1. JCM
4th June 2014

2. History M/28 Chinese Police Cadet
History of back pain treated conservatively 2011
Severe upper back pain after firing a pistol in Cadet School
No SOB, no weakness, no radiation

3. Examination Triage Cat 4 BP 124/66 mmHg, P63/min Temp 35.7C, SpO2 100%
Mild tenderness at the paraspinal area of T-spine
Chest clear
Abdomen soft and no tenderness

4. CXR

5. Our management CXR: no pneumothorax, pneumomediastinum
Ketorolac IMI given
Pain decreased after IMI
Advised to avoid physical exercise
Discharged with NSAIDs and sick leave for 1 day

6. 4 days later Noticed right leg pain and numbness
Feeling coldness of right leg
Patient worried about side effects related to the previous IM Ketorolac
Circulation normal
No neurological deficit
Lower limb power full

7. X-ray T-L spine

8. DDx? Sprain back? PID with radiculopathy? Right leg DVT?
Other possibilities? ……

9. Outcome Admitted to Ortho QMH in view of pain
Suspected T9 collapse at lateral X-ray by Ortho
Private MRI spine referred
Noticed type B aortic dissection on MRI
Both leg warm and abdomen soft
Vascular team consulted and agreed to takeover

10. CT Aortogram

11. CT Aortogram

12. CT Aortogram

13. CT Aortogram
Type B aortic dissection from distal aortic arch down to right iliacs/ CFA
No coronary artery stenosis
Both kidneys perfused symmetrically
False lumen compressing true lumen leading to decreased blood flow to both lower limbs

14. Management BP controlled with beta-blockers Pain well controlled
Discharged home D13 after admission

16. 2 months later, endovascular stenting was done in QMH in view of young age and involvement of the right iliacs/ CFA

17. Long term management Follow up with contrast CT in 6 months
BP control with home BP monitoring
Advised light duty and to avoid competitive sports/ collision

18. Acute aortic dissection (AAD)
A potentially catastrophic disease that remains difficult to diagnose in the emergency department
Circulation 2010
Mortality 40% for immediate death
1% per hour for incremental death thereafter
20% for perioperative death
50% to 70% reported survival rate after initial surgery
Part of the acute aortic syndrome (AAS)
Age dependent, life threatening CV disease associated with high morbidity and mortality due to potentially fatal complications =
Recently published guideline from the American College of Cardiology (ACC)/ American Heart Association (AHA)

19. Epidemiology True incidence is unknown
Population-based prevalence studies have estimated the incidence to be about 3 cases per people per year
Higher incidence in men (65%) and with increasing age
Undetermined number of undiagnosed or misdiagnosed cases result in sudden death and do not undergo an autopsy =
International Registry of Acute Aortic Dissection (IRAD) created in 2000
464 cases
Overall mortality 27.4%
Surgical vs non-surgical mortality 26% vs 58% for type A dissections
Medical vs surgical mortality 10.7% vs 31% for type B
90% uncomplicated type B dissections survived to hospital discharge
Left untreated, type A mortality of 75% within 2 weeks
With successful initial therapy, 5y survival rate 75%
10y survival rate for surgically repaired dissections 40%-60%
Instantly fatal in prehospital setting (and death may be attributed to other causes)
May be missed on initial presentation, leading to early martality as a result of misclassification

20. Significant medicolegal issues surrounding missed diagnosis of AAD
Common misdiagnoses
Acute coronary syndrome (19%)
Musculoskeletal pain (20%)
Pneumonia/ pulmonary embolism (20%)
Pericarditis (12%)
Gastrointestinal pain (9%)
Other causes (20%)
Canadian Medical Protection Agency (CMPA) 2 recent bulletins concerning AAD cases and outcomes

21. Consider the diagnosis of AAD in situations of
Sudden severe chest pain
Accompanying visceral symptoms (nausea, vomiting, pallor, diaphoretic)
Normal/ minimally abnormal ECG findings
Inappropriate reliance on classic features
Classic symptoms/ signs: tearing chest pain, blood pressure/ pulse discrepancies, new cardiac murmurs, CXR mediastinal widening

