JCM 4th June 2014

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

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

CXR

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

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

X-ray T-L spine

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

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

CT Aortogram

CT Aortogram

CT Aortogram

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

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

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

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

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)

Epidemiology True incidence is unknown Population-based prevalence studies have estimated the incidence to be about 3 cases per 100000 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

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

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

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

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

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

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)

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

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 20-30 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)

Unreliable and frequently absent in patients with AAD

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…

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

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%

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 http://www.medinterestgroup.com/portfolio-items/aortic-dissection-cxr-findings/ Mediastinal widening Widening of aortic contour

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. http://www.wikiradiography.com/page/Calcium+Sign

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

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

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

Endovascular Interventions (TEVAR) Thoracic endovascular aortic repair

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

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

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

References Upadhye S, Schiff K. Acute aortic dissection in the emergency department: diagnostic challenges and evidence-based management. Emerg Med Clin North Am. 2012 May;30(2):307-27, viii. De Leon Ayala IA, Chen YF. Acute aortic dissection: an update. Kaohsiung J Med Sci. 2012 Jun;28(6):299-305. Hiratazka LF, Bakris GL, Beckman JA, et al. 2010 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:e266-369.

References (continued) http://www.medinterestgroup.com/portfolio-items/aortic-dissection-cxr-findings/ http://www.wikiradiography.com/page/Calcium+Sign

Thank you