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276
J. C. Chaloupka et al.
infrequently internal carotid artery performed in
at least three different projections. Frequently the
pathology is obvious [4, 27], such as large pseu-
doaneurysm formation, active extravasation, or
fistula formation arising from the ICA, ECA or
CCA (Figs. 21.1–21.3). In some cases the source of
bleeding is not from a ruptured vessel within the
carotid tree, but rather from a recurrent tumor
arising from primary or nodal metastatic sites.
The mechanism of such bleeding may be either
secondary to invasion and/or erosion through an
oro-pharyngeal or cutaneous anatomic barrier
or from stimulation of tumor neoangiogenesis
resulting in hypervascularity [27].
It must be emphasized, however, that obvious
pathology is not always apparent, requiring one to
maintain a very high index of suspicion when scru-
tinizing the angiographic images. In such cases we
have frequently observed very subtle, and/or non-
specific alterations in endoluminal contour on close
inspection of selective (and occasionally superse-
lective) injection DSA runs that have ultimately
turned out to be the source of bleeding in patients
with Groups 2 and 3 CBS (Fig. 21.4a). The areas that
require the closest scrutiny are around the common
carotid bifurcation, including the external carotid
trunk and its lower branches (e.g. superior thyroid,
facial and lingual branches), and the interna l carotid
bulb.
If bleeding is encountered within the lower
neck (particular when involving a tracheostomy
site), bilateral selective arteriography of the sub-
clavian, costocervical, and thyrocervical arter-
ies also must be performed. Angiographic study
of these vessels usually can be closely correlated
with the actual site of bleeding (which should be
marked by a radio-opaque object). In our experi-
ence, the tracheostomy site or underlying distal
margins of a surgical neopharynx are the most
commonly affected structures, which typically
bleed from tumor recurrences, erosions, and radi-
ation-induced necrosis.
The anatomic substrate of potential collat-
eral pathways (particularly involving the circle
of Willis) must also be assessed, which requires
angiographic study of the intracranial circula-
tion from selective carotid and vertebral injec-
tions. Prospective identification of major breaks
within the circle of Willis that result in partial
or complete isolation of the cerebral circulation
[e.g. ipsilateral absent A1 segment and posterior
communicating artery (PCoA)], is often enough
to dissuade one from performing a balloon test
occlusion in consideration for a deconstructive
intervention. Other anatomic variants, such as a
persistent trigeminal artery are also likely to dis-
courage consideration of a therapeutic occlusion
of the ipsilateral carotid artery.
Fig. 21.1. Angiogram shows a large pseudoaneurysm of the
common carotid artery (large arrow). Narrowing of the inter-
nal carotid artery (small arrows) is also present, most likely
related to postoperative cicatrization, radiation-induced
changes, or tumor encasement
Fig. 21.2. Left common carotid artery (CCA) angiogram shows
a small amount of extravasation from the CCA into the oro-
pharynx (arrow) from a fi stula that developed after rupture
of a pseudoaneurysm
Diagnosis and Endovascular Surgical Management of Carotid Blowout Syndrome 277
ba c
Fig. 21.3. a Right common carotid artery angiogram shows a large pseudoaneurysm of the mid-cervical right internal carotid
artery (ICA) (large solid arrow). Small concurrent pseudoaneurysms of the proximal right ICA (curved arrows) and right
external carotid artery (ECA) (open arrow) are also present. b Right common carotid artery injection after balloon occlusion
of right ICA shows the pseudoaneurysm of the right ECA (arrow) still fi lls. c Angiogram obtained after composite permanent
balloon occlusion shows embolization of the carotid system. A balloon had been positioned across the origin of the right ECA
(arrow)
21.5
Endovascular Techniques
Over the last decade, dramatic technica l and techno-
logical progress in endovascular surgery has greatly
expanded its role in the management of many types
of intracranial and extracranial cerebrovascular
diseases. These advances have been particularly
significant in two categories: (i) new micro-cath-
eterization technologies and (ii) new endovascular
stent systems. Both have yielded devices that are
safer, easier, and ultimately more effective to use.
