Diseases of the Great Vessels

Susan A. Raaymakers, MPAS, PA-C, RDCS (AE)(PE)Radiologic and Imaging Sciences - Echocardiography

Grand Valley State University, Grand Rapids, Michiganraaymasu@gvsu.edu

Tyler Kahle Story(20 minutes duration)

http://media.bestcare.org/TylerKahleStory

Normal Aortic Anatomy Six Segments

1. Annulus2. Sinuses of Valsalva 3. Sinotubular Junction4. Ascending Tubular Aorta5. Arch6. Descending Thoracic

Aorta

Normal Aortic Anatomy Six Segments

Annulus Represents the junction of the

prox. Ao and the LVOT.

Part of fibrous skeleton of the heart and is contiguous with the anterior mitral valve leaflet and perimembranous septum

Fibrinous structure so relatively stable and resistant to dilation:useful for indexing to remaining aortic sizing

NL 13 +/-1 mm/m2 NL size 2.0-3.1cm

Normal Aortic Anatomy Six Segments

Sinuses of Valsalva Normal aorta dilates at

the level of the sinuses by approximately 6 mm/m2

Three sinuses of Valsalva of equivalent size

Right and left contain ostia of right and left coronaries respectively

Non

Normal Aortic Anatomy Six Segments

Sinotubular Junction Aorta tapers to within 2 to 3 mm

of annular size Crucial to nature of aortic valve

coaptation Insertion of aortic valve cusps:

continuous from the level of the annuls up through the sinuses to the level of the sinotubular junction

Dilatation of sinotubular junction may result in splaying of coaptation line of the aortic cusps leading to secondary aortic insufficiency

Normal Aortic Anatomy Six Segments

Ascending Tubular Aorta Dimension similar to sinotubular

junction

Ascending aorta terminates at the left innominate artery (brachiocephalic) where aortic arch begins and continuous to the left subclavian and ligamentum arteriosum

Normal Aortic Anatomy Six Segments

Arch Three major branch vessels

Innominate artery (brachiocephalic), left common carotid and left subclavian

Descending Thoracic Aorta

Walls of the Aorta Intima

Thin and smooth Media

Elastic and muscular Adventitia

Outer layer

Echocardiographic Evaluation

Echocardiographic Evaluation Evaluation of the intrathoracic portion of

the aorta and of aortic disease TTE: limited to proximal ascending aorta and a

small portion of the descending aorta behind LA

Major use of TEE: high-resolution view of entire length of aorta form aortic valve to approximately the diaphragm

Accuracy equivalent to computed tomography (CT) and magnetic resonance imaging (MRI)

Echocardiographic Evaluation Superior angulation in parasternal long-

axis view Emphasizes visualization of normal ascending

aorta (typically 4 -5 cm may be seen)

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Echocardiographic Evaluation Suprasternal notch view

Images more feasible in children and adolescents

Occasional discomfort of ultrasound probe in this area

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Echocardiographic Evaluation Descending thoracic aorta seen in

Parasternal long axis behind LA Level of the gastroesophageal junction,

posterior apical four chamber view

Non-dynamic

Echocardiographic Evaluation

Echocardiographic Evaluation Transesophageal

Broader window than transthoracic Visualization from annulus through ascending and

arch to level of gastroesophageal

Non-dynamic

Echocardiographic Evaluation Transesophageal

Typically imaging begins with imaging of the ascending aorta with probe behind the left atrium

Proximal 5 to 10 cm of the ascending aorta can be visualized

Scanning at a 120-degree imaging plane

Non-dynamic

Echocardiographic Evaluation Transesophageal

Rotate probe 30-60° Series of short-axis views of

proximal ascending aorta including short axis of aortic valve

Non-dynamic

Echocardiographic Evaluation Transesophageal

Descending aorta Insertion of TEE probe deeper

toward gastroesophageal junction

Non-dynamic

Intravascular Ultrasound Performed with high-frequency: 20-30 MHz

Used in diagnosis and management of aortic dissection and as a primary imaging tool

Allows highly detailed, high-resolution

Aortic rupturePlaque

Diseases of the Aorta Aortic Dilatation Aortic Dissection Thoracic Aortic Aneurysms Traumatic Injury Aortic Atherosclerosis Sinus of Valsalva Aneurysms

