We would like to thank our colleagues for reading our publication and
for the thorough review of the paper. We greatly look forward to reading
their own experience and believe that it will add substantially to the
literature on this new and interesting device.
At the outset we would like to make it clear that we stand by our
initial comment in saying that we believe the combination of a MED and
other devices,...
We would like to thank our colleagues for reading our publication and
for the thorough review of the paper. We greatly look forward to reading
their own experience and believe that it will add substantially to the
literature on this new and interesting device.
At the outset we would like to make it clear that we stand by our
initial comment in saying that we believe the combination of a MED and
other devices, in particular intra-luminal FDS may have excellent and
extremely rapid results. To that end we are currently in the process of
collating our cases of this nature in preparation to submit for
publication but we have seen extremely rapid aneurysm exclusion.
The use of adjunctive devices in some instances was not planned. In
one case, which was discussed in the original article, after deployment of
the MED it was noted that the residual flow into the aneurysm had been
inadvertently redirected into an aneurysm bleb. We do not believe this
was due to a sizing issue but rather an effect that can occur from the
position of the petals which can in our experience be relatively difficult
to determine even after deployment of the MED. We did not feel this was a
safe situation to leave the aneurysm and therefore treated the bleb with
coils. A similar situation was encountered with the basilar tip aneurysm.
In both scenarios we felt uncomfortable leaving parts of the aneurysm
unprotected. The use of FDS was to treat the aneurysm neck in certain
cases e.g. the patients represented in Fig. 8 and 9. However, in another
case the use of the FDS was not to treat the aneurysm with MED's but an
adjacent blister like aneurysm (Fig. 10). Furthermore, in patient 9, again
there were multiple aneurysms on the right with only one suitable for
treatment with MED and therefore the placement of the FDS subsequently
served as an additional treatment strategy for the other smaller aneurysms
as well as the aneurysm that contained the MED. This patient represented
one of our first patients in whom we used the MED and hence our
understanding of its pro's and con's was not fully developed.
Our reasoning for the deployment of MED and FDS was covered in the discussion section of our publication. However, in our literature search for our upcoming paper we have come across evidence which we believe supports our initial assertion of the effectiveness of MED+FDS. Jing et al [1] recently published their work on the heamodynamic effect of flow diverters in combination with coils in large and giant aneurysms. The FDS used in this study was the Tubridge FDS. Their computational fluid dynamics (CFD) study showed that the combination of coils and FDS resulted in significantly decreased intra-aneurysmal flow velocity, wall shear stress and increase in low wall shear area with a decrease of 54%, 66% and increase of 1001% respectively. Damiano et al [2] recently showed that the principle action of FDS, in the early stages of treatment, are flow redirection away from the aneurysm with 2 overlapping FDS compounding the effect but no significant increased effect seen with the addition of a third FDS. In this study the role of coils was to disturb aneurysmal flow, reduce intra-aneurysmal flow velocity and WSS and disturb aneurysmal flow patterns when the coil packing density exceeds 11%. Below this level the coils may have a scaffolding effect for intra-aneurysmal thrombus but do not appear to have a significant heamodynamic effect. It is likely that the MED has a heamodynamic effect greater than 11% coil packing density, although we are unaware of any studies that have looked at this. Therefore, the combination of MED and FDS is likely similar to that of FDS and coils with high packing density, a strategy which has shown a higher occlusion rate and lower rate of retreatment in a recent study by Lin et al. [3].
Whilst it is indeed true that the MED was not used as the sole device
in many of our aneurysms our primary aim when using this device was to
determine its effectiveness in a 'real-world' setting. As the device is
designed to adopt a spherical shape, and if it was only used in spherical
aneurysms, it would only be suitable for use in approximately 1/3 of
unruptured aneurysms according to the study of You et al [4]. This
problem was covered in the discussion. We chose to use the MED in non-
spherical aneurysms because we believed that the flow disruption caused by
the device inside the aneurysm would nevertheless promote thrombosis.
Furthermore, in the first publication regarding the MED, by Turk et al[5],
1/3 of the aneurysms were not 'spherical'. For example, patient 1 in the
series of Turk et al. had an aneurysm with dimensions 12.1 x 7.24 x 5.47mm
and yet at 1 month follow-up occlusion was reported as 95%. In addition
this group also used a 'sequential' filling of an ACOM aneurysm that is
represented in Fig. 3 and 4 in their publication. This was a strategy that
we have used that takes advantage of the flow disrupting effect but not
really of the shape the MED adopts.
The use of adjunctive devices such as the pCONus may or may not
hamper the deployment of the device but as of yet there is no evidence to
suggest a conclusion. The assertion that the pCONus somehow interfered
with the deployment of the MED appears to be nothing more than conjecture.
Our standard procedure is to mechanically detach the pCONus as the last
step in any procedure involving it. As such we may reposition it in
during the coiling or MED deployment procedure and hence we may reposition
it to allow maximum neck protection and minimum 'hampering' with any intra
-saccular devices be they coils or MED's.
We agree with the authors that the follow-up period is short and we
hope to publish subsequent studies in the future with longer-term follow-
up. However, the follow-up period in the original Turk et al. [5] paper
was also short with 1 month angiographic follow-up available for 5/9
aneurysms and no occlusion seen in 2 of the 5 with early follow-up. Our
publication was not meant to be a study with long term follow-up, rather
our initial experience and insights that we believed may be useful to our
colleagues should they wish to use the MED. We are therefore slightly
confused as to why short-term follow-up is a problem in our paper but not
in the paper of Turk et al.
With regards to sizing, this is perhaps also a matter of debate. It
is important to recall that very recently the sizing recommendations of
the WEB were altered based on clinical experience and observation. As
discussed earlier the problem with sizing relates to the spherical shape
of the MED. In our cases that are said to be undersized the MED was
actually sized to fit the most 'spherical' part of the aneurysms. By
oversizing the MED one cannot predict how the leaflets will position
themselves and then one cannot predict the effect on flow created by the
device. This was described for one of our cases (Fig. 5c) despite using
our sizing technique and this inability to accurately predict the position
of the leaflets has been one of our main observations.