For now nearly two decades it has been increas-
ingly recognized that the acquired arterial injuries
of CBS are often readily amenable to endovascular
intervention. However, the specific indications and
appropriate selection of techniques and technology
had only recently become better defined in the past
decade [3, 4, 21]. This definition is already undergo-
ing substantial revision and evolution in response to
inherent limitations and complications of various
endovascular approaches [21, 43] and our expanded
technical and technological capabilities.
Endovascular management of CBS can now be
broadly defined into the two following categories:
“deconstructive” and “reconstructive” approaches.
The former consists of various techniques and tech-
nology used to produce therapeutic occlusion or
“sacrifice” of an affected artery. In contrast, the
latter category consists of various techniques and
technology for eliminating bleeding while preserv-
ing the patency of an affected carotid artery.
21.5 .1
“Deconstructive” Techniques
Therapeutic occlusion of major brachiocephalic
arter ies is one of the oldest neuroendovasc ular thera-
peutic techniques, originally having been developed
for the treatment of inoperable aneurysms of the
cranial base using simple open ligation or gradual
clamping (e.g. Seleverstone clamp) of the carotid
arteries. Both Serbinenko [30, 31] and Debrun [32,
44] are credited with pioneering the endovascular
equivalent of such an approach through their use
of detachable balloons for the treatment of certain
types of giant aneurysms (e.g. cavernous segment
in the mid and late 1970s). Today, besides detach-
able balloons, a wide variety of embolic devices
and endovascular techniques may be employed for
deconstructive therapy of CBS. The selection of a
particular device or technique for therapeutic arte-
rial occlusion may be based upon a variety of fac-
tors, including: the specific pathoetiologic lesion
identified on angiography, prevailing cerebrovas-
278
J. C. Chaloupka et al.
cular hemodynamics, perceived tolerance to inter-
nal carotid artery occlusion based upon balloon
test occlusion (BTO), access to the lesion, urgency
for rapid and definitive occlusion, and availability
and/or comfort level with certain techniques/tech-
nologies.
Detachable latex (Goldvalve, Nycomed) or sili-
cone detachable (DSB, Boston Scientific-Target) bal-
loons remain as one of the easiest and most reliable
means of achieving rapid occlusion of a large vessel,
such as the common or internal carotid arteries,
and therefore in my view continue to be essential
embolic devices for such applications. These devices
can be readily mounted on various conventional
microcatheters (e.g. Tracker 18 HiFlo Unibody,
Boston Scientific-Target, or Prowler 14 (Cordis Neu-
rovascular, Miami Lakes, FL), and once navigated
into the targeted vasculature, rapidly inflated and
deployed by simple traction detachment (Figs. 21.3,
21.4) As a general rule it is most desirable to place
the first balloon into a fairly distal purchase within
the ICA (typically the petrous segment), owing to
the risk of thromboembolism that may occur from
the creation of a long propagating thrombus in case
of more proximal placement of the balloon within
the cervical carotid [4]. A second important rule
for therapeutic carotid occlusion is to always use a
second so-called “safety” balloon (Figs. 21.3c, 21.4b)
to ensure permanent occlusion, since detachable
balloons on occasion are well know to prematurely
deflate. Optimal placement of the second balloon
will largely depend upon the location of the breach
within the carotid artery, since trapping of the
defect is the effective means of stopping/preventing
further hemorrhage [4]. In some cases, therapeutic
occlusion of the entire carotid system (ICA, CCA,
and ECA origin) is necessary or desirable, such as in
cases of multifocal pseudoaneurysms and fistulae or
in patients with Group 1 CBS who are candidates for
salvage surgical resection of local recurrent disease.
In such case performance of a so-called composite
carotid occlusion is indicated [4, 21, 27].
Unfortunately, the use and availability of detach-
able balloons has been steadily on the decline over
the last few years, which just recently were mark-
edly amplified by the abrupt discontinuation of the
only FDA approved detachable balloon in the United
States (DSB; Target-BSC). Currently, it remains
unclear if this device will be reintroduced, which
has created a new impetus in utilizing alternative
techniques and technology.
