Diseases of the Aorta. Oh’s The Echo Manual Aortic aneurysm Aneurysm of the sinus of Valsalva...

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 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– Intima– Media– Adventitia

• Physiology– 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– AA & arch

• Ehlers-Danlos syndrome– AA & arch

• Cystic medial degeneration– AA & arch

• 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 LR 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– 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%)

Krinsky G et al. N Engl J Med 1997;337:1475-1476

Gadolinium-enhanced, three-dimensional MRA showing an aneurysm of the aortic arch (arrow) as well as a concomitant atherosclerotic ulcer (arrowhead)

Kawasaki S and Kawasaki T. N Engl J Med 2007;356:1251

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

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

Kouchoukos N and Dougenis D. N Engl J Med 1997;336:1876-1889

Transverse epiaortic ultrasonographic image of the ascending aortain a patient with severe atherosclerosis of the ascending aorta

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.

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– Hypotension– Pseudohypotension

• Diastolic murmur of AR

• Signs of CHF

• Pulse deficits

• Neurologic deficits

Diagnosis

• CXR– 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– Better for AA than DA – Sensitivity = 59-85%– Speficificty = 63-96%

• TEE– Sensitivity = 98-99%– Specificity = 77-97%– Depends on experience of operator

Pasic M et al. N Engl J Med 1999;341:1775

CT Scan Showing Localized Dissection of the Aortic Arch with an Intimal Tear (Arrows)


MRI of type B aortic dissection

Pineiro D and Bellido C. N Engl J Med 1999;340:1553

A 68-year-old woman was admitted to the emergency room with sudden left hemiparesis

O'Gara P et al. N Engl J Med 2004;350:1666-1674

TEE of type A aortic dissection

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


Equation for predicting mortality

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


Computed Tomographic Scan of an Intramural Hematoma (Arrows) of the Ascending Aorta

Schmidli J and Carrel T. N Engl J Med 2003;348:1776

A 68-year-old man presented with acute thoracic, abdominal, & back pain & progressive shock

Harris K and Rosenbloom M. N Engl J Med 1997;336:1875

A 77-year-old woman with a history of hypertension and an abdominal aortic aneurysm presented with acute upper back discomfort

Aortitis

• Inflammation of aortic wall

• Etiologies include– Infectious

• Syphilitic & mycotic

– Vasculitis• Giant cell arteritis & Takayasu’s disease

– Connective-tissue disease• Ankylosing spondylitis & rheumatoid arthritis

Pugh P and Grech E. N Engl J Med 2002;346:676

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

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

Bruce C and Breen J. N Engl J Med 2000;342:249

A 30-year-old farmer was referred for evaluation of a bicuspid aortic valve

References

• Oh’s The Echo Manual

• Topol’s Manual of Cardiovascular Medicine

Diseases of the Aorta. Oh’s The Echo Manual Aortic aneurysm Aneurysm of the sinus of Valsalva...

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