Atherosclerosis is a systemic vascular disease that often affects multiple vascular territories and leads to peripheral artery disease (PAD). The age-adjusted prevalence of peripheral atherosclerotic disease is approximately 12%.¹ However, patients with established risk factors for this condition, such as diabetes mellitus, or patients with known coronary artery disease (CAD), have a much higher prevalence of peripheral athero-occlusive disease.² Peripheral atherosclerotic disease remains poorly recognized, as recently demonstrated by the PARTNERS (Peripheral Arterial Disease Awareness, Risk and Treatment: New Resources for Survival) Investigators, a US national survey of almost 7000 patients seen in 320 primary care clinics. The survey showed that only 45% of the patients with peripheral vascular disease had been diagnosed with this condition prior to the PARTNERS Program.³

Consequently, clinicians must have a high grade of suspicion for detecting PAD in patients with known risk factors or with established CAD, and these patients must undergo a detailed history and physical examination as well as non-invasive tests such as ankle-brachial index and/or arterial duplex ultrasound to rule out the presence of peripheral vascular disease. In those with significant symptoms, assessment of the peripheral vascular anatomy is necessary if intervention is being considered.⁴

Despite major advances in noninvasive imaging techniques such as duplex ultrasonography, angiographic computerized tomography (CTA) (Fig. 23-1), and magnetic resonance angiography (MRA) (Fig. 23-2), contrast angiography remains the gold standard method for diagnosing peripheral arterial vascular disease, because it provides the anatomic details necessary to plan percutaneous or surgical revascularization. In the present chapter, we will address the basic anatomy and angiographic procedures for the vascular territories that more commonly undergo percutaneous or surgical intervention.

The operator must be familiar with the techniques and equipment for different arterial vascular access sites (ie, common femoral artery [CFA], brachial artery, and radial artery). To obtain high quality angiographic images, it is essential to have a radiographic gantry with angulation capability in both the axial and sagittal planes as well as a large-field (14-16-in or 36-41-cm) image intensifier capable of capturing the larger regions of interest, such as the entire aortic arch, entire pelvic vasculature, and both legs.⁵

Digital angiography allows immediate monitor display of the acquired image, as well as electronic processing to enhance contrast, reduce noise, and subtract bony and soft-tissue density. Digital subtraction angiography (DSA) significantly enhances the angiographic anatomical detail and allows less contrast to be used, which shortens procedure time. A preliminary image (mask) is recorded immediately prior to the contrast injection, so that any background densities—such as bone, calcification, radiopaque objects, soft tissue, and air densities—can be subtracted from subsequent images (Fig. 23-3). Quantitative online angiographic analysis is available and often helps to provide an objective method of measurement.⁵ We have presented the most common angiographic views for performing peripheral angiography in Table 23-1.

The use of low or iso-osmolar contrast agents is preferred to the use of high osmolar agents. These new agents are better tolerated since they produce fewer undesirable side effects such as nausea, vomiting, lightheadedness, or pain.⁶ In addition, low/iso-osmolar agents carry a lower osmotic load. This results in less fluid retention, which is desirable in patients with impaired left ventricular and/or renal function.

Alternatives to iodinated contrast, including carbon dioxide (CO₂) and gadolinium (eg, gadopentetate dimeglumine), are available to patients with severely impaired renal function and/or a history of life-threatening contrast allergy; however, these agents can also cause complications in a small percentage of patients, including distal embolization and stroke if used above the diaphragm (occurring with CO₂), or nephrogenic systemic fibrosis (occurring with gadolinium).^7-10

A wide variety of diagnostic catheters and guidewires are available for vascular angiography. Standard guidewires vary in diameter from 0.012 to 0.052 inch, but the most commonly used sizes are 0.035 and 0.038 inch. The length of most standard guidewires is between 100 and 180 cm, and the longer exchange guidewires measure between 260 and 300 cm. Tip configurations include straight or angled tip and “J” shape. Shafts may have varying degrees of stiffness. Devices with stiff, rigid shafts allow advancement through tortuous vessels, and low-friction, hydrophilic-coated wires allow passage in tortuous or difficult-to-cross lesions.