Aortic Dilatation Dilatation can occur at any point along

aorta Primary Secondary

Idiopathic dilatation Also referred to as Anuloaortic ectasia Unclear whether distinct disease entity due

to aging, hypertension or unrecognized disease of aorta

Aortic Aneurysm Definition: Localized abnormal dilatation of aorta

containing all three layers of the aortic wall Pathophysiology: Weakened media of the aorta

Tunica externa

Tunica media

Tunica intima

Aortic AneurysmTypes

Saccular Fusiform

Locations Ascending aorta 45% Aortic Arch 10% Descending Thoracic Aorta 35% Abdominal Aorta 10%

Causes for Aortic Aneurysms Atherosclerosis Medial Degeneration

Idiopathic (annuloaortic ectasia) Marfan's Syndrome Other heritable disorders Associated with Bicuspid Aortic Valve

More Causes Aortic Dissection with Dilitation of

persisting false lumen Trauma with incomplete aortic rupture Syphilis Mycotic (Bacterial, Fungal, Tuberculous

aortitis) Noninfectious aortitis (Giant-cell,

Takayasu’s Syndrome)

Aortic Dilatation Primary

Occurs with cystic medial necrosis Typified by Marfan’s

May be seen in other connective ts disorders Results in weakening of medial layers

Subsequent dilation and aneurysm formation

Aortic DilatationPrimary

Marfan’s Characteristically involves ascending aorta and sinuses Imaging recommendations:

Radiography for skeletal abnormalities Serial chest radiography for demonstration of progressive

aortic dilation 2D echocardiography for early dx and monitoring of aortic

dilation CT or MRI for evaluation of aortic disease

Aortic DilatationSecondary

Volume or pressure overload states AI or HTN

Post stenotic aortic dilation Valvular aortic stenosis

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Aortic Dilatation Dilated ascending aorta

Effacement (loss of tapering) of the sinotubular junction

Classic effacement Sinotubular junction: same dimension as Valsalva sinus

Non-dynamic

Aortic ANEURYSMS May occur in ascending aorta

Typically past sinotubular junction Better visualized with TEE

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Aortic ANEURYSMS

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Aortic ANEURYSMS and DILATION Rupture or dissection

Directly related to degree of dilation Indication for prophylactic aortic surgery

55 mm Many centers use 50 mm

Rapid change in dilation (<than 5 mm per year)

Non-dynamic images

Marfan’s Syndrome Inherited connective tissue disorder Echocardiography: initial screening tool for

patients or first-degree relatives TEE for more specific information

Marked dilation of ascending aorta Disproportionate involvement of sinuses of

Valsalva Early cases

Mild dilation of sinus Sinotubular effacement

Malcoaptation of aortic cusps Resultant in AI

Marfan’s Syndrome

Level of sinuses: 5.8 cm

Aortic annulus: 2.8 cm

Patient #2

Patient #1

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Valsalva Sinus Aneurysm May form from any of the three

Valsalva sinuses Most often arise form the right sinus

Size: highly variable Aneurysms arising from the right

Valsalva sinus typically protrude down into the right atrium Appear as “windsock” structure in the

right atrium

Valsalva Sinus Aneurysm Right sinus of Valsalva aneurysm

Protruding into right ventricular outflow tract

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Valsalva Sinus Aneurysm Right sinus of Valsalva aneurysm

Protruding into right ventricular outflow tract

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Valsalva Sinus Aneurysm Colorflow

Major complication of Valsalva Sinus Aneurysm: rupture Most common location for rupture: right atrium

Results in instantaneous elevation of right heart pressures Jugular distension Loud continuous murmur

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Valsalva Sinus Aneurysm Colorflow

Major complication of Valsalva Sinus Aneurysm: rupture Most common location for rupture: right atrium

Results in: Instantaneous elevation of right heart pressures

Aortic DissectionAcute Symptoms

Sudden onset of severe chest pain and/or back pain

Wide range of secondary cardiovascular and physiologic abnormalities

Typically occurs with pre-existing Aortic dilation Cystic medial fibrosis due to Marfan’s

syndrome Long standing hypertension

Any aspect of the aorta may dissect

Aortic Dissection

Two Basic Variants Classic Spontaneous hematoma

Aortic Dissection Classic

Tear from lumen through the intima into the medial layer with subsequent propagation of a column of blood