Many centers have been using various types of
embolic coils (e.g. non-retrievable fibered plati-
num, detachable bare platinum) as an alternative or
adjunct to balloon occlusion of the carotid arteries.
Our group was first to propose using detachable coils
in combination with detachable balloons in cases
where composite carotid occlusion was needed [4].
Although these conventional embolic coils can pro-
duce therapeutic occlusion of large caliber vessels,
such as the common and internal carotid arteries,
there are several intrinsic disadvantages in using
them as the sole embolic agent. These disadvantages
include: (i) lack of precision in deposition within the
distal targeted vessel segment; (ii) frequent instabil-
ity of the first “framing coils” in large caliber arter-
Fig. 21.4. a Right common carotid artery angiogram shows a subtle pseudoaneurysm of the cavernous internal carotid artery
(ICA) (arrow). b Lateral radiograph shows three detachable balloons used in permanent balloon occlusion of the right ICA.
The most distal balloon covers the orifi ce of the pseudoaneurysm (arrow)
a b
Diagnosis and Endovascular Surgical Management of Carotid Blowout Syndrome 279
ies that are typically carrying high volumetric blood
flow; (iii) need to use a relatively large number of
coils to achieve occlusion; (iv) increased procedure
time and expense owing to the typically long times
required to achieve arterial occlusion; and (v) pos-
sible increased risk of artery to artery thromboem-
bolism as progressive thrombosis within the coils
occurs when there is still antegrade flow within the
artery.
A new detachable platinum coil coated with a
hydrogel polymer recently has been introduced
for intracranial aneurysm therapy (HydroCoil,
Microvention), which our group and others have
found to be also useful for carotid occlusion, at least
in potentially decreasing the number of coils needed
to occlude the targeted artery. Unfortunately theses
coils still suffer from many of the same above-men-
tioned disadvantages. Although no definite proto-
types have been revealed, a few device companies
have indicated some interest in creating more novel
large vessel occlusion devices that may incorporate
certain already existing technologies, such as down-
stream embolic filtering devices, stent grafts, and
hydrogel polymers.
In cases requiring smaller vessel occlusion, such
as pseudoaneurysms or tears to the ECA and bra-
chiocervical branches, both nonretrievable plati-
num microcoils (e.g. Tornado, Cook, Indianapolis,
IN; Vortex, Boston Scientific-Target, Freemont,
CA), and various retrievable/detachable platinum
microcoils (e.g. GDC, Boston Scientific-Target) can
be used. Owing to the enhanced control and safety of
the latter type systems, our group has long switched
over to using them exclusively. Occasionally, our
group has utilized careful injections of small ali-
quots of cyanoacrylate-iodinized oil embolic mix-
tures (Trufill-nBCA, Cordis Neurovascular) to very
effectively obliterate small distal pseudoaneurysms
of the ECA circulation [45] (Fig. 21.5).
Occasionally some cases of CBS are ultimately
found to be the result of hemorrhage from a hyper-
vascular neoplasm (typically in our experience
from transformed squamous cell carcinomas that
have exuberant induction of angiogenesis after mul-
timodality treatment). Endovascular therapeutic
devascularization can be achieved with superselec-
tive transarterial embolization using either con-
ventional embolic agents such as polyvinyl alcohol
(PVA) particles (Contour, ITC/Target Therapeutics/
Boston Scientific, Freemont, CA) or more recently
with the slow polymerizing cyanoacrylate 2-octyl
cyanoacrylate (e.g. Dermabond) [46]. Additionally,
in cases where superselective catheterization of sup-
plying arteries is not feasible, we have successfully
utilized direct puncture tumor embolization with
either absolute alcohol or cyanoacrylate embolic
mixtures [47].
