Determinants of radiation exposure during EVAR

Endovascular aneurysm repair (EVAR) is an established method of aortic aneurysm repair, in favourable anatomical configurations. It does however expose patients to radiation. The study aim was to determine if the aneurysm neck morphology influenced radiation exposure.

All elective and emergency EVAR patients were identified. Elective patients had a bifurcated stent-graft deployed, while emergency patients were repaired with an aorto-uni-iliac stent-graft and fem-fem crossover bypass. Proximal and distal aortic neck diameters, neck length, neck angles and sac diameter were recorded, with the radiation dose, screening time and contrast volume. The two subgroups of elective and emergency patients were compared and correlation between anatomical and radiological parameters calculated by using Pearson's correlation coefficient.

320 (270 male) elective patients and 64 (55 male) emergency patients from October 1998 to October 2008 underwent EVAR. The mean proximal (p = 0.004) and distal (p = 0.01) neck diameters were smaller and mean sac diameter (p < 0.0001) was greater in emergencies. No difference between groups existed in the neck length (p = 0.36) and suprarenal diameter (p = 0.30), sagittal (p = 0.05) and coronal (p = 0.62) neck angles. The screening time (p = 0.053) and contrast volume (p = 0.04) were lower, with a slightly higher radiation dose (p = 0.12) in emergencies. There was no definite correlation between the seven anatomical and three radiological parameters.

While radiation exposure is different in emergency patients, this is thought due to surgical technique rather than the aneurysm neck morphology.