Do abdominal aortic aneurysm necks increase in size faster after endovascular than open repair?

Progression of aneurysmal disease in the aortic neck poses a threat to durable abdominal aortic aneurysm (AAA) repair. We tested the hypothesis that 2 years after AAA repair the size of the aortic neck increased more after endovascular (EVAR) than open repair.

For a subset of EVAR 1 trial patients, true outer-wall area at three levels of the aortic neck was measured using a Vitrea2 workstation, and rate of change over 2 years analysed.

The 67 EVAR patients and 56 open repair patients were well-matched, very similar to the total EVAR 1 cohort. The mean area change over 2 years at the superior mesenteric artery was small for both groups. However at the caudal renal artery (CRA), adjusted regression coefficient was 0.68 cm(2)/y greater after EVAR (p<0.001) and 0.77 cm(2)/y at a level 15 mm distal to it (p<0.001). The area at the CRA of 45 available post-procedure scans showed a large proportion of the increase had occurred by 3 months (mean 4.8 cm(2) to 5.9 cm(2) versus 6.7 cm(2) at 2 years).

The increase in aortic neck size was much greater 2 years after EVAR versus open repair. Further research is ongoing to establish whether the dilatation is progressive after stent-graft placement.