Prognostic Value of Initial Aneurysmal Sac Regression after EVAR

The objective of the study was to evaluate the impact of initial aneurysmal sac reduction after endovascular aneurysm repair on the evolution of aneurysmal sac over follow-up.

A retrospective cohort study was made of patients subjected to elective treatment between January 2005 and December 2014, with a minimum follow-up of 18 months. An analysis was made of the evolution of the aneurysmal sac according to its condition one year after surgery, defining of two groups: A (sac reduction) and B (stable sac). Follow-up by computed tomography (CT) angiography was made after one month and then every 6 months or annually, depending on the presence of endoleak.

A total of 128 patients were included. Fifty-one patients (39.8%) showed a significant decrease in diameter during the first year (group A), whereas 77 patients (60.2%) showed no initial decrease (group B). Preoperative CT angiography showed the patients in group A to have larger aneurysms (63.5 mm vs. 59.25; P = 0.048), a greater presence of posterior thrombus (68.6% vs. 30.7%; P < 0.001), and fewer patent lumbar vessels (56.9% vs. 83.1%; P = 0.001). The prevalence of endoleak at some point during follow-up was lower in group A (31.4% vs. 74% in group B; P < 0.001), and 100% of all aneurysmal growths were associated to the presence of endoleak. After 5 years, significant differences were observed in the growth-free rate (96.9% in group A vs. 85.2% in group B; hazard ratio [HR] 4.8 [1.1-21.4; P = 0.036]) and in the reintervention-free rate (95,7% vs. 84.6%; HR 6.6 [0.8-52.4; P = 0.07]). No reoperation in group A was due to type II endoleak.

The aneurysmal sac can be expected to take a favorable course in those cases characterized by initial aneurysmal sac reduction. These findings may imply a change in the follow-up protocol, even in cases with type II endoleak.