As suggested by the authors coils would be an alternative, and in
fact would be an excellent alternative in all of these cases, although the
additional uses of stents, neck bridging devices etc. may still be needed.
The issue of cost is of course important however, with the current cost of
the device relative to coils, the use of 2 MED's is approximately the
equivalent cost to 40coils - and very few aneurysms would require this
many coils. In fact very few aneurysms require 20 coils and therefore, the
issue reverts to the speed and security of any occlusion obtained. This
then reverts back to our original supposition that the combination of
intra-saccular and intra-luminal flow diversion. We believe that a rapid
and durable aneurysm exclusion can be achieved through a single intra-
luminal flow diverter and in all likelihood only one or two MED's.
In conclusion we thank the authors for their comments and look
forward to reading their publication in the coming months. We hope they
will also enjoy our second publication dedicated to the use of intra-
luminal and intra-saccular flow diversion.
Funding Statement
This research received no specific grant from any funding agency in the
public, commercial or not-for-profit sectors
Conflict of interest
MAP, PB and RMM serve as proctors and consultants for phenox GmbH, with
moderate financial compensation.
HH is a co-founder and shareholder of phenox GmbH.
The other authors have no potential conflict of interest.
References:
1 Jing L, Zhong J, Liu J, et al. Hemodynamic Effect of Flow Diverter and
Coils in Treatment of Large and Giant Intracranial Aneurysms. World
Neurosurg 2016;89:199-207. doi:10.1016/j.wneu.2016.01.079
2 Damiano RJ, Ma D, Xiang J, et al. Finite Element Modeling of
Endovascular Intervention Enables Hemodynamic Prediction of Complex
Treatment Strategies for Coiling and Flow Diversion. J Biomech
2015;48:3332-40. doi:10.1016/j.jbiomech.2015.06.018
3 Lin N, Brouillard AM, Krishna C, et al. Use of coils in conjunction
with the pipeline embolization device for treatment of intracranial
aneurysms. Neurosurgery 2015;76:142-9. doi:10.1227/NEU.0000000000000579
4 You S-H, Kong D-S, Kim J-S, et al. Characteristic features of
unruptured intracranial aneurysms: predictive risk factors for aneurysm
rupture. J Neurol Neurosurg Psychiatry 2010;81:479-84.
doi:10.1136/jnnp.2008.169573
5 Turk AS, Maia O, Ferreira CC, et al. Periprocedural safety of aneurysm
embolization with the Medina Coil System: the early human experience. J
Neurointerventional Surg 2016;8:168-72. doi:10.1136/neurintsurg-2014-
011585
Conflict of Interest:
MAP, PB and RMM serve as proctors and consultants for phenox GmbH, with moderate financial compensation.
HH is a co-founder and shareholder of phenox GmbH.
The other authors have no potential conflict of interest.
Dear Editor,
We read with great interest the original article by Boned S. et al. (1)
which demonstrates that CT perfusion (CTP) may overestimate the final
infarct core, especially in the early time window. Interestingly, the
authors introduce the "ghost infarct core" concept in ischemic stroke,
referring to that particular condition where the final infarct core at
follow up imaging may be smaller than the one observed on...
Dear Editor,
We read with great interest the original article by Boned S. et al. (1)
which demonstrates that CT perfusion (CTP) may overestimate the final
infarct core, especially in the early time window. Interestingly, the
authors introduce the "ghost infarct core" concept in ischemic stroke,
referring to that particular condition where the final infarct core at
follow up imaging may be smaller than the one observed on admission CTP.
We think that some considerations on this topic might be useful.
The "ischemic core" and "penumbra" theoretical concepts are now fully
accepted as they identify respectively the tissue which is already dead
(core), whilst the so-called "penumbra" is the ischemic but still living
brain tissue which is no longer functional and will therefore die, unless
blood flow is rapidly restored. With current advances in endovascular
treatment, the identification by imaging techniques of both core and
penumbra is constantly changing. However, the possibility to identify them
with CTP through blood flow measurements is unfortunately affected by
conceptual and technical pitfalls.
First of all, a single time point perfusional measurement, such as
cerebral blood volume (CBV) or other related parameters, may not be a
reliable indicator of whether that tissue will live if left alone or,
conversely, survive if reperfused (2). It is known that any attempt to
determine the tissue vitality or its necrosis with hemodynamic perfusion
can only be represented from a single snapshot in time, but this
assumption is however misleading. Conversely, core and ischemic penumbra
concepts are both "time" and "intensity" dependent (3). For example, the
tissue with a CBV of less than 2 mL/100 g/min may survive for 10 minutes,
but probably not for 3 hours. Cell death following ischemic stroke is a
dynamic process depending on numerous variables (collateral vessels,
metabolic state, depolarization, apoptosis, etc) which are not yet fully
understood (4). This condition makes a single time perfusion study easily
prone to errors and, therefore, it may be expected that this method will
provide an unreliable estimate extension of the final infarct core.
There are also few technical limitations inherent to the imaging
technique: the calculation methods (either deconvolution or non-
deconvolution based), the choice of the arterial input function (AIF), the
lack of standardization in post-processing between vendors and
laboratories and, lastly, the poor signal-to-noise ratio (SNR) of CTP
derived images which makes them too "noisy" (5). Accordingly, we are of
the opinion that CTP cannot compete with the sensitivity (which is nearly
100%) (6) of the diffusion weighted imaging (DWI) technique in detecting
the ischemic core. Indeed, DWI is able to identify the tissue that is
irreparably damaged, as it shows the cytotoxic edema due to metabolic
impairment and irreversible energetic failure of the cell. Although it may
be argued that DWI abnormalities might sometimes reverse, this is however
rather unusual (7). The uncertainty of measurements based on CTP may also
limit the number of patients for whom the decision on whether to proceed
with endovascular treatment based on core infarct size could be justified
or not.
