Aortic Dissection Flashcards
What is the mortality of Tx and UnTx Aortic Dissection?
Untreated
- 1% per hour for 48 hours
- 90% at 3 months
Early, aggressive Tx:
- 20-40%
Pathophysiology and sequelae of dissection:
Arterial HTN + weak media
Intimal tear not mandatory
False lumen
—> Anterograde extension
—> Retrograde extension
—> Contained haematoma
—> Rupture back into true lumen
—> Free rupture
Aortic valve incompetence
AV node compromise
Tamponade
Ischaemia to any aortic branch
Free haemorrhage: pleural space, mediastinum, retroperitoneum
Stanford Classification for dissection:
Type A
Ascending involved
—> Surgery
Type B
Distal ONLY -beyond L subclavian
—> Medical Mx
De Bakey Classification for dissection:
‘BAD’
Type 1
Both
Type 2
Ascending only
Type 3
Descending only
ie. beyond L subclavian
- 3b= extends to abdominal aorta
Like Stanford:
Types 1 and 2: OT
Type 3: MMx
Where does descending aorta begin? Where does abdominal aorta begin?
Descending
= beyond L subclavian artery
Abdominal
= Beyond diaphragm
Most common location of dissection?
Stanford A/ De Bakey 1
Ie. Both asc/desc- 60%
Origins:
- Just above aortic valve
- Ligamentim arteriosum
Clinical features of dissection (and %):
Pain (95%)
Severe, sudden, max at onset, unremitting
Chest, interscap, back, flank, abdo.
Only 50% ‘tearing’ and 15% ‘migratory’!
Current HTN (50%)
Neurology (20%)
Stroke, coma, confusion
Syncope
Seizure
Limb parapleg/thesia
BEWARE:
1- Symptoms ABOVE AND BELOW diaphragm
2- Chest pain PLUS neurology
3- Male >50, HTN
OTHER:
Visual deficit
Dysphasia
Dysphagia
Dyspnoea/ airway obstruction
Horners
In dissection, how common is:
1- Pulse deficit
2- UL BP differential in dissection
3- Radio radial delay
15% only
CXR in aortic dissection:
Normal in 20%!
Wide mediastinum (65%)
—> >8cm at knob (AP)
Abnormal aortic contour (50%)
—> incl. dynamic change on serial
Cardiomegaly (20%)
Calcium sign (15%)
—> >6mm between calcium line and outside at knob
Double density aorta
Apical cap
_____________
SECONDARY SIGNS
Pleural effusion L
Tracheal shift
Cardiomegaly
APo
Etc.
CT aortagram findings in dissection:
Intimal flap
False lumen (delayed contrast)
Internal displacement of calcification
Secondary signs:
—> eg. Effusion, organ ischaemia..
Compare diagnostic imaging modalities in dissection:
CXR
20% normal
Not adequate for rule in or out
CT Aortagram
100% sensitive and specific!
- Can see complications/sequelae
X- Contrast, transport
USS
TOE:
- Rapid, Bedside
- Just as highly sens/spec as CT
- Functional info
- Info re valve function, tamponade
X- Skill
- May need sedation
- CI in oesoph path
TTE not useful
- Poorly sensitive (low as 80%) and specific (low as 60%)
- Partic bad for distal (sensitivity as bad as 30%!)
MRI
- Just as good as CT with similar additional info
X- Length, poor patient access. Not suitable for unstable/potentially unstable- ie. most.
- Surveillance role
Aortography
Invasive, impractical.
Discuss the role of Ddimer in diagnosing aortic dissection:
Not validated, don’t use to exclude.
False neg in:
- young patients
- short dissections
-Intramural thrombus (not exposed to serum)
Indication for OT in dissection:
Type A - all
Type B
- Extension despite MMx
- MMx inadequate: eg. Uncontrolled HTN
- Refractory pain
- Leak or rupture
- Significant and ongoing organ ischaemia
Management of aortic dissection:
Call CTX
Pain control with FENTANYL (will help PR/BP)
Beta blocker FIRST
ESMOLOL 0.5mg/ kg IV then 0.05mg/kg/min titrated
OR
LABETALOL 10-20mg IV then 0.5-2mg/min
….. if further BP control required after BB……….
Vasodilator SECOND
GTN 5-20mg/hr
OR
SODIUM NITROPRUSSIDE
GOALS
PR < 60
SBP < 110
Manage SHEAR stress
BB first to avoid reflex tachycardia
