phenox pCANVAS Mode D'emploi page 6

pCANVAS
®
8. Angiographic visualization of the internal and external carotid arteries on both sides and
of the vertebral artery on at least one side is recommended, along with the respective
dependent vessels. Enlarged images and, where necessary, oblique images of the aff ected
vessel(s) are recommended.
9. The target vessel(s) for the endovascular treatment must be defi ned.
10. A 6F or 8F guide catheter, or the combination of an 8F guide catheter and a suitable distal
access/extension catheter (e.g. Fargo Max, Neuron, Refl ex), is inserted into the aff erent
cervical vessel, avoiding vasospasm.
11. Measure the diameter of the target vessel and the aneurysm (neck, maximum transverse
diameter, maximum longitudinal diameter) as accurately as possible, using calibrated measuring
methods. Performing the procedure on the basis of estimates increases the risk of complications.
Document the result of your measurements. It is crucial that the instrument is only inserted into
target vessels and aneurysms of suitable size. In this connection, observe the specifi cations
regarding the minimum and maximum vessel diameters stated on the packaging, as well as
the Information on size selection (see below). The length of the pCANVAS must be selected so
that, where possible, the implant does not jail other vessels proximally (example: when treating
an aneurysm on the anterior communicating artery, the shaft should not, as far as possible, jail
the bifurcation of the internal carotid artery in the A1 segment). The jailing of side branches has
proved to be non-critical to date (example: in the treatment of aneurysms at the bifurcation of
the basilar artery, the exits of the superior cerebellar artery are always jailed and the exits of
the anterior inferior cerebellar artery are usually overlapped. As in cases in which other self-
expanding extra-aneurysmal stents are used, there are no resulting complications to fear).
12. Using a hemostatic valve and pressurized irrigation, insert a suitable microcatheter (see
Compatibility, Versions) with an inside diameter of 0.027 inches into the target vessel along with
a corresponding microguidewire. Here, the use of so-called "road map" technology is advisable.
Never probe against resistance! Aim to position the tip of the microcatheter around 1-2 mm distal
to the entrance to the aneurysm. Once you have reached this position, pull carefully on the
microcatheter in order to remove any surplus catheter length again and to straighten the catheter.
13. Make sure that the microcatheter is aligned along the longitudinal axis of the aneurysm
fundus. The tip of the microcatheter must NEVER be directed toward or make contact with
the wall of the aneurysm!
14. Remove the microguidewire from the microcatheter under X-ray fl uoroscopy.
15. Immerse the pCANVAS implant and the distal tip of the introducer sheath in heparinized
physiological saline solution and pull it inside the introducer sheath until the region spanned
with microporous membrane reaches the ring marker on the introducer sheath.
16. With the aid of a tight-closing hemostatic valve and under continuous pressurized irrigation with
heparinized physiological saline solution, the pCANVAS is transferred from its insertion system
into the microcatheter. For this purpose, the hemostatic valve is opened. The introducer sheath
of the pCANVAS is pushed through the open valve. The hemostatic valve is closed carefully and
the introducer sheath of the pCANVAS is de-aired by the retrograde entry of the irrigation fl uid.
17. Once the introducer sheath of the pCANVAS is completely de-aired in this form, it is advanced
until it enters the adapter (hub) of the microcatheter. It is fi xed in this position using the hemostatic
valve and additionally held in place by hand, if necessary. The pCANVAS is then advanced from
the introducer sheath into the microcatheter using the insertion wire to which the implant is fi xed.
This process is continued until approx. 60 cm of the insertion wire is inside the microcatheter.
18. The pCANVAS is advanced until the black marking on the insertion wire (described as
"MARKER" on the product label) meets the entrance opening of the hemostatic valve.
This process does not have to be carried out under continuous fl uoroscopy, as the marker
("MARKER") identifi es the position to which the system can be advanced without the tip of the
device emerging from the microcatheter. The introducer sheath is then withdrawn proximally. It
is imperative to avoid buckling the insertion wire during insertion of the pCANVAS!
19. The process of inserting the pCANVAS generally corresponds to that of inserting similar
familiar implants. Should you encounter particular resistance which can only be overcome
with eff ort, the implant and possibly also the microcatheter must be removed and the vessel
or aneurysm accessed once more.
