Page 2 - Carotid and peripheral vascular interventions textbook

CHAPTER 6
CAROTID AND PERIPHERAL VASCULAR INTERVENTIONS: STEP-BY-STEP

Carotid artery disease

Thosaphol Limpijankit

INTRODUCTION needs a thorough understanding about basic intracranial
and extracranial circulation, as well as understanding
Stroke is one of the main causes of mortality and about common anatomic variants.
morbidity worldwide, and causes substantial health burden.
Approximately 15-20% of ischemic stroke is linked with AORTIC ARCH TYPES

atherosclerosis of the carotid arteries, typically stenosis
which occurs at the bifurcation of the external and internal It is important to identify the type of aortic arch
carotid arteries (1,2). Importantly, carotid atherosclerosis as well as conf guration concerning the great vessels,
is frequently asymptomatic until the appearance of a fatal because these anatomic features affect procedure
or disabling stroke occurs. Once patients develop symptoms complexity. In normal anatomy, the most common aortic
[i.e., stroke or transient ischemic attack (TIA)], the risk arch branching has separate origins for the brachiocephalic
of recurrent ipsilateral stroke is even higher, with the (or innominate), left common carotid artery (CCA),
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risk being highest immediately after the initial ischemic and left subclavian artery (Fig. 6-1 A). The second most
events. Moreover, nearly 80% of strokes occurs secondary frequent aortic arch branching uses a common origin
to artery-to-artery embolization in the carotid distribution for the brachiocephalic and left CCA (Fig. 6-1 B).
and may present as the initial event without warning (3). In other variants, the left CCA begins directly at the
All of these reasons emphasize the need for early detection, brachiocephalic artery (Fig. 6-1 C). These last two patterns
treatment and prevention of carotid artery stenosis. are also called a “bovine arch” (7). On rare occasions,
Medical, surgical, and endovascular treatments a single brachiocephalic trunk beginning from the aortic
are commonly used to treat carotid artery stenosis. arch can eventually split into bilateral subclavian arteries
In symptomatic carotid stenosis, revascularization was with a bicarotid trunk, though this aortic arch branching
found to have an incremental benef t over medical therapy pattern is only found in cattle (Fig. 6-1 D).
in regards to preventing recurrent stroke (4,5). Carotid Moreover, the aortic arch can be classif ed into
endarterectomy (CEA) was f rst performed by DeBakey 3 types, based on the relationship of the brachiocephalic
in 1975 (6) and has been recommended as the standard (or innominate) artery to aortic arch. Type I aortic
treatment for carotid artery stenosis. However, there arch is characterized by all three great vessels originating
are limitations of CEA, such as patients’ comorbidities, from the outer aortic arch’s curvature within the same
surgical complications and unfavorable neck anatomy. horizontal plane (Fig. 6-2 A). For type II aortic arch,
During the last decades, there has been a rise of endovascular the brachiocephalic artery originates between the
techniques, more experienced operators, and new devices horizontal planes of the inner and outer of aortic arch
available. All of these components lead to a paradigm curvatures (Fig. 6-2 B). For type III aortic arch, the
shift from CEA to carotid artery stenting (CAS). brachiocephalic artery originates below the horizontal
plane of the aortic arch’s inner curvature (Fig. 6-2 C).
ANATOMIC CONSIDERATION The more inferior the origin of the treated artery (i.e.,

Type II or III aortic arch), the more diff cult it is to
It is essential that any operator contemplating CAS obtain carotid artery access.