Further dissect the intima away form the media Propagation may be both proximal and distal to the

initial intimal tear

Aortic Dissection Classic

Typically begins either At the area of the ligamentum arteriosum

Propagates through the arch and into the ascending aorta

Or starts in ascending aorta and propagate distally

Aortic Dissection Spontaneous Intramural Hematoma

Clinical presentation with respect to nature of symptoms: virtually identical to classic dissection

Hemorrhage into the medial layer then dissects proximally or distally to a variable degree WITHOUT rupture into the adventitia

Aortic Dissection Two schemes for identification

Stanford (A-B) DeBakey (1, 2, 3)

Types Type A(1): (70% occurrence)

Throughout ascending and descending aorta

Type A(2): (5% occurrence) Confined to ascending aorta

Type B(3): (25% occurrence) Confined to descending aorta

Isolated: Aortic arch

Type II Dissection

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Type II Dissection

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True and False Lumens True lumen

Pulsatile aortic flow Expand w/systole Circular or ovale typically In descending aorta: usually

smaller of the two lumens False lumen

Continuous flow in venous flow pattern

Often filled with twirling homogenous echoes (stasis of blood or frank thrombus)

Tags of tissue (small muscle remnants where the intima has been sheared from the media)

Non-dynamic

True and False Lumens

True lumen

False lumen

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Type III Aortic Dissection Descending aortic dissection

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Imaging Goals for Dissection Ascending dissection

Most are detected by TEE rather than TTE

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Intramural Hematoma May occur at any point along the aorta More common in the descending aorta and arch Appears as a smooth homogenous concentric

thickening of the wall Typically > 7 mm in thickness

No active flow with the “lumen” and no tear in the intima

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Goals of Imaging Confirmation of diagnosis Location Extent of dissection Mechanism of AI Presence of pericardial or pleural effusions Coronary artery involvement Head vessel involvement Detection of rupture Location of:

Intimal tear (entry) Re-entry site

Transesophogeal Echo Superior over transthoracic echo CT, MRI and Aortography are also

common methods of diagnosis Pitt falls of TEE

Reverberations, catheters Mirror image artifacts Thoracic aneurysm with mural thrombus

Echo Findings 2D

Presence of an intimal flap, which may appear as a thin linear structure

A true and a false lumen Pericardial effusion

MM Dilated aorta >4.2cm Increased aortic wall thickness

Color/Doppler AI Flow between the true and false lumen

Role of TEE Best for seeing ascending aortic

aneurysms Helps rule out aortic dissection versus

aortic aneurysm Instant results

Non-dynamic

Mechanisms of AI Dilatation of aortic root Asymmetric dissection causes faulty

coaptation of the aortic valve Prolapsing intimal flap back through the

aorta

Aortic Atheroma Atherosclerosis of the aorta

Frequently encountered in TEE May be identified in SSN view Common in advanced age, HTN, elevated

cholesterol May be a component of atherosclerotic

aneurysm and intramural hematoma of the aorta

Most common in descending aorta Less frequently in ascending aorta

Aortic Atheroma Characterized as symmetric and

crescentic (curved shaped) Smooth, homogenous crescent filling a portion

of the aortic lumen, protruding or complex Complex: defined as atherosclerotic disease with

epedunculated or mobile components

Grading System I = 1 – 3.9mm thickness II = > 4mm thickness III = Debris (mobile regardless of size)

Aortic AtheromaTwo Different Patients

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Miscellaneous ConditionsAortic Pseudoaneurysm Contained rupture of the aorta Characterized by an extraluminal aneurysmal sack communicating

with the true lumen by a relatively narrow neck Occur in several situations

Spontaneous rupture of an aortic aneurysm with subsequent sealing off of the hemorrhage

Sequelae of aortic dissection with further rupture through the adventitial layers

Rare occasions: iatrogenic injury

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Miscellaneous ConditionsAortic Trauma Wide spread of extent of injury/pathology

Simple contusion Intimal tear Intramural hematoma False Aneurysm Frank rupture (transection) Major dissection NOT a feature of aortic trauma(usually

no underlying medial disease)

Miscellaneous ConditionsAortic Trauma Blunt chest injury

High-speed impact injury (i.e. unrestrained MVA) Partial or complete transection of the descending aorta,

classically at area of ligamentum arteriosum Complete = nearly instantaneous fatal event Partial = hemorrhage and shock CT or MRI typically primary diagnostic tool

Traumatic Injury Cont. Intimal Lacerations (transection)

The mechanism of injury historically was thought to be rapid deceleration with "whipping" of the aorta at points of attachment (i.e., aortic root, ligamentum arteriosus, diaphragmatic hiatus).

