International Angiology 2021 Jan 19

DOI: 10.23736/S0392-9590.21.04591-0

Copyright © 2021 EDIZIONI MINERVA MEDICA

language: English

A comparison of subjective clinical and objective judgement of abdominal aortic aneurysm morphology

Kazumasa HANADA ¹, Katsuyuki HOSHINA ¹ ✉, Takumi IWAKIRI ², Takafumi AKAI ¹, Kazuhiro MIYAHARA ¹, Toshihiko ISAJI ¹, Toshio TAKAYAMA ¹, Sota YAMAMOTO ²

¹ Division of Vascular Surgery, Department of Surgery, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; ² Department of Mechanical Engineering, Graduate School, Shibaura Institute of Technology, Tokyo, Japan

BACKGROUND: We compared the subjective, clinical judgement of “saccular” morphology with the objective judgement of mechanical structural analysis.
METHODS: Using structural analysis with the finite element method, we previously created a simple model of abdominal aortic aneurysm (AAA) that visualized the distribution of the maximum principal stress (MPS) in the aortic wall and identified the area of prominent stress. AAA “saccular” morphology was determined according to the area showing MPS > 0.03 MPa. AAAs with low aspect ratio (horizontally-long AAA sac) and small fillet radius were defined as “saccular”. Twelve vascular surgeons were recruited. First, they judged the AAA as saccular or fusiform with 3-dimensional images at their clinical impression (subjective “eyeball” judgement). Second, they applied the deformable figure tools on the simple AAA-shaped sagittal view in the application model for 30 AAA cases. From the data of the tools applied, the mechanical structural analysis was performed semi-automatically and the morphology was judged with the objective “simple application”.
RESULTS: The structural analysis revealed that only one case was judged as saccular by 11 out of 12 surgeons and the other 29 AAAs were judged as fusiform by two-thirds or more of the surgeons. In contrast, 5 cases were subjectively judged as saccular by eight and more of the surgeons.
CONCLUSIONS: The clinical judgement of AAA saccular morphology by the vascular surgeons was different from the judgement derived from the mechanical structural analysis using the application model. The saccular morphology may be theoretically rare in AAAs.

KEY WORDS: Application model; Saccular; Abdominal aortic aneurysm; Structural analysis; Finite element method