21.5 .2
“Reconstructive” Techniques
In lieu of the inherent risks of unilateral therapeutic
ICA occlusion, the unfeasibility of bilateral ther-
apeutic ICA occlusion in most patients who have
already undergone a previous carotid occlusion, and
the high rate of recurrent disease resulting in future
episodes of CBS, there has been a growing impetus
to alternatively consider endovascular repair of the
damaged arterial segment, in an effort to preserve
flow within the vessel. Therefore an alternative
strategy for the management of CBS is to reconstruct
the damaged artery through the various mechani-
cal and biological effects of endovascular stents [38,
40–43, 48].
With the increasing use of stent-assisted angio-
plasty for the treatment of extracranial carotid
occlusive disease, it is becoming more widely
acknowledged that such endovascular reconstruc-
tive techniques can be performed with a relatively
low rate of peri-operative cerebral ischemic compli-
cations [42, 49–52]. These ischemic complications,
on average appear to be lower than those for thera-
peutic occlusion of the carotid artery using either
open or endovascular techniques.
There are clearly a few important theoretical
advantages afforded by stent reconstruction of the
carotid artery that may ultimately enhance the over-
all efficacy of endovascular management of CBS.
First and foremost, such techniques are aimed at
preservation of the affected carotid artery, thereby
having the combined effect of broadening applica-
tion of endovascular intervention (for example in
patients who outright fail carotid BTO or possess
an isolated circulation from an incomplete circle
of Willis), and reducing delayed ischemic compli-
cations (which can be both thrombo-embolic and
hemodynamic) Second, the scaffolding and posi-
tive remodeling force induced by placement of one
or more self expanding stents not only maintains
endoluminal patency, but likely reinforces the
mechanical integrity of the arterial wall, which in
the case of CBS has been damaged by the previously
described processes developing as a consequence of
therapy. This ultimately should result in an artery
that is more resistant to future spontaneous rup-
280
J. C. Chaloupka et al.
Fig. 21.5a–f. Iatrogenic pseudoaneurysm of an external carotid artery branch after CT-guided biopsy. a Axial nonenhanced
CT image shows the tip of a 22-gauge Chiba needle within the anterior aspect of a soft-tissue abnormality (curved arrow) that
was concerning for recurrent squamous cell carcinoma. Histologic analysis showed only infl ammatory changes. b,c Two weeks
later the patient presents with arterialized epistaxis. b Selective right external carotid arteriogram, lateral projection, shows
mild irregularity of the distal internal maxillary artery and focal dilatation of the distal buccal branch (arrow). c Delayed image
from same injection shows fi lling of a 5-mm pseudoaneurysm (arrow). d-f Endovascular surgical management. d Superselective
arteriogram, lateral projection after catheterization of the common trunk of the descending palatine and buccal arteries, shows
fi lling of the pseudoaneurysm (large arrow) and adjacent extravasation (small arrow). e Delayed image (unsubtracted) from
same injection shows persistent fi lling of the pseudoaneurysm. f Selective right external carotid arteriogram immediately after
embolization shows complete occlusion of the buccal branch pseudoaneurysm
a b
c d
e f
Diagnosis and Endovascular Surgical Management of Carotid Blowout Syndrome 281
ture. Another putative benefit of stent-assisted
reconstruction of an affected carotid artery is the
favorable alteration in flow mechanics that lead to
a reduction in disturbed blood flow and eddy for-
mation that has been linked to cerebral artery-to-
artery thromboembolism [42,52]. Such favorable
alterations in hemodynamics may translate into a
significant risk reduction of thromboembolic isch-
emic complications.
