Introduction
Splenic artery aneurysms (SAA) are the most common true aneurysms, comprising 50 %
to 75 % of all visceral artery aneurysms (VAA). Prevalence of SAAs varies between
0.04 % and 0.10 % at autopsy and 0.8 % on nonselective angiogram [1].
Pseudoaneurysms occur secondary to infectious, inflammatory or iatrogenic causes,
are usually asymptomatic and are therefore detected as incidental findings during
abdominal imaging. They are mostly saccular and situated in the mid to distal splenic
artery [2]. The rate of rupture is higher than true aneurysm and is around 3 % to 20 % [3].
VAAs can be treated by surgery or radiographic intervention depending on their location
and configuration and the patient’s comorbidities and clinical condition. While some
authors suggest that all splanchnic aneurysms should be treated, others propose that
conservative management also has a place [4]
[5]. Single-institutional series with more than 50 patients are uncommon [5].
We describe here a series of six patients with splenic artery pseudoaneurysm in whom
we achieved successful obliteration using a new technique of endoscopic ultrasound
(EUS)-guided glue and coil injection.
Patients and methods
Patients
Case records of six adult (18 years or older) patients with splenic artery pseudoaneurysm
who underwent EUS-guided placement of coil and glue in the pseudoaneurysm over a 1-year
period (Jul 2016 to Sep 2017) were reviewed. Three patients had a history of gastrointestinal
bleeding (hematemesis 2, melena 1) and the remaining three were asymptomatic. All
six patients had failed radiographic angiographic embolization due to inability to
catheterize the tortuous splenic artery.
Clinical details, including age, gender, co-existing conditions, and presenting symptoms
and hemodynamic status at the time of treatment were recorded. Information on characteristics
of the aneurysms, including size, localization, rupture and anatomic variation, was
also extracted. All patients signed an informed consent for this experimental treatment.
Contraindications included hemodynamic instability, coagulopathy, and general contraindication
for endoscopic procedures.
EUS-guided coil and glue
All procedures were performed by one endoscopist (PR) and were done under propofol
sedation and after a prophylactic dose of ceftriaxone (1 g intravenously). A linear
echoendoscope (GF UCT 180; Olympus, Tokyo, Japan) was positioned in the stomach and
the splenic artery pseudoaneurysm was identified using color Doppler. The pseudoaneurysm
was punctured using a 19-gauge EUS-guided fine-needle aspiration (FNA) needle (Expect;
Boston Scientific, United States), while taking care to avoid any intervening blood
vessels ([Fig. 1a], [Fig. 1b], [Video 1]).
Fig. 1 a Large splenic artery pseudoaneurysm. b Color flow in the pseudoaneurysm. c 19 gauge fine-needle aspiration needle used to puncture the splenic artery pseudoaneurysm.
d Coil injected into the pseudoaneurysm.
Video 1 EUS-guided coil and injection done in a large splenic artery pseudoaneurysm using
a 19-gauge fine-needle aspiration needle leading to complete obliteration of aneurysm.
After puncturing the aneurysm, the stylet of the needle was withdrawn and embolization
coils (Cook Medical Inc., Bloomington, Indiana, United States) were pushed through
the FNA needle into the aneurysm followed by injection of glue (n-butyl-2-cynoacrylate)
([Fig .1c], [Fig. 1d], [Fig. 2a]). The diameter (8, 14 or 16 mm) and number of the coils used and amount of glue
injected varied with size of the pseudoaneurysm. In general, one 8-mm coil and 1 mL
of glue was used if the pseudoaneurysm size was up to 3 cm and a 14 or 16 mm coil
and 2 mL of glue was used if it was larger than 3 cm. More coils were injected if
the aneurysm was not obliterated. The end-point of treatment was complete obliteration
of the aneurysmal sac, as confirmed by Doppler ([Fig. 2b]). Computed tomography (CT) images before and after EUS-guided coil placement and
glue injection are shown in [Fig. 3a] and [Fig. 3b].
Fig. 2 a Glue injected into the pseudoaneurysm. b No flow in the pseudoaneurysm at color Doppler examination.
Fig. 3 a CT angiography before EUS-guided coil and glue. b CT angiography 3 months after EUS-guided coil and glue.
Follow up
An EUS was done 2 days after the procedure to confirm obliteration of the pseudoaneurysm
([Video 2]). More coils and glue were placed if there was still flow within the pseudoaneurysm. All
patients were followed up on outpatient basis at weeks 4 and 12. At each follow-up,
a clinical evaluation was done, hemoglobin level was measured and any adverse events
(AEs) were recorded. CT angiography was done at 4 weeks and an EUS was done at 12
weeks to confirm obliteration of the pseudoaneurysm.
Video 2 EUS done 48 hours after first session showed flow in the aneurysm and repeat coil
and glue injection was done.
Outcome measures
The procedure was considered to be a technical success if the coil as well as glue
could be injected into the pseudoaneurysm. Clinical success was defined as complete
obliteration of the pseudoaneurysm at 12 weeks without any fall in hemoglobin. Any
AEs, such as occurrence of abdominal pain, fever, hemorrhage or death, which could
be attributed to the procedure were recorded.
Results
Patient characteristics
All six patients (median age: 36.7 [range:19 – 60] years, 5 men) with splenic artery
pseudoaneurysm had underlying chronic pancreatitis. All patients underwent EUS-guided
coil and glue injection after an attempt at radiologic angioembolization had failed
([Table 1]).
Table 1
Baseline characteristics, technique, success and follow-up of splenic artery pseudoaneurysm.
|
Pt.
