Diseases of the Aorta

Oh’s The Echo Manual Aortic aneurysm Aneurysm of the sinus of Valsalva Atherosclerosis & aortic debris Aortic dissection & intramural hematoma Aortitis Coarctation of the aorta

Feigenbaum’s Echocardiography Aortic dilatation & aneurysm Valsalva sinus aneurysm Aortic dissection Aortic atheroma Miscellaneous conditions

Thoracic Aorta Anatomy Ascending aorta Aortic arch Descending aorta Aortic root & sinuses of Valsalva Aortic arch Great vessels: brachiocephalic, left common carotid, & left subclavian arteries Descending aorta Intercostal arteries Anterior spinal artery Abdominal aorta begins below diaphragm

Thoracic Aorta Histology Physiology Intima Media Adventitia Systole  elastic stretch  potential energy Diastole  elastic recoil  kinetic energy

Aortic Aneurysm Pathologic dilatation > 1.5 times the normal diameter Fusiform = symmetric dilatation Saccular = asymmetric outpoutching False = contained rupture Thoracic much less common than abdominal AAA = 36.5 per 100,000 person-years TAA = 5.9 per 100,000 person-years

Etiology Marfan syndrome Ehlers-Danlos syndrome AA & arch Ehlers-Danlos syndrome Cystic medial degeneration Atherosclerosis DA Traumatic Proximal DA Inflammatory Variable Infectious AA (syphilis) Variable (mycotic) Poststenotic AA (aortic stenosis) DA (coarctation) Postsurgical AA (s/p AVR)

Clinical Course Natural history & progression of TAA not as well defined as AAA Onset of symptoms heralds a more rapid course Dichotomous growth rate TAAs < 5.0 cm grow 0.17 cm/year TAAs ≥ 5.0 cm grow 0.79 cm/year 5-year survival = 20-50% Rupture is most common cause of death

Clinical Presentation Vascular complications AR, CHF, ischemia from compression of coronary artery, sinus of Valsalva rupture into RA or RV with LR shunt, thromboembolism Compression of external structures SVC syndrome, dysphagia, hoarseness, respiratory complaints, chest or back pain Rupture Sudden, severe, sharp chest or back pain Left pleural space > pericardium > esophagus

Physical Exam Diastolic murmur of AR Signs of CHF Pulsatile mass in suprasternal notch Differential pulses in extremities Signs of SVC syndrome Decreased air movement or stridor

Diagnosis CXR – shows widened mediastinum CT – defines size & extent MRA – also defines size & extent TTE – limited use TEE – role is under evaluation Aortography – reserved for pre-op eval

Therapy Medical Percutaneous Surgical β-blockers decrease dP/dT (sheer stress) Percutaneous Stent graft for DA distal to left subclavian a. Surgical Recommended when maximal diameter is greater than 6 cm 7 cm for high-risk patients 5.5 cm for Marfan patients

Surgery Dacron tube graft Bentall procedure = valve + graft Survival Perioperative mortality = 5-10% 1-year survival ≥ 70% 5-year survival = 50-60% Complications MI (7.2%), CVA (4.8%), ARF (2.4%), hemorrhage (7.2%), & paraplegia (6.0%)

Gadolinium-enhanced, three-dimensional MRA showing an aneurysm of the aortic arch (arrow) as well as a concomitant atherosclerotic ulcer (arrowhead) Figure 1. Gadolinium-Enhanced, Three-Dimensional Magnetic Resonance Angiogram Showing an Aneurysm of the Aortic Arch (Arrow) as Well as a Concomitant Atherosclerotic Ulcer (Arrowhead). The angiogram was obtained while the patient held his breath. Krinsky G et al. N Engl J Med 1997;337:1475-1476

An 84-year-old man with a history of gastric cancer and hypertension was admitted to the emergency department in shock after loss of consciousness An 84-year-old man with a history of gastric cancer and hypertension was admitted to the emergency department in shock after loss of consciousness. Ten years earlier he had been given a diagnosis of a thoracic aortic aneurysm, 56 mm in diameter, and had declined surgical treatment. Although the aneurysm had increased in size over the decade -- as documented at various years of age on computed tomographic (CT) studies -- and had reached 98 mm in diameter, he had been asymptomatic until the current episode. CT scans revealed a rupturing aneurysm involving the ascending aorta, aortic arch, and descending aorta. He died shortly thereafter without having undergone emergency surgery. An autopsy confirmed that the aneurysm had ruptured into the left thoracic cavity, leaving a massive amount of blood in the subpleural space. Kawasaki S and Kawasaki T. N Engl J Med 2007;356:1251