The "small core-occlusion paradigm" (8) through good quality non-enhanced
CT and CT angiography (also called "CT-based paradigm") might represent
instead a simple, alternative and pragmatic approach for selecting those
patients eligible for endovascular treatment, without the risk of
incurring in CTP-based over- or under-estimated measurements of the core.
Thus, every effort to define the ischemic core in a reliable manner would
be vain due to the inability in exceeding the intrinsic limit of
hemodynamic measurement carried out "at a single time" with perfusion
imaging.
References
1) Boned S, Padroni M, Rubiera M, Tomasello A, Coscojuela P, Romero
N, Muchada M, Rodriguez-Luna D, Flores A, Rodr?guez N, Juega J, Pagola J,
Alvarez-Sabin J, Molina CA, Rib? M. Admission CT perfusion may
overestimate initial infarct core: the ghost infarct core concept. J
Neurointerv Surg. 2016 Aug 26. pii: neurintsurg-2016-012494. doi:
10.1136/neurintsurg-2016-012494. [Epub ahead of print]
2) Lev MH. Acute stroke imaging: what is sufficient for triage to
endovascular therapies? AJNR Am J Neuroradiol. 2012;33(5):790-2.
3) Davis S, Donnan GA. Time is Penumbra: imaging, selection and
outcome. The Johann jacob wepfer award 2014. Cerebrovasc Dis.
2014;38(1):59-72.
4) Sheth SA, Liebeskind DS. Collaterals in endovascular therapy for
stroke. Curr Opin Neurol. 2015;28(1):10-5.
5) Gonzalez RG. Low signal, high noise and large uncertainty make CT
perfusion unsuitable for acute ischemic stroke patient selection for
endovascular therapy. J Neurointerv Surg. 2012;4(4):242-5.
6) Schellinger PD, Bryan RN, Caplan LR et al. Evidence-based
guideline: The role of diffusion and perfusion MRI for the diagnosis of
acute ischemic stroke: report of the Therapeutics and Technology
Assessment Subcommittee of the American Academy of Neurology. Neurology
2010; 75:177-185.
7) Campbell BC, Purushotham A, Christensen S, Desmond PM, Nagakane Y,
Parsons MW, Lansberg MG, Mlynash M, Straka M, De Silva DA, Olivot JM,
Bammer R, Albers GW, Donnan GA, Davis SM; EPITHET-DEFUSE Investigators.
The infarct core is well represented by the acute diffusion lesion:
sustained reversal is infrequent. J Cereb Blood Flow Metab. 2012;32(1):50-
6.
8) Demchuk AM, Menon B, Goyal M. Imaging-based selection in acute
ischemic stroke trials - a quest for imaging sweet spots. Ann N Y Acad
Sci. 2012;1268:63-71.
1. Department of Interventional Neuroradiology. Pitie-Salpetriere Hospital.
APHP. Paris France.
2. Paris VI University Pierre et Marie Curie. Paris. France
* Corresponding author
We read with great interest the case series entitled: "The Medina
Embolic Device: early clinical experience from a single center" by Aguilar
Perez M et al, recently published online in JNIS. 1 We would like to
congratulate the authors for this interesting feedback from their
preliminary experience, the largest published to date, with a new device
that combines the design of a detachable coil and the one of a
intrasaccular flow disrupter device: the Medina Embolization Device (MED)
(Medtronic, Irvine, CA). 2
However, we would like to make some comments and raise some disagreements
with the Methods used in this retrospective case series.
First, in the Abstract, the authors state that their objective was "To
report (their) initial experience with the Medina Embolic Device (MED) in
unruptured intracranial aneurysms either as sole treatment or in
conjunction with additional devices". However, only 2/15 patients (13%)
were treated by means of MED alone or MED with filing coils. Although we
agree with the authors that the use of adjunctive devices such as balloon
remodeling, support devices such as pCONus (Phenox, Bochum, Germany) or
PulseRider (Codman Neurovascular, Raynham, MA) or even filing coils
deployed in the MED's mesh, may not, by themselves, dramatically affect
the angiographic outcome and the occlusion rate, we would like to stress
the fact that additional flow diverter stent (FDS) deployed during the
same session or after early follow-up, prevents from any conclusion about
the angiographic outcome with the MED. Indeed, FDS (p64, Phenox) were
deployed in 47% (7/15) of the cases in this series either during the
procedure or after early follow-up. Since, FDSs are not adjunctive tools
but therapeutic tools by themselves, they may have a dramatic influence on
the angiographic outcome. Additionally, one may wonder why using MED for
loose intra-saccular packing in large paraclinoid aneurysms treated by FDS
(like in Patients # 9 and 14). The use of regular coils would be easier,
sufficient for aneurysm occlusion and more cost-effective.
Second, we would like to underline the fact that the use of a support
device like the pCONus (20% [3/15] of the cases in this series), with
flares deployed inside the aneurysm, may hamper the satisfactory
deployment of the MED's petals, especially at the neck. This may lead to
an incomplete sealing of the neck and finally to inadequate occlusion of
the aneurysm, as shown in the Figure 7 of the article.
Third, the delay for the angiographic follow-up is very short
(average: 2.2 months). We believe that it is impossible to evaluate the
effect of an endosaccular device with such a short-term follow-up,
especially if patients are under dual anti-platelet therapy (in at least
13/15 patients in this series). As observed with other endovascular flow
disruption devices such as the WEB (Sequent Medical, Aliso Viejo, CA) or
LUNA (NFocus/Covidien, Irvine, CA), the mechanism that leads to aneurysm
occlusion is a gradual thrombosis triggered by the flow disruption effect.
3 Consequently, the occlusion of the aneurysm's sac obtained with MED may
be delayed and cannot be evaluated with an as short delay as the one
provided in this article.
