Keywords
EVAR - intraoperative - aortic rupture - open conversion - acute conversion
Introduction
Endoleaks are considered significant adverse events after endovascular repair of abdominal
aortic aneurysms (EVAR), since persistence of blood flow and pressure in the aneurysm
sac may lead to graft failure with an unfavorable outcome. A Type 1a endoleak is defined
as a persistent perigraft channel of blood flow caused by a failure of the graft to
adequately seal at the proximal landing zone. Type-1a endoleaks are present on the
initial angiogram after endograft deployment in 6 to 8% of procedures. There may be
excessive graft undersizing or oversizing due to the presence of mural thrombus, angulation,
calcification, or neck tapering.[1]
Initial management of Type 1a endoleak is angioplasty with a compliant balloon.[1]
[2] However, repeated attempts at balloon inflation or overdilation can produce high-radial
pressures and lead to aortic rupture. Aortic neck rupture during EVAR is an underreported
serious emergency situation requiring conversion to open repair in the majority of
cases. Rupture is associated with higher morbidity and mortality rates compared with
standard open aneurysm repair.[3]
[4]
There are few reports regarding aortic rupture caused by a molding balloon during
EVAR. We report three cases complicated by procedure-related aortic neck wall rupture
caused by the molding balloon during EVAR. We also review the literature regarding
the causes and outcomes of this potentially fatal complication.
Materials and Methods
A retrospective review of all patients treated with EVAR for abdominal aortic aneurysm
(AAA) with commercially available endografts at Attikon General Hospital, Greece,
between January 2009 and March 2019 was performed. A team of vascular surgeons performed
all EVARs in an operating room equipped with a portable C-arm with angiographic and
road-mapping capabilities. Overall, 824 EVAR procedures were performed, and rupture
of the aortic wall was observed in three patients. This study was approved by the
Committee on Research Ethics at Attikon University Hospital, Athens, Greece.
Results
Case 1
An 84-year-old man underwent elective endovascular AAA repair EVAR for a 5.8-cm infrarenal
AAA ([Fig. 1A]).[5] The patient's past medical history included chronic pulmonary obstructive disease
and arterial hypertension. During the EVAR procedure, a stent-graft (28 mm Zenith,
Cook, Inc., Bloomington, IN) was deployed below the lowest right renal artery. The
neck aneurysm was conical, with diameters of 22 mm just below the lowest right renal
artery and 25-mm, 1-cm distally. Low-pressure ballooning was performed with a Coda
32-mm balloon catheter (Cook, Inc., Bloomington, IN) in the area of the most proximal
covered stent and after complete deflation in the distal fixation sites, as well as
in the overlap zones between the main body and the iliac limbs. The final angiography
revealed a Type 1a endoleak that was attributed to the conical shape and the slight
angulation of the infrarenal neck, leading to imperfect apposition of the endograft.
Low-pressure reballooning was performed proximally in the neck, but the angiography
showed persistence of the Type 1a endoleak. Reballooning with gradual slow inflation
was performed for the third time, and we observed a sudden abrupt increase of the
diameter of the endograft during balloon inflation. A volume of less than 25 cc was
inflated during each ballooning. In the subsequent final angiography, extravasation
around the right part of the infrarenal neck of the aorta was observed ([Fig. 1B], white arrow), associated with a sudden and significant decrease in systemic arterial
pressure (from 120 to 55 mm Hg). The balloon was immediately advanced and inflated
above the renal arteries. Aterial pressure increased, and the patient became hemodynamically
stable. Conversion to open repair was performed.
Fig. 1 (A) Angiography shows the Type 1a endoleak and (B) extravasation around the right part of the infrarenal neck of the aorta (white arrow)
after balloon inflation. (C) A conversion to open repair was performed and effective external banding of the
infrarenal neck with two polyester limbs, tied in the same fashion, close to one another
and parallel just below the renal arteries was performed, also sealing the tear of
the aortic wall and stopping the hemorrhage. (D) A computed tomography angiography on the fifth postoperative day showed complete
sealing in the proximal neck with no evidence of endoleak.
After laparotomy, a large hematoma with active bleeding was found in the retroperitoneal
space. The left renal vein was ligated and proximal control was achieved by placement
of a vascular clamp above the renal arteries. A longitudinal tear of 0.8-cm length
below the right renal artery was found. Initially, we attempted to suture the lesion
with 4–0 Prolene stitches. We included the stent graft in the sutures to reinforce
the aortic wall, but when we released the clamp, due to the radial tension of the
endograft, the lesion was fragile and started bleeding again. We placed again the
clamp above the renal arteries. To avoid endograft explantation, control the bleeding,
and solve the problem of the Type 1a endoleak, we performed external banding of the
infrarenal neck with a polyester prosthesis covering the tear of the aortic rupture
and effectively plicating the aortic neck ([Fig. 1C]).[5] The patient's computed angiography 1 week later showed no endoleak ([Fig. 1D]), and the patient was discharged on the sixth postoperative day in good general
condition. Three months after the operation, he remains in excellent condition.
