Impact of suprarenal neck angulation on endovascular aneurysm repair outcomes

Background: Hostile infrarenal proximal neck (β) anatomy of abdominal aortic aneurysm has been associated with increased risk of aneurysm-related complications after endovascular aneurysm repair (EVAR). However, there is a paucity of literature addressing the suprarenal angle (α). The aim of this study was to evaluate short- and long-term outcomes after EVAR in patients with severe suprarenal neck angulation (α >60 degrees).

Methods: A retrospective review of the medical records of 561 patients who underwent EVAR between January 2005 and December 2017 was performed. The main exclusion criteria were preoperative aneurysm rupture and fenestrated or branched endograft placement. High-resolution computed tomography images of 452 patients were available. Patients were grouped into angulated (α >60 degrees) and nonangulated (α ≤60 degrees) groups. The primary end point was freedom from type IA endoleak. Secondary end points included 30-day mortality, long-term survival, primary clinical success, and freedom from aneurysm rupture and graft migration. Primary clinical success was defined according to Society for Vascular Surgery guidelines as clinical success without the need for an additional or secondary surgical or endovascular procedure.

Results: Of 452 patients, 45 (10%) were included in the angulated group (α >60 degrees). Median follow-up time was 34 months (interquartile range, 14-56 months). Compared with patients in the nonangulated group, those in the angulated group had larger neck diameter at the level of the renal arteries (mean [standard deviation], 25.6 [3.8] mm vs 24.6 [3.4] mm; P = .06) and increased β angle (mean [standard deviation], 50.5 [22.9] degrees vs 41.6 [23.9] degrees; P = .01). The 3-year freedom from type IA endoleak estimate was 80.2% for the angulated group compared with 97.8% for the nonangulated group (P < .001). The angulated group showed significantly higher 30-day mortality (11.1% vs 0.25%; P < .001).The 3-year results showed that patients in the nonangulated group had higher rates of primary clinical success (90.2% vs 67.1%; P < .001), freedom from rupture (99% vs 97.1%; P = .02), freedom from migration (100% vs 92.4%; P < .001), and long-term survival (91.6% vs 75.8%; P = .006) compared with those in the angulated group. After adjustment for age, sex, neck diameter, and β angle, severe suprarenal neck angulation was associated with higher odds of type IA endoleak (adjusted hazard ratio, 8.9; 95% confidence interval [CI], 2.9-27), loss of primary clinical success (adjusted hazard ratio, 4.8; 95% CI, 2.6-8.9), and 30-day mortality (adjusted odds ratio, 52.5; 95% CI, 5.3-514) compared with α ≤60 degrees (all P < .001).

Conclusions: This is the first report to show a significant increase in operative mortality in patients undergoing EVAR with severely angulated suprarenal neck. Patients who survive the operation are at increased risk of secondary interventions. These findings suggest that EVAR should be used with caution in patients with severe α angulation and underpin the role of close follow-up in this particular population.