Aneurysm Sac Enlargement after Endovascular Abdominal Aortic Aneurysm Repair

A Novel methodology for improved imaging analysis pre- and post-EVAR

“…Highly intercorrelated variables were tested with the Pearson correlation coefficient and excluded to reduce the effects of multicollinearity. 13 For highly intercorrelated variables with R > .7, the paired variable with the lowest p-value from the ANOVA was included in the regression model. Backward stepwise logistic regression eliminated variables with least significance until significance of all remaining variables was < .05.…”

“…The RC is defined as 1.96 times the SD of the difference between two paired measurements, which is a good measure of repeatability, described by Bland and Altman. 13 It is expected that 95% of the differences between the paired measurements are less than the observed RC. Interobserver agreements were calculated with the intraclass correlation coefficient (ICC).…”

“…The third point was measured (1) along the CLL 40 mm distal of the aortic neck or (2) at the aortic bifurcation flow divider. The methodology is described by Ouriel et al 13 The aortic neck tortuosity index was calculated as the …”

“…[11][12][13] The average curvature was calculated over six predefined regions: the aortic neck (between the lower renal artery and the start of the aneurysm), the aneurysm sac (between the end of the infrarenal neck and 20 mm proximal to the aortic bifurcation), and the terminal aorta (between 20 mm proximal to the aortic bifurcation and the aortic bifurcation). The aortic region surrounding the lower renal artery was further subdivided into suprarenal aortic neck (30 to 10 mm proximal to lower renal artery), juxtarenal aortic neck (10 mm proximal and to 10 mm distal to lower renal artery), and infrarenal aortic neck (10 to 30 mm distal to the lower renal artery).…”

“…13 They calculate the angle between fixed points on the aorta CLL. The suprarenal angulation is measured between the orifice of the celiac trunk, the orifice of the lowermost renal artery, and the proximal aspect of the aneurysm sac.…”