Evaluation of angiography as the sole imaging study for the proximal aortic neck prior to EVAR

BACKGROUND Angiographic assessment is an alternative to computerised tomography (CT) prior to endovascular aneurysm repair (EVAR). We evaluated angiography in aortic neck morphology assessment as an alternative investigation. METHODS Patients admitted for elective or emergency EVAR were assessed by pre-operative CT and intra-operative angiography. The proximal and distal aortic neck diameters, and neck length were measured. Measurements were expressed as median (95% CI). RESULTS 35 patients (20 male) were assessed from August 2003 to January 2005 for elective (26) and emergency (9) EVAR. In the overall group, the proximal neck diameter was 22.0mm (21.0-23.0) on CT, and 20.7 mm (19.3-22.3) on angiography. The distal neck diameter was 23.0mm (22.0-24.0) on CT, and 22.3mm (20.3-24.6) on angiography, while the neck length was only slightly greater on angiography [23.0mm (17.5-28.4)] relative to CT [23.0mm (20.0-28.0)]. The stent-grafts deployed were oversized by 26.8% (+/- 14.8%) relative to the CT measurements, and 33.7% (+/- 15.6%) relative to angiographic measurements. Good correlation was found for all three measurements between CT and angiography. CONCLUSIONS Angiography alone is inadequate for endovascular aneurysm repair. Although it has timesaving potential, the accuracy achieved is not sufficient to use alone.