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Vol. 66, No. 3 2015
Northeast Florida Medicine
Endovascular Neurosurgery
debris from entering the intracranial circulation. Proxi-
mal occlusion systems are increasingly attractive because
complete cerebral protection is obtained before crossing
the lesion with a catheter.
13
The major incentive to adopt endovascular treatment
of carotid disease occurred after development of stents
designed specifically for the carotid system. Current com-
mercially available self-expanding stents are comprised
of either nitinol (nickel-titanium alloy) or stainless steel
(cobalt alloy). These stents are placed across the stenotic
carotid segment and, once deployed, the struts andmetallic
mesh engage the plaque material, preventing dislodgment
of debris, as well as providing support to the vessel wall
to restore luminal patency. The purported advantages of
stents over simple balloon-angioplasty include prevention
of plaque dislodgment, management of intimal dissection,
decreased rate of recurrent stenosis, and vessel recoil.
Following the results of the Stenting and Angioplasty
with Protection in Patients at High Risk for Endarterec-
tomy (SAPPHIRE) Trial,
14
the neurovascular community
recognized that certain patients considered high risk for
CEA were less likely to have complications if treated with
carotid artery stenting (CAS) with distal embolic protec-
duplex ultrasonography and CTA has been shown to be the
most cost effective and is therefore highly recommended
(Figure 2).
5
While still considered the gold standard, DSA is
necessary only in selected cases tomake a therapeutic decision.
DSA still has the advantage over non-invasive technologies
to dynamically evaluate with reasonable precision the status
of collateral flow in the intracranial circulation.
Management Strategies
The fundamental nature of carotid disease management
has not changed significantly since the 1950s when carotid
artery endarterectomy (CEA) was first introduced. The
goal of surgical treatment is to provide carotid revascu-
larization and restoration of a near-normal vessel lumen
without incurring significant morbidity and mortality.
For the most part, CEA has been established as the main
surgical option for management of carotid disease, which
has been corroborated by nearly 99,000 inpatient carotid
endarterectomy procedures performed in the United States
in 20063 and by evidence from several seminal studies
in the 1990s.
6-10
Nevertheless, an increased risk of CEA
in certain patients has lead to development of minimally
invasive therapies beginning with the first angioplasty of
the carotid bifurcation in 1980.
11
Balloon angioplasty of carotid stenosis gained increased
acceptance among interventionalists, but it was initially
associated with a high risk of distal embolic complications
and major neurological deficits.
12
In order to overcome this
problem, embolic protection devices (EPDs) were devel-
oped. An EPD can be classified into three main groups,
each with its own working principle: (1) distal occlusion
devices, (2) distal filtration systems, and (3) proximal
occlusion devices. In brief, distal occlusion devices work
by inflating a balloon in the internal carotid artery (ICA)
between the lesion and the brain to stop blood flow during
manipulation of the stenotic segment and therefore, prevent
debris from entering the cerebral circulation. Any embolic
material created by the procedure is later aspirated and
flushed either into the external carotid artery or out of
the circulatory system through a sheath in the common
carotid artery. Distal filtration systems function similarly
to an umbrella and are placed between the carotid lesion
and the brain to capture all debris during the procedure.
At the end of intervention, the filter and captured material
are removed.The main advantage of distal filtration systems
is that cerebral perfusion and angiographic assessment are
maintained throughout the procedure.
13
Lastly, proximal
occlusion systems are comprised by two compliant bal-
loons, of which one is inflated in the proximal common
carotid artery and another in the external carotid artery.
This double-balloon arrangement creates either a no-flow
or a reversed-flow pattern within the ICA that prevents
Figure 2:
Computed tomography angiography (CTA)
of the neck showing calcifications at the origin of the
internal carotid artery compatible with a high-grade
stenotic lesion (white arrow).
