EVAR Outcomes in Patients With Large Neck Diameters Studied

October 4, 2018—Patients with abdominal aortic aneurysm (AAA) with large neck diameters have a higher risk of type Ia endoleaks and aneurysm rupture after standard endovascular aneurysm repair (EVAR), according to a study published online by Nelson F.G. Oliveira, MD, et al in Journal of Vascular Surgery (JVS). The study investigated the outcomes of EVAR in patients with neck diameters ≥ 30 mm in the prospectively maintained Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE).

This retrospective study compared patients with neck diameters ≥ 30 mm with patients with neck diameters < 30 mm. The primary endpoint was type Ia endoleak (EL1A). Secondary endpoints included secondary interventions to correct EL1A, aneurysm rupture, and survival.

As summarized in JVS, the study included 1,257 patients (mean age, 73.1 years; 89.4% men) observed for a median of 4.0 years (interquartile range, 2.7–4.8 years). A total of 97 (7.7%) patients had infrarenal neck diameters ≥ 30 mm and were compared with the remaining 1,160 (92.3%) patients with neck diameters < 30 mm.

At baseline, there were no differences between groups regarding demographics and comorbidities other than cardiac disease, which was more frequent in the ≥ 30-mm neck diameter group (P = .037). There were no significant differences between the groups regarding neck length, angulation, thrombus, or calcification. Mean preoperative AAA diameter was 64.6 ± 11.3 mm in the ≥ 30-mm neck diameter group and 60.0 ± 11.6 mm in the < 30-mm neck diameter group (P < .001).

Stent graft oversizing was significantly less in the ≥ 30-mm neck diameter group (12.2% ± 8.9% vs 22.1% ± 11.9%; P <. 001).

The investigators found that five (5.2%) patients in the ≥ 30-mm neck diameter group and 30 (2.6%) patients with neck diameters < 30 mm developed EL1A, yielding a 4-year freedom from EL1A of 92.4% versus 96.6%, respectively (P = .09).

Oversizing was 21.8% ± 13.0% for patients developing EL1A and 21.3% ± 12.4% for the remaining cohort (P = .99).

In adjusting for neck length, AAA diameter, and device oversizing, patients with neck diameter ≥ 30 mm were at greater risk for development of EL1A (hazard ratio [HR], 3.0; 95% confidence interval [CI], 1.0–9.3; P = .05). Secondary interventions due to EL1A did not differ between groups (P = .36).

AAA rupture occurred in three patients with neck diameter ≥ 30 mm (3.1%) and in eight patients with neck diameter < 30 mm (0.7%; HR, 5.1; 95% CI, 1.4–19.2; P = .016); two cases were EL1A related in each group.

At 4 years, overall survival was 61.6% for the ≥ 30-mm neck diameter group and 75.2% for the < 30-mm neck diameter group (P = .009), which remained significant on correcting for sex and AAA diameter (P = .016).

"In this study, patients with infrarenal neck diameter ≥ 30 mm had a threefold increased risk of EL1A and fivefold risk of aneurysm rupture after EVAR as well as worse overall survival. This may influence the choice of AAA repair and underlines the need for regular computed tomography-based imaging surveillance in this subset of patients. Furthermore, these results can serve as standards with which new, possibly improved technology, such as EndoAnchors (Medtronic), can be compared," concluded the investigators in JVS.