Keywords
aortoiliac - aneurysm - rupture - giant - open - repair
Introduction
The natural history of an aortoiliac aneurysm (AIA), as with every aneurysm, is progressive
expansion and at the end, if not treated, rupture. Rupture is a catastrophic complication
because it incurs an extremely high mortality rate. Most patients with ruptured AIA
do not reach the hospital. Those who survive to be subjected to an intervention have
an elevated mortality and morbidity rate. The annual risk of rupture increases with
aneurysm expansion. It is calculated that the annual risk of rupture of an abdominal
aortic aneurysm (AAA) with a diameter of >70 mm is 30 to 33%.[1] Ruptured AIA represents a special surgical challenge. Specific surgical skills are
required. Giant AIAs are defined as those having a transverse diameter >13 cm. Herein,
a case of a giant ruptured AIA treated successfully is described.
Case Presentation
A 72-year-old man presented to the emergency department with pain in his right lower
abdominal quadrant of 4 hours. His past medical history was significant for smoking
(50 packs/year) and poorly controlled hypertension. He had no history of previous
abdominal surgery. On admission, the patient had hypotension (84/46 mm Hg) and tachycardia
(106 beats/min). Palpation of his abdomen revealed a large, tender pulsatile mass
around the umbilicus.
Emergency contrast-enhanced computed tomography revealed a giant infrarenal AAA extending
to both common iliac arteries ([Fig. 1]) with evident rupture at the medial wall of the right iliac aneurysm ([Fig. 2]). This AIA measured 17 cm × 10 cm at the aortic bifurcation, 12 cm × 10 cm at the
ruptured common right iliac artery aneurysm, and 9 cm × 8 cm at the left common iliac
aneurysm. The aortic and both iliac aneurysms presented with extensive thrombus within
the aneurysmal sacs. Both internal iliac arteries were patent.
Fig. 1 Contrast-enhanced computed tomography demonstrates a giant aortoiliac aneurysm at
the level of the aortic bifurcation with extensive thrombus.
Fig. 2 Appearance of giant iliac aneurysms with extensive thrombus and signs of rupture
in the medial wall of the right iliac artery. Significant retroperitoneal pelvic hematoma
is shown (arrows).
The patient was immediately transferred to the operating theater.
An open transperitoneal approach was chosen. Through a midline incision, aortic cross-clamping
was performed within a few minutes. Both external iliac arteries were dissected and
controlled. Patent internal iliac arteries were controlled from within with inflatable
balloons after opening the AIA. A Y-shaped Dacron graft 18 mm × 9 mm was used. Proximal anastomosis at the infrarenal
aorta was performed just below the renal arteries. Distal anastomoses were performed
in an end-to-end fashion with the external iliac arteries. The right internal iliac
artery was oversewn from within at the ostium, while the left was revascularized via
a jump graft from the iliac limb of the bifurcated graft. The jump graft was anastomosed
in an end-to-end fashion to the ostium of the left internal iliac artery.
At the end of the procedure, the sigmoid colon had no signs of ischemia. During surgery,
the patient was stable and received 8 units of packed red blood cells.
His postoperative course was uneventful and he was discharged from hospital on postoperative
day 8. The patient continues to do well 3 years later. The last follow-up ultrasound
imaging at 3 years from surgery revealed normal findings ([Figs. 3] and [4]).
Fig. 3 B-mode image of the proximal anastomosis.
Fig. 4 Color-flow Doppler image of the proximal anastomosis.
Discussion
In the literature, giant AAAs occur almost exclusively in male patients. Clear predilection
for male sex also characterizes aortic and iliac aneurysmal disease. The incidence
of ruptured AIA seems to have declined in recent years, and this is partly due to
the proliferation of screening in the population. The prevalence of giant AIAs is
hard to estimate and is largely unknown. There are only a few reports in the literature,
which means that giant AIAs are infrequently detected. The aforementioned screening
protocols aim to timely detect AAAs in the population, recommending repair or surveillance
according to their diameter, thus limiting the possibility for an aneurysm to excessively
expand.