22. Classification Anatomic distribution Acuity of dissection =
Important prognostic and therapeutic implications
Stanford:
A: any dissection involving the ascending aorta (proximal to the brachiocephalic artery)
B: dissections involve only the descending aorta (distal to subclavian artery)
DeBakey
I: intimal tear originates in the ascending aorta and exends to te arch and often beyond to the descending aorta
II: originate in, and are confined to, only the ascending aorta
III: originate in and propagate to the descending aorta
IIIa: involves only thoracic descending aorta
IIIb: extends below the diaphragm
Accurate assessment of ascending vs descending aorta involvement can be made to differentiate management strategies
Temporal classification:
acute: within 2 weeks pain onset
Subacute: 2-6 weeks
Chronic: 6 weeks
IRAD: 62% type A, 38% type B

23. Clinical assessment in the ED
Risk factors
Presentations
Physical findings
End-organ presentations

24. Risk factors Common: HT (70-90%)
Prior cardiac surgery/ catheterization (18%)
Bicuspid aortic valve (14%)
Connective tissue disorders (Marfan syndrome, Ehler-Danlos syndrome)
Inflammatory vascular disorders

25. Presentations Sudden-onset severe chest pain (91%)
Visceral symptoms – pallor, vomiting, diaphoresis (78%)
Intermittent pain (75%)
Radiation to back/ neck/ arms/ jaw (69%)
Pleuritic/ positional pain (44%)
Pyrexia (22%)
Syncope (9%)
Tearing quality (3%)…
Typical features:
Sudden acute chest pain (90%), excruciating, severe at onset, of sharp/ ripping/ tearing quality, may be possible to localize the dissection origin based on location of pain (anterior = ascending aorta, neck/ jaw = arch, interscapular = descending aorta, lumbar/ abdominal = sub diaphragmatic), migratory pain (17%)
Visceral symptoms: nausea, vomiting, diaphoresis, apprehension, lightheadedness =
12% painless & present only with complication involving other body systems
Patient tended to be older, possible steroid users or patients with Marfan, or presenting with syncope, stroke, congestive heart failure
CMPA case review series of missed AAD (n = 32 patients)

26. Poor reliance on the presence or absence of these features
High level of suspicion is needed
Although there may be some classic findings of TAD that should prompt the inclusion of TAD in a DDx of acute chest pain in the ED, the reliance on the presence of these features, or the absence thereof, may not be sufficient to include or exclude the diagnosis

27. Physical findings
Peripheral pulses in the upper extremities/ blood pressure differentials
New aortic regurgitation murmurs
Complications of acute aortic regurgitations
Congestive heart failure, cardiogenic shock, pericardial tamponade,
Mass compression effects on adjacent structures
SVC, sympathetic chain, recurrent laryngeal nerve, tracheobronchial tree, esophagus…
BP differential of mmHg (>20 mmHg significant predictor of AAD – confirmed in prospective study by von Koloditsch and colleagues)
Up to 20% of normal patients may have a pulse differential of 20 mmHg without AAD
53% normal normal patients have difference of 10 mmHg
New aortic regurgitation murmurs (32%-76% of patients with AAD) =
Pericardial tamponade: jugular venous distension, muffled heart sounds, tachycardia, hypotension
SVC (superior vena cava syndrome),
sympathetic chain (Horner syndrome),
recurrent laryngeal nerve (hoarseness),
tracheobronchial tree (dyspnea),
Esophagus(dysphagia)