Consequently, over the last 6 years our group has
progressively moved from a primarily “deconstruc-
tive” to a primarily “reconstructive” paradigm for
t h e e n d o v a s c u l a r m a n a g e m e n t o f C B S . T h i s a p p r o a c h
first originated in the mid 1990s at Yale, when we
occasionally encountered patients who were not
candidates for therapeutic carotid occlusion owing
to outright failure of a balloon test occlusion or
angiographic demonstration of an isolated anterior
hemispheric circulation (i.e. hypoplasia/aplasia of
the ipsilateral A1 segment and posterior communi-
cating artery). During this time our experience with
carotid stenting was starting to evolve, providing an
opportunity to try this alternative technique in a few
selected patients [39, 43]. Over time we broadened
inclusion criteria to all patients presenting with CBS
who were at high risk of a stroke from therapeu-
tic carotid occlusion. This included patients with
advance age (>65 years), significant cardiovascu-
lar and/or pulmonary co-morbidities, significant
relative reduction of CBF (t0%) based on cere-
bral SPECT imaging during BTO, and contralateral
carotid occlusive disease. Within the last 3 years at
UIHC, we have now shifted to attempting a recon-
structive procedure whenever feasible if the affected
arterial segment involves the common or internal
carotid artery, with the expectation that such a shift
in therapeutic strategy could serve the primary
purpose of reducing overall risk of peri-operative
stroke, while at the very least keeping the rates of
immediate and delayed hemorrhagic arrest at the
same level of our previous experience with decon-
structive techniques [43]. Arterial injuries involving
the external carotid tree or rarely branches arising
from the subclavian arteries continue to managed
by deconstructive techniques as was originally con-
ceived in our early experience.
We have successfully utilized a few different tech-
niques of stent-reconstruction for the management
of CBS, which can be broadly classified as follows.
First, in a similar fashion to techniques developed
for the treatment of wide-neck aneurysms of the
intracranial circulation [37,53–56], endovascu-
lar stenting across a pseudoaneurysm can be per-
formed for neck-bridging scaffolding to eventually
support endosaccular embolization [38,39,43,48]
(Figs. 21.6, 21.7). The rationale for such an approach
originally derived from animal studies of experi-
mentally constructed side-wall aneurysms, which
showed that stent placement alone could result in
sufficient flow diversion and altered recirculation
that ultimately produces thrombosis and neointi-
malization of the aneurysm sac and ostium, respec-
tively [53–55,57]. However, the time required for
aneurysm obliteration can be substantial in such
circumstances, which prompted the idea of trying
to conjointly use thrombogenic coils placed within
the aneurysm after deployment of the stent, in order
to promote rapid thrombotic occlusion [37,55].
This strategy has indeed been used successfully in
an increasing number of clinical cases [39,43,48],
although its application in the treatment of large
pseudoaneurysms is questionable [39]. We have
also experimented with use of alternative embolic
agents, such as liquid adhesives [39], which can be
delivered either by endovascular catheterization or
direct puncture (Fig. 21.7e) of the pseudoaneurysm.
Although we have had success with such techniques
in a small number of cases, widespread adaptation
has been limited owing to concerns of proper con-
trol and stability of the liquid embolic agent.
The second technical strategy that we have suc-
cessfully employed for management of CBS is the
use of overlapping, self-expanding stents deployed
across the neck of a pseudoaneurysm or along a
weakened segment of the affected artery [43,58].
The major advantage of such a strategy is that the
effective porosity of the stent cell configuration is
substantially decreased, resulting in a combination
of additional flow diversion away from the aneu-
rysm sac, and markedly reduced bulk f low out of the
aneurysm sac. Such alterations in fluid mechanics
may diminish growth and re-rupture of the pseu-
doaneurysm, as well as promote its thrombotic
occlusion (both spontaneously and iatrogenically
with the assistance of embolic agents). Further-
more, the added relative coverage and scaffolding
afforded by placement of a second stent allows for
better bridging of a pseudoaneurysm neck, which
in turn facilitates more secure placement of embolic
agents (particularly coils). In fact this approach has
overall been so successful that it has now become
essentially a standard strategy in all our cases when
utilizing uncovered stents for endovascular recon-
struction (Fig. 21.6).
