Jean Jeudy, MD. Disease is very old, and nothing about it has changed. It is we who change as we learn to recognize what was formerly imperceptible.

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1 Armed Forces Institute of Pathology D e p a r t m e n t o f D i a g n o s t i c R a d i o l o g y T h e A c u t e A o r t i c S y n d r o m e s Jean Jeudy, MD BB aa lltt iimm oo rr e e,, MM aa rr yy llaa nn dd Jean Martin Charcot Disease is very old, and nothing about it has changed. It is we who change as we learn to recognize what was formerly imperceptible. On 25 October 1760 George II, then 76, rose at his normal hour of 6 AM, called as usual for his chocolate, and repaired to the lavatory. The German valet de chambre heard a noise, memorably described as louder than the royal wind', and then a groan; he ran in and found the King lying on the floor, having cut his face in falling. Jean Martin Charcot King George II Necroscopy Findings pericardium distended with a pint of coagulated blood transverse fissure on the inner side of the ascending aorta 3.75 cm long blood had recently passed in its external coat to form a raised ecchymosis King George II A c u t e A o r t i c S y n d r o m e Intramural Hematoma (IMH) Aortic Dissection (AD) Penetrating Atherosclerotic Ulcer (PAU) 1

2 PAU IMH AD P a t h o p h y s i o l o g y Intima Media Adventitia Aortic hypertrophy Higher wall stress Medial wall weakening Aorta unable to further deal with stress Aortic dilatation and aneurysm formation Acute aortic syndrome Intramural hematoma Symptomatic aortic ulcer Aortic dissection Hypertension Intimal integrity Genetic abnormalities Intimal integrity Chronic exposure to high systemic pressure Intimal thickening Fibrosis Calcification Fatty acid deposition Aortic dilataion and aneurysm formation Increased wall stress Acute Aortic Syndromes Aortic Dissection Intramural hematoma Penetrating Atherosclerotic Ulcer Dedifferentiation of vascular smooth muscle cells Enhanced elastolysis of aortic wall components Increased wall stress Acute Aortic Syndromes Aortic Dissection Intramural hematoma Penetrating Atherosclerotic Ulcer F r e q u e n c y o f f a c t o r s p r e d i s p o s i n g t o A o r t i c D i s s e c t i o n I n t e r n a t i o n a l R e g i s t r y o f A c u t e A o r t i c D i s s e c t i o n ( I R A D ) Hypertension Marfan Syndrome Bicuspid Aortic Valve NONE Type A Type B Total JAMA, :

3 C y s t i c m e d i a l d e g e n e r a t i o n Most common histologic feature underlying seen in the majority of aortic dissections Most common conditions include Hypertension Bicuspid aortic valve Marfan syndrome Idiopathic aortic root dilatation (annuloaortic ectasia) Hum Pathol. 1983;14: ; Histopathology. 1977;1: ; Am. J. Surg. Pathol Sep;30(9): * Flap Thrombus Intimomedial flap AORTIC DISSECTION A man was seized with a pain of the right arm and soon after of the left after these there appeared a tumor on the upper part of the sternum False lumen True lumen He was ordered to think seriously and piously of his departure from this mortal life, which was very near at hand and inevitable. Giovanni Battista Morgagni 3

4 A o r t i c D i s s e c t i o n M>F, primarily in 5 th and 6 th decades Risk factors Hypertension (most common) Marfan s, Ehlers-Danlos, etc. Pregnancy Bicuspid aortic valve Iatrogenic (catheters, balloon pumps) A o r t i c D i s s e c t i o n E t i o l o g y Most caused by intimal tear rupture of blood into media Entry tear seen in virtually all cases Minority arise in aortic wall and secondarily rupture into lumen Creates true and false lumen P r o g n o s i s T y p e A Dissection into the ascending aorta is highly lethal with a mortality of 1-2% per hour after onset of symptoms Time 24h 48h 7d Medical management 24 % 29 % 44 % Surgical repair 10 % 12 % 16 % JAMA, : d 49 % 20 % TYPE A, AORTIC DISSECTION P r o g n o s i s T y p e B Less lethal than Type A lesions Uncomplicated 30d mortality of 10% Ischemic complications Renal failure, visceral ischemia, contained rupture 20% by Day 2 25% by Day 30 TYPE A, AORTIC DISSECTION 4