Case 2
A 73-year-old man underwent elective EVAR for a 5.5-cm infrarenal AAA. His past medical
history included coronary artery disease, hyperlipidemia, and arterial hypertension.
The aneurysm had a conical neck measuring 18 mm in diameter at the level of the renal
arteries, 22 mm 1 cm below the arteries, and 24 mm 1.5 cm below the renal areteries.
Calcification covering approximately 25% of the aortic neck perimeter was also noted.
The advancement of wires and catheters was easy, and a 28-mm Anaconda stent-graft
was deployed just below the renal arteries.
Low-pressure ballooning ([Fig. 2A]) was performed with a Coda 32-mm balloon catheter (Cook, Inc., Bloomington, IN)
in the area of the most proximal covered stent, in the distal fixation sites, as well
as in the overlap zones between the main body and the iliac limbs. The final angiography
revealed a Type 1a endoleak, which was attributed to the conical neck and the presence
of the atherosclerotic plaque ([Fig. 2B], white arrow). Reballooning was performed proximally at the neck of the aneurysm
([Fig. 2C]), but a new intraoperative angiography revealed persistence of the Type 1a endoleak,
which was reduced ([Fig. 2D], white arrow). Reballooning was performed once more with less than 25-cc inflation
volume ([Fig. 2E]). In the subsequent final angiography, extravasation to the right of the infrarenal
neck of the aorta was observed. This was associated with a modest decrease of arterial
pressure ([Fig. 2F]). Conversion to open repair was performed. A hematoma around the aorta without active
bleeding was found. A proximal clamp was placed just below the renal arteries, the
sac was excised, and the graft was removed. A tubular 18-mm graft was placed, and
the postoperative course was uneventful. The patient was discharged 7 days later in
good general condition.
Fig. 2 (A) After balloon inflation, (B) the angiography revealed a Type 1a endoleak (white arrow). (C) Reballooning was performed proximally in the neck of the aneurysm, (D) but a new intraoperative angiography revealed the persistency of the Type 1a endoleak,
which was reduced (white arrow). (E) Reballooning was performed once more with less than 25-cc inflation volume. (F) In the subsequent final angiography, extravasation around the right part of the
infrarenal neck of the aorta was observed.
Case 3
A 77-year-old man underwent elective EVAR for a 6.2-cm infrarenal saccular AAA. His
past medical history included chronic obstructive pulmonary disease, arterial hypertension,
and hostile abdomen due to previous abdominal operations (peritonitis because of small
bowel perforation, gastrectomy, and large incisional hernia). Regarding the characteristics
of the AAA, there was calcification in the proximal neck (diameter of the neck 19 mm
and length 3 cm), and the aorta at the level of the bifurcation was 16 mm in diameter
and calcified ([Fig. 3A, B]).
Fig. 3 (A,
B) Regarding the characteristics of the abdominal aortic aneurysm, there was calcification
in the proximal neck and the aorta at the level of the bifurcation was 16 mm in diameter
and calcified. (C,
D) Through a rooftop approach with a left-side visceral rotation, a local hematoma
was found with no active hemorrhage, biological glue was applied. (E–G) He was discharged on the 19th postoperative day in good general condition. At 1-year
follow-up, a computed tomography scan showed no evidence of endoleak and complete
exclusion of the aneurysm.
An aortouniliac endograft 22 mm in diameter (Cook, Bloomington, IN) was deployed 1 cm
below the left renal artery, intending to avoid the calcified plaque, and sealed in
the left common iliac artery, while an occluder plug was inserted into the right common
iliac artery. Low-pressure ballooning was performed manually with a Coda 32-mm balloon
catheter (Cook, Inc., Bloomington, IN) in the area of the most proximal covered stent
and the distal fixation sites, as well as in the overlap zones between the main body
and the iliac limbs. The final angiography revealed a Type 1a endoleak, which was
attributed to calcification of the infrarenal neck leading to poor apposition of the
endograft. Multiple attempts to balloon the proximal neck were performed (with inflation
volumes of less than 25 cc), and the patient developed a drop in blood pressure. In
the intraoperative angiography, an “ulceration bulge” of the aortic neck was observed
without extravasation. A cuff was placed just below the lowest left renal artery covering
the bulging area of the aorta. The patient was hemodynamically stable and the procedure
was completed with a femoral-femoral bypass.
Two hours later, while the patient was in the recovery room, he developed tachycardia,
emergency CT angiography was performed, which revealed a local contained extravasation
around the proximal neck of the aorta. The patient was transferred to the operating
room; through a rooftop approach with a left-side visceral rotation the proximal aortic
neck was exposed. A local hematoma was found with no active hemorrhage ([Fig. 3C, D]). Biological glue was applied, and the abdomen was closed. In the postoperative
course, the patient developed atrial fibrillation and depressed pulmonary function.
