Sole stenting of large and giant intracranial aneurysms with self-expanding intracranial stents-limits and complications.
ABSTRACT Intracranial aneurysms may be difficult for endovascular treatment due to size, fusiform shape, or wide neck. In such patients, intracranial stents are used to support the coils in the aneurysm sac, or they may be used as a sole stenting technique to divert the blood flow without coils. The aim of this paper is to contribute to the existing data by reviewing the risks of sole stenting of large and giant aneurysms.
We treated seven patients with nine aneurysms by self-expanding intracranial stents, either by a single or multiple stents in a stent-in-stent configuration. The follow-up was performed by digital subtraction angiography with a mean follow-up time of 6 months.
A positive response to stenting occurred in five out of seven patients (71%) and six out of nine aneurysms (67%). The aneurysms were occluded in two patients, and incomplete results were noted in three patients. The symptoms due to the compression of cranial nerves resolved in four patients (57%). Procedure-related subarachnoid hemorrhage occurred in two out of seven patients (29%), with death of one patient as a result of hemorrhage (14%).
Sole stenting of large and giant aneurysms with self-expanding intracranial stents may be associated with a higher risk than previously reported. The effect of stenting on intra-aneurysmal flow in such aneurysms, even after the placement of multiple overlapping stents, seems to be unpredictable.
- World Neurosurgery 01/2013; · 2.42 Impact Factor
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ABSTRACT: Fusiform aneurysms of vertebrobasilar arteries pose great challenge to surgical and endovascular treatment, especially large and giant aneurysms. We retrospectively reviewed our experiences and results of endovascular treatments for a series of 10 consecutive patients with large and giant fusiform aneurysms. Eight patients underwent stents placement (5 patients) or stent-assisted coiling (3 patients), and 2 patients underwent proximal occlusion of the parent arteries. Retreatment was needed in 2 patients. With the exception of 1 patient who died of rebleeding after sole stenting, the remaining 9 patients had good outcome. Reconstructive strategies using stents is a useful alternative for large and giant fusiform aneurysms of the vertebrobasilar arteries.Clinical imaging 03/2013; 37(2):227-31. · 0.73 Impact Factor
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ABSTRACT: Carotid pseudoaneurysms of petrous localization are rare. They are mostly due to trauma, tumoral or infectious diseases, or a result of iatrogenic complications after skull base surgery. Symptoms such as facial paralysis are exceptional and have rarely been described in the literature until now. We report the case of a 64-year-old woman, who developed left peripheral facial paralysis induced by two carotid pseudoaneurysms in their intrapetrous section. The treatment is endovascular, despite the high morbidity rate. She was first put on antiplatelet medications, before the left carotid aneurysm was bypassed thanks to a self-expanding pipeline-type stent with flow diversion. The left peripheral facial paralysis was due to the compression exerted by the left carotid aneurysm, probably a congenital malformation. The progressive palsy recovery was fist due to the aneurysmal thrombosis, then to the secondary fibrosis.Skull base reports. 11/2011; 1(2):133-8.
Središnja medicinska knjižnica
Pavliša G., Ozretić D., Murselović T., Pavliša G., Radoš M. (2010) Sole
stenting of large and giant intracranial aneurysms with self-expanding
intracranial stents-limits and complications. Acta Neurochirurgica, 152
(5). pp. 763-9. ISSN 0001-6268
University of Zagreb Medical School Repository
Sole stenting of large and giant intracranial aneurysms with self-expanding intracranial
stents – limits and complications
Goran Pavlisa1, David Ozretic1, Tamara Murselovic2, Gordana Pavlisa3, Marko Rados1
1Clinical institute of diagnostic and interventional radiology, University hospital center
Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
2Clinic of anesthesiology, reanimatology and intensive care, University hospital center
Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
3Special hospital for pulmonary diseases, Rockefellerova 3, 10000 Zagreb, Croatia
Goran Pavlisa, MD, PhD
Clinical institute of diagnostic and interventional radiology, University hospital center
Kispaticeva 12, 10000 Zagreb
Intracranial aneurysms may be difficult for endovascular treatment due to size, fusiform
shape or wide neck. In such patients, intracranial stents are used to support the coils in the
aneurysm sac, or they may be used as a sole stenting technique to divert the blood flow
without coils. The aim of this paper is to contribute to the existing data by reviewing the
risks of sole stenting of large and giant aneurysms.