Finally, we have some concerns about the choice of the aneurysms
treated by MED in this series and about the sizing. Indeed, the MED is a
spherical device that may be suitable mostly for spherical or ovoid
aneurysm, especially with wide neck. Probably a conical shape (patient #
6) or an irregular giant aneurysm as presented in Figure 12, are a priori
not suitable for the MED.
We also tried to find the aneurysms' size as well as necks' size in the
article, in vain. For instance, on Figure 8, the aneurysm's largest
diameter is obviously over 10 mm. However, the largest diameter available
to date in MED in 9 mm. Additionally, why the authors chose to undersize
the MED in spherical aneurysms ("In spherical saccular aneurysms with a
fundus diameter of 9 mm or less, the size of the first framing MED was
purposely undersized by about 1 mm"). We do believe that one should at
least use the same size as the aneurysms' maximum diameter for the first
MED Framer or even oversize by 1 mm. The rational of our strategy is that
it allows for a satisfactory application of the petals along the
aneurysm's wall, and across the neck, which is of tremendous importance to
obtain a neck sealing and subsequently a flow disruption effect. In the
Figures 5, 6 and 8, the MED is obviously undersized, which lead to
incomplete covering of the neck by the petals and thus to residual filing
of the sac and the bleb. In our early monocenter experience, presented at
the ABC-WIN 2016 congress 4 and under consideration for publication in
another journal, using a proper sizing strategy, we obtained an 83% (10/12
cases) occlusion rate at angiographic follow-up (average delay: 5.2
months).
Owing to the above-mentioned drawbacks in the Methods of this case
series, we think that the only conclusion that can be drawn from this
article is that the MED can be safely deployed in an intracranial aneurysm
in a human been. Other considerations on the effectiveness in terms of
angiographic outcome cannot be supported by the data presented in this
series.
References
1. Aguilar Perez M, Bhogal P, Martinez Moreno R, et al. The Medina Embolic
Device: early clinical experience from a single center. J Neurointerv Surg
2016.
2. Turk AS, Maia O, Ferreira CC, et al. Periprocedural safety of aneurysm
embolization with the Medina Coil System: the early human experience. J
Neurointerv Surg 2015.
3. Asnafi S, Rouchaud A, Pierot L, Brinjikji W, Murad MH, Kallmes DF.
Efficacy and Safety of the Woven EndoBridge (WEB) Device for the Treatment
of Intracranial Aneurysms: A Systematic Review and Meta-Analysis. AJNR Am
J Neuroradiol 2016.
4. Sourour N, Di Maria F, Vande Perre S, Gabrieli J, Chiras J, Clarencon
F. Medina devices in the treatment of wide neck intracranial aneurysms:
single-center preliminary experience. ABC-WIN annual congress, 2016.
Conflict of Interest:
F. Clarencon is consultant for Medtronic and Codman Neurovascular
NA Sourour is consultant Medtronic , MicroVention and investor for Medina
Letter by Parthasarathy et al. regarding article, "Unwanted
detachment of the Solitaire device during mechanical thrombectomy in acute
ischemic stroke ".
Letter by Parthasarathy et al. regarding article, "Unwanted
detachment of the Solitaire device during mechanical thrombectomy in acute
ischemic stroke ".
Department of Neurointerventional surgery, Institute of Neuroscience,
Medanta, the Medicity, Gurgaon, India.
Title word count: 14
Word Count: Abstract: 157; Manuscript count excluding references: 554
References: 4
Key words:Stentriever, mechanical thrombectomy, detachment, stent
based retrieval
Corresponding Author
Dr Vipul Gupta MD,
Additional Director and Head, Neurointerventional Surgery,
Medanta Institute of Neurosciences
Medanta - the Medicity,
Gurgaon 122001
Tel: 00919810542372
drvipulgupta25@gmail.com
Abstract:
Stent detachment is a dreaded device complication in the setting of
acute stroke management and may result in poor outcome. The principal
objective in the event of stent detachment is to establish flow in the
occluded territory. Techniques including balloon angioplasty, local
infusion of antiplatelet or thrombolytic agent and suction have been
described with variable success in achieving meaningful reperfusion. Stent
retrieval can potentially restore flow to the occluded territory and
negate the need for administering dual antiplatelet. We read with interest
the article by Castano et al (2016) on unwanted detachment of the
Solitaire device during mechanical thrombectomy in acute ischemic
stroke.Stents with type 'A' detachment were retrievable; whereas, attempts
at retrieving stents with type B detachment were invariably unsuccessful.
Therefore, a rescue strategy, 'stent based retrieval',may prove to be
useful when snare retrieval fails. Stent based retrieval could be
considered in both type A and type B detachments when snare retrieval is
unsuccessful.
Letter to the Editor
We read with great interest the article by Casta?o et al (2016) on
unwanted detachment of the Solitaire device(Medtronic/Covidien/ev3,
Dublin, Ireland) during mechanical thrombectomy in acute ischemic stroke.1
Stent detachment in their series was invariably associated with a poor
outcome, higher rates of symptomatic intracranial hemorrhage and higher
mortality.
They had classified stent detachment as either type A or type B based
on if the separation occurred before or after the proximal radiopaque
stent marker. They attempted stent retrieval with an Amplatz GooseNeck
snare (Medtronic/Covidien/ev3, Dublin, Ireland) in all irrespective of the
type of detachment.A rescue strategy in case of failure of snare retrieval
was not described.Stents were retrievable with 'type A' detachments;
however, attempts to retrieve stents with 'type B' detachmentwere
invariably unsuccessful. The likely explanation is that with type B
detachment the 'stent legs' either open or stay together making a
'spearhead' that digs into the wall of the artery making snare retrieval
not possible.
The primary aim in such a situation is to re-establish flow in the
occluded territory. A number of techniques including balloon angioplasty,
local infusion of antiplatelet/ thrombolytic agent, and suction have been
described with variable success in achieving meaningful reperfusion.(2,3)
Furthermore, leaving a stent in situ necessitates administration of dual
antiplateletto a patient in whom the infarct core can increase either due
to delayed occlusion or failure to recanalise. Therefore, an attempt to
restore flow by retrieving the detached stent is likely to be crucial to
achieving a good outcome. Castano et al (2016) were able to achieve
meaningful reperfusion in 50% of patients; however, the outcomes were poor
despite device retrieval.(1) This further reiterates the importance of
time and the need to establish perfusion early. Therefore, a second
strategy may be beneficial when snare retrieval fails.
