With each heartbeat, blood is ejected into the aorta generating multiple mechanical forces including pressure, radial stress and longitudinal stress. These forces increase aortic wall tension potentially leading to the development of aortic dissections and aortic aneurysms that may require surgical or endovascular repair.
The aorta ascends in the anterior mediastinum, curves backward into the aortic arch from which emanate the great vessels of the head and the upper extremities, descends into the posterior mediastinum and beyond the diaphragm continues into the abdomen providing blood to the spinal cord, gut, kidneys, ultimately dividing to deliver blood to the lower extremities (Figure 9–1).
Diseases that interfere with the delivery of blood to the tissues (e.g., aortic dissections, atherosclerosis, and emboli) place patients at great risk for organ ischemia. Other disease conditions (e.g., aneurysms) weaken the wall of the aorta and often result in aortic rupture and sudden death. Many patients with aortic disease present emergently secondary to acute dissection, aneurysm rupture, or following traumatic aortic injury. Others, with long-standing aortic aneurysms, present for elective surgical or, increasingly common, for endovascular repair.
Normal anatomy of the thoracoabdominal aorta with standard anatomic landmarks for reporting aortic diameter as illustrated on a volume-rendered CT image of the thoracic aorta. CT indicates computed tomographic imaging. Anatomic locations: 1, aortic sinuses of Valsalva; 2, sinotubular junction; 3, mid ascending aorta (midpoint in length between numbers 2 and 4); 4, proximal aortic arch (aorta at the origin of the innominate artery); 5, mid aortic arch (between left common carotid and subclavian arteries); 6, proximal descending thoracic aorta (begins at the isthmus, approximately 2 cm distal to left subclavian artery); 7, mid descending aorta (midpoint in length between numbers 6 and 8); 8, aorta at diaphragm (2 cm above the celiac axis origin); 9, abdominal aorta at the celiac axis origin. [Reproduced with permission from Hiratzka LF, Bakris GL, Beckman JA, et al: ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the diagnosis and management of patients with thoracic aortic disease: Executive summary: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine, Anesth Analg. 2010 Aug;111(2):279-315.]
DISEASES OF THE ASCENDING THORACIC AORTA
Patients with ascending thoracic aortic aneurysms present either acutely or electively (Figure 9–2). Crushing chest pain often heralds acute presentations. Some of these acute patients never undergo surgery as they develop lethal complications such as coronary ischemia, pericardial effusion and tamponade, or intrathoracic bleeding. In most cases, patients will present emergently for repair following diagnosis in the emergency room. Acute, contained ascending aortic aneurysm ruptures require immediate surgical correction. Radiographic (MRI, CT) ...