ID
|
Age and sex
|
Aneurysm size (cm)
|
Session number[1]
|
Technique
|
Technical success
|
Follow-up imaging[2]
|
Clinical success
|
|
Coil size (mm)
|
Number of coils
|
Glue volume (mL)
|
|
1
|
33 M
|
2.0 × 2.5
|
1
|
8
|
1
|
1
|
Yes
|
Complete obliteration
|
Yes
|
|
2
|
37 M
|
2.0 × 2.5
|
1
|
8
|
1
|
1
|
Yes
|
Complete obliteration
|
Yes
|
|
3
|
19 M
|
3.0 × 3.0
|
1
|
8
|
1
|
1
|
Yes
|
Complete obliteration
|
Yes
|
|
4
|
60 M
|
4.2 × 2.7
|
1
|
16
|
2
|
1
|
Yes
|
Complete obliteration
|
Yes
|
|
2
|
14
|
1
|
1
|
|
5
|
46 M
|
5.5 × 5.6
|
1
|
16
|
3
|
1
|
Yes
|
Complete obliteration
|
Yes
|
|
2
|
16
|
2
|
1
|
|
6
|
25 F
|
6.0 × 6.5
|
1
|
16
|
3
|
1
|
Yes
|
Complete obliteration
|
Yes
|
|
2
|
16
|
2
|
1
|
Pt, patient
1 Patients #4, #5 and #6 underwent 2 sessions each; for these patients, data for each
of the two sessions are shown in a different row
2 Follow-up imaging included computed tomography at 4 weeks and endosonography with
color Doppler study at 12 weeks after the initial procedure
Success rates
EUS-guided coil and glue injection was technically successful in all six patients.
Three patients with aneurysm smaller than 3 cm needed one 8-mm coil and 1.0 mL of
glue each for complete obliteration. EUS done after 48 hours showed obliterated aneurysm
in all three patients.
One patient with a large 4.2 × 2.7-cm pseudoaneurysm needed two coils (16-mm) along
with 1.0 mL of glue in the first session. EUS done after 48 hours showed a patent
aneurysm. Therefore, one more 14-mm coil was placed and 1.0 mL of glue was injected
([Table 1]).
Two patients with aneurysms larger than 5 cm received three 16-mm coils and 1 mL of
glue each in the first session. EUS at 48 hours showed a patent aneurysm in both these
patients, necessitating injection of two additional 16-mm coils and 1 mL of glue in
each case to achieve complete obliteration.
Adverse events
No patient had any procedure-related AE. There was no procedure-related death.
Follow-up
In all six patients, follow up EUS at 4 weeks and CT angiography at 3 months did not
show any flow in the pseudoaneurysm.
Discussion
In our experience, attempt at EUS-guided injection of coil and glue was associated
with technical and clinical success in all six patients with splenic artery pseudoaneurysm.
Patients with smaller aneurysms achieved complete obliteration after only one session
whereas those with larger aneurysms needed two sessions each. Also, the number and
size of the coils and volume of glue used were larger for larger pseudoaneurysm. Aneurysms
up to 3 cm needed only one coil each, whereas larger ones (3 – 5 cm) needed four coils,
and those with diameter exceeding 5 cm needed five coils each. No patient developed
any complication. Pseudoaneurysm remained obliterated during 12-week follow-up.
Splenic artery pseudoaneurysms are potentially fatal and hence treatment is recommended
if these exceed 2 cm in diameter, are increasing in size, are associated with inflammation,
are symptomatic or occur in pregnant women or individuals with portal hypertension
[6].
Treatment options for splenic artery pseudoaneurysms include surgery and an endovascular
approach. Surgery carries a 1 % to 3 % risk of mortality and 9 % to 25 % risk of perioperative
complications arising primarily from splenic or pancreatic injury [7]. By comparison, endovascular therapy is associated with lower morbidity and mortality
and is thus the preferred treatment. The success rate for endovascular embolization
is 95 % and complications include technical failure to catheterize the artery, arterial
thrombosis or embolism resulting in organ infarctions or abscesses, coil migration,
aneurysm recurrence, and hematoma or pseudoaneurysm at the arterial puncture site
[7]
[8]. Minor complications (abdominal pain, fever) may follow endovascular repair as a
manifestation of postembolization syndrome (PES) [7]
[8].
EUS-guided therapy of splenic artery pseudoaneurysm is an evolving procedure with
only a few published cases [9]. It primarily involves targeting the pseudoaneurysm via the transgastric route and
obliterating it by injecting thrombin, coil and/or glue. Doppler confirms the presence
of aneurysm and absence of flow after obliteration.
EUS-guided coil and glue injection was technically and clinically successful in all
six patients. This compares well with the 95 % success rate for the endovascular approach
[6]. The number of sessions needed was two in patients with pseudoaneurysm exceeding
3 cm in diameter and one in patients with pseudoaneurysm smaller than this. The second
session could be safely done in all patients.
None of the patients with EUS-guided injection developed post-embolization syndrome,
an advantage over the endovascular approach. In a study by Lakin et al, three (6 %)
of 49 patients with splenic artery aneurysm treated by the endovascular approach needed
intervention for splenic abscess and 5 (10 %) patients developed post-procedure upper
abdominal pain with or without a documented splenic infarct. In addition, nine (18.4 %)
patients had some evidence of postembolization splenic infarction in the absence of
any symptoms or sequelae [10]. Patients with distal SAAs were at a higher risk for PES and/or asymptomatic splenic
infarction. There was no rupture or mortality in patients treated with treated with
EUS-guided coil and glue.
Conclusion
To conclude, EUS-guided coil and glue injection for splenic artery pseudoaneurysm
is feasible with high technical and clinical success rates, and without any AEs and
can be repeated safely if needed. Considering the rarity of the disease and the technical
expertise needed, there is need for a multicenter study to further assess the role
of this therapy in treatment of splenic artery pseudoaneurysms.