He was discharged on postoperative day 19 in good general condition. At 1-year follow-up,
a CT scan showed no evidence of endoleak and complete exclusion of the aneurysm ([Fig. 3E–G]).
Discussion
Most often, vascular injury during EVAR occurs in the iliac vessels due to severe
tortuosity, diminished diameter, and/or calcification of the iliac arteries.[6] Fernandez et al[6] reported a 2.98% chance of iliac rupture during EVAR and 8.9% during TEVAR.[3] More than 95% of these iliac injuries were adequately treated endovascularly with
covered stents or limbs.
Aortic neck wall rupture during EVAR is an underreported potentially fatal complication,
and only a few cases have been described in the literature. Schlösser et al[7] reviewed the literature regarding early or late aneurysm rupture after EVAR. Overall,
270 patients with ruptures were identified. In 13 cases, the ruptures occurred intraoperatively
during endovascular repair, and the mortality rate was 44.4%. Balloon dilatation of
proximal aortic neck was the cause of rupture in 4 out of the 13 cases. Other causes
were instrumentation and perforation of the aneurysm sac, rupture during attempts
to remove insufficiently deployed proximal stent grafts, and poststent deployment.
Lee et al[8] reported a case of aortic neck rupture after repeat ballooning for a Type 1a endoleak.
The authors explained the rupture as the result of rapid inflation of the balloon
catheter. They concluded that gentle, slow inflation of the balloon is important to
prevent vascular rupture. Jimenez et al[9] reported two cases of aortic rupture during elective EVAR with a 50% mortality rate,
while Verzini et al[10] reported a single-fatal case of aortic rupture that occurred at the bottom of a
conical angulated neck during deployment of the endograft.
Our experience with these three cases raises important points that should be highlighted
and analyzed as follows:
-
In all cases, a Type 1a endoleak was observed, and in all cases, repeated ballooning
attempts were performed to resolve the endoleaks. We believe that if a Type 1a endoleak
persists after a maximum two ballooning attempts, other endovascular options should
be considered, such as placement of an aortic cuff or use of a Palmaz's stent.[11] If these options also fail to seal the endoleak, coil and/or glue embolization or
endostaples can be used at a second stage.[1]
[12] Chimney grafts and fenestrated cuffs have also been used to treat Type 1a endoleaks.
-
It is well known that an abdominal aortic aneurysm with conical or heavily calcified
aortic neck may inhibit good fixation and promote migration and early/late Type 1a
endoleak. A conical neck in hostile anatomies represents the strongest factor associated
with proximal failure of standard EVAR.[13]
-
In all cases, a Coda balloon catheter was used. The Coda is a semicompliant polyurethane
balloon used for expansion of AAA endografts. The catheter balloon maintains a constant
pressure while conforming to the shape of the endograft in which it is expanded, resulting
in greater contact of the balloon with the inner surface of the endograft. According
to the instructions for use, overdilatation can lead to aortic rupture. The molding
balloon should only be applied within the covered part of the stent graft. The maximum
inflation volume is 30 mL for the 32-mm catheter and 40 mL for the 40-mm catheter.
We believe that repeated attempts of ballooning in challenging necks, even with less
inflation volume than indicated by the user's manual, can lead to aortic neck rupture.
Thus, manual slow inflation of the balloon for a maximum of two times is recommended
to prevent vascular rupture.
-
Aortic rupture during EVAR is a devastating complication. Prompt diagnosis and treatment
can improve the survival of patients who develop this complication. In our experience,
all patients survived due to prompt open conversion. According to the literature,
mortality from this complication can be high. In the review paper by Schlösser et
al,[7] the mortality rate in cases of aortic rupture was 44.4%. Control of the hemorrhage
by advancing the balloon above the site of rupture is crucial for the patient to achieve
hemodynamic stability.
-
Neck banding is a useful technique for simultaneously treating a Type 1a endoleak
and aortic neck rupture during EVAR.[5]
[13] Effective external banding of the infrarenal neck with polyester prosthesis strips
at the level of the rupture may lead to control of the hemorrhage and exclusion of
blood flow to the aneurysm sac.[5]
[14]
Conclusion
During EVAR, a maximum of two ballooning attempts should be performed even if a Type
1a endoleak persists. In cases of aortic neck wall rupture, control of the hemorrhage
should be achieved immediately by advancing the balloon above the site of rupture.
Emergency surgical conversion in case of hemodynamic stability is the first choice.
However, it should be highlighted that emergency surgical conversion, especially in
cases of endograft with suprarenal fixation, is associated with significant morbidity
and mortality rates, mainly due to hemorrhage and to the length of the procedure required
to restore the aortic neck wall injury.
