Page 2 - Carotid and peripheral vascular interventions textbook
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                    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),
                    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.
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