Snare retrieval may not be successful in type A detachments and not likely
to be the appropriate strategy in type B stent detachments. Therefore, an
alternate strategy, 'Solitaire stentectomy' may prove to be effective
under these circumstances. (4) 'Stent based retrieval' using a Solitaire
device can be performed as a '4 step' process in a patient with stent
detachment. Step 1: Partial deployment of an appropriately sized solitaire
device proximal to the detached stent [the distal end of microcatheter is
positioned proximal to the proximal radiopaque marker/ proximal legs
(struts) of the detached stent and then the stent is partly unsheathed to
allow for its expansion]. Step 2: Engaging the proximal end of the
detached stent by the distal end of the second stent by advancing the
microcatheter and the stent together. Step 3: re-sheathing the device in
an attempt to capture the proximal legs/ struts of the detached stent.
Step 4: retrieval of microcatheter, device and detached stent. This
strategy may be useful in both type A and type B detachments when snare
retrieval fails.
Clearly, stent detachment is a dreaded device complication for the
neurointerventionist in the setting of acute stroke management and may
result in poor outcome. Development of methods and techniques is crucial
to dealing with stent detachments in a timely and effective manner. "Stent
based retrieval" can be a useful alternate technique when snare retrieval
fails and may be employed as the primary technique in type B detachments.
References:
1. Castano C, Dorado L, Remollo S, et al. Unwanted detachment of the
Solitaire device during mechanical thrombectomy in acute ischemic stroke.
J Neurointerv Surg. 2016 Jan 27. [Epub ahead of print]
2. Kim ST, Jin SC, Jeong HW, et al. Unexpected detachment of
solitaire stents during
mechanical thrombectomy. J Korean Neurosurg Soc 2014;56:463-8.
3. Yub Lee S, Won Youn S, Kyun Kim H, et al. Inadvertent detachment
of a retrievable intracranial stent: review of manufacturer and user
facility device experience. Neuroradiol J 2015;28:172-6.
4. Chapot R, Stracke P, Nordmeyer H, Heddier M. Stentectomy:
Retrieval of stents after stent assisted coiling. Interventional
Neuroradiology 2015; 21(1S):160
Dear Editor,
we read with great interest the paper by Durst at al. [1], aimed to define
the anatomy of cerebral dural sinus system in the generalized population,
evaluating the prevalence of sinus venous stenosis and hypoplasia. This
condition is considered of pathogenetic relevance in idiopathic
intracranial hypertension (IIH) [2-4] and has been also associated to
chronic and, mostly, to refractory headaches [5-7].
We a...
Dear Editor,
we read with great interest the paper by Durst at al. [1], aimed to define
the anatomy of cerebral dural sinus system in the generalized population,
evaluating the prevalence of sinus venous stenosis and hypoplasia. This
condition is considered of pathogenetic relevance in idiopathic
intracranial hypertension (IIH) [2-4] and has been also associated to
chronic and, mostly, to refractory headaches [5-7].
We appreciate the Authors' efforts in reconstructing the venous system
anatomy by using as source the CT Angiography (CTA) of a large sample of
selected patients. However, we would point that their sample cannot be
easily considered representative of the "generalized population" and that
study results might be appreciably overestimated.
The study has been performed on a large series of cases selected among
patients that, on the basis of their own clinical presentation, underwent
a CTA. At the Author's institution, a CTA was routinely performed in "all
suspected strokes, many trauma patients, and anyone suspected of having a
vascular disorder". In order to make their sample representative of the
general population, out of 600 screened examinations, 245 have been
excluded for technical reasons or because of clinic presentations or
pathologic findings that could "conceivably alter venous outflow".
However, according to the exclusion criteria list, posterior fossa lesions
were excluded, but anterior focal ischemia and head trauma - both
conditions usually running with at least a mild brain edema and consequent
raised intracranial pressure (ICP) - were presumably included. There is
evidence that raised ICP is associated with focal or diffuse narrowing of
sinus venous tree [8].
Moreover, a number of other clinical presentations that could prompt
neurovascular investigations but might result from a cerebral venous
outflow derangement despite a negative CTA, are not listed within the
exclusion criteria. These include: responsive chronic migraine [9-10]
(only refractory chronic headaches were excluded but there is evidence of
> 50% sinus stenosis prevalence in chronic migraine); acute vertigo
(often comorbid with episodic or chronic migraine); cough, exertional and
sexual activity-associated headaches [11], and idiopathic stabbing
headache [12]. Finally, Transient global amnesia may result from a
deranged cerebral venous outflow with jugular valve incompetence [13].
Based on the above considerations, we believe that the design of this
otherwise excellent study implies a not negligible overestimation of the
prevalence of sinus stenosis and hypoplasia in the general population. The
true prevalence of sinus stenosis in healthy subjects remains unknown.
1. Durst CR, Ornan DA, Reardon MA, et al.. Prevalence of dural venous
sinus stenosis and hypoplasia in a generalized population. J Neurointerv
Surg. 2016. [Epub ahead of print]. doi: 10.1136/neurintsurg-2015-012147
2.Farb RI, Vanek I, Scott JN, et al. Idiopathic intracranial
hypertension: the prevalence and morphology of sinovenous stenosis.
Neurology. 2003 May 13; 60(9):1418-24.
