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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3733_Библиотеки_им_академика_М_И_Перельмана.pdf
Corporation, Natick,
Massachusetts)
tip to prevent snaring other coils;
not retractable once interlocking
arm exits catheter tip
Axium Detachable Coil System
(Covidien, Irvine, California)
Very soft coils; minimal catheter
kick out at detachment link
Ruby Coil (Penumbra, Inc.,
Alameda, California)
Long coil lengths and graded
softness allow for tight coil
packing (from the manufacturer)
Retracta Detachable
Embolization Coils (Cook
Medical, Inc., Bloomington,
Indiana)
Detaches from pusher wire with
8–10 counterclockwise twists;
keep detachment juncture zone
just inside catheter tip to assure
detachment
CONCLUSIONS
The use of detachable coils for extracranial indications has increased over the
past several years and should continue to do so as more operators become
comfortable with these devices and appreciate the level of safety and
precision that they add to patient care. This newer technology can facilitate
endovascular treatment of lesions that historically have required open
surgery. The limit to more widespread use is cost because detachable coils
can be 5 to 10 times more expensive than pushable coils. Future directions
may include development of novel materials used to engineer and coat these
coils and advances in delivery wire and detachment zone technology.
REFERENCES
1. Guglielmi G. History of the genesis of detachable coils. A review. J
Neurosurg. 2009;111(1):1–8.
2. Molyneux A, Kerr R, Stratton I, et al; International Subarachnoid
Aneurysm Trial (ISAT) Collaborative Group. International
Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus
endovascular coiling in 2143 patients with ruptured intracranial
aneurysms: a randomized trial. Lancet. 2002;360(9342):1267–1274.
3. Klein GE, Szolar DH, Breinl E, et al. Endovascular treatment of renal
artery aneurysms with conventional non-detachable microcoils and
Guglielmi detachable coils. Br J Urol. 1997;79(6):852–860.
4. Reidy JF, Qureshi SA. Interlocking detachable platinum coils, a
controlled embolization device: early clinical experience. Cardiovasc
Intervent Radiol. 1996;19(2):85–90.
5. White JB, Ken CGM, Cloft HJ, et al. Coils in a nutshell: a review of coil
physical properties. AJNR Am J Neuroradiol. 2008;29(7):1242–1246.
6. Milic A, Chan RP, Cohen JH, et al. Reperfusion of pulmonary
arteriovenous malformations after embolotherapy. J Vasc Interv Radiol.
2005;16(12):1675–1683.
7. Hui FK, Fiorella D, Masaryk TJ, et al. A history of detachable coils:
1987-2012. J Neurointerv Surg. 2014;6(2):134–138.
8. White PM, Lewis SC, Gholkar A, et al; for the HELPS Trial
Collaborators. Hydrogel-coated versus bare platinum coils for the
endovascular treatment of intracranial aneurysm (HELPS): a
randomized controlled trial. Lancet. 2011;377(9778):1655–1662.
9. Greben CR, Setton A, Gandras EJ, et al. The use of hydrogel detachable
coils in the treatment of pulmonary fistulas. Presented at: SIR Annual
Meeting; March 2006; Toronto, Canada.
10. Bui JT, West DL, Pai R, et al. Use of a hydrogel-coated self-expandable
coil to salvage a failed transcatheter embolization of a mesenteric
hemorrhage. Cardiovasc Intervent Radiol. 2006;29(6):1121–1124.
11. Greben CR, Axelrod DJ, Charles H, et al. Treatment of posttraumatic
aortic pseudoaneurysms using detachable hydrogel-coated coils. J
Trauma. 2009;66(6):1735–1738.
12. Nambiar AP, Bozlar U, Angle JF, et al. Initial clinical experience with
biopolymer-coated detachable coils (HydroCoil) in peripheral
embolization procedures. J Vasc Interv Radiol. 2008;19(7):995–1001.
13. Greben CR, Setton A, Putterman D, et al. Double microcatheter single
vascular access embolization technique for complex peripheral vascular
pathology. Vasc Endovascular Surg. 2010;44(3):217–222.
14. Eddleman CS, Welch BG, Vance AZ, et al. Endovascular coils:
properties, technical complications and salvage techniques. J
Neurointerv Surg. 2013;5(2):104–109.
