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, Michigan raaymasu@gvsu.edu

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Normal Aortic Anatomy Six Segments Annulus Sinuses of Valsalva Sinotubular Junction Ascending Tubular Aorta Arch Descending Thoracic Aorta Anulus: Represents the junction of the prox. Ao and the LVOT NL size 2.0-3.1cm Sinus of Val.: Three sinus of equal size. Left, Right, Noncoronary . left –left Main Coronary artery, Right- RCA NL size 2.9-4.5cm ST Junction: narrowing just after the sinus of valsalva NL size 2.2-3.6cm Three Head vessels: Inominate, left common carotid, left subclavian

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 Proximal portion: annulus to proximal ascending aorta commonly referred to as the root Anulus: Represents the junction of the prox. Ao and the LVOT NL size 2.0-3.1cm Sinus of Val.: Three sinus of equal size. Left, Right, Noncoronary . left –left Main Coronary artery, Right- RCA NL size 2.9-4.5cm ST Junction: narrowing just after the sinus of valsalva NL size 2.2-3.6cm Three Head vessels: Inominate, left common carotid, left subclavian

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 Anulus: Represents the junction of the prox. Ao and the LVOT NL size 2.0-3.1cm Sinus of Val.: Three sinus of equal size. Left, Right, Noncoronary . left –left Main Coronary artery, Right- RCA NL size 2.9-4.5cm ST Junction: narrowing just after the sinus of valsalva NL size 2.2-3.6cm Three Head vessels: Inominate, left common carotid, left subclavian

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 Anulus: Represents the junction of the prox. Ao and the LVOT NL size 2.0-3.1cm Sinus of Val.: Three sinus of equal size. Left, Right, Noncoronary . left –left Main Coronary artery, Right- RCA NL size 2.9-4.5cm ST Junction: narrowing just after the sinus of valsalva NL size 2.2-3.6cm Three Head vessels: Inominate, left common carotid, left subclavian

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 Anulus: Represents the junction of the prox. Ao and the LVOT NL size 2.0-3.1cm Sinus of Val.: Three sinus of equal size. Left, Right, Noncoronary . left –left Main Coronary artery, Right- RCA NL size 2.9-4.5cm ST Junction: narrowing just after the sinus of valsalva NL size 2.2-3.6cm Three Head vessels: Inominate, left common carotid, left subclavian

Normal Aortic Anatomy Six Segments Arch Descending Thoracic Aorta Three major branch vessels Innominate artery (brachiocephalic), left common carotid and left subclavian Descending Thoracic Aorta Anulus: Represents the junction of the prox. Ao and the LVOT NL size 2.0-3.1cm Sinus of Val.: Three sinus of equal size. Left, Right, Noncoronary . left –left Main Coronary artery, Right- RCA NL size 2.9-4.5cm ST Junction: narrowing just after the sinus of valsalva NL size 2.2-3.6cm Three Head vessels: Inominate, left common carotid, left subclavian

Walls of the Aorta Intima Media Adventitia Thin and smooth 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) 20.03 Feigenbaum

Echocardiographic Evaluation Suprasternal notch view Images more feasible in children and adolescents Occasional discomfort of ultrasound probe in this area 20.4 Feigenbaum

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 Left: FIGURE 20.6. Transesophageal longitudinal view of the heart including visualization of the ascending aorta. Transesophageal echocardiogram of the ascending aorta recorded in a normal disease-free individual. A: Longitudinal (127-degree) view that provides imaging analogous to that of the transthoracic long-axis view seen in Figure 20.3. Again note the symmetric dilation at the level of the sinuses and the narrowing at the level of the sinotubular junction. Right: FIGURE 20.7. Transesophageal echocardiogram recorded at 53-degree probe rotation at the base of the heart. These images were acquired at the same transducer position as those in Figure 20.6. With this probe orientation, a short-axis view of the aorta is obtained at the level of the sinuses, revealing the left (L), right (R), and non (N) coronary sinuses. The left atrium (LA), right atrium (RA), and proximal pulmonary artery (PA) are well visualized. A: Image recorded in diastole, and three symmetric sinuses are noted as well as three coaptation lines of the cusps. 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 Note: probe is not inserted very deeply for imaging of aorta and therefore results in more curvature and may be less tolerated 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 Plaque Aortic rupture