20. The pCANVAS is slowly inserted further up to the tip of the microcatheter under continuous
fl uoroscopy. In doing so, ensure that the position of the tip of the microcatheter does not change
either proximally or distally. As soon as the distal end of the pCANVAS reaches the tip of the
microcatheter, the latter should be located 1 to 3 mm distally to the entrance of the aneurysm and
centered within the entrance as accurately as possible. Never actively push the pCANVAS
beyond the distal tip of the microcatheter! This can lead to perforation of the aneurysm.
21. Release the pCANVAS implant fully by carefully and very slowly withdrawing the
microcatheter. In the process, it is imperative to continuously push the insertion wire of
the pCANVAS in the opposite direction slightly in order to ensure the constant position of
the pCANVAS. The deployment of the pCANVAS must only take place under continuous
fl uoroscopy. Ensure that the position of the distal end of the implant is unchanged during
deployment and that the implant deploys fully.
22. The pCANVAS deploys by itself. The crown of the pCANVAS centers itself within the
aneurysm. The shaft of the pCANVAS deploys in the parent vessel in the way that is familiar
to other self-expanding aneurysm stents. Upon its release, the shaft comes to rest against
the vessel wall during deployment.
23. Position of the crown of the pCANVAS within the aneurysm: the crown of the pCANVAS
should cover the entrance to the aneurysm as symmetrically as possible. If the crown of the
pCANVAS is deployed too far into the aneurysm fundus, this can impede the insertion of the
coil in the neck area of the aneurysm (distal misplacement). If the crown is positioned too
far proximally, parts of the petals can, unnoticed, jail the vascular bifurcation which it should
be protecting. This may lead to the closure of outgoing branches (proximal misplacement).
A proximal misplacement may also mean that the position of the crown of the pCANVAS is
unstable, which may then lead to the coil loops or parts of the pCANVAS being displaced
into the bifurcation which is to be protected when the coil is inserted.
24. It has proven successful to deploy the crown of the pCANVAS slightly distally to the
entrance and to then pull the opened crown 1-2 mm into the entrance whilst the shaft is
still in a compressed state.
25. As soon as this position has been reached, the shaft of the pCANVAS is deployed by
withdrawing the microcatheter further. In doing so, you must not pull on the pCANVAS crown. If
a tensile load were applied to the pCANVAS during its deployment, the vessel geometry could
be changed temporarily. Even a perforation of the base of the aneurysm would be a possibility.
B835B pCANVAS IFU / 2017-01-23
6
26. The position of the crown can be verifi ed using the partially radiopaque marking of the
individual petals. It is advisable to take 2D DSA images and possibly carry out a fl at panel
CT examination (e.g. DynaCT, XperCT).
27. It has proven a successful strategy, where possible and if applicable, to detach the
pCANVAS only once an additional coil occlusion has been completed. The insertion wire
and the microcatheter stabilize the position of the pCANVAS. This assumes that a second
microcatheter can be inserted into the aneurysm and used for the coil occlusion.
28. Accessing and coil occlusion of the aneurysm: the simultaneous use of two microcatheters
(dual-catheter) provides the best solution for checking the position of the pCANVAS and
the progress of coil insertion. The fi rst microcatheter is used to access the aneurysm
(e.g. Echelon10, Echelon14, Headway17, Excelsior SL10 amongst others). The second
microcatheter is used to insert and release the pCANVAS. As a result of the subsequent
release of the pCANVAS, the microcatheter for the coil insertion is fi xed in its position (jailed
catheter). Fixing the position of the microcatheter (for coil insertion) in this way can aid
the stability of the catheter. On the other hand, targeted maneuvering within the aneurysm
is then made considerably more diffi cult. The microcatheter for pCANVAS insertion
remains in place until the electrolytic detachment of the pCANVAS, which represents
the last step in the procedure. Alternatively, it is also possible to fi rst insert and release
the pCANVAS. To access the microcatheter for coil insertion in this case, the membrane
must be perforated. This is done by approaching the tip of the microcatheter closely to
the membrane and then perforating it with the tip of the microguidewire. After a successful
perforation the microcatheter can be advanced into the aneurysm. The hole in the elastic
membrane, caused by the perforation, will mostly seal itself, but the fl ow modulating eff ect of
the pCANVAS might be reduced. It is also possible to access the aneurysm at a later stage
as long as the neointima formation on the membrane does not impair access or openings
lateral to the membrane can be used. In such a procedure it must be considered that the
already released pCANVAS can be displaced. It may not be possible to then correct the
resulting incorrect position of the pCANVAS.