P
4
Vascular Plugs
Sang Joon Park
ercutaneous embolization has become a common procedure to treat
acute bleeding and vascular abnormalities. A permanent occlusion can
be created with an embolization procedure with various embolic
materials, including polyvinyl alcohol (PVA) particles, embolic
microspheres, glue, coils, and occlusion balloons; coils are the most
commonly used device.1 The major disadvantages of coils are that multiple
coils are often required for the complete occlusion of the targeted vessel and
that accurate placement can be challenging depending on the vessel size and
blood flow rate. Moreover, the chance of coil migration is always high when
embolizing large feeding vessels with a high flow rate. To overcome this
shortcoming of coils, the Amplatzer Vascular Plug (AVP; St. Jude Medical,
Inc., St. Paul, Minnesota) was introduced and approved by the U.S. Food and
Drug Administration (FDA) in 2004 for peripheral embolization. The first
report on the successful use of the AVP was published by Hill et al.2 in
December 2004. Since then, numerous reports have been published in various
medical journals. The device has shown an excellent technical success rate
for an expanding number of indications,3 and no significant contraindication
to embolization using this device has been recognized.4 As described in
Chapter 1, new plugs such as the Medusa Vascular Plug (EndoShape Inc.,
Boulder, Colorado) and the MVP Micro Vascular Plug System (Reverse
Medical Corporation, Irvine, California) have been recently introduced. This
chapter will focus on use of the AVP given the extensive experience with this
device.
DEVICE DESCRIPTION
The original AVP was derived from the Amplatzer septal occluder and the
Amplatzer duct occluder. The AVPs consist of a self-expanding cylindrical
nitinol mesh that can be deployed both rapidly and accurately. The elasticity
of the nitinol allows the device to become firmly anchored to the vessel wall
due to its outward radial force.
5
There are radiopaque platinum marker bands
at both ends for high visibility under fluoroscopy. The plug is attached to a
delivery wire with a stainless steel screw on one of the platinum marker
bands.6 One significant advantage of the AVP as an embolic device is that it
can be repositioned before final release, which is performed by rotating the
delivery wire.
After the introduction of the first AVP, the AVP family has grown to
four types: AVP I, AVP II, AVP III, and AVP IV (Fig. 4.1). Each type has a
unique design and features making it suitable for different vascular
anatomies, hemodynamics, and clinical situations. Subsequently, a newer
generation does not mean that it can replace the older type. In appearance, the
AVP I has a single lobe, the AVP II has three lobes, and the AVP III and IV
have two lobes. In addition, the AVP I and IV have single-layered braids,
whereas the AVP II and III have a multiple-layered design, except for the 3mm AVP II. The characteristics of the AVPs are described in Table 4.1.
The AVP I was the first product of the AVP family. Most of the
published case reports have been performed with this device.7 The diameters
of the AVP I range from 4 to 16 mm with increases in 2-mm increments. This
device is well suited for landing zones that are limited in length.
8
The AVP II is the second-generation product in the AVP family; it
received FDA approval in 2007. It has been used in various clinical
settings,
9–13
but no randomized trials comparing the AVP II with wellestablished embolization devices has been reported to date. This device is
multiple layered and made of more densely woven nitinol mesh than the AVP
I, except for the 3-mm device, which is single layered. It consists of three
segments with a central lobe and two discs on each side of the lobe.
Compared to the AVP I, the AVP II exerts greater radial force, over four
axes, and may thus be expected to migrate less and cause more rapid
occlusion.
14
The AVP III has a unique, oblong, cross-sectional shape and multiple
nitinol mesh layers. It also has rims that extended beyond the device body,
which may enhance stability. There are only few reports on the clinical
application of this device.15 This device received CE mark approval of
Europe in 2008.
The AVP IV has a double-cone shape and is mounted on a fixed-core
wire guide with a 20-cm floppy distal tip. Unlike other AVPs, it can be
delivered through a 4-Fr or 5-Fr diagnostic catheter with a 0.038-in inner
lumen without the need to exchange for a sheath or a guiding catheter. This
feature enables this device to be used in smaller and tortuous vessels in the
arterial or venous vasculature.
16,17
This is the biggest advantage of this
device over other generations of the AVPs. Like other plugs, the AVP IV can
be recaptured and repositioned if necessary. It received CE mark approval in
2009 for Europe and was cleared by the FDA in 2012.
TECHNIQUE
When treating vascular pathology with the AVP, the size of the target vessel
and the length of the landing zone for the device must be determined to
choose the most appropriate AVP for use. It is currently suggested that the
AVP be oversized by 30% to 50% relative to the diameter of the target
vessel. The elasticity of nitinol allows the plug to fully expand within the
vessel for adequate wall apposition.
Once the device has been selected, the initial consideration for its
placement is the determination regarding what catheter will be used to deliver
the plug to the site of deployment. A 4-Fr sheath or 5-Fr guiding catheter is
required for the AVP I and AVP II, whereas a 4-Fr sheath or 6-Fr guiding
catheter is required for the AVP III. Therefore, a relatively straight segment
of target vessel with a relatively constant diameter is needed for deployment
for the AVP I, AVP II, and AVP III.
3
The newest device, the AVP IV, can be delivered through a 4-Fr or 5-Fr
diagnostic catheter without an additional sheath or guiding catheter. The
combination of low profile and flexible delivery wire tip makes it possible for
this device to be used in smaller vessels such as the splenic, lumbar, and
gluteal arteries.16 The size of this device is limited, covering vessels with
diameters of 2.6 to 6.2 mm, providing the requirement for at least 30%
oversizing.