For reconstruction of the common carotid or
proximal cervical internal carotid artery, we have
282
J. C. Chaloupka et al.
Fig. 21.6a–f. Stent-assisted coiling of pseudoaneurysm. a Pre-treatment angiogram, right common carotid injection (lateral
projection) shows two large pseudoaneurysms of the right common carotid artery in a patient with Group 2 CBS. Note that
the internal carotid artery had been previously occluded from an earlier episode of CBS. b Control angiogram during stent
navigation confi rms proper positioning of the stent over the diseased segment of the right common carotid artery. c Delayed
control angiogram after placement of a single Smart Stent. Note the markedly diminished fi lling of the ventral pseudoaneurysm
and moderately reduced fi lling of the dorsal aneurysm. Active bleeding stopped shortly after deployment. e-f Right common
carotid injection 48 h after fi rst intervention. d The patient developed a second episode of CBS 2 days later, in which the angio-
gram shows persistence of the dorsal aneurysm after stent placement. e The pseudoaneurysm is entered through a stent cell
with a microcatheter, and a framing detachable coil is placed. f The fi nal control angiogram shows complete obliteration of the
pseudoaneurysm. No recurrent bleeding was subsequently encountered. A 66-year-old woman with recurrent carotid blowout
syndrome in whom a large pseudoaneurysm developed
a b c
d e f
Diagnosis and Endovascular Surgical Management of Carotid Blowout Syndrome 283
favored using Nitinol self-expanding stents (e.g.
Precise, Cordis Endovascular or Acculink, Guidant),
owing to a combination of factors that include: ease
of access with a long (90-cm) 6-F sheath, high pre-
cision and accuracy of delivery, good conformity
within tapering segments, and relatively high posi-
tive remodeling force after deployment. Our pre-
ferred techniques for carotid stenting are similar to
those used for extracranial atherosclerotic revascu-
larization [42]. For initial access into the carotid cir-
culation, there are two basic techniques commonly
employed. In both cases, a large inner diameter
guiding catheter or sheath must be positioned into
the common carotid (or occasionally the innomi-
nate artery). It has been our experience that place-
ment of a long arterial sheath from a percutaneous
common femoral artery puncture is preferable from
multiple perspectives, including enhanced stability,
ease of coaxial delivery of PTA and stent catheters,
and minimization of the size of arteriotomy. This
technique is performed as follows. A standard 6-F
arterial sheath is inserted into the common femo-
ral artery after single wall percutaneous puncture
and guide wire insertion. A 5-F diagnostic cath-
eter is carefully positioned within the appropriate
great vessel (usually the external carotid artery
origin during internal carotid artery PTA/Stenting),
for subsequent placement of an exchange length
(260 cm) 0.035” or 0.038” (e.g. Amplatz regular or
extra-stiff) wire. The diagnostic catheter and sheath
are carefully removed, while maintaining the distal
purchase of the guide wire. For extracranial stent
cases where a 0.018” SmartStent (O.D. = 2.3 mm) or
Wallstent (O.D. = 2.4 mm) will be deployed, a 7-F,
90 cm Shuttle Sheath (I.D. = 0.10”, O.D. = 0.131”)
is carefully advanced over the stiff exchange wire,
until a stable position within the parent lesion vessel
(distal common carotid artery) is obtained. We
prefer the final sheath position to be at least 1–2 cm
below the lowest planned stent placement to mini-
mize potential stent deployment difficulty. We also
find that placing a wide arcing curve on the Shuttle
inner dilator and distal sheath, as well as removal of
the intervening rotating hemostatic valve facilitates
navigation of tortuous aortic arches and brachioce-
phalic vessels. Care must be ta ken to hold both com-
ponents (dilator and sheath) together during initial
advancement. Subsequently, the outer sheath is
independently advanced into position over the dila-
tor and guide wire within the proximal brachioce-
phalic vessels. This latter maneuver is critical, since
the dilator is poorly seen on f luoroscopy (without a
marker band), and therefore may be inadvertently
advanced too far distally into the stenotic lesion if
both components are advanced in tandem. An alter-
native approach that may be employed requires a
coaxial technique utilizing a diagnostic catheter (5-
F, 120-cm) and guide wire (0.035” or 0.038”) within
the 90 cm Shuttle sheath, and subsequent staged
advancement of each into the appropriate position.
