Study in The Netherlands Evaluates Risks of EVAR in Large-Diameter Necks

January 18, 2017—In order to determine the impact of infrarenal neck diameter on midterm outcomes following endovascular aneurysm repair (EVAR) with a single stent graft with suprarenal fixation, Nelson F.G. Oliveira, MD, et al conducted a retrospective study, with the findings available online ahead of print in Journal of Vascular Surgery (JVS).

The background of the study is that EVAR has progressively expanded to treat more challenging anatomies; however, in patients with wide infrarenal necks, EVAR has been reported with acceptable results, but there is still controversy regarding the longer-term outcomes.

The investigators concluded that EVAR in patients with large-diameter necks is associated with an increased risk of neck-related adverse events at midterm follow-up. They suggested that this may influence the clinical decision regarding choice of repair and toward a more intensive surveillance following EVAR in these patients in the long-term.

The investigators designed a retrospective case-control study using data from a prospective multicenter database. The study was composed of 427 patients who electively underwent standard EVAR with an Endurant stent graft (Medtronic) for a degenerative abdominal aortic aneurysm from January 2008 to December 2012 in three high-volume centers in The Netherlands. 

As summarized in JVS, all measurements were obtained using dedicated reconstruction software and center lumen line reconstruction. Patients with an infrarenal neck diameter of ≥ 30 mm were compared with patients with a neck diameter of < 30 mm. The primary endpoint was freedom from neck-related adverse events (a composite of type Ia endoleak, neck-related secondary intervention, and endograft migration). Secondary endpoints were primary clinical success, type Ia endoleak, neck-related reinterventions, endoleaks, and aneurysm-related secondary interventions.

Of the 427 patients, 74 patients (17.3%) with a neck diameter of ≥ 30 mm were compared with a control group of 353 patients. There were no significant differences at baseline between the groups in terms of demographics, comorbidities, baseline aneurysm diameter, infrarenal neck length, suprarenal angulation, or infrarenal neck angulation.

Median stent graft oversizing was 12.5% (7.9%–16.1%) and 16.6% (12%–23.1%) in the ≥ 30-mm neck-diameter and control groups, respectively (P < .001). Median follow-up was 3.1 years (1.2–4.7 years) and 4.1 years (2.7–5.6 years) for the large-neck and control groups, respectively (P < .001). Type Ia endoleaks occurred in 17 patients (4%) and were significantly more frequent in patients with ≥ 30-mm neck diameters (9.5% vs 2.8%; P = .005).

Neck-related secondary interventions were performed in 20 patients (4.7%) and were also more common among patients with neck diameters ≥ 30 mm (9.5% vs 3.7%; P = .04). The 4-year freedom from neck-related adverse events were 75% and 95% for the large-neck and control groups, respectively (P < .001).

On multivariable regression analysis, infrarenal neck diameter ≥ 30 mm was an independent risk factor for neck-related adverse events (odds ratio [OR], 3.8; 95% confidence interval [CI], 1.6–9.1), type Ia endoleak (OR, 2.7; 95% CI, 1.0–8.3), and neck-related secondary interventions (OR, 3.2; 95% CI, 1.1–9.2), reported the investigators in JVS.