Giant
superior mesenteric artery aneurysm associated with infrarenal abdominal aortic
aneurysm
(Portuguese
PDF version) Ricardo
César Rocha Moreira1, Marcio Miyamotto2
1. PhD in
Clinical Surgery, Universidade Federal do Paraná. Chief of Prof. Dr. Elias
Abrão Division of Vascular Surgery, Curitiba, PR, Brazil.
2.
Vascular Surgeon, Prof. Dr. Elias Abrão Division of Vascular Surgery, Curitiba,
PR, Brazil. Correspondence:
Rua Pedro Muraro, 50/24
CEP 82030-620 - Curitiba - PR
Tel.: +55 (41) 244.8787
Fax: +55 (41) 335.3233
E-mail: ina@onda.com.br
ABSTRACT The
authors present a case of a patient with a giant atherosclerotic superior mesenteric
artery aneurysm, associated with infrarenal abdominal aortic aneurysm. Extensive
investigation failed to demonstrate an embolic source or a connective tissue disease.
The patient was successfully treated by open repair of both superior mesenteric
artery and abdominal aortic aneurysms. The authors were unable to find in the
literature a similar report of such a large superior mesenteric artery aneurysm,
or such an association with abdominal aortic aneurysm.
Key-words:
superior mesenteric artery aneurysm, abdominal aortic aneurysm, mycotic aneurysm.
Palavras-chave: aneurisma, artéria mesentérica
superior, aneurisma da aorta abdominal.
J
Vasc Br 2003;2(3):227-29
Superior mesenteric
artery (SMA) aneurysm is rare, being observed in one in every 12,000 autopsies.1
Only 5.5 to 8% of cases of visceral aneurysms and less than 0.5% of all intra-abdominal
aneurysms are SMA aneurysms.2 The authors report a
case of a 66-year-old patient with a giant atherosclerotic SMA aneurysm, associated
with infrarenal abdominal aortic aneurysm. This association and the size of the
SMA aneurysm have not been previously described in the literature. CASE
REPORT
A white, 66-year-old tradesman was referred to us by a general surgeon, who noted
an abdominal murmur and a pulsatile mass in the right hypochondrium while examining
an umbilical hernia. The patient had a history of cigarette smoking and drug-controlled
hypertension. The physical examination was otherwise normal. Initial exams did
not show active infectious or inflammatory processes. The abdominal echography
revealed an intraperitoneal mass with thickened walls and liquid content. The
computed tomography angiography (CTA) showed an SMA aneurysm measuring 11 cm in
diameter, in addition to a fusiform infrarenal aortic aneurysm with a diameter
of 6.0 cm (Figure 1). The arteriography confirmed the tomographic findings and
showed an initially normal 3-cm long segment of the SMA and a patent inferior
mesenteric artery (Figure 2). The patient was surgically treated through an extraperitoneal
approach on the left side. The suprarenal aorta was initially approached with
control of the proximal superior mesenteric and renal arteries. The SMA aneurysm
was ligated proximally with later opening of the aneurysm sac and internal suture
ligation of its branches. The AAA was corrected by the implantation of a 20-mm
straight Dacron graft using the inclusion technique with reimplantation of the
inferior mesenteric artery. After concluding the distal anastomosis of the aorta,
a small opening was made on the peritoneal sac for inspection of the intestinal
loops, which were pale and cyanotic. The evidence of acute intestinal ischemia,
prompted the decision to perform SMA revascularization. A reverse greater saphenous
vein graft, extending from the proximal stump of the SMA to the middle colic artery,
was carried out (Figure 3). Ischemia was immediately reversed. The patient had
transient diarrhea in the postoperative period. The diet was reintroduced on the
fourth day. Bacterioscopy and the culture of aneurysm material yielded negative
results. The patient was discharged from hospital after nine days.
 Figure
1- Abdominal CT-scan showing: a) SMA aneurysm and b) abdominal aortic aneurysm
and SMA aneurysm.
