Identifying high risk for proximal endograft failure after endovascular aneurysm repair in patients suitable for both open and endovascular elective aneurysm repair

OBJECTIVE: Proximal endograft failure (type Ia endoleak or migration) after endovascular aneurysm repair (EVAR) is associated with hostile aneurysm neck morphology. Neck scoring systems were developed to predict proximal endograft failure but were studied in retrospective studies, which, due to selection bias, may have led to an overestimation of bad outcomes after EVAR. To predict patients who benefit from open repair, preoperative neck morphology and occurrence of long-term proximal endograft failure were investigated in patients enrolled in the endovascular arm of the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial who were suitable for open repair by definition and have long-term follow-up. METHODS: A post-hoc on-treatment analysis of patients after EVAR was performed in 171 patients. Aneurysm neck morphology was quantified using the aneurysm severity grading (ASG) neck score calculated on preoperative computed tomography angiography images. The ASG neck score was used to predict proximal endograft failure. Receiver operating characteristic analysis was performed to calculate a threshold to divide favorable and unfavorable aneurysm necks (low and high risk); positive and negative likelihood-ratios were calculated accordingly. Freedom from proximal endograft failure was compared between groups using Kaplan-Meier analysis. RESULTS: During a median follow-up of 7.6 years, 20 patients suffered proximal endograft failure. Receiver operating characteristic analysis showed an area under the curve of 0.77 (95% confidence interval [CI], 0.65-0.90; P < .001), indicating acceptable prediction. The threshold was determined at ASG neck score ≥5; 30 patients had unfavorable neck morphology, of whom 11 developed proximal endograft failure. The positive likelihood-ratio was 4.4 (95% CI, 2.5-7.8), and the negative likelihood-ratio was 0.51 (95% CI, 0.3-0.8). Twelve years postoperatively, freedom from proximal endograft failure was 91.7% in the favorable group and 53.2% in the unfavorable group, a difference of 38.5% (95% CI, 13.9-63.1; P < .001). CONCLUSIONS: In this study, the ASG neck score predicted proximal endograft failure during the entire follow-up. This exhibits the persistent risk for proximal endograft failure long after EVAR and calls for ongoing surveillance especially in patients with unfavorable aneurysm necks.