PSI - Issue 49

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S. McLennan et al. / Procedia Structural Integrity 49 (2023) 51–58 Author name / Structural Integrity Procedia 00 (2023) 000–000

Fig. 2 PWS variation for each investigated region of the aorto-iliac structure: EAS - entire aorto-iliac structure, N - neck, A - aneurysm, B - bifurcation, HCWB - healthy-calcified wall boundary. The horizontal bar inside the boxes indicates the median, the square in the boxes indicates the mean, and the lower and upper ends of the boxes are the first and third quartiles. The whiskers indicate the minimum and maximum values. The relationship between the increase in PWS due to calcification inclusion and RCP is also shown. Solid line indicates least squares linear regression; dashed lines, 95% confidence interval. The occurrence of iliac rupture during EVAR procedure has been reported and is more frequently observed in women with smaller arteries Fernandezet al.(2009). In that study it was found that 2.98 % of the 369 EVAR patients being studied experienced ruptured iliac arteries while undergoing EVAR procedure. The presence of calcification in iliac arteries has been associated with more adjunctive manoeuvres during deployment of branched or fenestrated devices because of reduced navigability of endovascular tools during fenestration cannulation and more stent-graft twisting and rotation during stent-graft deployment Gallitto et al. (2017). As seen in Figure 2, the healthy-calcified wall boundary region in the With-Ca simulations experienced the second highest mean PWS of the five aortoiliac regions, after the iliac region. Figure 3 highlights how the von Mises stress concentrated around the calcified geometry. This finding supports the prior research of Barrett et al. (2018) who suggests the healthy wall undergoes a greater mechanical response when surrounding a less compliant material, in this case calcification.

Fig. 3 Von Mises stress contour plots of the aorto-iliac structure for six patients to illustrate the PWS occurrence during interventional tool deployment. Area in which PWS occurs has been windowed and enlarged for each patient. RCP is the relative calcification presence