Figure
2- Arteriography: a) aortic aneurysm and SMA aneurysm, b) SMA aneurysm and c)
abdominal aortic aneurysm. 
Figure
3- a) left extraperitoneal approach to the abdominal aorta and origin of the SMA,
the image of the left kidney was removed, b) after aneurysm correction (continuous
arrow- saphenous vein graft between the stump of the SMA and the medial colic
artery; dotted arrow- aorto-aortic graft coated with Dacron, with reimplantation
of the inferior mesenteric artery). 
DISCUSSION
The first surgical
treatment of the SMA aneurysm was reported in 1953 by De Bakey & Cooley. The
correction consisted of proximal and distal ligation with resection of the area
affected by the aneurysm.3 Until 1997, more than 100
SMA aneurysms had been diagnosed and treated by way of several surgical techniques.4
Most SMA aneurysms are symptomatic. The most frequent symptom is moderate
to severe abdominal pain, which increases gradually. Nausea, vomiting, jaundice,
hemobilia and gastrointestinal bleeding may occur occasionally. A pulsatile mass
is observed in over 50% of cases, and is distinguished from AA by palpation. The
most dreaded complications are aneurysm rupture and thrombosis. In these cases,
the distinction between the sudden increase of the aneurysm and angina or intestinal
ischemia caused by aneurysmal thrombosis is extremely difficult.2,4,5
All diagnosed SMA aneurysms must be treated. Spontaneous rupture may occur
in up to 50% of the cases. Intraoperative death rates amount to 30% when the patient
is operated on in these conditions.4 The type of treatment
depends mainly on the etiology of the aneurysm and on intestinal viability. According
to the literature, until 1997, 35% of SMA aneurysms were treated by simple proximal
and distal ligation, 35% by ligation and aneurysmectomy of the affected area and
21% by aneurysmorrhaphy only. Revascularization was necessary in 15% of the cases,
due to intestinal ischemia.5
The simple ligation
proximally and distally to the aneurysm with intraoperative assessment of intestinal
viability is the treatment of choice, when there is no evidence of infection.
Mycotic aneurysms should be treated by aneurysm resection, debridement of the
infected area and with broad-spectrum antibiotics. Aneurysmorrhaphy can be used
for saccular aneurysms and disease-free arteries, thus preserving the arterial
lumen. However, this technique is seldom used.2,5
Revascularization is indicated if there is visceral ischemic involvement
after arterial ligation. The use of prostheses is prohibited in the presence of
infection. In these cases, we use saphenous vein interposition graft or a graft
with the same material. Aorto-mesenteric bypasses are less frequently used.2,5-7
The presence of abdominal aortic aneurysm was taken into account for the
selection of the surgical technique. The left extraperitoneal approach was chosen
for offering good exposure of the proximal portion of the SMA, in addition to
allowing for AAA correction. The restriction of this route on the inspection of
the intestine after the ligation of the SMA was overcome with a small opening
made anteriorly to the peritoneal sac. After the inspection, the opening was closed
in order to protect the Dacron prosthesis from probable sources of infection due
to bacterial translocation after transient ischemia. The high prevalence of mycotic
aneurysm in this area rules out this hypothesis before and during surgery. This
is the reason why the SMA aneurysm was approached first, as AAA correction routinely
requires the use of a prosthesis. The lack of reliable methods for the intraoperative
detection of intestinal ischemia after arterial ligation poses a major problem.
The presence of a prosthesis in the aorta justifies routine mesenteric revascularization,
thus eliminating the disastrous consequences arising from an intestinal ischemia,
even if transient.
Although the size of the SMA aneurysm does not influence
the selection of the surgical technique, its association with abdominal aortic
aneurysm requires some care, especially with regard to infection. This association
and the size (11 cm) of the true SMA aneurysm have never been reported in the
literature.
REFERENCES
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Kanazawa S, Inada H, Murakami T, et al. The diagnosis and management of splanchnic
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Messina LM, Shanley CJ. Visceral artery aneurysm. Surg Clin North Am 1997;77:425-41. 6.
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