The diagnostic catheter and its associated curves
may assist in distal navigation, while also minimiz-
ing wire/catheter/sheath transitions. Following sta-
bilization, the sheath is then connected to a large
bore rotating hemostatic valve, and continuous pres-
surized heparinized saline infusion. In some cases,
smaller delivery devices may be utilized, such as
coronary PTCA and stent microcatheters, in which
case a 6- or 7-F thin walled guiding catheter with
larger internal diameters (e.g. Envoy, Guider, Plat-
form) may be placed primarily or over an exchange
guide wire. Appropriate testing of device/catheter
compatibility is recommended before attempting
therapy.
Generally, self-expanding stents (Smart Stent,
Wallstent, Precise stent) are preferred within the
extracranial vessels, especially at the level of the
common carotid bifurcation. The Wallstent has
a greater strut density, but has a tendency to fore-
shorten significantly during deployment, which
makes accurate sizing and placement more dif-
ficult. Although more porous, the Smart Stent
deploys with relative precision and minimal fore-
shortening. The Precise and Acculink stents have
a much lower profile than the Smartstent, allow-
ing facile, less traumatic passage through tortu-
ous anatomy or stenotic segments. Of the two, the
Acculink has somewhat less radial force (positive
remodeling force), which may be an advantage for
treating pseudoaneurysms(i.e. less risk of iatrogenic
rupture). Appropriate measurements of the parent
vessel diameter and length of desired coverage are
required. For the management of CBS, we prefer to
use a stent of 1- to 2-mm greater diameter than the
parent vessel (e.g. a 6-mm ICA would receive a 7- to
8-mm diameter stent). Slight oversizing of the stent
ensures adequate radial tension and approximation
of the device to the endoluminal surface, preventing
migrat ion and early thrombosi s. This oversizing a lso
may promote a delayed mechanical and biological
remodeling of the diseased segment through grad-
ual continued dilatation, and stimulation of various
growth factors and extracellular matrix proteinases
(occurring over days to weeks). Excessive oversiz-
ing of the self-expanding stents should be avoided,
since this may result in vessel wall necrosis, and pro-
284
J. C. Chaloupka et al.
Fig. 21.7. a Oblique view of a right common carotid artery injection shows large pseudoaneurysm (straight arrow). Note evi-
dence of prior surgery, including ligation of the external carotid artery (curved arrow). b Angiogram after deployment of an
8×20-mm Wallstent across the rent in the carotid artery shows good distal runoff but persistent fi lling of the pseudoaneurysm.
c Repeat angiogram after deployment of a second, overlapping (8×60-mm) Wallstent shows slower fi lling of the pseudoaneurysm.
d Delayed image shows stagnation of contrast material within the pseudoaneurysm (arrow). e Fluoroscopic spot fi lm shows a
balloon occlusion catheter within the stents, with the balloon partially infl ated (straight arrow). This allowed some retrograde
fl ow of opacifi ed blood to fi ll the pseudoaneurysm, which was percutaneously punctured with a 200-gauge needle (curved
arrow). f Control angiogram after two direct-puncture acrylic embolizations shows complete obliteration of the pseudoaneu-
rysm with patency of the carotid artery. Subtraction artifact is seen where NBCA was injected at the site of rupture (arrow).
Endovascular treatment of a head and neck cancer-related CBS by use of the self-expanding, covered Wallgraft stent
b
d
f
a c
e
Diagnosis and Endovascular Surgical Management of Carotid Blowout Syndrome 285
tracted carotid body stimulation of varying severity
and clinical sequelae. We also prefer to use a stent
5-10 mm longer than the lesion, to ensure adequate
coverage of both the distal and proximal stenotic
segments. Often it is necessary to cross the exter-
nal carotid artery with a stent, owing to extension
of disease into the common carotid bifurcation that
needs revascularization. Our group and others have
observed that this can be done with impunity, since
the ECA in most cases remains patent on follow-up
examinations. In the rare cases when the ECA does
occlude (usually from severe coexistent atheroscle-
rotic disease), patients always remain asymptomatic
secondary to the presence of abundant collaterals.
