Aortic Dissection & Aneurysm

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Aortic Dissection Aneurysm
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Aortic Dissection Epidemiology

• 2-3 x more common than aortic aneurysm rupture
• Male to Female (31)
• Mean age is 63
• Incidence 3.5 per 100,000
• Risk Factors
• Systemic HTN (present in 70-90)
• Connective Tissue disorders (Ehlers-Danlos
  Marfans Lupus Giant Cell Arteritis Cystic
  Medial Necrosis)
• Pregnancy (3rd Trimester)
• Congenital Heart Disease (bicuspid aortic valve
  coarctation)
• Turners
• Trauma
• Aortic Valve Stenosis
• ID Syphilis, endocarditis
• Drug Tobacco Cocaine Methamphetamines

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Pathophysiology

• Intimal tear that allows blood to leak through
  the media and adventitia
• Propagation depends on BP and the pulse wave
  (rate of change in pressure/time)
• High BP and rapid ventricular contractions
  further migration

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Natural History

• If untreated
• 33 die within 24 hours
• 50 die within 48 hours
• gt75 die within 2 weeks
• 90 die within 3 months

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Classification

• Debakey
• Type I ascending aorta part of distal aorta
• Type II ascending aorta only
• Type III descending aorta only
• IIIa extension limited to diaphragm
• IIIb continuation beyond diaphragm
• Stanford
• Type A ascending aorta (debakey I II)
• Type B descending aorta (debakey III)

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Clinical Presentation

• Pain most common symptom usually aburpt,
  tearing/ripping, migrating, and maximal at onset
• Pain neurologic symptoms think dissection
• Syncope (9) decreased LOC (20) Paraplegia
  (5) Monoplegia (6) Vision changes (2)
• Physical Exam
• 49 have absent or decreased pulses distal to
  dissection
• Difference in BP (20mmHg between upper
  extremities or 30mmHg between upper and lower
  extremities)
• 20 have new murmur (aortic insufficiency)
• Signs of cardiac tamponade (Becks)

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Diagnosis

• Chest Xray normal in 11
• Mediastinal widening (gt8cm) (63)
• Change in the aortic formation
• Loss of A/P window
• Eggshell sign Extension of aortic shadow gt3mm
  beyond calcified aortic wall
• Blurred aortic knob
• Lt. Pleural effusion (19)
• Double Density sign of the aorta
• ECG
• 20 showed evidence of ischemia
• Varying AV blocks
• Signs of LVH

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Diagnosis

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Diagnosis

• Transesophageal Echocardiography
• Sensitivity specificity nearly 100
• Can confirm diagnosis, define intimal tear site,
  aortic regurgitation, pericardial effusion, does
  not require IV contrast, performed in ED
• Disadvantage not readily available in all EDs
• CT
• Almost 100 sensitivity and specificity
• Can confirm the diagnosis, define the extent of
  dissection, and distinguish between Type A and
  Type B
• Disadvantage patient leaves ED, requires IV
  contrast

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Treatment

• All patients require 10-15 units of blood on
  stand-by and immediate thoracic surgery
  consultation
• All initial treatment is medical
• Decrease pulse rate and BP
• Goal is systolic 100-120 mmHg HR 50-60
• Esmolol gtts Nitroprusside combination
• Labetolol single agent
• IV narcotics
• Ascending require medical stabilization then
  surgery
• Descending require medical stabilization
  monitoring

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Aortic Aneurysm Epidemiology

• Defined as dilation of the abdominal aorta gt 3cm
  and consists of all layer of the aorta
• 15,000 deaths annually in the US
• 97 occur between the renal arteries and inferior
  mesenteric artery
• Clinically important aneurysms over 4 cm in
  diameter are present in about 1 percent of men
  between the ages of 55 and 64 the prevalence
  increases by 2 to 4 percent per decade thereafter
  
• Smoking is the greatest risk factor for aneuryms
  (OR 5.07) also aneurysm growth rate
• 5 x more likely in men
• CAD PVD are significant risk factors
• HTN is a small risk factor (OR 1.15)
• 1st degree blood relative increases odds by
  4.3-fold

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Pathogenesis

• Combination of genetic, structural metabolic
  factors
• Genetic predisposition
• Increased levels of elastase/collagnase
• Loss of blood vessel elastin
• Copper deficiency
• Infection (mycotic aneurysms)
• Inflammatory disorders
• Local Mechanical forces

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Clinical Presentation

• Non-ruptured are usually incidental findings
• Two most common findings of recent expansion
  abdominal/ back pain tender to palpation
  (usually epigastric region)
• Pulsatile tender mass is highly suggestive of
  recent rupture (found in 77 of ruptures)
• Bruits over aorta or femoral arteries
• Unequal distal pulses
• Presentation mimics numerous common ED diagnoses

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Diagnosis

• sensitivity of physical examination for the
  detection of an abdominal aortic aneurysm ranges
  from 22 to 96 percent
• Most non-ruptured aneurysms are incidental
  findings
• Plan abdominal films 75 have suspicious
  findings
• Aneurysmal calcification, loss of renal shadow,
  soft tissue mass
• Real-time ultrasonography is the preferred
  modality for screening and for assessing and
  following abdominal aortic aneurysms since the
  sensitivity approaches 100 percent, not good at
  detecting ruptures
• CT with contrast sensitivity around 100 and
  can detect rupture plus alternative diagnoses

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Treatment

• Mortality rate on elective repair 5
• Mortality rate on emergency repair of ruptured
  aneurysms 50
• Risk of Rupture (5 cm is the usual surgical
  cutoff)
• Zero in aneurysms less than 4.0 cm in diameter
• 0.5 to 5 percent for those 4.0 to 4.9 cm in
  diameter
• 3 to 15 percent for those 5.0 to 5.9 cm in
  diameter
• 10 to 20 percent for those 6.0 to 6.9 cm in
  diameter
• 20 to 40 percent for those 7.0 to 7.9 cm in
  diameter
• 30 to 50 percent for those 8.0 cm in diameter

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Treatment

• Indications for surgical intervention
• Patients with symptomatic aneurysms should
  undergo repair, regardless of aneurysm diameter.
• Early repair may be beneficial in patients whose
  aneurysm increases 0.5 cm in diameter in six
  months.
• Repair of suprarenal and/or thoracoabdominal
  aneurysms involves more extensive surgery and
  greater operative risk. Repair of such aneurysms
  may be beneficial at diameters gt5.5 to 6.0 cm in
  diameter.
• ED treatment
• If suspected rupture
• Two large bore Ivs
• Type Cross 10 units
• Order ECG
• Obtain immediate vascular surgery consultation

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Questions