We treated 7 patients with 9 aneurysms by self-expanding intracranial stents, either by a
single or multiple stents in a stent-in-stent configuration. The follow-up was performed
by digital subtraction angiography, with a mean follow-up time of 6 months.
A positive response to stenting ocurred in 5 out of 7 patients (71%), and 6 out of 9
aneurysms (67%). The aneurysms were occluded in 2 patients, and incomplete results
were noted in 3 patients. The symptoms due to the compression of cranial nerves
resolved in 4 patients (57%). Procedure-related subarachnoid hemorrhage occurred in 2
out of 7 patients (29%), with death of one patient as a result of hemorrhage (14%).
Sole stenting of large and giant aneurysms with self-expanding intracranial stents may be
associated with a higher risk than previously reported. The effect of stenting on
intraaneurysmal flow in such aneurysms, even after the placement of multiple
overlapping stents, seems to be unpredictable.
Keywords: Intracranial aneurysm; sole stenting; self-expanding stent; large and giant
Endovascular options in the treatment of intracranial aneurysms are expanding by the
recent advances of materials and techniques. Aneurysms which are difficult for treatment
due to wide neck, fusiform shape and incorporation of arterial branches are being treated
by three-dimensional coils, balloon or stent-assisted coiling, parent artery occlusion,
liquid embolics or combinations of these approaches [1,12,21,22,]. Various types of
coronary and intracranial stents are used to support the coils in the aneurysm sac and/or
to promote the thrombosis of the aneurysm and neointimal proliferation at the aneurysm
neck by flow diversion. Stents may be used without coiling for the purpose of aneurysm
thrombosis, in sole stenting technique, with favourable results [4,17,27,28,29,30,31,32],
although serious complications have been described . New devices in forms of stents
with a high-density wire mesh are being investigated and used in daily practice, with a
potentially good compromise between flow diversion and preservation of perforating
arterial branches [13,19]. However, the publications concerning sole stenting include a
relatively small number of patients with limited follow-up time.
We retrospectivelly analyzed our results on 7 patients with large and giant aneurysms
treated by sole stenting with self-expanding intracranial stents. The aim of this paper was
to contribute to the existing data and emphasise possible risks of this technique.
METHODS AND MATERIALS
Indications for treatment were assessed for every patient by neuroradiologist performing
endovascular treatment, vascular neurosurgeon and neurologist. The patients were
referred to endovascular treatment due to the location of aneurysms on cavernous internal
carotid artery (ICA) and basilar artery and their large and giant size, both of which factors
are associated with higher surgical risks [9,25]. Extradural location of aneurysms and
their wide neck or fusiform shape were considered suitable for sole stenting. All the
patients were treated on a single-plane digital angiography system (Axiom Artis FA;
Siemens AG, Erlangen, Germany), by self-expanding stents designed for intracranial
vessels: Enterprise vascular reconstruction device (Codman Neurovascular, Warren, NJ),
LEO Plus stent (Balt Extrusion, Montmorency, France) and Neuroform3 stent (Boston
Scientific, Natick, MA). We aimed to use multiple closed-cell stents in a stent-in-stent
configuration to achieve higher surface area coverage of the aneurysm neck. An open-cell
Neuroform3 stent was placed in one patient, before the introduction of Enterprise and
LEO stents in our practice. The choice between Enterprise and LEO stents was mostly
influenced by their availability in our institution, as were the decisions to place a single
stent in two patients. Pre-procedural dual antiplatelet medication consisted of 75 mg of
clopidogrel daily and 100 mg of acetylsalicylic acid (ASA) daily during 3 days, or a
loading dose of 300 mg of clopidogrel and 325 mg of ASA at least 4 hours before the
procedure. The patients were heparinized during the procedure in order to double the
baseline activated clotting time. The procedures were performed with patients in general
After the treatment, dual antiplatelet regimen was maintained for 6 weeks, and 100 mg of
ASA daily was administered lifelong.