28. Unreliable and frequently absent in patients with AAD

29. End-organ presentations
Cardiovascular: AR and related disorders, pulse deficits, BP differentials, syncope, MI, CHF, cardiogenic shock, conduction abnormalities…
Syncope: cardiovascular, neurologic
Neurologic: intracranial, brainstem, spinal cord, lower extremities
Ears/ nose/ throat: mass effects on trachea, esophagus, RLN, sympathetic chain
Respiratory: mass effects on tracheobronchial tree, hemorrhage into lung tissue/ pleural space, pleural effusions
GI: mesenteric ischemia, aortoenteric fistula
STEMI in potential proximal AAD (3%) – thrombolytic therapy is contraindicated
Most common in the right coronary circulation, leading to posteroinferior infarction caused by dissection into the right coronary ostium =
Conduction abn: AF, intractable supraventricular tachycardia
Syncope:
acute cardiac dysfunction
Vascular outflow obstruction in the arch/ carotid arteries
Neurologic vasovagal pain responses
Acute hypervolemia caused by hemorrhage into third spaces
AAD in acute stroke syndrome: contraindicated thrombolytic therapy
Hypotension, malperfusion, distal thromboembolism, nerve compression from mass effects
Proximal arch vs distal arch
Cerebral ischemia and stroke syndromes
Sudden coma, transient locked-in syndrome, acute vertigo (basilar artery occlusion)
Transverse myelitis, anterior cord syndromes, paraplegia, quadraplegia (intercostal spinal arteries, thoracic radicular artery)
ENT: mass compression effect to nearby structures
trachea, esophagus, RLN, sympathetic chain  dyspnea, stridor, dysphagia, hoarseness, ipsilateral Horner syndrome…
Sore throat, hoarseness, hoarseness with collapse and neck bruising…

30. Diagnostic tests ECG (non-specific change)
Laboratory markers (currently no sensitive/ specific test)
Soluble elastin fragments, smooth muscle myosin heavy chain, WBC, hsCRP, fibrinogen, D-dimer
ECG: 31% normal, 26% LVH
To consider/ rule out other alternatives
Consider the possibility of aortic dissection in the setting of ischemic, esp inferior ischemic (proximal dissections may extend to involve the RCA)
AHA 2010 guidelines on thoracic aortic disease: STE should be treated as a primary cardiac event unless the patient is considered to be at high risk for aortic dissection because of the uncommon event of dissection-associated coronary disorder =
2010 AHA guidelines: D-dimer was not recommended at this time because of lack of large prospective evaluation, limitations in accurately assessing posttest probability of a negative D-dimer, and the potential for intramural hematoma

31. Diagnostic images Chest X-ray
Abnormal aortic contour, mediastinal widening, pleural effusion, displacement of intimal calcifications, abnormal aortic knob, displacement of trachea or NG tube deviation to the right…
Lack of sensitivity and nonspecific CXR findings in aortic dissection =
Sensitivity 64%, specificity 86%

32. Widening of aortic contour
Widened mediastinum is a mediastinum with a measured width greater than 6 cm on an upright PA chest X-ray or 8 cm on supine AP chest film.
Opacification of aorto-pulmonary window
Pleural effusion (L>R)
Left apical pleural cap
Displaced calcification
Aortic kinking
Tracheal or esophageal displacement
Depressed left main bronchus
Mediastinal widening
Widening of aortic contour

33. Calcium sign
The calcium sign is a finding on chest x-ray that suggests aortic dissection. It is the separation of the intimal calcification from the outer aortic soft tissue border by 10 mm.

34. Diagnostic images (continued)CT
Transesophageal echocardiography
MRI
All show acceptable diagnostic abilities and the initial imaging modality should be dictated by patient characteristics and availability of resources =
Considerations: Testing risks and benefits, access and availability to imaging modalities, accuracy of technique, individual patient variables
TTE does not have sufficient sensitivity 59.3% or specificity to be the solitary diagnostic modality used, not able to visualized the entire aorta
Sensitivity 77%-80%, specificity 93%-96%
TEE: useful in hemodynamically unstable patients, in which a timely diagnosis is imperative and transfer out of an acute care setting to the radiology department is not possible
Sensitivity 99% and specificity 89%
Able to show AR/ pericardial effusion, +/- visualization of the branches of the aortic arch and distal ascending aorta
CT: most common diagnostic modality initially used
100% sensitivity, 98% sensitivity
Limitations = use of ionizing radiation and contrast media, need for patient transfer out of the acute care setting, limited ability to assess the aortic valve
Readily available, quick to complete, delineates anatomy of the entire aorta well, may show alternative disorders considered in the differential diagnosis for aortic dissection
MRI: most accurate diagnostic modality
Sensitivity 100% and specificity 94%
Not applicable for hemodynamically unstable patients, incompatible with implanted metal devices, limited availability, takes time to process the images, often monitoring difficulties during examination