Aneurysm of Sinus of Valsalva Results from absence of media Typically does not cause symptoms Can compress adjacent structures Can rupture into adjacent structures Most commonly into RA or RV Ventricular septum Surgical repair typically recommended Even in asymptomatic patients

Atherosclerosis Common finding in elderly patients Aortic plaques are more common in descending aorta > aortic arch > ascending aorta Typically are irregularly-shaped & frequently are mobile Can be flow-limiting or hemodynamically-compromising

Atherosclerosis Independent predictor of long-term neurologic morbitity & mortality In one study, ulcerated plaque present in 26% of patients with CVA but only 5% of patients without CVA Plaques > 4 mm thick are more likely to cause an embolic event

Transverse epiaortic ultrasonographic image of the ascending aorta in a patient with severe atherosclerosis of the ascending aorta Figure 6. Transverse Epiaortic Ultrasonographic Image of the Ascending Aorta (Panel A) and the Corresponding Segment of Resected Aorta (Panel B) in a Patient with Severe Atherosclerosis of the Ascending Aorta. In each panel, the arrowhead shows an area of dense calcification, and the arrow shows an area of ulceration and calcification. Reprinted from Wareing et al.18 with the permission of the publisher. Kouchoukos N and Dougenis D. N Engl J Med 1997;336:1876-1889

Aortic Dissection Incidence = 2,000 cases per year in US 2-to-1 male-to-female ratio Peak incidence in 6th & 7th decade of life 65% occur in AA, 20% in DA, 10% in arch, & 5% in abdominal aorta Mortality (75-80%) is greatest during acute phase (< 2 weeks)

Nienaber CA, Eagle KA. Circulation 2003; 108: 628-625.

Nienaber CA, Eagle KA. Circulation 2003; 108: 628-625.

Nienaber CA, Eagle KA. Circulation 2003; 108: 628-625.

Clinical Presentation Sudden, severe chest and/or back pain Tearing, stabbing, or ripping Less common presentations CHF (due to AR) Syncope (due to tamponade) CVA Paraplegia Cardiac arrest

Physical Exam Hypertension Diastolic murmur of AR Signs of CHF Hypotension Pseudohypotension Diastolic murmur of AR Signs of CHF Pulse deficits Neurologic deficits

Diagnosis CXR CTA MRA Widened aortic silhouette Calcium sign = displacement of intimal calcium > 1 cm from outer aortic soft tissue CTA Sensitivity = 83-94% Specificity = 87-100% MRA Gold standard Sensitivity & specificity ~ 98%

Diagnosis TTE TEE Better for AA than DA Sensitivity = 59-85% Speficificty = 63-96% TEE Sensitivity = 98-99% Specificity = 77-97% Depends on experience of operator

CT Scan Showing Localized Dissection of the Aortic Arch with an Intimal Tear (Arrows) Figure 1. CT Scan Showing Localized Dissection of the Aortic Arch with an Intimal Tear (Arrows). Pasic M et al. N Engl J Med 1999;341:1775

MRI of type B aortic dissection Figure 5. Type B and Type A Aortic Dissection. Panel A shows a sagittal, spin-echo magnetic resonance image of a type B aortic dissection. The dissection begins at the origin of the left subclavian artery. The proximal entry is clearly defined 3 cm distal to the origin and appears as a disruption of the flap (arrow). The distal part of the false lumen appears partially thrombosed (arrowhead). Reprinted from Nienaber et al.66 with the permission of the publisher. Panels B and C show transesophageal echocardiograms of a type A aortic dissection. In Panel B, a longitudinal-plane image of the ascending aorta (AA) shows the intimal flap (arrows) extending from the aortic root to the distal ascending aorta (on the right). In Panel C, a transverse-plane image shows the intimal flap (arrows) in the aortic root. LA denotes left atrium, RPA right pulmonary artery, and AV aortic valve. Kouchoukos N and Dougenis D. N Engl J Med 1997;336:1876-1889

