Adverse events at the aneurysmal neck identified at follow-up after endovascular abdominal aortic aneursym repair: how do they correlate?

The objective of this study was to assess the prevalence of and the correlation between dilatation of the infrarenal neck and proximal device migration after endovascular abdominal aortic aneurysm repair (EVAR). The analysis made use of the EUROSTAR registry. Between 1994 and 2004, 4,233 patients with an abdominal aortic aneurysm larger than 4 cm underwent EVAR. Only patients with available follow-up data regarding neck size and device position were included in this assessment. Chi-square and t-tests or Wilcoxon rank sum tests were used for comparison of discrete and continuous variables, respectively. Time-dependent variables were evaluated by log-rank tests. In addition, multivariate analysis was performed to determine anatomic and operative variables with an independent correlation with neck growth and device migration, respectively. In addition, the association with proximal endoleak was assessed. Neck dilatation and proximal migration were found in 1,342 (32%) and 192 (4.5%) of the 4,233 patients, respectively. One hundred twelve patients (2.5%) had neck dilatation and migration of the proximal device extremity. The correlation between proximal migration and neck dilatation was statistically significant (p < .0001). Other independent variables for migration were a wider neck and aneurysmal diameter, shorter necks, proximal endoleak, and absence of suprarenal fixation. Neck dilatation was predicted by narrow necks, use of devices with suprarenal fixation, and larger device diameters. Proximal endoleak occurred in 136 (3.2%) patients and was significantly associated with shorter, angulated necks and proximal migration. The present study documented that migration may be caused by neck dilatation. However, neck dilatation was not significantly promoted by proximal migration. Other factors, such as dimensions of the neck, the device fixation system, and perhaps progressive wall degeneration, are also likely to play a role in the pathogenesis of neck dilatation. To obtain good results from EVAR, accepted criteria of neck dimensions should be adhered to.