Acute Aortic Dissection

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Acute Aortic Dissection

• AM Report 6/29/09
• Brandon M. Williams, MD

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Classification

• Two systems
• DeBakey
• Daily (Stanford) most used

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DeBakey

• Type 1 origin in ascending aorta and propagates
  to at least arch
• Type 2 origin in ascending and confined within
  ascending
• Type 3 origin in descending and extends
  (distally or proximally)

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Daily (Stanford)

• Type A involves ascending aorta
• Type B all others
• - Nomenclature doesnt change secondary to site
  of origin

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Daily (Stanford)
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Pathophysiology

• Tear in aortic intima
• Need degeneration of media or cystic medial
  necrosis for nontraumatic dissections
• Blood crosses into media via tear and separates
  intima from media/adventitia creating a false
  lumen
• ? If rupture of intima or hemorrhage within media
  causing rupture of intima is initiating event

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Incidence

• Acute aortic dissection
• - 2.6-3.5/100,000 person years

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Incidence

• Classic is 60 80 yo males (mean 63yo)
• Women 67
• Ascending 2x more likely than descending, with
  right lateral wall most common site

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Risk Factors

• 13 with known aortic aneurysm (19 if lt 40yo)
• Inflammatory disease vasculitis
• -giant cell arteritis
• -takayasu arteritis
• -rheumatoid arthritis
• -syphilitic aortitis

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Risk Factors

• HTN (71)
• Atherosclerosis (31)
• DM (5.1)
• Collagen disorders (Marfan, Ehlers-Danlos)
• 19 of thoracic with family history
• Bicuspid aortic valve (9 lt 40yo)
• Aortic coarctation (post intervention)
• CABG
• AVR
• Cardiac catheterization
• Trauma
• High-intensity weight lifting and cocaine via
  transient HTN
• - cocaine 37 of AA inner city population

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Signs and Symptoms

• Abrupt, tearing pain, back (if distal to L
  subclavian) or anterior (ascending)
• Associated syncope, CVA, MI, HF
• Syncope assoc with worse outcome (almost all type
  A)
• Pulse deficit
• Aortic insufficiency murmur more at RSB than
  valve assoc AI (LSB)
• gt20mmHg difference in SBP between UE
• Vocal cord paralysis (compression of L laryngeal
  nerve)
• Hypotension (hemorrhage, tamponade, HF)
• Spinal cord ischemia
• STEMI 3/820 EKGs showing STEMI found to have
  ascending aortic dissection

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Images
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Diagnosis

• Abrupt onset of pain, tearing/ripping
• Mediastinal/aortic widening on Chest X ray
• Variation in pulse

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Imaging

• Chest Xray
• TTE
• TEE
• CTA chest
• MRI
• Coronary angiography

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Images
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Treatment

• Involvement of ascending aorta surgical
  emergency
• Descending aorta medical management unless
  progression or hemorrhage into pleural or
  retroperitoneal space
• -morphine
• -SBP 100-120 or lowest tolerated
• beta blocker titrate to HR lt 60 (labetalol,
  propranolol, esmolol)
• if beta blocker intolerant verapamil,
  diltiazem
• no nitroprusside until HR lt 60
• no hydralazine
• no inotropic agents, if hypotensive look for
  bleeding
• A-line in radial artery with highest auscultatory
  pressure

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References

• UpToDate
• Management of Patients with Aortic Dissection.
  Weigang et al. Dtsch Arztebl Int. 2008 Sep. 105
  (38) 639-645
• Conditions mimicking acute ST-segment elevation
  myocardial infarction in patients referred for
  primary percutaneous coronary intervention. Gu
  et at. Neth Heart Journal. 2008 Oct 16 (10)
  325-31
• Google images