29. The technique involved in inserting the coil in the aneurysm when using a pCANVAS is the same
as for coil occlusion of wide-necked aneurysms using other aids such as stents or a pCONus
implant. It has proved successful to begin the coil occlusion with a 3D coil of a nominal diameter
which roughly corresponds to the largest diameter of the aneurysm fundus. In order to avoid the
formation of inaccessible compartments, the used coils should not be too rigid. When inserting
the coil, ensure that the vascular bifurcation which is to be protected by the pCANVAS can be
visualized without any jailing and can be controlled. It is imperative to avoid inserting the coil
into the vascular bifurcation which is to be protected or into one of the side branches originating
there. In the coil insertion sequence, ensure that subsequent coils never have a higher rigidity
than the preceding ones. Otherwise there is an increased risk that the already detached coils
may be displaced by the subsequent coil, and their position cannot be corrected.
30. It is possible that the pCANVAS has no signifi cant hemodynamic eff ect on the aneurysm.
In such cases, it is essential to aim for as dense a coil fi lling of the aneurysm fundus as
possible. This concerns the neck section of the aneurysm in particular.
31. Detachment of the pCANVAS takes place electrolytically using a current and voltage, as is
usual in the detachment of corresponding coils. Commercially available detachment devices
and detachment cables (NXT Detachment System, ev3/Covidien/Medtronic, oder Boston
Scientifi c Detachable Coil Power Supply, Boston Scientifi c/Stryker Neurovascular) are
suitable. First, bring the detachment point (cobalt-chromium bridge) to a point immediately
distal to the tip of the microcatheter; the 30 mm-long, radiopaque marker can assist this
process, particularly when microcatheters with 2 distal markers are used.
32. Following the implantation of a pCANVAS, antiplatelet medication should be administered in
the way normally used when an aneurysm stent is used. A daily 100 mg oral dose of ASA on
an ongoing basis is essential. In addition, a daily 75 mg oral dose of clopidogrel must be taken
for at least 6 weeks, but preferably 12 weeks. Be mindful of possible interactions with other
medications (e.g. with proton pump inhibitors). For safety reasons, the effi cacy of the antiplatelet
medication can be verifi ed by means of appropriate tests (e.g. Multiplate®, VerifyNow®).
Information on the selection of patients and lesions
If the antiplatelet medication described above is not ensured following the implantation of a
pCANVAS, thrombotic closure of the implant and the parent vessel may occur within just a
few days. Patients who cannot guarantee regular intake of medication may not be suitable for
treatment with a pCANVAS.
As a rule, the implantation of a pCANVAS and the possible subsequent coil occlusion lead to an
aneurysm being immediately cut off from the blood circulation. In this respect, the procedure is
suitable for treating aneurysms in the acute phase following an aneurysm rupture. However, since
a dual antiplatelet therapy is essential for the implantation of a pCANVAS, surgical measures,
such as the insertion of an external ventricular drain or the placement of intraparenchymatous
measuring probes, must be taken before treatment with these drugs can begin.
Types of aneurysms which are suitable for treatment with pCANVAS
pCANVAS was developed to treat wide-necked bifurcation aneurysms with or without supporting
coil occlusion.
• The parent vessel should have a diameter of between 2.5 and 3.5 mm.
• The fundus of the aneurysm should off er enough space for the crown of the pCANVAS
to deploy.
• Ideally, the longitudinal axis of the aneurysm fundus should form an imaginary extension of
the longitudinal axis of the parent vessel.
• Aneurysms which are symmetrically positioned at the bifurcation of a vessel are particularly
suitable.
• However, an angle between the aforementioned longitudinal axes and/or a pronounced
asymmetry are not necessarily contraindications for the use of a pCANVAS.
• The parent vessel in which the stent shaft is to reside must not be stenosed or itself widened
by an aneurysm!
Information on size selection
Select the crown diameter of the pCANVAS so that its nominal diameter is slightly larger than
the diameter of the aneurysm neck. It is imperative to avoid undersizing the crown, as then
protection for the bifurcation is not guaranteed. Oversizing by 1-2 mm is not critical.