The aortic arch and thoracic aorta include the ascending, transverse, and descending aorta to the diaphragm. The ascending aorta begins just distal to the sinus of Valsalva and courses from anterior to posterior in the chest. The transverse portion begins as the aorta crosses the main pulmonary artery and the left mainstem bronchus, and stretches to the ligamentum arteriosum (the remnant of the fetal ductus arteriosum). The descending portion begins distal to the ligamentum arteriosum and continues to the diaphragm.¹¹ The normal aortic diameter ranges from 2.2 to 3.8 cm.¹²

The transverse portion of the thoracic aorta courses posteriorly and gives rise to the brachiocephalic trunk proximally, the left common carotid artery in the mid portion, and the left subclavian artery in its distal portion. In 10% to 20% of patients, the left common carotid artery may originate from a common ostium with the brachiocephalic trunk or from the brachiocephalic trunk itself, an anatomic variation also known as a “bovine arch” (Fig. 23-4).¹³ Other less common anatomic variations also occur, including origination of the left vertebral artery directly from the aortic arch between the left common carotid artery and the left subclavian artery, and the origination of the right subclavian artery from the aortic arch distal to the origin of the left subclavian artery.¹³ The descending aorta courses anterior to the spine and gives origin to nine pairs of intercostal arteries (T3 to T11).

Thoracic Aortography

Thoracic aortography is usually performed for the diagnosis of vascular diseases such as aneurysms, aortic dissection, coarctation of the aorta, patent ductus arteriosus, or vascular rings, as well as for the evaluation of vascular injuries such as blunt or penetrating chest trauma and stenoses in the origin of the great vessels. It is also useful prior to planning cerebrovascular intervention, to determine whether a brachial or femoral access site would be most beneficial. However, most of this pathology may also be diagnosed with high accuracy using non-invasive tests such as CT scan, magnetic resonance imaging, ultrasonography, and transesophageal echocardiography.¹⁴

The common femoral arterial access is the most frequently used vascular access, although the brachial or radial approaches are also useful for performing thoracic aortography. A 4- to 6-French (Fr) pigtail catheter is advanced into the ascending aorta and positioned just above of the sinus of Valsalva. Using a power injector, a total of 40 to 60 mL of contrast material is injected at 20 to 30 mL/sec. For cine imaging, 15 to 30 frames/sec is commonly used. The left anterior oblique (LAO) projection (30°-60°) best separates the ascending from the descending aorta and allows visualization of the origin of the great vessels. The anteroposterior (AP) and right anterior oblique (RAO) views may be helpful to assess the cervical branching vessels (vertebral, subclavian, common carotid).

The anatomy of the aortic arch has recently been classified into three types based on the relationship between the origin of the great vessels and a transverse line drawn at the level of the apex of the aortic arch. The Type I aortic arch is characterized by origin of all three great vessels in the same horizontal plane as the outer curvature of the aortic arch. In the Type II aortic arch, the innominate artery originates between the horizontal planes of the outer and inner curvatures of the aortic arch. In the Type III aortic arch, the innominate artery originates below the horizontal plane of the inner curvature of the aortic arch. (Fig. 23-5).¹⁵ This classification has practical clinical applications since the degree of difficulty and complication rates for performing selective cervical and cerebrovascular angiography and intervention are related to the aortic arch type (III > II > I).