If a second stent is required, a self-expanding stent
of equal or greater diameter is overlapped with the
primary stent and appropriately deployed. If a self-
expanding stent of a smaller diameter is positioned
within a larger self-expanding stent, the risk of
delayed dilatation and subsequent migration of the
inner stent arises. On occasion, self-expanding cor-
onary stents (e.g. Radius, Magic Wallstent, Boston
Scientific), balloon expandable coronary stents (e.g.
S7-Medronic AVE, Vision-Guidant), or the recently
FDA approved self-expanding neurovascular stent
(Neuroform, Boston Scientific) may be required for
use in smaller arteries (e.g. distal cervical or skull
base portions of the internal carotid) or in chal-
lenging anatomy (e.g. excessive tortuosity or loops).
Great care in proper sizing is requiring preventing
excessive trauma (e.g. oversizing balloon expanding
stents) or stent migration (undersizing both balloon
expandable and self-expanding stents). On post-
deployment angiography, the stent margins should
approximate the luminal diameter and geometry of
the parent vessels, proximal and distal to the dis-
eased segment. If poor approximation of the stent
margins is observed, post stent dilatation or “flar-
ing” using PTA balloons may be required, although
in the setting of CBS may entail additional risk of
carotid r upture. An alternative strategy is to use tele-
scoping “bridging” stents (typically self-expanding)
to remodel variations in contour and diameter of an
arterial segment [58].
Finally, our group has slowly begun to utilize
covered stents or “stent grafts”, as a third alterna-
tive technical strategy for endovascular reconstruc-
tion of CBS (Fig. 21.8). These devices have slowly
evolved over the last several years in which both bal-
loon expandable and more recently, self-expanding
designs have been devised using eit her native venous
grafts or synthetic materials (e.g. PTFE) sewn into
the inner portion of the metallic stent frame. Such
devices have the major advantage of being more
likely to produce immediate exclusion of an aneu-
rysm from the parent arterial blood flow, which
effectively results in an endoluminal bypass of the
aneurysm. As with bare stent reconstruction for the
management of CBS, proper sizing and precision
of deployment are critical for technical and clini-
cal success. However, unfortunately there remain
significant major disadvantages of covered stents at
this time. In general both balloon expandable and
self-expanding designs are inherently larger in pro-
file for a given targeted vessel diameter, therefore
requir ing larger access sheat hs and delivery systems.
These larger profile systems can be very difficult, if
not impossible to safely navigate into the cervical
carotid system. The balloon expandable stent grafts
also suffer from problems related to the need for an
open surgical harvesting of a vein graft, increased
danger of pseudoaneurysm/parent artery rupture
from high pressure inf lation, poorer f lexibility for
navigation into carotid arteries, and less availabil-
ity. Finally, all current stent-graft designs suffer
from inherent increased thrombogenicity, resulting
in increased risk of immediate or delayed in-stent
thrombosis or thromboembolic cerebral ischemia.
Unfortunately, although aggressive anti-thrombotic
adjunctive therapy using systemic anticoagulation
and anti-platelet drugs diminishes this risk, there
is a commensurate increased risk of perioperative
hemorrhage (often catastrophic) from the CBS.
Despite these limitations our group [43] and
others [59–63] have successfully treated a limited
number of pseudo-aneurysms of the common and
internal carotid arteries. It is anticipated that future
advances in material sciences and engineering will
result in lower profile and more f lexible self-expand-
ing stent-graft systems that will pose comparable
technical demands to bare stents. Partially porous
synt he tic graft materials also hold the promise of less
acute and subacute thrombogenicity, since they will
be composed of more biologically inert compounds
and may more readily permit neointimalization.
21.6
Outcomes
Since 1993, the senior author has managed over 150
CBS events by various endovascular approaches,
likely representing the largest single operator expe-
rience in the world. With this greater than a decade
of cumulative experience, much has been learned in
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