5 A o r t i c D i s s e c t i o n First successful treatment reported in 1955 Debakey and Cooley performed surgical repair Medical management first reported in 1965 First percutaneous repair reported in 1990 Incidence: 5-30 per million per year JAMA 2000;283: Circulation 2005;112: CLASSIFICATION: Stanford DeBakey 60 % % % DeBakey I DeBakey II DeBakey III Stanford A Stanford B Proximal Distal I m a g i n g O p t i o n s C h e s t R a d i o g r a p h Chest radiography Conventional Angiography Transesophageal Echocardiography Computed Tomography Magnetic Resonance Imaging ~90% of patients have an abnormal CXR No findings are specific Hagan PG, et al. The international registry of acute aortic dissection (IRAD) new insights into an old disease. JAMA 2000;283: ~20% without aortic abnormalities C o n v e n t i o n a l A n g i o g r a p h y C o n v e n t i o n a l A n g i o g r a p h y Previous method of choice prior to crosssectional techniques Requires that intimal flap be tangential beam Advantages - superior assessment of coronary arteries Disadvantages - invasive, expensive, can overlook thrombosed false lumen Previous method of choice prior to crosssectional techniques Requires that intimal flap be tangential beam Advantages - superior assessment of coronary arteries Disadvantages - invasive, expensive, can overlook thrombosed false lumen Sensitivity: 85-90% 5

6 I m a g i n g M o d a l i t i e s Outdated Aortography Sensitivity: 88% Specificity: 94% Current modalities: Helical CT, MRI, or TEE Shiga, T, et al. Archives of Internal Medicine. 2006; 166: I m a g i n g M o d a l i t i e s T r a n s e s o p h a g e a l e c h o c a r d i o g r a p h y ( T E E ) Sensitivity and specificities of TEE, CT, and MRI are comparable Choice of diagnostic test is determined by individual clinical scenario and by test availability Method useful in patients who are too ill to transport Flap - waving linear echo Sensitivity %, specificity % T r a n s e s o p h a g e a l e c h o c a r d i o g r a p h y ( T E E ) M u l t i d e t e c t o r C T Advantages: Shortest diagnostic time needed for diagnosis Evaluates aortic valve structure Doppler can detect associated aortic regurgitation Evaluates heart and pericardium Disadvantages: Cannot adequately evaluate distal ascending aorta and great arteries Trachea and left stem bronchus create a blind spot Contraindicated in patients with esophageal varices Operator dependant Most widely used technique Flap is low attenuation structure in contrast column Intramural (thrombosed) dissection visible on pre-contrast study as rim of high attenuation 3D reconstructions 6

7 M u l t i d e t e c t o r C T Advantages - easy, quick to perform Disadvantages - requires contrast, can t visualize regurgitation, fast scanners have artifact at aortic root Sensitivity - 95%, Specificity - 95% Intimomedial rupture A o r t i c D i s s e c t i o n True lumen often compromised Medial calcification * CT MRI 7

8 A O R T I C D I S S E C T I O N A O R T I C D I S S E C T I O N Single slice Multislice A O R T I C D I S S E C T I O N Pericardial hemorrhage Different flow in kidneys M a g n e t i c R e s o n a n c e I m a g i n g M a g n e t i c R e s o n a n c e I m a g i n g Flap medium signal intensity structure on dark blood, low signal intensity on bright blood Advantages - versatile, contrast optional, can assess regurgitation Disadvantages - monitoring issues, set-up time Flap medium signal intensity structure on dark blood, low signal intensity on bright blood Advantages - versatile, contrast optional, can assess regurgitation Disadvantages - monitoring issues, set-up time Sensitivity %, Specificity % 8