The follow-up of patients with endovascularly treated aneurysms in our institution is
routinely performed 3 months after the treatment by 3D time-of-flight magnetic
resonance angiography, and 6-12 months after the treatment by digital subtraction
angiography (DSA). In patients treated by sole stenting, however, the follow-up was
performed by DSA to avoid misinterpretation due to magnetic resonance signal from
expected thrombus in the aneurysm and artifacts caused by metallic stents. The follow-up
examinations were performed after 3 months and in the period from 6-12 months after the
This paper has been written in accordance with ethical standards laid down by the
declaration of Helsinki and after the appropriate insitutional clearance. All the patients
gave their informed consent for enrollment in this retrospective research.
Among 311 patients with intracranial aneurysms treated endovascularly in our institution
from 2003 to 2009, 7 patients (6 female, 1 male) with large and giant aneurysms were
treated by sole stenting. The mean age of the patients was 59 years, ranging from 43 to
81. Three patients had giant aneurysms, over 25 mm in diameter, while 4 patients had
large aneurysms, measuring 10-25 mm. The mean size of large and giant aneurysms was
20 mm. One patient with a large cavernous ICA aneurysm had two additional small
aneurysms at C7 segment of the same artery, and stents covered the necks of all three
Demographic data, characteristics of the aneurysms, type and number of implanted stents
and results of the treatment are provided in Table 1. The Enterprise stent is manufactured
only in a diameter of 4.5 mm, so Table 1 provides only the lengths of implanted stents.
All the patients were symptomatic with ophtalmoplegia present in five patients, due to
cranial nerve compression. One patient with a partially thrombosed basilar trunk
aneurysm (Patient 3) presented with right-sided hemiparesis caused by brainstem
ischemia. One patient had impaired conscioussness, paresis of tongue and palate and
progressive tetraparesis due to brainstem compression by the giant basilar artery
A total of 16 intracranial stents were deployed, the majority of which were closed-cell
stents: 12 Enterprise stents and 3 LEO stents, while one stent was an open-cell
Neuroform3 stent. 5 patients were treated by multiple stents, and 2 patients received a
There were no immediate complete angiographic exclusions of the aneurysms from
circulation. Immediate partial result, seen angiographically as partial exclusion of the
aneurysm from circulation or slower intraaneurysmal flow, occured in 5 patients, while in
2 patients there were no immediate results.
Angiographic follow-up ranged from 3 months to 1 year, with a mean follow-up time of 6
months. At follow-up, the aneurysms were completely thrombosed in 2 patients and
incomplete results were noted in 3 patients, for a total of 5 patients or 71%. This positive
response to stenting occurred in 6 out of 9 aneurysms (56%): 5 large and giant
aneurysms and 1 small aneurysm in a patient with multiple aneurysms. In one patient
there was no change in aneurysm size and morphology after one year. Two patients with
previously unruptured aneurysms suffered subarachnoid hemorrhage on the second and
third day after the treatment, respectivelly. One of these patients died 3 days after the
treatment and the death was considered procedure-related.
The overall complication rate was 29% (2/7 patients), which included SAH in one patient
and SAH and ischemia in the other patient. The procedure-related mortality was 14% (1/7
The symptoms due to the compression of surrounding structures, mainly cranial nerves,
resolved in 4 patients (57%) with ICA aneurysms: in one patient with a complete
occlusion of the aneurysm, in two patients with partial results and in one patient with no
One patient with an immediate partial result had no further angiographic improvement
after 6 months and was treated by additional coiling. One patient that had no
angiographic result 1 year after sole stenting remained in follow-up without further
treatment, since her symptoms due to extradural ICA aneurysm were gradually resolving.
A 51-year old man was hospitalized for a planned treatment of an unruptured giant
basilar trunk aneurysm. Patient had altered consciousness with somnolence progressing
to stupor during weeks before the treatment, paresis of tongue and palate and progressive
tetraparesis due to brainstem compression by the giant basilar artery aneurysm.
