ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

EFFECT OF POST TREATMENT FOR MULTIPLE AORTIC
ANEURYSMS USING CFD
M.N. Bui 1 , F. Mori 1 , S. Hanida 1 , H. Ohtake 2 , G. Watanabe 2 , and T. Matsuzawa 3
1. ABSTRACT
In case of staged surgery treatment for patients have thoracic aortic aneurysm (TAA)
and abdominal aortic aneurysm (AAA), the AAA is treated first in generally. However
TAA was expanded after the treatment of AAA according to clinical reports. And the
cause for this sudden expansion of TAA after the treatment of AAA is not clarified. In
this research, we examined the effect to aneurysm after treatment for multiple aortic
aneurysms (MAA) using computational fluid dynamics (CFD). As results, at
acceleration phase of flow, the pressure distribution of TAA on outer aorta wall was
increased after AAA treatment. Moreover, we observed the WSS distribution on
aneurysm wall. WSS distribution was unchanged in each case. This simulation results
was agreed with medical report. Therefore, we thought that the expansion of aneurysm
is related to the increase of pressure on aneurysm wall in TAA.
2. INTRODUCTION
Aortic aneurysm (AA) is a part of the blood vessels that expands due to the weakening
of the arterial wall. As the site of aneurysm prediction, the TAA and AAA are well
known. If untreated AA has ruptured, it leads to the worst death. Recently, case that AA
may be seen in other positions when a patient is diagnosed with an AA has increased (1) .
Crawford et al., showed that 12.6% of patients who are diagnosed with an AA have
MAA (2) . Currently, there are two types of surgery treatment for MAA: Simultaneous
surgery in which all aneurysms are treated at the same time and staged surgery in which
aneurysms are treated one by one. Simultaneous surgery is a high invasiveness for
patient body. Moreover, the staged surgery is undertaken in the majority of cases (3) . To
minimize the invasiveness of surgery treatment, endovascular aortic repair (EVAR)
using stent graft has been introduced for the treatment of AA. In case of staged surgery
for patients that have TAA and AAA, the AAA is treated first in generally (4) . However
Yamazaki et al., reported (5) that the TAA expand and may rupture after the treatment of
the AAA. The cause for this sudden expansion of TAA after the treatment of AAA is
not clarified.
In CFD studies, the pressure and wall shear stress (WSS) at aneurysms are examined to
1
Information Science student, School of Information Science, Japan Advanced institute of Science and
Technology, Asahidai 1-1, Nomi, Ishikawa, Japan
2
Professor, Department of General and Cardiothoracic Surgery, Kanazawa University, 13-1 Takaramachi,
Kanazawa, Ishikawa, Japan
3
Professor, Research Center for Advanced Computing Infrastructure, Japan Advanced Institute of
Science and Technology, Asahidai 1-1, Nomi, Ishikawa, Japan