9 A O R T I C D I S S E C T I O N A O R T I C D I S S E C T I O N M a g n e t i c R e s o n a n c e I m a g i n g AORTIC INSUFFICIENCY Advantages: Considered the most accurate test Highest positive predictive value Multiplanar imaging No radiation, potentially no contrast Disadvantages: Time consuming Rarely used as initial imaging technique Incompatible with implanted metal devices Cannot test hemodynamically unstable patients A o r t i c D i s s e c t i o n Vasa vasorum Which technique? Depends on institution Referral patterns Machine availability (esp. MRI) Personnel experience, availability (esp. TEE) We use CT, except if patient can t get contrast, then MRI 9

10 INTRAMURAL HEMATOMA A o r t i c I n t r a m u r a l H e m a t o m a In the early 1900 s Krukenberg proposed that a rupture of the vasa vasorum initiated the process of dissection Gore, in the 1950 s, suggested that medial degeneration predisposed the vasa vasorum toward hemmorhage may be the usual rather than the uncommon mechanism of hemorrhagic dissection I n t r a m u r a l H e m a t o m a ( I M H ) I n t r a m u r a l H e m a t o m a ( I M H ) Considered a variant of aortic dissection and can be both a precursor and complication Rupture of vasa vasorum in media resulting in localized aortic wall infarct Hemorrhage with lack of both a detectable intimomedial flap and direct flow communication between the true and false May result in secondary tear causing dissection I n t r a m u r a l H e m a t o m a INTRAMURAL HEMATOMA CT MRI 10

11 I n t r a m u r a l H e m a t o m a ( I M H ) I n t r a m u r a l H e m a t o m a Prognosis of IMH is similar to aortic dissection and also varies by level of aortic involvement Regression 10% Progression 28-47% Risk rupture 20-45% Evangelista, et al. Circulation. 2003;108: c May extend, progress, regress, or Resorb in 10% of reported cases Most occur in descending aorta and typically associated with hypertension Clinical manifestations are similar to AD however the diagnosis is most often made on cross sectional imaging I n t r a m u r a l H e m a t o m a May extend, progress, regress, or Resorb in 10% of reported cases Most occur in descending aorta and typically associated with hypertension Clinical manifestations are similar to AD however the diagnosis is most often made on cross sectional imaging TYPE B, INTRAMURAL HEMATOMA TYPE A, INTRAMURAL HEMATOMA 11

12 PENETRATING ATHEROSCLEROTIC ULCER P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r Pseudoaneurysm Less known about this entity in comparison with IMH and AD Generally elderly (>70yoa) ALWAYS severe atherosclerosis PROBABLY a high incidence of early rupture SOME may be treated conservatively or with consideration of stent grafting P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r Commonly secondary to deep ulceration of atherosclerotic aortic plaques Can lead to AD or IMH Symptomatic ulcers with evidence of deep erosion are at increased risk for aortic rupture Ulceration extends into aortic wall Symptoms often mimic aortic dissection Most commonly in descending thoracic aorta P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r Complications include aortic dissection, pseudoaneurysm rupture CT/MRI show deep ulceration of aortic wall and complications PENETRATING ATHEROSCLEROTIC ULCER 12

13 P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r P e n e t r a t i n g A t h e r o s c l e r o t i c U l c e r AORTIC 3 WEEKS RUPTURE LATER S u m m a r y P a t h o p h y s i o l o g y Intimal integrity S u m m a r y HYPERTENSION Increased wall stress Aortic Dissection (AD) GENETIC FACTORS Cystic Medial Necrosis ATHEROSCLEROSIS Acute Aortic Syndromes Aortic Dissection Intramural hematoma Penetrating Atherosclerotic Ulcer Intramural Hematoma (IMH) Penetrating Atherosclerotic Ulcer (PAU) 13