35. Circulation 2010 Medical: BP HR
Pain: titratable opioids – relieve pain, decrease sympathetic tone, augment the effects of rate control and vasodilation =
Beta-blocker +/- vasodilator
esmolol, labetalol (contraindicated in COPD/ high-risk bronchospasm; consider selective BB such as metoprolol or atenolol)
Sodium nitroprusside (caution: concomitant use of BB to avoid reflex tachycardia, possible cyanide toxicity with prolonged use)
Patients with acute or chronic renal insufficiency should be treated with VI fenoldopam instead of sodium nitroprusside
If contraindicated to BB  IV CCB (diltiazem and verapamil)
Refractory hypertension  IV ACEI (enalapril)
Hypotensionin cardiac tamponade or aortic rupture:
Rapid volume expansion
If refractory hypotension  vasopressors (norepinephrine [Levophed]/ phenylephrine [Neo-Synephrine])
Reserve dopamine for improving renal perfusion, very low dose, may increase dP/dt max
Pericardiocentesis only in cardiac tamponade and shock complicating aortic dissection, may be successful in patient with PEA/ chock while waiting for a definitive surgical repair
Circulation 2010

36. Management of type B AD Mainly Medical treatment in form of BP control
Maintain PR <60/min by Beta blockers and SBP <120mmHg [Class I; level C]
1 month survival 89%
1 year survival 84%
But poor long term outcome: Mortality 30-50% at 5 year
Surgical Intervention
Indicated in complicated AD: malperfusion, rupture, rapid expansion esp false lumen, extension, severe pain, failed to control BP [Class I; level B]
Open Surgery: High mortality in the past
Endovascular Stenting: Maybe more superior but lacking evidence on long term survival
Esmolol
Labetalol
Type B dissections initially managed medically often go on to elective surgery because of aneurismal dilatation or limb ischemia
Circulation 2010

37. Endovascular Interventions (TEVAR)
Thoracic endovascular aortic repair

38. Follow up Close follow-up visits
Long-term medical therapy with beta-blockers
Serial imaging
1, 3, 6 and 12 months post-dissection
Annually thereafter if stable
10%-20% needs repeat surgery – redissection, compression of mediastinal structures, blood leakage, aneurysm formation
Regardless of the type of dissection and treatment, at 10 years, 15-30% of patients require new surgery for threatening conditions: aortic dilatation and rupture, progressive aortic regurgitation, organ malperfusion, irreversible ischemia
re-operation or endovascular stenting is needed if the maximum diameter of the dissected aorta >=55mm, there is a rapid enlargement of dissected aorta (>10mm/year), rupture of dissected aorta, aortic valve insufficiency, aortic root dilatation =
Routine FU 3-6 months

39. Summary for AAD Rare but potentially catastrophic
Presentation and initial assessment findings are always non-specific
High index of suspicion is needed
CT is the most common diagnostic modality initially used
Initial management with BP, heart rate and pain control important
Subsequent definitive surgical consultation

40. Failure to consider AAD in these situations (and document risk assessments accordingly) can lead to clinically adverse outcomes for patients and medicolegal liability for physicians

41. References
Upadhye S, Schiff K. Acute aortic dissection in the emergency department: diagnostic challenges and evidence-based management. Emerg Med Clin North Am May;30(2):307-27, viii.
De Leon Ayala IA, Chen YF. Acute aortic dissection: an update. Kaohsiung J Med Sci Jun;28(6):
Hiratazka LF, Bakris GL, Beckman JA, et al ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease. Circulation 2010;121:e

42. References (continued)

43. Thank you