3. De Simone R, Ranieri A, Montella S, et al. The role of dural sinus
stenosis in idiopathic intracranial hypertension pathogenesis: the self-
limiting venous collapse feedback-loop model. Panminerva Med. 2014 Sep;
56(3):201-9
4. Puffer RC, Mustafa W, Lanzino G. Venous sinus stenting for
idiopathic intracranial hypertension: a review of the literature. J
Neurointerv Surg. 2013;5(5):483-486
5. Bono F, Salvino D, Tallarico T, et al. Abnormal pressure waves in
headache sufferers with bilateral transverse sinus stenosis. Cephalalgia
2010; 30: 1419-1425
6. De Simone R, Ranieri A, Montella S, et al. Sinus venous stenosis-
associated idiopathic intracranial hypertension without papilledema as a
powerful risk factor for progression and refractoriness of headache. Curr
Pain Headache Rep. 2012 Jun;16(3):261-9.
7. De Simone R, Ranieri A, Montella S, et al. Intracranial pressure
in unresponsive chronic migraine. J Neurol. 2014 Jul;261(7):1365-73.
8. Rohr A, Bindeballe J, Riedel C, et al. The entire dural sinus tree
is compressed in patients with idiopathic intracranial hypertension: a
longitudinal, volumetric magnetic resonance imaging study. Neuroradiology.
2012 Jan;54(1):25-33
9. Bono F, Cristiano D, Mastrandrea C, et al. The upper limit of
normal CSF opening pressure is related to bilateral transverse sinus
stenosis in headache sufferers. Cephalalgia 2010; 30: 145-151.
10. Fofi L, Giugni E, Vadal? R, et al. Cerebral transverse sinus
morphology as detected by MR venography in patients with chronic migraine.
Headache. 2012 Sep;52(8):1254-61.
11. Donnet A, Valade D, Houdart E. Primary cough headache, primary
exertional headache, and primary headache associated with sexual activity:
a clinical and radiological study. Neuroradiology 2013; 55:297-305
12. Montella S, Ranieri A, Marchese M, De Simone R. Primary stabbing
headache: a new dural sinus stenosis-associated primary headache? Neurol
Sci. 2013 May;34 Suppl 1:S157-9.
13. Chung CP, Hsu HY, Chao AC, et al. Transient global amnesia:
cerebral venous outflow impairment-insight from the abnormal flow patterns
of the internal jugular vein. Ultrasound Med Biol. 2007 Nov;33(11):1727-
35. Epub 2007 Jul 16.
Optimal outcome of intra-arterial treatment for Acute ischemic stroke
(AIS) requires the involvement of appropriately trained and qualified
providers from diverse specialties working together in synchrony under
tight time line, communicating effectively to provide evidence-based
clinical care. Hence, we welcome the international multi-society consensus
document on training guidelines for the interventionalists involved in...
Optimal outcome of intra-arterial treatment for Acute ischemic stroke
(AIS) requires the involvement of appropriately trained and qualified
providers from diverse specialties working together in synchrony under
tight time line, communicating effectively to provide evidence-based
clinical care. Hence, we welcome the international multi-society consensus
document on training guidelines for the interventionalists involved in
intra-arterial treatment of AIS.(1) However, we wish to point out the
critical missing link in the consensus document - the role of
anesthesiologists.
We wish to offer a brief outline of the importance of anesthesiology
inputs in stroke care. Given the emergent and complex nature of the
interventional procedures for AIS, frequent association of multiple co-
morbidities, the need for strict hemodynamic management and ensuring
homeostasis, it is recommended to have a qualified and experienced
anesthesiologist to provide monitored anesthesia care (MAC) or general
anesthesia (GA), as deemed suitable based on the patient
characteristics.(2) Providing an optimal milieu for the procedure while
poised to quickly manage complications and concurrently maintaining the
blood pressure in a tight range in patients who often have associated
cardiovascular diseases is challenging. Optimal hemodynamic management of
these patients requires judicious fluid, vasopressor / inotrope selection.
Moreover, oxygenation and ventilation patterns during intra-arterial
therapy can impact cerebral blood flow and contribute to outcome.
Additionally, glycemic management in accordance with current guidelines is
critical. These skill sets are uniquely possessed by anesthesiologists
experienced in the care of stroke patients. Further underscoring the
complexity mandating this expertise is the fact that type of GA including
the choice of anesthetic/sedative agents may impact the ischemic brain and
can affect the outcome of AIS.(3) Not surprisingly, it has been
recommended that acute stroke interventions, even when performed on awake
patients, should be carried out in the presence of experienced anesthesia
providers who can rapidly manage untoward events.(2) Essentially, the
involvement of a qualified and experienced anesthesiologist can have
significant bearing on the outcome. The anesthetic management should
follow the evidence based recommendations made by the Society for
Neuroscience in Anesthesiology and Critical Care (SNACC) consensus
statement.(2)
Although some studies reported that GA, as a generic and
uncharacterized therapy, is associated with poor outcome in patients
undergoing intra-arterial treatment of AIS, these investigators did not
recognize that GA constitutes a continuum of central nervous system
depression, wherein effects on the brain are dose-related, disparate, and
protean in terms of neurochemistry, perfusion, neuroprotection, and
neurotoxicity.(4) This has led to the initiation of clinical trials
randomizing the patients with AIS to GA or MAC. However, these trials
suffer from significant limitations due to lack of anesthetic insight /
involvement and do not reflect the relevant clinical and protean
neuropharmacology of GA.(4) We offer the similar criticism for the
Training Guidelines for Endovascular Ischemic Stroke Intervention.(1)
While this document provides crucial recommendations for not only
physician training and qualification but also essential hospital
requirements like 24/7 access to all relevant expertise such as vascular
neurology, neurosurgery and neurocritical care; it fails to address the
fundamental need of the 24/7 availability of a qualified anesthesiologist.
We encourage the various disciplines involved in stroke care to work
together and we urge the community of stroke providers to actively engage
SNACC and the anesthesiology community in order to effectively enhance the
care of patients with AIS.