Although rupture rates are high for AAAs measuring >7 cm, strangely enough a small
number of them, due to unidentified protective factors, do not rupture and continue
to grow reaching extreme diameters.
The diameter and shape of the aneurysm are determining factors, closely related to
the risk of rupture.
Sandhu and Pipinos[2] categorized iliac artery aneurysms based on their anatomical features. Combined
aneurysms of the common iliac arteries and abdominal aorta are categorized as Type-E
aneurysms and may be treated with bifurcated grafts.
The decision to take when facing with ruptured AIA concerns whether to treat it by
open or endovascular means. Open repair is still the gold standard and always bears
consideration in ruptured aneurysms. In experienced hands, complication rates are
significantly reduced. Obviously, the presence of a giant AIA notably obfuscates the
surgical field, making surgical maneuvers more demanding. Adjacent organs become adherent
due to the extreme dimensions of the aneurysm, making dissection more difficult. On
the other hand, endovascular repair has several limitations related to the anatomy
of the diseased vessels, especially of the infrarenal aortic neck. Extreme angulation,
large diameter, short length, and significant thrombus burden, all may accompany the
extreme dimensions of the aneurysmal sac.[3] The anatomical suitability for endovascular treatment of ruptured AAA is reported
at 46%.[4] Additionally, in the EUROSTAR (European collaborators on stent/graft techniques
for aortic aneurysm repair) registry, larger (nonruptured) aneurysms were associated
with increased incidence of endoleaks following endovascular repair, especially when
there is concomitant aneurysmal pathology in abdominal aorta and iliac arteries.[5] In the IMPROVE trial (immediate management of patients with rupture: open versus
endovascular repair), the 30-day mortality is similar among patients treated by open
or endovascular means, with a shorter length of stay for those treated endovascularly.[6]
The decision on how to treat a patient presenting to the emergency department with
ruptured AIA is quite complex and multifactorial. This depends mainly on the experience
of the operating doctor and his team. Special technical expertise is required. For
both approaches if the experience is larger in one of the two treatment modalities,
this is the case not to try the other one. If the availability of stent grafts, wires,
catheters, balloons is limited, the endovascular way should not be attempted. Also,
that endovascular treatment in emergency cases requires a readily available multidisciplinary
staff with dedicated equipment. If there is no time to size the aneurysms and choose
the best endograft, open repair is the only way.
In our particular case of giant ruptured AIA, the choice to immediately transfer the
patient in the operating theater and obtain rapid aortic control represented an undoubtedly
salvage procedure.
We are not aware of other reports of a giant aortic aneurysm measuring as much as
17 cm in transverse diameter combined with giant right and left common iliac aneurysms
of as large as 12 and 9 cm, respectively.
The presence of bilateral common iliac artery aneurysms may be a limitation for endovascular
treatment, due to the need for embolization of both internal iliac arteries to prevent
retrograde flow and subsequently continuous bleeding. The risk of pelvic ischemia,
with buttock claudication, bowel and urinary bladder ischemia, or erectile dysfunction,
is high when both internal iliac arteries are sacrificed. On the other hand, the use
of branched iliac devices combined with aortic bifurcated stent, grafts did not seem
a safe option in our emergency situation. These procedures may be time consuming.
Finally, it has been observed that concomitant aortic and common iliac aneurysms treated
by endovascular means incur a high rate of endoleaks.[5] For this reason, prophylactic secondary interventions are frequently needed.
Open repair of AAAs may be related with several complications that become more prominent
when dealing with giant AAAs. Significant displacement of adjacent organs enhances
the risk of iatrogenic injuries especially when rupture of such aneurysms occurs.
Venous injuries or small bowel serosal tears may also occur. To avoid such unpleasant
surprises, cautious dissection after aortic cross clamping is mandatory, taking care
to identify meticulously the surrounding anatomic structures. Additionally, pelvic
revascularization in the presence of giant internal iliac aneurysms may be extremely
challenging due to the limited surgical field in association with their location deep
in the pelvis. Attempts to preserve at least one internal iliac artery should be made,
as in our case.
