Study on the rupture risks of abdominal aortic aneurysm based on computational fluid dynamics

Objective: To discuss the rupture risks of abdominal aortic aneurysm (AAA) through analyzing the actual hemodynamic parameters and thrombus index of AAA. Methods: The clinical data of 12 patients with ruptured AAA (ruptured group) and 26 patients with unruptured AAA (unruptured group), who were admitted to the First Affiliated Hospital of Chongqing Medical University of China during the period from February 2016 to September 2018, were retrospectively analyzed. The computed tomography angiography (CTA) image materials of patients were collected. By using computational fluid dynamics (CFD) method the hemodynamic parameters and thrombus index of AAA were obtained. The hemodynamic characteristics of AAA were compared between the two groups. Results: In the ruptured group, the wall shear stress of blood flow in the ruptured area of AAA and in the maximum impact area was (0.031 ± 0.017) Pa and (0.630 ± 0.215) Pa respectively, the difference between the two areas was statistically significant (P < 0.001). In the unruptured group, the wall shear stress of blood flow in the maximum impact area was (1.345 ± 0.253) Pa, which was significantly different with that in the ruptured group (P < 0.001). In the ruptured group, the mean intraluminal thrombus indexes at the plane of the maximum diameter and at the ruptured plane of AAA were 0.551 ± 0.188 and 0.630 ± 0.190 respectively, the differences between the two planes were statistically significant (P < 0.002). In the unruptured group, the mean intraluminal thrombus index at the plane of the maximum diameter of AAA was 0.525 ± 0.188, which was not significantly different with that in the ruptured group (P = 0.699). Conclusion: The hemodynamic parameters combined with the intracavitary thrombus index have a certain value in predicting the rupture risk of AAA. (authors)