Angiography preceding the implantation of stent was performed by double injection of
the contrast agent in both vertebral arteries to precisely evaluate the aneurysm, since there
was no adequate visualization of basilar artery itself in previous examination. The
aneurysm was arising at the level of anterior inferior cerebellar arteries, with slow and
diminished distal flow, which was visible only after an injection through a microcatheter
(Prowler select plus, 0,021, Codman Neurovascular, Warren, NJ) (Figure 2a,b). Three
Enterprise stents (two stents 4,5 mm x 37 mm, one stent 4,5 mm x 28 mm) were
implanted in a stent-in-stent configuration across the aneurysm neck with a marked
reduction of flow in the aneurysm and improvement of distal flow (Figure 2c,d). The
patient has been kept on dual antiplatelet regimen after the procedure, and experienced
significant improvement of his clinical condition, untill on the third day after the
treatment he lost conscioussness. Computed tomography (CT) scan revealed diffuse
subarachnoid and intraventricular hemorrhage with brain edema, and the patient died.
Retrograde analysis of angiographic images led to a conclusion that the site of rupture
may have been at the distal part of the aneurysm, near the neck, probably due to the
redistribution of blood inflow (Figure 2d). Contrast retention in the aneurysm may have
been associated with reduced blood outflow.
A 54-year old female patient presented with left retroorbital pain and diplopia of the left
eye. She had prominent palsy of the left abducens nerve. CT and CT angiography
disclosed a large unruptured aneurysm of the C7 segment of the left ICA and she was
referred to endovascular treatment. After dual antiplatelet preparation, the neck of the
aneurysm was bridged by 4 closed-cell stents in a stent-in-stent configuration, with
immediate slowing of the blood flow in the aneurysm with narrower inflow and improved
distal flow (Figure 3a,b). There were no intraprocedural complications, and the patient
was kept on dual antiplatelet medications. 24 hours after the procedure, she developed
sudden right hemiparesis and lost conscioussness. CT scan revealed acute subarachnoid
hemorrhage and an acute ischemia in the left anterior and middle cerebral artery territory
(Figure 3c,d). At MR angiography there was no flow in the left terminal ICA, the
aneurysm and left MCA. The patient gradually stabilized and was transferred to a
Sole stenting was reported for the first time as an ancillary method to stent-assisted
coiling [14,18], and is recently receiving attention as a planned definitive method of
treatment of intracranial aneurysms. This method is appealing since modern intracranial
stents are easily deployed, even in a stent-in-stent fashion, with low risk for vessel injury
and short procedure times. Furthermore, thromboembolic events seem to be less frequent
in patients who undergo stent-assisted coiling then in those treated by coiling alone,
probably attributed to antiplatelet medications, accentuating the safety of stenting . In
comparison with coiling, which aims to fill the aneurysmal sac, stenting has the
theoretical advantage of treating the diseased segment of the parent artery wall where the
aneurysm arises. Published results are mostly in favor of this technique, although the rate
of complications may reach up to 10% [8,17,32].
We retrospectivelly analyzed our results on 7 patients treated by stenting. These results
are poor, with complete occlusion of aneurysms in 2 patients at the mean follow-up time
of 6 months, which may not be the sufficient follow-up time for the full effect of stent to
Aneurysms in two patients ruptured within 3 days of the procedure and one patient died
as a result of treatment. These results may be partially due to the fact that the patients had
large and giant symptomatic aneurysms with wide neck or fusiform in shape, which are
difficult for any type of treatment. Nevertheless, the rupture of 2 out of 7 treated large
and giant aneurysms within days of the procedure represents a high bleeding rate of 29%
which was unexpected, especially having in mind that these two aneurysms were treated
by 3 and 4 overlapping stents, respectively. This was expected to result in a higher
surface area coverage of the orifice of the aneurysm, providing additional security against
rupture. The pathogenesis of rupture of these aneurysms after treatment is not entirely
clear. Both procedures were uneventful, with short procedure times and with standard
pre- and postprocedural antiplatelet regimen, which is accepted by most authors. After
the procedures, the patients were monitored in neurological intensive care units, with no
adverse events noted. In these two patients, we speculate that the causes of rupture may
have been a changed direction and narrowing of blood inflow, since the computational
dynamics of in-vivo intraaneurysmal flow showed that ruptured aneurysms may have a
changing region of impingement as well as narrower inflow jets, compared to unruptured
ones . The sizes of aneurysms in these two patients were 31 mm and 20 mm,
respectively. Such size inevitably stretches the wall of the aneurysm, making it thin and
inflexible. Therefore it is more vulnerable to rupture by the suddenly narrowed inflow jet
of blood, which is directed to a different part of the aneurysm as a result of stents at the
orifice of the aneurysm. In both patients, at final angiograms at the end of the procedure,
the inflow jets were oriented slightly more distally at the upper portions of the
aneurysms, compared to pre-treatment angiograms, supporting this hypothesis.