References
1. Lavine SD, Cockroft K, Hoh B, et al. Training Guidelines for
Endovascular Ischemic Stroke Intervention: An International Multi-Society
Consensus Document. AJNR Am J Neuroradiol. 2016 Feb 18. [Epub ahead of
print]
2. Talke PO, Sharma D, Heyer EJ, et al. Society for Neuroscience in
Anesthesiology and Critical Care Expert consensus statement: anesthetic
management of endovascular treatment for acute ischemic stroke: endorsed
by the Society of NeuroInterventional Surgery and the Neurocritical Care
Society. J Neurosurg Anesthesiol. 2014 Apr;26(2):95-108.
3. Sivasankar C, Stiefel M, Miano TA, et al. Anesthetic variation and
potential impact of anesthetics used during endovascular management of
acute ischemic stroke. J Neurointerv Surg. 2015 Nov 27. [Epub ahead of
print]
4. Kofke WA, Sharma D. SIESTA trial: Is GA a drug you get from the
hospital pharmacy? International Journal of Stroke. (In Press)
I am glad to see that my letter has piqued the interest of
interventional neuroradiologists like Dr. Jagadeesan. I agree with him
that no one should be running a fellowship that does not have the volume
to expose trainees to enough cases so that they may obtain the necessary
experience to practice safely. However, I think he has misunderstood my
point. As I stated about the original piece, "I have no objection to the
lo...
I am glad to see that my letter has piqued the interest of
interventional neuroradiologists like Dr. Jagadeesan. I agree with him
that no one should be running a fellowship that does not have the volume
to expose trainees to enough cases so that they may obtain the necessary
experience to practice safely. However, I think he has misunderstood my
point. As I stated about the original piece, "I have no objection to the
logic and opinions expressed, and actually have no opinion on the issue
for or against these fellowships." My only request was for the authors of
the original article to disclose the fact (as Dr. Jagadeesan has nicely
done in his own letter) that they may have potential conflicts of interest
by way of already completed and reaping the potential rewards of the very
same fellowship training that they now advocate curtailing, so that the
reader may use this information when making up his or her own mind. I have
no interest in standing between interventional neuroradiologists and their
patients (unless one is trying to run over the other, in which case I hope
I could intervene). As far as taxi drivers, I would applaud their
specialty if one disclosed that he gotten his driver's license from the
black market instead of completing the required training and tests -
indeed, that information might affect my decision to ride in his or
another cab.
Re: Ogata A et al. Carotid artery stenting without post-stenting
balloon dilatation. J NeuroIntervent Surg 2013; Dec 6: (Epub ahead of
print)
We read with interest this article regarding carotid stenting (CAS)
without post-stent balloon angioplasty. The authors believe that this
method reduces the risk of embolic complications. They point out that
every passage of a device across a carotid stenosis can generate...
Re: Ogata A et al. Carotid artery stenting without post-stenting
balloon dilatation. J NeuroIntervent Surg 2013; Dec 6: (Epub ahead of
print)
We read with interest this article regarding carotid stenting (CAS)
without post-stent balloon angioplasty. The authors believe that this
method reduces the risk of embolic complications. They point out that
every passage of a device across a carotid stenosis can generate emboli,
and that the post-stent angioplasty is the most embologenic part of
standard CAS techniques.
Our group and others (1,2) have shown that primary carotid stenting
(PCS), in which a self-expanding stent alone, without the use of an
embolic protection device or balloon angioplasty, can safely and
effectively treat the majority of carotid stenoses. PCS is particularly
effective in patients with moderate amounts of "soft" plaque and minimal
plaque calcification. PCS minimizes the potential for embolus generation,
results in less hemodynamic depression, is faster and cheaper and may be
safer than standard techniques. Although re-stenosis rates are higher,
these patients are rarely symptomatic and re-angioplasty of recurrent
lesions with neointimal formation is usually straightforward.
Ogata et al are on the right path towards making CAS safer, but in
appropriate patients, PCS may be an even better option.
1. Bussiere M, Pelz DM, Kalapos P et al. Results using a self-
expanding stent alone in the treatment of severe, symptomatic carotid
bifurcation stenosis. J Neurosurg 2008; 109: 454-460
2. Baldi S, Zander T, Rabellino M, Gonzalez G, Maynar M. Carotid artery
stenting without angioplasty and carotid protection: a single center
experience with up to 7 years follow-up. AJNR Am J Neuroradiol 2011; 32
(4): 759-763
David M. Pelz, MD, FRCPC
Department of Medical Imaging
Stephen P. Lownie, MD, FRCSC
Department of Clinical Neurological Sciences
Division of Neurosurgery
Schulich School of Medicine and Dentistry
Western University, London, Ontario
Canada
The interesting paper by Li et al. reports an important series of
cases treated appropriately and carefully followed-up, but unfortunately
the diagnosis may not be correct in all cases.
Fusiform aneurysms appearing in angiograms may represent a variety of
different histopathological pictures, including dissection, but also other
types of aneurysms.
A light to this question, quite recurrent in my p...
The interesting paper by Li et al. reports an important series of
cases treated appropriately and carefully followed-up, but unfortunately
the diagnosis may not be correct in all cases.
Fusiform aneurysms appearing in angiograms may represent a variety of
different histopathological pictures, including dissection, but also other
types of aneurysms.
A light to this question, quite recurrent in my practice, is bring by
Mizutani et al.(1). They studied 85 patients with fusiform or non-
branching zones aneurysms, either operated or post-mortem. Four types of
aneurysms were found, one of witch is what the literature came to call a
"blood-blister- like aneurysms", and is not fusiform. The fusiform
aneurysms were found to have 3 different patterns. One of them is a
segmental ectasia with regular walls and a benign course. Two other types
are symptomatic and may share some features that bring confusion. First,
the classic dissecting aneurysm has typically an acute presentation with
ischemic or hemorrhagic stroke. Angiography shows fusiform dilatation with
irregular wall and associated with stenosis. Pathology was characterized
by disruption of internal elastic lamina, a false lumen packed with fresh
thrombus, no intimal thicketening and no organized thrombus. The second
is the dolichoectatic aneurysm, clinically characterized by compressive
symptoms or brainstem ischemic changes, with a chronic evolution, that may
bleed, but rarely in previously asymptomatic cases. The angiography shows
marked tortuosity and very irregular walls. The most common localization
is basilar artery. Pathology shows organized luminal thrombus, disrupted
internal elastic lamina without false lumen. As a chronic condition with
organized thrombus, parietal calcification can occur.
