Aortic Dissection

1
Aortic Dissection

• By
• Jagroop Basraon D.O
• April 1, 2007

2
Aorta Anatomy

• Ascending Aorta Aortic root, L R coronary
  arteries
• Aortic Arch great vessels of head and upper
  extremities. . Brachiocephalic, L Common carotid
  and L subclavian
• Descending Aorta Spinal artery vascular supply
• Abdominal Aorta Splanchic, Renal and Illiac
  arteries.

3
Aorta - Histology

• Intima internal layer of aorta, easily damaged
• Media main structural layer of elastic tissue
  and smooth muscle
• Adventia outer layer which anchors aorta within
  the body
• Aorta stores pressure as kinetic energy and
  controls systemic vascular resistance
• Etiology Aging, Uncontrolled HTN (80 of
  patients), Pregnancy assoc w/increased risk,
  Marfan/Ehler-Danlos, Trauma

4
Classification

• STANFORD
• TYPE A anything involving ascending aorta
• TYPE B anything NOT involving ascending aorta
• DEBAKEY
• TYPE 1 Entry point in ascending aorta, and
  extends to aortic arch and often beyond
• TYPE 2 Confined entirely to ascending aorta
• Type 3 Descending aorta and exceeding distally
  most of the time

5
Classification
6
Symptoms

• Severe Chest and/or Back pain (74-90 of time)
• Sudden onset (vs. MI which is gradual)
• Pain quality is tearing, ripping or stabbing
• Less common presentation is CHF, Syncope (from
  rupture into cardiovascular space and tamponade),
  CVA, Paraplegia, or Cardiac arrest

7
Physical Exam

• HTN seen as cause and as a complication
  (usually from renal ischemia)
• Hypotension from tamponade, hemopericardium
• Diastolic murmur of Aortic Insufficiency (16-67)
• Vascular Pulse deficits
• Neurological signs of CVA (3-6 in prox
  dissection)

8
Diagnostic Testing

• MRI current gold standard. Demonstrates all
  planes involved and branch vessel involvement.
  Usually costly and time consuming, and lack of
  availability
• TTE/TEE quick non-invasive difficulty in
  descending aorta. Other factors, i.e. operator
  experience, obesity, intimal flap visualization
• CT fast and available, but difficult to
  visualize branches involvement. Also need for
  contrast
• Aortogrpahy original means. Can also look at
  coronary arteries at same time. Risk of invasive
  procedure and contrast complications
• Currently most places use CT for acute evaluation
• MRI for chronic dissection (gt2 wks) Evaluation

9
Therapy - Surgical

• Death is usually from progression of dissection
  resulting in vascular compromise or rupture
• Proximal (type A), mandate Surgical Treatment. 1
  per hour mortality and halts progression
• Type B w/pain or poor medical control w/end organ
  compromise require surgical intervention. CONSULT
  CV SURGERY
• Surgical repair w/Grafts, with concomitant
  coronary artery repair if needed
• Surgical complication most feared is
  paraplegia, others include repeat dissection,
  aneurysm, and progressive Aortic Insufficiency.

10
Therapy Medical

• Priority of therapy in all dissections is
  reduce blood pressure.
• Goal MAP of 60-70mmHg, and HR lt60
• B-blocker therapy w/Labetelol or Esmolol IV drip.
  
• Ca channel blocker second line. Usually Diltiazem
  drip

11
Special Clinical Situation

• Hypotension w/Dissection aggressive volume
  replacement. Think TAMPONADE or AORTIC WALL
  RUPTURE. Vassopressors may be required.
  Norepinephrine and Phenylephrine are drugs of
  choice. Avoid Epinephrine and Dopamine because of
  less effect on vascular walls
• ACUTE MI can be see in dissection. Thrombolysis
  is contraindicated. IMMEDIATE CONSULT with
  multi-team approach required

12
Special Clinical situation

• Intramural Hematoma local dissection of
  superficial layer into the media. Does not
  communicate with lumen of aorta. Same as
  classical presentation and same course. Thus same
  management as standard dissection
• Penetrating Atherosclerotic Ulcer management
  depending on clinical presentation. Future course
  variable. Consult with emphasis on individualized
  treatment options depending on compromise and
  severity.

13
Conclusion

• Aortic Dissection emergency, immediate surgery
  for ascending dissection.
• B-blocker, or Ca-channel 2nd line for goal MAP of
  60-70, and HR 60
• CT or TEE fastest and currently accepted
• Hypotensive aggressive fluid and/or pressors,
  keep Cardiac Tamponade and Rupture in mind
  always.

14
References

• -Nienaber CA, Von Kodolitsch Y, Nicholas V. The
  diagnosis of thoracic aortic dissection by
  non-invasive imaging procedure
• -Dapunt OE . The natural history of thoracic
  aortic aneurysms
• -Pretre R, Von Segesser LK, Aortic dissection
  review article. Lancet 1997