Assessment of aortic hemodynamics in patients with thoracoabdominal aortic aneurysm using four-dimensional magnetic resonance imaging: a cross-sectional study

Wen Zeng; Jiarong Wang; Chengxin Weng; Wanlin Peng; Tiehao Wang; Ding Yuan; Bin Huang; Jichun Zhao; Chunchao Xia; Zhenlin Li; Yingkun Guo

doi:10.21037/qims-23-1321

Assessment of aortic hemodynamics in patients with thoracoabdominal aortic aneurysm using four-dimensional magnetic resonance imaging: a cross-sectional study

Quant Imaging Med Surg. 2024 Apr 3;14(4):2800-2815. doi: 10.21037/qims-23-1321. Epub 2024 Mar 28.

Authors

Wen Zeng^#¹, Jiarong Wang^#², Chengxin Weng², Wanlin Peng¹, Tiehao Wang², Ding Yuan², Bin Huang², Jichun Zhao², Chunchao Xia¹, Zhenlin Li¹, Yingkun Guo³

Affiliations

¹ Department of Radiology, West China Hospital, Sichuan University, Chengdu, China.
² Division of Vascular Surgery, Department of General Surgery, West China Hospital, Sichuan University, Chengdu, China.
³ Department of Radiology, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, China.

^# Contributed equally.

Abstract

Background: Thoracoabdominal aortic aneurysms (TAAAs) are rare but complicated aortic pathologies that can result in high morbidity and mortality. The whole-aorta hemodynamic characteristics of TAAA survivors remains unknown. This study sought to obtain a comprehensive view of flow hemodynamics of the whole aorta in patients with TAAA using four-dimensional flow (4D flow) magnetic resonance imaging (MRI).

Methods: This study included patients who had experienced TAAA or abdominal aortic aneurysm (AAA) and age- and sex-matched volunteers who had attended China Hospital from December 2021 to December 2022 in West. Patients with unstable ruptured aneurysm or other cardiovascular diseases were excluded. 4D-flow MRI that covered the whole aorta was acquired. Both planar parameters [(regurgitation fraction (RF), peak systolic velocity (V_max), overall wall shear stress (WSS)] and segmental parameters [pulse wave velocity (PWV) and viscous energy loss (VEL)] were generated during postprocessing. The Student's t-test or Mann-Whitney test was used to compare flow dynamics among the three groups.

Results: A total of 11 patients with TAAA (mean age 53.2±11.9 years; 10 males), 19 patients with AAA (mean age 58.0±11.7 years; 16 males), and 21 controls (mean age 55.4±15.0 years; 19 males) were analyzed. The patients with TAAA demonstrated a significantly higher RF and lower Vmax in the aortic arch compared to healthy controls. The whole length of the aorta in patients with TAAA was characterized by lower WSS, predominantly in the planes of pulmonary artery bifurcation and the middle infrarenal planes (all P values <0.001). As for segmental hemodynamics, compared to controls, patients with TAAA had a significantly higher PWV in the thoracic aorta (TAAA: median 11.41 m/s, IQR 9.56-14.32 m/s; control: median 7.21 m/s, IQR 5.57-7.79 m/s; P<0.001) as did those with AAA (AAA: median 8.75 m/s, IQR 7.35-10.75 m/s; control: median 7.21 m/s, IQR 5.57-7.79 m/s; P=0.024). Moreover, a greater VEL was observed in the whole aorta and abdominal aorta in patients with TAAA.

Conclusions: Patients with TAAA exhibited a stiffer aortic wall with a lower WSS and a greater VEL for the whole aorta, which was accompanied by a higher RF and lower peak velocity in the dilated portion of the aorta.

Keywords: Thoracoabdominal aortic aneurysm (TAAA); abdominal aortic aneurysm (AAA); four-dimensional flow magnetic resonance imaging (4D flow MRI); hemodynamics.