In the series, at least four patients had no acute presentation, and there
was no hemorrhagic stroke.
The images presented for cases 3, 4 and 8, although they had sudden
presentation, are characterized by tortuosity, ectasia and irregular
walls, extension to vertebral arteries and no stenosis. In one case the CT
images show wall calcifications. These images are more consistent with
dolichoetatic fusiform than with acute dissecting aneurysms.
More rigid criteria are needed to define dissecting aneurysms and
differentiate them from dolichoectatic aneurysms.
1- Mizutani T, Miki Y, Kojima H, Suzuki H. Proposed classification of
nonatherosclerotic cerebral fusiform and dissecting aneurysms.
Neurosurgery. 1999 Aug;45(2):253-9.
We read with interest Dr. Ding's response to our manuscript,
"Angioarchitectural features associated with hemorrhagic presentation in
pediatric cerebral arteriovenous malformations," and we thank him for his
gracious comments. In response to his question regarding whether brain AVM
angioarchitecture influences our particular treatment strategy, we would
point out that the overwhelming majority of our pediatric patients wi...
We read with interest Dr. Ding's response to our manuscript,
"Angioarchitectural features associated with hemorrhagic presentation in
pediatric cerebral arteriovenous malformations," and we thank him for his
gracious comments. In response to his question regarding whether brain AVM
angioarchitecture influences our particular treatment strategy, we would
point out that the overwhelming majority of our pediatric patients with
brain AVM present with hemorrhage or with an AVM-related neurological
symptom. Thus, we are rarely in the position of evaluating an entirely
asymptomatic AVM, in which case particular features of the
angioarchitecture might weigh heavily in assessing whether to proceed. Our
treatment strategy, once the decision has been made to proceed, is
designed to as definitively as possible ensure complete removal of the
AVM, wherever feasible. We thus favor surgical resection, with
preoperative embolization used where this would lower morbidity and
improve surgical outcome. Given the age of our patients, we tend to favor
radiotherapy less than would typically be the case in an adult cohort. We
hope to describe the details of our multidisciplinary approach to
treatment in a future publication.
We would like to thank our colleagues for reading our publication and for the thorough review of the paper. We greatly look forward to reading their own experience and believe that it will add substantially to the literature on this new and interesting device.
At the outset we would like to make it clear that we stand by our initial comment in saying that we believe the combination of a MED and other devices,...
Dear Editor, We read with great interest the original article by Boned S. et al. (1) which demonstrates that CT perfusion (CTP) may overestimate the final infarct core, especially in the early time window. Interestingly, the authors introduce the "ghost infarct core" concept in ischemic stroke, referring to that particular condition where the final infarct core at follow up imaging may be smaller than the one observed on...
Frederic Clarencon, MD, PhD 1, 2, Nader-Antoine Sourour, MD 1 *
1. Department of Interventional Neuroradiology. Pitie-Salpetriere Hospital.
APHP. Paris France. 2. Paris VI University Pierre et Marie Curie. Paris. France
* Corresponding author
We read with great interest the case series entitled: "The Medina Embolic Device: early clinical experience from a single center" by Aguilar Per...
Letter by Parthasarathy et al. regarding article, "Unwanted detachment of the Solitaire device during mechanical thrombectomy in acute ischemic stroke ".
Rajsrinivas Parthasarathy MRCP (UK) Neurology, Vipul Gupta MD, Gaurav Goel MD DM
Department of Neurointerventional surgery, Institute of Neuroscience, Medanta, the Medicity, Gurgaon, India.
Title word count: 14
Word Count: Abstract: 1...
Dear Editor, we read with great interest the paper by Durst at al. [1], aimed to define the anatomy of cerebral dural sinus system in the generalized population, evaluating the prevalence of sinus venous stenosis and hypoplasia. This condition is considered of pathogenetic relevance in idiopathic intracranial hypertension (IIH) [2-4] and has been also associated to chronic and, mostly, to refractory headaches [5-7]. We a...
Optimal outcome of intra-arterial treatment for Acute ischemic stroke (AIS) requires the involvement of appropriately trained and qualified providers from diverse specialties working together in synchrony under tight time line, communicating effectively to provide evidence-based clinical care. Hence, we welcome the international multi-society consensus document on training guidelines for the interventionalists involved in...
I am glad to see that my letter has piqued the interest of interventional neuroradiologists like Dr. Jagadeesan. I agree with him that no one should be running a fellowship that does not have the volume to expose trainees to enough cases so that they may obtain the necessary experience to practice safely. However, I think he has misunderstood my point. As I stated about the original piece, "I have no objection to the lo...
Re: Ogata A et al. Carotid artery stenting without post-stenting balloon dilatation. J NeuroIntervent Surg 2013; Dec 6: (Epub ahead of print)
We read with interest this article regarding carotid stenting (CAS) without post-stent balloon angioplasty. The authors believe that this method reduces the risk of embolic complications. They point out that every passage of a device across a carotid stenosis can generate...
To the editor,
The interesting paper by Li et al. reports an important series of cases treated appropriately and carefully followed-up, but unfortunately the diagnosis may not be correct in all cases. Fusiform aneurysms appearing in angiograms may represent a variety of different histopathological pictures, including dissection, but also other types of aneurysms. A light to this question, quite recurrent in my p...
We read with interest Dr. Ding's response to our manuscript, "Angioarchitectural features associated with hemorrhagic presentation in pediatric cerebral arteriovenous malformations," and we thank him for his gracious comments. In response to his question regarding whether brain AVM angioarchitecture influences our particular treatment strategy, we would point out that the overwhelming majority of our pediatric patients wi...
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