A 68-year-old woman was admitted to the emergency room with sudden left hemiparesis A 68-year-old woman was admitted to the emergency room with sudden left hemiparesis. A computed tomographic scan of the brain showed an image consistent with infarction of the right frontal lobe. A transthoracic echocardiogram suggested that dissection of the ascending aorta had occurred. Transesophageal echocardiography was performed immediately thereafter and confirmed the diagnosis. A wide dissection of the proximal aorta compromised more than 270 degrees of the vessel's circumference and extended to the descending thoracic aorta. The redundant, dissected wall was plicated, producing a wave-shaped image in the transverse plane of the echocardiogram (Panel A) and duplicated aortic planes, with two lines (Panel B) or four lines (Panel C), in the longitudinal plane. The patient died two hours after admission, before surgery could be performed. In this patient, aortic dissection had occurred painlessly, with ischemic stroke as its only symptom. The circumferential dissection produced not only uncommon echocardiographic images but also flap intussusception, leading to an ischemic stroke. Pineiro D and Bellido C. N Engl J Med 1999;340:1553

TEE of type A aortic dissection Figure 2. Transesophageal Echocardiogram. Panel A shows a dissection flap (arrows) in the proximal ascending aorta (Ao). A color Doppler study of the same view (Panel B) shows an eccentric jet of aortic regurgitation (arrows) directed toward and impinging on the anterior mitral leaflet. AoV denotes aortic valve, LA left atrium, and LV left ventricle. O'Gara P et al. N Engl J Med 2004;350:1666-1674

Nienaber CA, Eagle KA. Circulation 2003; 108: 772-778.

Nienaber CA, Eagle KA. Circulation 2003; 108: 628-625.

Mehta RH, et al. Circulation 2002: 105: 200-206.

Mehta RH, et al. Circulation 2002: 105: 200-206.

Equation for predicting mortality Mehta RH, et al. Circulation 2002: 105: 200-206.

Mehta RH, et al. Circulation 2002: 105: 200-206.

Intramural Hematoma Thrombus between intima & adventitia Typically occurs in elderly patients with hypertension Precursor for aortic dissection 15-20% of dissections present with hematoma 12-45% of hematomas progress to dissection Managed similarly to aortic dissection

Reprinted from Robbins et al.14 with the permission of the publisher. Computed Tomographic Scan of an Intramural Hematoma (Arrows) of the Ascending Aorta Figure 3. Computed Tomographic Scan of an Intramural Hematoma (Arrows) of the Ascending Aorta. Reprinted from Robbins et al.14 with the permission of the publisher. Kouchoukos N and Dougenis D. N Engl J Med 1997;336:1876-1889

A 68-year-old man presented with acute thoracic, abdominal, & back pain & progressive shock A 68-year-old man presented with acute thoracic, abdominal, and back pain and progressive shock. In the past, he had undergone repair of an abdominal aortic aneurysm, bilobar wedge resection, and chest-wall resection because of a left-sided Pancoast's tumor. At that time, the thoracic aorta measured 5.6 cm in diameter just above the diaphragm, but there was kinking in the lower third of the descending aorta with a large mural thrombus (Panel A). On admission, physical examination revealed a cyanotic face and neck with distended neck veins. The blood pressure was 88/47 mm Hg. Computed tomographic scanning revealed a ruptured aneurysm of the descending thoracic aorta with a diameter of 6.5 cm. The aneurysm was leaking just above the thoracoabdominal junction, and the heart was compressed by a massive dorsal hematoma (Panel B) in a manner resembling cardiac tamponade. The patient underwent urgent replacement of the thoracoabdominal aorta. He survived surgery but died of myocardial infarction three days later. Schmidli J and Carrel T. N Engl J Med 2003;348:1776

A 77-year-old woman with a history of hypertension and an abdominal aortic aneurysm presented with acute upper back discomfort A 77-year-old woman with a history of hypertension and an abdominal aortic aneurysm presented with acute upper back discomfort. The physical examination on admission was unremarkable, and a chest film revealed dilatation of a tortuous thoracic aorta. Transesophageal echocardiography (Panel A) showed severe atherosclerosis of a mildly enlarged descending aorta. There was eccentric thickening of one wall of the aorta (arrowhead) that was consistent with thrombus or intramural hematoma. A computed tomographic (CT) scan confirmed these findings. The patient was treated with aggressive blood-pressure control but had recurrent back discomfort, and another CT scan (Panel B) suggested enlargement of the descending aorta (arrowhead). Aortography was performed and showed no evidence of dissection but did reveal an ectatic descending aorta with a penetrating aortic ulcer on the lateral aspect (arrowhead, Panel C). At surgery the descending aorta was found to be markedly enlarged, discolored, and aneurysmal. There was severe atherosclerosis of the descending aorta, with a penetrating aortic ulcer and hematoma within the aortic wall (Panel D). The patient underwent graft repair of both the descending aorta and the abdominal aneurysm. Paraplegia developed postoperatively, and after a prolonged hospitalization the patient was discharged to an extended-care facility. Harris K and Rosenbloom M. N Engl J Med 1997;336:1875

