Adapted from Pantin EJ, Cheung AT. Transesophageal echocardiographic evaluation of the aorta and pulmonary artery. In: Konstadt S, Shernan S, Oka Y, eds. Clinical Transesophageal Echocardiography: A Problem-Oriented Approach. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2003:215-244.

Figure 7-2 TEE ME aortic valve long-axis image at 140 degrees in a patient with a Stanford type A aortic dissection. An intimal flap within the aorta that begins in the aortic root extends into the ascending aorta. Calipers were used to measure the diameter of the aortic valve annulus (A), sinuses of Valsalva (SoV; B), STJ (C), and ascending (ASC) aorta (D).

Figure 7-3 The TEE ME ascending aortic short axis image at a multiplane angle between 0 and 60 degrees provides a cross section for measuring the ascending aortic diameter at the level of the RPA. PA, main pulmonary artery; SVC, superior vena cava.

Figure 7-4 The TEE ME ascending aortic long axis image at a multiplane angle between 90 and 150 degrees provides a cross section for measuring the ascending aortic diameter at the level of the RPA.

The aortic arch is the segment containing the origin of the aortic arch branch vessels, the innominate artery, the left carotid artery, and the left subclavian artery (Figures 7-5 and 7-6).

• The descending thoracic aorta is the segment between the origin of the left subclavian artery and the diaphragmatic hiatus (Figures 7-7 and 7-8).

• The paired intercostal arteries are branch vessels of the descending thoracic aorta.

• The aortic isthmus is the segment of the proximal descending thoracic aorta just beyond the origin of the left subclavian artery at the site of the ligamentum arteriosum, the vestige of the ductus arteriosus in the fetus.

• The abdominal aorta is the segment of the aorta between the diaphragmatic hiatus and the aortic bifurcation where it becomes the internal iliac arteries.

• Major branch vessels of the abdominal aorta include the celiac trunk, superior mesenteric artery, renal arteries, inferior mesenteric artery, and the lumbar segmental arteries.

Figure 7-5 The TEE upper esophageal (UE) aortic arch long axis image at a multiplane angle of 0 degrees provides a cross section through the distal aortic arch.

Figure 7-6 The TEE UE aortic arch short axis image at a multiplane angle of 90 degrees provides a cross section through the distal aortic arch that often provides images of the origin of the subclavian artery, the origin of the left carotid artery, the main pulmonary artery, and the innominate vein. IV, innominate vein.

Figure 7-7 The TEE ME descending aortic short axis image at a multiplane angle of 0 degrees provides a cross section for measuring the descending aortic diameter. The entire descending thoracic aorta can be examined by advancing or withdrawing the TEE probe along the length of the descending aorta.

Figure 7-8 The TEE ME descending aorta long axis image at a multiplane angle of 90 degrees provides a cross section for the intimal surface of the descending aorta.

Segmental Anatomy of the Aorta for Thoracic Endovascular Aortic Repair (Figure 7-9)

• The thoracic aorta can be segmented into five anatomic zones for purposes of endovascular repair.

• Zones 2 to 4 are accessible landing zones for descending thoracic aortic endovascular repair procedures, although landing into zone 2 requires coverage of the origin to the left subclavian artery.

• Endovascular stent graft landing in zones 0 and 1 requires debranching of the brachiocephalic vessels to provide cerebral perfusion.

• Zone 0: ascending aorta and proximal aortic arch to the innominate artery.

• Zone 1: segment between the innominate artery and left carotid artery.

• Zone 2: segment between the left common carotid artery and the left subclavian artery.

• Zone 3: curved segment of the distal aortic arch and proximal descending thoracic aorta beyond the left subclavian artery.

• Zone 4: the straight portion of the descending thoracic aorta beginning at approximately the level of the fourth thoracic vertebrae.

Figure 7-9 The thoracic aorta can be segmented into five anatomic zones for purposes of endovascular repair: Zone 0, the ascending aorta and proximal arch to the innominate artery; zone 1, the segment between the innominate artery and the left common carotid artery; zone 2, the segment between the left common carotid and left subclavian arteries; zone 3, the segment beyond the left subclavian along the curved portion of the distal arch; and zone 4, the straight portion of the descending thoracic aorta starting at the level of the fourth thoracic vertebrae.

From Desai ND, Szeto WY. Complex aortic arch aneurysm and dissections: Hybrid techniques for surgical and endovascular therapy. Curr Opin Cardiol. 2009;24:521-527.

Position of the Aorta in Relation to the Esophagus and Other Structures

• The aortic root and proximal ascending aorta lie within the pericardial sac. The aortic root is anterior to the esophagus and left atrium (see Figure 7-1).

• The ascending aorta is anterior to the esophagus. The right pulmonary artery (RPA) lies between the esophagus and the proximal ascending aorta (Figure 7-10; see also Figures 7-1 and 7-3).

• The distal trachea and left mainstem bronchus lies between the esophagus and the distal ascending aorta and proximal aortic arch (see Figure 7-10).

• The proximal descending thoracic aorta is initially anterior to the esophagus, then lateral to the esophagus in the midthorax, then posterior to the esophagus at the diaphragmatic hiatus (see Figure 7-10).

• The left atrium provides an acoustic window for TEE imaging of the aortic valve, aortic root, and proximal ascending aorta (see Figure 7-1).

• The RPA provides an acoustic window and anatomic reference for transesophageal echocardiography (TEE) imaging of the proximal and mid ascending aorta (see Figures 7-3 and 7-4).

• The distal trachea and left mainstem bronchus obstruct TEE imaging of the distal ascending aorta and proximal aortic arch (see Figure 7-10).

• Rupture of the aortic root or proximal ascending aorta will cause cardiac tamponade because it lies within the pericardial sac (Figure 7-11).

Figure 7-10 The anatomic relationships among the thoracic aorta (red), the main PA (blue), the left pulmonary artery, the RPA, the SVC (blue), the inferior vena cava, the esophagus (yellow), the trachea (gray), and the left mainstem bronchus. The descending thoracic aorta is anterior to the esophagus near the aortic arch, lateral to the esophagus in the mid-thorax, then posterior to the esophagus at the diaphragmatic hiatus. The distal trachea and left mainstem bronchus lies between the esophagus and the aortic arch.

From Pantin EJ, Cheung AT. Transesophageal echocardiographic evaluation of the aorta and pulmonary artery. In: Konstadt S, Shernan S, Oka Y, eds. Clinical Transesophageal Echocardiography: A Problem-Oriented Approach. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2003:215-244.