Cervical Vessels

Three arteries originate in the transverse portion of the thoracic aorta, the brachiocephalic trunk, the left common carotid, and the subclavian artery. The brachiocephalic trunk or “innominate artery” bifurcates into the right common carotid artery and the right subclavian artery.¹¹ Although the left common carotid most commonly arises separately from the aortic arch, in 10 to 20% the left common carotid artery may originate from a common ostium or from the proximal portion of the innominate artery and is termed a “bovine arch.”¹³

The common carotid arteries run lateral to the cervical vertebral bodies in the AP view and bifurcate into the external and the internal carotid arteries at the level of C4 vertebrae.¹¹ The internal carotid artery does not give origin to branches in its extracranial portion. It then enters the skull through the petrous portion of the temporal bone, after which it becomes very tortuous in a portion known as the carotid siphon, which courses within the cavernous sinus and the supraclinoid segment. Thereafter, it terminates into the anterior cerebral artery (ACA) and middle cerebral artery (MCA).

The most important branches of the subclavian artery are the internal mammary and the vertebral arteries, which arise at the inferior and the superior aspects of this vessel, respectively, opposite each other. The vertebral artery is the first, and usually the largest, branch of the subclavian artery, arising from the upper and posterior surface of the vessel. It angles backward to the transverse process of the C₆ vertebra and courses cephalad through the foramina of the transverse processes of the upper five cervical vertebrae, where it enters the skull. After penetrating the foramen of the atlas, it turns medially and posteriorly to enter the skull through the foramen magnum. It then gives origin to the posterior inferior cerebellar artery (PICA), and subsequently joins the contralateral vertebral artery to form the basilar artery.

The vertebral artery is divided into four segments, identified as V₁ to V₄ (Fig. 23-6). This division is of clinical importance because atherosclerotic disease is commonly located in the most proximal 2-cm segment, sometimes called V₀, and within the first 2 segments of the vertebral artery (V₁ and V₂). V₁ begins after the ostial (V₀) portion and continues to the vertebral artery’s entrance into the foramen of the 6^th transverse process (in 88% of cases). V₂ courses cephalad through the foramina of the transverse processes until it reaches the transverse process of the axis. V₃ continues to its entrance into the spinal canal, and it courses laterally and posteriorly to pass through the transverse foramen of the atlas, approaching the midline and then cephalad to perforate the posterior atlanto-occipital membrane to enter the vertebral canal. V₄ perforates the dura mater and passes thorough the foramen magnum, then joins the contralateral vertebral artery to form the basilar artery.

Angiography of the Brachiocephalic and Cervical Arteries

Vascular access may be obtained at the common femoral artery, the brachial artery, or the radial artery. An aortic arch aortogram (30°-60° LAO) is performed prior to selective angiography. This nonselective angiogram allows the operator to identify ostial disease, significant tortuosity, or anatomic variations in any of the brachiocephalic vessels.

Carotid Angiography

Carotid angiography remains the gold standard diagnostic technique for estimation and quantitation of stenoses of the carotid arteries,¹⁴ despite major advances in non-invasive diagnostic modalities such as duplex ultrasonography, MRA, and CTA in recent years.^16-19 Selective carotid angiography is performed after obtaining an aortic arch aortogram in the LAO (30°-60°) view, which allows the operator to visualize the level at which the brachiocephalic trunk and left common carotid artery originate from the aortic arch. Using the same LAO angle, the brachiocephalic trunk may be easily engaged from the femoral access with a variety of shaped catheters: 4- or 6-Fr angled catheters such as right Judkins-4, internal mammary, and Berenstein; or shepherd’s crook shapes, such as Vitek, Headhunter, and Simmons Types I, II, and III. From the arm access, selective angiography may be performed with the shepherd’s crook shapes, particularly the Simmons catheters.

For selective angiography, after the ostium of the primary branch vessel has been cannulated, a 0.035-in “J” tip or soft-tip guidewire (Wholey wire, Covidien/Medtronic, Dublin, Ireland) is steered into the proximal portion of the common carotid artery and the catheter advanced over the guidewire, positioning it at the origin of the common carotid artery. The catheter is then aspirated and cleared to minimize the risk of embolization. Injections of contrast by hand are preferred to power injections for selective angiography (Fig. 23-7 and Fig. 23-8). When using small catheters and DSA, iodinated contrast may be diluted with saline 1:1 or 1:2 to enable better filling of the vessels.