anastomosis dilated a mean of 1 mm, from 23 to 24 mm (p = 0.00 1), but in 21 patients (8%), it dilated more than 5 mm. There was a we ak positive correlation between the increase in residual native aortic diameter and duration of follow-up. There was a negative correlation between this increase and the initial size. The diameters of the proxi mal anastomosis and proximal graft did not change. Marked variability in the changes in aortic dimensions was observed. Conclusions: A mean period of 42 months after conventional AAA repair, the native infraren al aortic segment elongates and dilates. Although such enlargement is statistically significant, the average increase appears to be small. H owever, residual aortic cuff diameter increased more than 5 mm and nec k length more than 10 mm in a significant number of patients, with pot entially serious implications for endovascular treatment of AAA.