More recent evidence suggests that injury at the most common site, the aortic isthmus, is due to

Compression of the anterior chest wall and pinching of the aorta between structures of the anterior bony thorax and the thoracic spine.

Aortic Infections – mentioned earlier under causes of aortic aneurysm Bacterial or fungal infections of the aorta

is rare Manifest as a pedunculated mobile mass Syphilic aortic disease: rare encountered

in contemporary practice Results in inflammatory thickening of the

proximal aorta

Aortic Thrombus Rare Bland mobile thrombus form within the thoracic aorta More common in the proximal descending thoracic aorta

and is often associated with evidence of peripheral embolization

Thrombi are highly mobile echo-dense masses within the lumen, appear attached to the aortic wall by a fairly thin stalk

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Takayasu Arteritis Inflammatory disease of the aorta and its proximal branches Occurs in patients <40 years old Results in marked, irregular intimal thickening and accumulation

of inflammatory tissue in the proximal aorta and ostia of major branches including the coronary arteries

Echo: appears similar to atheroclerotic disease

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Pulmonary Artery Abnormalities

Pulmonary Artery Abnormalities Most abnormalities of PA: congenital

Postenotic dilation Branch pulmonary artery stenosis Abnormal position of the pulmonary artery Transposition of the great vessels

May also be involved by systemic diseases such as Takayasu arteritis

Pulmonary artery dissection: rare Reported in patients with chronic pulmonary

hypertension

Pulmonary Artery Abnormalities Dilated pulmonary arteries

Right-sided volume overload (e.g., atrial septal defect)

Pulmonary hypertension Idiopathic dilation of the pulmonary artery

(Rare)

Finding of dilated PA mandates careful evaluation for: Right-sided pressure or volume overload

Pulmonary Artery Abnormalities Standard views

PSAX RVOT Subcostal four with severe anterior tilt SSN (right pulmonary artery)

High parasternal short axis

RPA LPA

Non-dynamic

Pulmonary Artery Abnormalities Transesphageal

0° esophageal level superior the LA Long axis of pulmonary artery

May not be obtained in all patients d/t interposition of the air-filled bronchus

AO

SVC

MPA

RPA LPA

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Pulmonary Artery Abnormalities Transesphageal

90° plane (analogous to TTE RVOT view) Image quality may be suboptimal due to

distance of PA from transducer in this view

Alternative studies CT MRI Contrast angiography Radionuclide ventilation/perfusion scan for

evaluation for pulmonary embolism

Pulmonary Artery Abnormalities Limitations and alternative approaches

Acoustic access and quality Body habitus and skill of sonographer Interpretation must consider the likelihood of

False-positive findings from beam-width artifacts, reverberations and oblique image planes

False-negative findings due to limited acoustic access and poor resolution

Chest CT Advantages: wide field of view, high accuracy and wide

availability Disadvantages: ionizing radiation and non-portable nature

of the study MRI

Advantages: high resolution, high diagnostic accuracy, wide field of view and ability to orient the images along the long axis of the aorta

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Edition). Indianapolis. Lippincott Williams & Wilkins.

Goldstein S., Harry M., Carney D., Dempsey A., Ehler D., Geiser E., Gillam L., Kraft C., Rigling R., McCallister B., Sisk E., Waggoner A., Witt S., Gresser C.. (2005). Outline of Sonographer Core Curriculum in Echocardiography.

Otto C. (2004). Textbook of Clinical Echocardiography. (3rd Edition). Elsevier & Saunders.

Reynolds T. (2000). The Echocardiographer's Pocket Reference. (2nd Edition). Arizona. Arizona Heart Institute.