The delivery catheter is not the only part of the system that needs to be
advanced to the anticipated site of deployment. The plug and delivery wire
must be advanced through the delivery catheter or sheath, and this can be
problematic in some cases. The delivery wire is stiff and may be difficult to
advance through the delivery catheter. This is especially the case when the
target vessels are tortuous. To overcome the tortuosity of the artery, two
methods can be used. One is to use a guiding catheter within the sheath to
increase the stability and ease of deployment according to Zhu et al.,18 and
the other is the use of a larger introducing system to gain access to the
landing zone.
19
When the desired position of the device is reached, the device can be
easily deployed by rotating the cable counterclockwise to complete
implantation. Subsequently, repositioning the device is possible before
release. Moreover, a test injection of contrast medium is possible through the
delivery catheter to verify the location of the device before deployment.
5
CLINICAL APPLICATIONS
The AVP has been used successfully for various indications suitable for the
use of a mechanical embolic agent. Often, the limiting factors in determining
whether a plug would be appropriate to use include the size of the target
vessel, the tortuosity of the vessels leading to the site targeted for occlusion,
the length of the landing zone, and the nature of the pathology being treated.
Several arterial indications for the AVP have been described. These
devices have been used successfully in the internal iliac artery for endoleak
prevention before endovascular aneurysm repair (EVAR)20 as well as to treat
pseudoaneurysms.21 They have also been used successfully for embolization
of the gastroduodenal artery before radioembolization with yttrium 90
microspheres. Both the AVP II and IV have been used successfully for this
indication.
14,22,23
Additional indications include embolization of the proximal
splenic artery as treatment for portal hypertension and splenic artery
syndrome after orthotopic liver transplantation,18 splenic artery aneurysms,
24
and splenic trauma to avoid splenectomy.
25,26
The use of the AVPs in the venous circulation has also been reported.
These devices have been used successfully in combination with coils and
gelatin sponge for portal vein embolization.
27,28
In addition, these plugs have
been used for the treatment of gonadal vein embolization for varicoceles and
pelvic congestion syndrome either alone or in combination with coils or
liquid embolic agents.
29,30
These devices essentially began in the cardiac setting, treating
conditions such as a patent ductus arteriosus (PDA) and patent ductus
venosus (PDV).7 Now, other congenital arteriovenous communication can
often be effectively treated with these plugs. For example, pulmonary
arteriovenous malformations can be treated with the AVP (Fig. 4.2), which
can be advantageous due to the low risk of migration into the pulmonary
venous outflow after deployment.
19,31–33
Other potential applications in this
area include splenorenal shunts,34 renal arteriovenous fistulae,35 mesocaval
shunts,36 and the rerouting of a scimitar vein to the left atrium.37 Acquired
lesions can also be treated with the AVP. This includes the treatment of
hemodialysis arteriovenous fistulae that require closure for steal syndrome or
enlarging aneurysms38 as well as for either occlusion of a transjugular
intrahepatic portosystemic shunt (TIPS) in the setting of refractory
postprocedure encephalopathy or for embolization of varices during TIPS
creation.
39
There are also potential nonvascular uses of the AVP that have been
reported. These include the closure of bronchopulmonary40 and
esophagopleural41 fistulae. In addition, the AVP can be used for ureteral
occlusion in patients with vesicovaginal, vesicointestinal or ureterointestinal,
or uterocutaneous fistulae secondary to pelvic cancers.
42
POSSIBLE COMPLICATIONS
The AVP has been shown to be a safe and effective embolic; complications
associated directly with the AVP are rare. Persistent patency after
deployment is one area of concern associated with these plugs. This can be
particularly seen after embolization of large-diameter, high-flow vessels in
coagulopathic patients. It is important to understand that occlusion takes time
after deployment of the AVP. When a rapid occlusion is unnecessary, time
can be taken for the vessel to occlude after deployment. However, when
embolization is being performed for more urgent indications, a supplemental
embolic agent may be required for a more rapid occlusion. In these cases,
agents such as coils, gelfoam, glue, and additional AVPs can be used as
adjuncts for the complete occlusion. Once occlusion occurs, recanalization is
rare due to the space-occupying nature of the AVP, but it can occur in
approximately 1% of cases compared to 8% to 15% with coil
embolization.
43,44
Migration is also possible45 but rare due to the radial force
seen when the plugs are oversized relative to the size of the target vessel.
TIPS AND TRICKS
• Oversizing of the AVPs at least 30%–50% is crucial.
• AVP I, II, and III require either a sheath or guiding catheter, whereas
AVP 4 only requires a standard 0.038-in diagnostic catheter for the
deployment. However, be aware of the fact that the maximal diameter
of the AVP IV is 8 mm.
• To overcome the tortuosity of the target vessel, the use of a guiding
catheter within the sheath can be useful to increase the stability and