Grand Rounds Presentation April 1st 2011 Guidelines For The Diagnosis And Management Of Patients With Thoracic Aortic Disease

Acknowledgments Julia Rissmiller MD Diana Litmanovich MD Satya Rao MD

A Report Of The American College Of Cardiology Foundation/American Heart Association Task Force On Practice Guidelines Endorsed by American College Of Radiology, Society Of Interventional Radiology, North American Society For Cardiovascular Imaging

Introduction Clinical practice guidelines for thoracic aortic disease Recommendations from expert panel Evidence based report

Key Topics Appearance of normal thoracic aorta Recommended imaging modalities Standards for reporting

Key Topics Acute aortic syndromes Special considerations in pregnant patients Atherosclerosis Future directions

Thoracic Aortic Anatomy 4 Parts Root Ascending Arch Descending

Aortic Terminology Sinuses of Valsalva Sinotubular junction Ascending aorta Proximal aortic arch Mid aortic arch Proximal descending TA Mid descending TA Aorta at diaphragm Abdominal aorta The thoracic aorta is divided into 4 parts: the aortic root (which includes the aortic valve annulus, the aortic valve cusps, and the sinuses of Valsalva); the ascending aorta (which includes the tubular portion of the ascending aorta beginning at the sinotubular junction and extending to the brachiocephalic artery origin); the aortic arch (which begins at the origin of the brachiocephalic artery and is the origin of the head and neck arteries, coursing in front of the trachea and to the left of the esophagus and the trachea); and the descending aorta (which begins at the isthmus between the origin of the left subclavian artery and the ligamentum arteriosum and courses anterior to the vertebral column, and then through the diaphragm into the abdomen).

Standards of Reporting Measurement Reproducible anatomic landmarks Aortic root measured at the mid-sinus level

Normal Thoracic Aortic Diameter Gender Body size Age

Normal Diameter Thoracic aorta Mean (cm) Root (F) 3.5 - 3.72 Root (M) 3.6 - 3.9 Mid-descending (F) 2.45 - 2.64 Mid-descending (M) 2.39 - 2.98

Normal Diameter in Males Root < 4 cm Descending < 3 cm

Normal Diameter in Females Root < 3.8 cm Descending < 2.8 cm

Aortic Diameter and Age Diameter increases with age Those with genetic syndromes or abnormal tissue morphology may have normal aortic diameter at time of aortic rupture

Standards Of Reporting Measurement Perpendicular to flow External diameter

Standards Of Reporting Abnormalities of morphology should be reported even if diameter is normal Dissection, aneurysm, traumatic injury, rupture should be communicated immediately Techniques to minimize radiation exposure should be utilized

Essential Elements Of Reports Location and length At risk patients need measurements Sinuses of Valsalva Sinotubular junction Ascending aorta Presence of thrombus or atheroma Presence of IMH, PAU, or calcification Involvement of branch vessels End-organ injury Evidence of aortic rupture Comparison with previous imaging , including periaortic and mediastinal hematoma, pericardial and pleural fluid, and contrast extravasation from the aortic lumen. Direct image comparison to determine if there has been any increase in diameter.

Diagnostic Approach to Acute Aortic Syndromes

Approach To Suspected Dissection © 2010 American Heart Association, Inc. Published by American Heart Association. 19

Step 1: Establishing Risk © 2010 American Heart Association, Inc. Published by American Heart Association. 20

Aortic Dissection Selecting The Correct Test Based on patient variables and institutional capabilities If a high clinical suspicion exists but initial aortic imaging is negative, a second imaging study should be obtained 21

Suspected Aortic Dissection EKG Chest radiograph In high risk patients: Transesophageal echocardiogram CT MRI A negative chest x-ray should not delay definitive aortic imaging in high risk patients 22

Selecting The Correct Test: The Evidence 1996 Nonhelical CT 0.5 T MR TEE 100% sensitivity for all modalities Better specificity of CT (100%) 2006 Helical CT MR All 3 imaging techniques equally reliable *Sommer T, Fehske W, Holzknecht N, et al. Aortic dissection: a comparative study of diagnosis with spiral CT, multiplanar transesophageal echocardiography, and MR imaging. Radiology. 1996;199:347–52. **Shiga T, Wajima Z, Apfel CC, et al. Diagnostic accuracy of transesophageal echocardiography, helical computed tomography, and magnetic resonance imaging for suspected thoracic aortic dissection: systematic review and meta-analysis. Arch Intern Med. 2006;166:1350–6. 23

Step 2: Expedited Aortic Imaging © 2010 American Heart Association, Inc. Published by American Heart Association. 24

Transesophageal Echocardiography Advantages Non-ionizing Portable Rapid imaging time Cardiac complications identifiable Disadvantages Operator dependent Blind spot Inability to visualize abdominal aorta

CT Advantages Disadvantages Images entire aorta Identify anatomic variants Branch vessel involvement Short imaging time Triple rule out Disadvantages Ionizing radiation Iodinated contrast After intervention/surgery to detect pseudoaneurysm or leak, Suspected acute aortic dissection, distinguish among types of acute aortic syndromes (IMH, PAU, dissection) Advantages Image entire aorta, including lumen, wall, periaortic regions Identify anatomic variants and branch vessel involvement Short imaging time