14 D e p a r t m e n t o f D i a g n o s t i c R a d i o g y T r e a t m e n t ( I n i t i a l M e d i c a l T h e r a p y ) Thank you for your attention! Hypertensive patients: Objectives: Reduce blood pressure Decrease dp/dt (aortic pulse wave) Goals: SBP: mmhg HR: < 60 Beta blockers first! If intolerant, consider calcium channel blockers U n iv e r s ity Nitroprusside o f M a ry lan d S ch o o l o f M e d ic in e Hypotensive patients: Obtain diagnosis prior to infusing volume (because of possible heart failure) STAT ECHO, etc. Consider intubation and mechanical ventilation prior to diagnostic imaging Avoid pericardiocentesis because of risk of recurrent bleeding and death Pain treatment Morphine Tsai, TT, et al. Acute aortic syndromes. Circulation. 2005;112: Khan, IA, and Nair, CK. Clinical, diagnostic, and management perspective of aortic dissection. Chest. 2002;122: T r e a t m e n t ( S u r g i c a l ) T r e a t m e n t ( S u r g i c a l ) Type A: Emergent surgical treatment required before hemodynamic instability or end organ damage Operative mortality rate: 15-35% rate Many variants of surgery All primarily involve resecting intimal flap Valve may need replacement or repositioning Glue aortaplasty Tissue adhesive used to conjoin dissected tissue walls > 50% with complete disappearance of false lumen Less postoperative complications and reoperations Nienaber, CA, & Eagle, KA. Aortic dissection: New frontiers in diagnosis and management. Part II: Therapeutic management and follow up. Circulation. 2003;108: Khan, IA, and Nair, CK. Clinical, diagnostic, and management perspective of aortic dissection. Chest. 2002;122: Type B: Limited to prevention or relief of life threatening complications Intractable pain Rapidly expanding aortic diameter or periaortic or mediastinal hematoma Signs of impending rupture Dissection of previous aneurysmal aorta An alternative is stent graft placement Variety of devices and techniques I.e. fenestration, stent-graft, staged therapy, etc. Nienaber, CA, & Eagle, KA. Aortic dissection: New frontiers in diagnosis and management. Part II: Therapeutic management and follow up. Circulation. 2003;108: A o r t i c R o o t a n d A s c e n d i n g A o r t a R e p a i r V a l v e S p a r i n g A o r t i c R o o t a n d A s c e n d i n g A o r t a R e p a i r Isselbacher, EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005;111: Isselbacher, EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005;111:

15 A s c e n d i n g T h o r a c i c A o r t a A n d A r c h R e p a i r D e s c e n d i n g T h o r a c i c A o r t a R e p a i r Isselbacher, EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005;111: Isselbacher, EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005;111: M i n i m a l l y I n v a s i v e D e s c e n d i n g T h o r a c i c A o r t a R e p a i r I m a g i n g INTRODUCTION Angiography traditional method of great vessel imaging Cross-sectional techniques now have major role CT MRI Transesophageal echocardiography (TEE) Isselbacher, EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005;111: T e c h n i q u e C T T e c h n i q u e - a o r t a Contrast enhancement usually necessary In some cases, need precontrast scanning For multiplanar or 3D reformations, spiral CT is required Use automatic timing for start of scan for optimal enhancement (e.g., smart prep) Technique (multislice) 100 cc 2.5 cc/sec 3 mm slice collimation 50% reconstruction overlap Thinner (1-2 mm) for targeted 3D-recons Technique (single slice) 100 cc 2.5 cc/sec 8 mm slice collimation 50% reconstruction overlap 15

16 T e c h n i q u e : P o s t p r o c e s s i n g T e c h n i q u e : P o s t p r o c e s s i n g Multiplanar (MPVR) = coronal, sagittal, oblique Shaded surface display - thresholding calcification not detected Maximum intensity projection (MIP) - image appears planar Endoluminal techniques - virtual endoscopy M R I v s C T M R I T E C H N I Q U E MRI advantages Direct multiplanar capability - no recon. Intravenous contrast optional Numerous sequences MRI disadvantages Higher costs Less availability Monitoring issues (claustrophobia) T1-weighted spin-echo (black blood) Gradient-echo (bright blood) Axial imaging Sagittal oblique (long axis of aorta) imaging - useful to assess arch vessels Contrast-enhanced with MRA - gadolinium 16