The other factor which we should consider is the outflow from the aneurysm, which is
most probably reduced as well, and may be seen angiographically as the retention of
contrast in the aneurysm. Although it suggests slowing of the intraaneurysmal blood flow
which promotes thrombosis, it may be dangerous if combined with persistent and
narrower inflow jet. The subsequent rise of intraaneurysmal pressure may result in
rupture . Although some authors report similar complications , the overall rate of
SAH after sole stenting is low, up to 2.1 % [10,11,32]. These reports focused on the
treatment of small aneurysms, in contrast to those in our patients, which may be the cause
of significantly higher rate of post-treatment aneurysm rupture in our series.
In patient 6, there were signs of bleeding as well as a large ischemic infarction. We
speculate that the aneurysm ruptured and subsequently the formation of thrombus
occluded both the aneurysm and the parent artery, causing ischemia.
Antiplatelet medication and risk of hemorrhage
Stenting is proposed to promote aneurysm thrombosis by redistribution of flow away
from the aneurysm, by bridging of the diseased vessel wall at the aneurysm neck and by
the change of arterial angle. At the same time, porosity of the stent preserves perforating
arteries. The process of aneurysm thrombosis is, however, hampered by the necessity of
antiplatelet medications, which may be an inherent problem of the technique.
We excluded the patients who had previous subarachnoid hemorrhage due to the need of
pre- and postprocedural antiplatelet therapy, although there is growing body of data
indicating that the risk of rebleeding after stenting of acutely ruptured aneurysms is very
low [11,20,24,26,32]. However, these studies varied regarding the timing and the type of
antiplatelet medication, using intraprocedural abciximab and postprocedural ASA and
clopidogrel therapy ; ticlopidine postprocedurally ; or intraprocedural tirofiban
and ASA and clopidogrel after the treatment . We avoid stenting in the setting of
acute SAH whenever possible, since there are no clear guidelines regarding antiplatelet
therapy, and the number of reported patients treated by this method is still relatively
Design and number of stents
We treated all the patients with dedicated intracranial stents, mostly of a closed-cell type.
These stents are, however, designed primarily for a purpose of stent-assisted coiling, not
for the reconstrution of blood flow in the parent artery. Other devices, such as balloon-
expandable coronary stents, are more rigidly structured and may provide additional
change of arterial angle with more accentuated flow redistribution . Such stents also
have up to three times higher surface area coverage than self-expanding stents. This may
contribute to a higher degree of aneurysm occlusion [30,31]. On the other hand, both
aneurysms that ruptured after stenting in our series were bridged by multiple stents,
which probably provided a comparable or even higher surface area coverage and rigidity
compared to balloon expanding stents. This density of mesh across the aneurysm neck
may, however, only be assumed, since there is no possibility of actual visualization of
overlapping stent struts during flouroscopy.
It may be difficult to decide how many intracranial stents should be applied across the
neck of the aneurysm to adequately redistribute the flow. Double-stenting method has
been suggested as more efficient [5,16,24], and we aimed to place multiple stents in our
patients. The drawback of such treatment is virtually impossible microcatheterization of
the aneurysm in case of recanalization or regrowth.
Our study is limited by a small number of patients and a heterogeneity regarding the type
of stents we used. Longer follow-up of the patients may be necessary.
In conclusion, this limited series suggests that the results of sole stenting in the
endovascular treatment of large and giant aneurysms may be unpredictable with the
possibility of severe complications. The use of coronary stents in the management of
small wide-necked aneurysms may bring more satisfying results.
The authors declare to have no conflict of interest.