Aortic Dissection Flashcards
1
Q
Outline 3 classification systems for Aortic Dissection.
A
- Stanford (most basic):
- Type A: Involves ascending aorta and can extend anywhere
- Type B: Begins distal to the (L) SCA
- NB Type A needs surgery Type B may be ok for medical mgt + endovascular stenting
- DeBakey:
- Class 1: Involves entire aorta (Stanford type A)
- Class 2: Confined to ascending aorta only (Stanford type A)
- Class 3: Begins distal to the (L) SCA (Stanford type B)
- Svensson (type of dissection):
- Class 1: Classic dissection with true and false lumen
- Class 2: Intramural haematoma w/ no tear or flap imaged
- Class 3: Intimal tear without haematoma
- Class 4: Atherosclerotic penetrating ulcer
- Class 5: Iatrogenic or traumatic dissection
2
Q
List 7 CXR findings in aortic dissection.
A
- Widened mediastinum >8cm at level of aortic knob on AP view (56-63%),
- loss of aortic pulmonary window
- (L) paraspinal stripe
- abnormal aortic contour (48%),
- aortic knuckle double calcium sign >5mm (14%),
- pleural effusion (L>R),
- tracheal shift,
- left apical cap,
- ‘Normal’ in 12-37%
3
Q
List ECG findings in aortic dissection.
A
- Normal ECG (~30%)
- Inferior STEMI - > dissections involving RCA
- Any other STEMI
- Changes of pericarditis
- Electrical alternans -> tamponade
4
Q
List possible lab findings in aortic dissection.
A
- Elevated cTnI
- D-dimer -> if negative, dissection v.unlikley but insuff’t for rule-out
- Raised Cr -> indicates renal a. involvement
- Leukocytosis
5
Q
List ten risk factors for aortic dissection.
A
Inherited disease:
- Ehlers-Danlos
- Marfan’s
- Turner syndrome
Aortic wall stress:
- HTN
- Smoking
- Dyslipidaemia
- Previous cardiac surgery
- Bicuspid aortic valve
- Recent PCI
- Arteritis (GCA or Takayasu’s)
- Sympathomimetic drugs - eg cocaine
Reduced aortic wall strength:
- Inc’g age
- ? pregnancy
6
Q
What are the complications of aortic dissection?
A
- Aortic rupture -> rapidly fatal
- Extension of the dissection
- Vessel branch occlusion -> brain, limbs, spine, kidneys, gut, liver
- Aortic regurgitation
- Pericardial effusion/tamponade
7
Q
What elements of the history point to aortic dissection?
A
- Chest pain
- Sudden onset
- Tearing in nature
- Radiation of pain - back or belly
- Migrating pain
- Intermittent pain
- Associated features
- CVA symptoms
- Paralysis
- Hoarseness - RLN ischaemia
- Limb ischaemia/pain
8
Q
Discuss the pros and cons of the various imaging modalities for aortic dissection.
A
CXR
- Easy to get in resus bay
- Will miss almost 40%
CT-aortogram
- Modality of choice
- Sensitivity and specificity both in high 90’s%
- Contrast load
- Trf to CT
TOE
- Almost as sensitive as CTA except the arch and extension to branches
- Requires operator and sedation
- Assesses cardiac function, valvular involvement
TTE
- Less sensitive and specific (70% sens for Type A; 40% Type B)
- Requires operator
- Assesses cardiac function, valvular involvement
MRI
- Highest sens and spec
- Availability and duration -> usually prohibitive
9
Q
What are the four elements of mgt of aortic dissection.
Outline each in detail.
A
-
Definitive treatment as appropriate
- Surgical
- Endovascular
-
Pain control
- Opiates to decrease sympathetic drive (BP and HR)
-
BP and HR control
- IABP monitoring
- IV beta-blocker
- Esmolol (0.5mg/kg bolus + 50-300mcg/kg/min)
- Labetalol (bolus 10-20mg over 2mins then infusion at 0.5-2mg/hr)
- GTN (start at 50mcg/min and titrate rapidly)
- Endpoints HR 60-80 and SBP 100-120 to minimise shearing forces
- Start beta-blocker first to avoid reflex tachycardia of GTN
-
Control / treat blood loss /resuscitation
- As above, minimise evolution of dissection via BP and HR control
- Blood transfusion -> massive transfusion protocol
- TXA
- Expedite trf to OT
10
Q
Discuss the use of D-Dimer in aortic dissection.
A
- Sensitivity of <500ng/ml - 97%
- Specificity 56%
- Some studies have shown that up to 18% of confirmed dissections will have a D-Dimer <400
- The D-dimer is not considered sufficient to rule out dissection!