MR Multiplanar evaluation Advantages Disadvantages Identify dissection, IMH, PAU Assess branch artery involvement Dynamic imaging Aortic valve pathology and LV dysfunction No radiation, no iodinated contrast Disadvantages Long acquisition time Contraindications Use of gadolinium : metallic implants, pacemakers, specifically the coronary arteries

When to use MR Allergy to iodinated contrast Mild and moderate renal failure: GFR > 30 Severe renal failure – non-contrast MRI Annual follow-up of young patients Lohan et al. MRI Clinic N Am.2008

Acute Aortic Syndromes

Intimal Tears I: Classic Dissection II: Intramural Hematoma III: Limited Dissection IV: Penetrating Atherosclerotic Ulcer V: Iatrogenic © 2010 American Heart Association, Inc. Published by American Heart Association. 30

Aortic Dissection Disruption of the media with bleeding within the wall Prevalence: 60’s Male predominance More common cause of death than AAA At sites of aneurysmal dilatation Treatment of aneurysm before dissection important to long-term survival 40% die immediately 1% mortality per hour after 5-20% perioperative mortality 31

Aortic Dissection

Aortic Dissection Traditionally urgent operative management for Stanford type A Delayed surgery/medical management considered Shock, ARF, prior repair, advanced age Patient factors are protective Prior valve repair Delayed presentation

Intramural Hematoma 10-20% of acute aortic syndromes Descending aorta; > 60 years Pain Imaging criteria Thrombus in wall Crescentic thickening (> 7 mm) No intimal flap, tear or longitudinal flow in false lumen No enhancement High Risk Ascending aorta > 4.8 cm Ascending aorta involvement Thickness > 11 mm * Song JM, Kim HS, Song JK, et al. Usefulness of the initial noninvasive imaging study to predict the adverse outcomes in the medical treatment of acute type A aortic intramural hematoma. Circulation. 2003; 108(suppl 1):II324 –II328. 34

Intramural Hematoma

Penetrating Atherosclerotic Ulcer Atherosclerotic lesion with ulceration penetrates internal elastic lamina hematoma formation Can predispose to dissection, IMH or rupture Descending aorta Elderly Chest pain 36

Penetrating Atherosclerotic Ulcer © 2010 American Heart Association, Inc. Published by American Heart Association.

Ascending Aortic Aneurysm

Ascending Aortic Aneurysm Permanent localized dilatation At least a 50% increase in diameter compared with the expected normal diameter

Diagnostic Approach

Determine Need For Urgent Repair © 2010 American Heart Association, Inc. Published by American Heart Association. 41

Ascending Aortic Aneurysm Surveillance

Special Considerations in Pregnancy

Pregnant Patients With Aortic Dilatation Increased Maternal blood volume Heart rate Blood pressure Stroke volume Cardiac output Arterial dissection/rupture highest incidence 3rd trimester (50%) Peripartum (33%) Marfan syndrome 4.4% developed aortic dissection *Pacini L, Digne F, Boumendil A, et al. Maternal complication of pregnancy in Marfan syndrome. Int J Cardiol. 2009;136:156–61. 44

Pregnant Patients With Aortic Dilatation If known aortic root or ascending aortic dilatation Monthly or bimonthly echocardiographic measurements of the ascending aortic dimensions until birth If aortic arch, descending, or abdominal aortic dilatation, MRI preferred to CT TEE also an option 45

Atherosclerosis Of Aortic Arch Risk factor for stroke Plaques proximal to left subclavian artery Independent predictor of stroke, MI and vascular death Embolization more likely in the presence of Ulceration Lack of calcification plaques 4 mm or greater in thickness proximal to the origin of the left subclavian artery are associated with stroke and constitute one third of patients with otherwise unexplained stroke.

Atherosclerosis Of Aortic Arch Imaging TEE Plaque mobility, composition Anatomic relationships CT Vascular calcification MRI Morphology Composition

Aortic Atherosclerosis Porcelain Aorta Severe and diffuse calcification, causing an eggshell appearance Interferes with aortic surgery Surgeons use alternative techniques to reduce adverse events cannulation of the aorta , crossclamping, and placement of coronary bypass grafts

Porcelain Aorta Interferes with surgery Increases risk of Stroke Irreparable aortic injury Distal embolization Surgeons use alternative techniques to reduce adverse events

Future Directions Risks and benefits of imaging technologies Radiation, contrast Surveillance in the young Biomarkers for dissection Quantification of risk in atherosclerosis

Summary Aortic diameter varies by age and gender Measurements should be consistent and reproducible Reporting should be consistent

Summary Acute Aortic Syndromes Pregnancy Future Directions Dissection TEE/CT/MRI equally accurate Aneurysm 5.5cm/5mm growth/symptoms = surgery Graded surveillance Pregnancy Routine echocardiographic surveillance Future Directions