Aortitis Inflammation of aortic wall Etiologies include Infectious Syphilitic & mycotic Vasculitis Giant cell arteritis & Takayasu’s disease Connective-tissue disease Ankylosing spondylitis & rheumatoid arthritis

Examination of a 74-year-old man with a one-year history of mild, stable angina revealed a murmur consistent with the presence of aortic regurgitation Examination of a 74-year-old man with a one-year history of mild, stable angina revealed a murmur consistent with the presence of aortic regurgitation. Echocardiography demonstrated severe aortic regurgitation as a result of marked dilatation of the aortic root (diameter, 5.4 cm in the proximal ascending aorta). Gadolinium-enhanced magnetic resonance angiography (Panel A) revealed saccular dilatation of the aorta from its root to beyond the distal arch (short arrows), with involvement of the innominate artery (long arrow). T1-weighted images also revealed evidence of mural thrombus in the superior aspect of the aneurysm, beyond the left subclavian artery (arrow in Panel B). Serologic immunofluorescence studies revealed the presence of Treponema pallidum antigen, confirming the clinical suspicion of syphilitic aortitis and aneurysm. The patient received 10 days of intramuscular penicillin G procaine with oral probenecid without complications, and he continues to receive medical therapy under close surveillance. The cardiovascular complications of syphilis predominantly involve the aorta, leading to the formation of aneurysms and aortic-valve incompetence. Angina may result from coronary ostial stenosis or associated atherosclerosis. The incidence of tertiary syphilis has declined in recent decades owing to the early recognition of the disease and the sensitivity of the pathogen to antibiotics. However, the reemergence of syphilis in the developing world, particularly among drug abusers and the sexually promiscuous, may mean that the delayed cardiovascular and neurologic complications of late syphilis will be seen with increasing frequency. Pugh P and Grech E. N Engl J Med 2002;346:676

Coarctation of the Aorta Potential cause of secondary hypertension Narrowing of descending thoracic aorta Typically distal to left subclavian artery Associated with bicuspid aortic valve, PDA, VSD, aneurysm of circle of Willis, & Turner syndrome

A 30-year-old farmer was referred for evaluation of a bicuspid aortic valve Figure 1. A 30-year-old farmer was referred for evaluation of a bicuspid aortic valve. He had no history of hypertension. He had no symptoms other than mild dyspnea and aching calves on walking briskly. On examination he had a regular pulse (78 beats per minute) with a pronounced radiofemoral delay. The blood pressure was 148/92 mm Hg in the right arm and 148/76 mm Hg in the left arm while he was sitting upright. A grade 3/6 mid-to-late systolic murmur was present at the apex. Electrocardiography revealed normal sinus rhythm without features of left ventricular hypertrophy. The chest roentgenogram revealed marked rib notching (arrows in Panel A). An echocardiogram confirmed the presence of a bicuspid aortic valve (Panel B) without stenosis, and continuous-wave Doppler scanning of the descending aorta showed marked diastolic runoff consistent with the presence of severe coarctation. Magnetic resonance imaging of the chest demonstrated severe focal coarctation (black arrow in Panel C), measuring 1 mm, just beyond the left subclavian artery. Numerous large collaterals were present (white arrows). The atretic segment of aortic arch was excised, and a 20-mm Hemashield graft was inserted. The blood pressure was 110/76 mm Hg six months after surgery. AC denotes anterior cusp, PC posterior cusp, AA ascending aorta, DA descending aorta, ITA internal thoracic arteries, LV left ventricle, and LA left atrium. Bruce C and Breen J. N Engl J Med 2000;342:249

References Oh’s The Echo Manual Topol’s Manual of Cardiovascular Medicine