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 Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN

Aortic Aneurysm Definition: Localized abnormal dilatation of aorta containing all three layers of the aortic wall Pathophysiology: Weakened media of the aorta Tunica intima Saccular: a weakening in the vessel wall at one point which results in a pouch with a small neck Fusiform: uniform dilitation of the entire circumference of the vessel Tunica media Tunica externa

Aortic Aneurysm Types Saccular Fusiform Saccular: a weakening in the vessel wall at one point which results in a pouch with a small neck Fusiform: uniform dilitation of the entire circumference of the vessel

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) Takayasu’s Def. Inflamation of the aorta and it’s proximal branches Typically in pts less than 40yrs Intima becomes thickened and inflamed can look like plaque

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 Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN

Aortic Dilatation Primary 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 Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN

Aortic Dilatation Secondary Volume or pressure overload states AI or HTN Post stenotic aortic dilation Valvular aortic stenosis Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN 20.11 Feigenbaum

Aortic Dilatation Dilated ascending aorta Effacement (loss of tapering) of the sinotubular junction Classic effacement Sinotubular junction: same dimension as Valsalva sinus Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN Non-dynamic

Aortic ANEURYSMS May occur in ascending aorta Typically past sinotubular junction Better visualized with TEE Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN 20.11 Feigenbaum

Aortic ANEURYSMS 20.13 Feigenbaum Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN 20.13 Feigenbaum

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) Primary: caused by cystic medial necrosis such as Marfans syndrome Secondary: caused by volume or pressure overload such as AI or HTN 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 Patient #1 Patient #2 20.20b Feigenbaum High prevalence for mitral valve prolapse. Range may be mild to massive. Aortic insufficiency due to dilation of the sinotubular junction, which results in loss of coaptation Level of sinuses: 5.8 cm Aortic annulus: 2.8 cm 20.21a Feigenbaum

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 20.24a Feigenbaum 20.24b Feigenbaum

Valsalva Sinus Aneurysm Right sinus of Valsalva aneurysm Protruding into right ventricular outflow tract 20.24a-c Feigenbaum

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 20.26 Feigenbaum 20.27 Feigenbaum

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 Dissection Acute 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 Types 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 Crucial factor: does it involve the ascending aorta: greater likelihood of rupture, pericardial effusion, aortic insufficiency or coronary involvement, which may be lethal. Ascending aortic dissection is considered surgical emergency. Descending is best managed medically

Type II Dissection 20.34 Feigenbaum 20.31 Feigenbaum 20.35 Feigenbaum

Type II Dissection 20.34 Feigenbaum 20.31 Feigenbaum 20.35 Feigenbaum

True and False Lumens True lumen False 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 20.36a Feigenbaum

Type III Aortic Dissection Descending aortic dissection 20.39b Feigenbaum

Imaging Goals for Dissection Ascending dissection Most are detected by TEE rather than TTE 20.30b Feigenbaum 20.30a Feigenbaum

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 20.44 Feigenbaum

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 MM Color/Doppler 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 Atheroma Two Different Patients 20.50a Feigenbaum 20.50b Feigenbaum

Miscellaneous Conditions Aortic 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 20.55 Feigenbaum

Miscellaneous Conditions Aortic 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 Conditions Aortic 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 20.59 Feigenbaum

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 20.61 Feigenbaum

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 RPA LPA SVC AO MPA 12-005 Feigenbaum

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

Sources Feigenbaum H, Armstrong W. (2004). Echocardiography. (6th 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.