Evaluation of the proximal aortic neck enlargement following endovascular repair of abdominal aortic aneurysm: 3-year experience

The aim of this study was to evaluate incidence, potential risk factors and effects on stent-graft migration of proximal neck dilatation after endoluminal repair of abdominal aortic aneurysm (EVAR), and the role of ultrasound (US) in detecting neck enlargement. From November 1998 to October 2001, 90 patients underwent EVAR. On follow-up, US and CT angiography (CTA) were performed, and diameters of the suprarenal and infrarenal aortic necks were monitored. Incidence of significant neck enlargement (> or =2.5 mm) and distal stent-graft migration (>10 mm) was calculated. Several factors were evaluated as predictive of neck enlargement. Ultrasound and CTA measurements were compared. The US and CTA examinations were available in 68, 39, and 11 patients at 1, 2, and 3 years follow-up (mean follow-up 15 months). Incidence of significant neck dilatation was 21.8% at the infrarenal level (13, 33, and 36% at 1, 2, and 3 years follow-up) and 13.8% at the suprarenal level (9, 18, and 27% at 1, 2, and 3 years follow-up). Significant stent-graft migration occurred in 14 of 87 patients (16%) and was associated with neck dilatation in 8 (2 suprarenal and 6 infrarenal). No risk factors were identified. Ultrasound was less accurate than CT in measuring neck diameter, in particular at the suprarenal level. Proximal aortic neck enlargement occurs in up to 30% of patients after EVAR and represents the main risk factor for stent-graft migration. The risk of infrarenal neck dilatation is higher at 2 years follow-up, whereas the suprarenal neck enlarges later. Ultrasound is not useful in monitoring neck diameter.