Aortic Emergencies

Question 1

What is aortic dissection?

Answer 1

Aortic dissection occurs due to an aortic intimal tear, intramural haematoma or separation of the tunica media creating a false lumen

Question 2

Predisposing factors of Aortic Dissection

Answer 2

Hypertension
Smoking
Atherosclerosis
3rd trimester pregnant patients
Disorders of collagen, or vasculitis (Marfan’s syndrome, Ehlers-Danlos syndrome or giant cell arteritis)

Question 3

Types of classifications used in Aortic Dissections

Answer 3

Stanford and Debakey

Question 4

Stanford system is divided into 2 groups

Answer 4

1. Type A involves the ascending aorta (+/- descending aorta)
2. Type B involves only the descending aorta

Question 5

DeBakey system is divided into 3 groups

Answer 5

1. Type I involves the ascending aorta, aortic arch and descending aorta
2. Type II involves the ascending aorta, but does not extend beyond the left subclavian artery
3. Type III involves only the descending aorta, starting at, or distal to, the left subclavian artery

Question 6

3 key questions to ask for AD

Answer 6

1. Intensity at onset
2. Quality of pain
3. Radiation of pain

Question 7

Classical clinical features of AD

Answer 7

Sudden, severe, maximal pain at onset, tearing migratory chest pain that radiates to the back

Question 8

What is another possible clinical feature of AD?

Answer 8

Ischemia of the Lower Extremities due to Aortic dissection:
- Migratory pain from the chest to the abdomen to the lower limbs

Question 9

If AMI (non-migratory) and AD occur together, which would begin first?

Answer 9

Dissection typically begins first and leads to the MI

Question 10

What type of MI would be seen in AD? Due to involvement of which coronary artery?

Answer 10

Inferior MI, due to involvement of right coronary artery

Question 11

PE findings for AD

Answer 11

• Hypertensive
• Radial-radial delay: Difference in systolic blood pressure in both arms (>20mmHg)
• Radial-femoral delay: Blood pressure in the upper limbs is greater than in the lower limbs
• New onset aortic regurgitation murmur

Question 12

New onset of what type of murmur can be observed in AD patients

Answer 12

Aortic regurgitation murmur (early diastolic murmur: URSE or Erb’s point)

Question 13

What can be seen in CXR in AD patients?

Answer 13

• Widened mediastinum of >8cm on PA CXR
• Loss of contour of aortic knuckle
• Aortic enlargement
• Double density of the aorta (false lumen less radiopaque)
• New pleural effusion (free haemothorax)
• Deviation of trachea to the right (away from the developing haematoma)

Question 14

Overarching principles in medical therapy for AD

Answer 14

Lower rate of rise of blood pressure by lowering mean blood pressure and heart rate and velocity of left ventricular contraction
-> leads to a decrease in aortic shear stress and minimise the tendency for propagation of the dissection

Question 15

What investigations should be sent off?

Answer 15

POCT:
POCUS
VBG - to look at electrolytes
ECG - look for concomitant AMI
+ CXR
+ Bedside 2D echocardiography

Bloods:
FBC
RP to assess kidney function (esp since there might be reduced perfusion)
Coagulation panel
GXM
Cardiac enzymes

Radiology:
CT aortogram once AD highly suspected

Question 16

Management of AD

Answer 16

1. ABCs and set 2 large-bore IV cannulas
   - Bedside: ECG TRO concomitant AMI, 2D echocardiography (>3.5cm root of aorta)
   - Run investigations: FBC, RP, coagulation panel, GXM, cardiac enzymes
   - Imaging: CXR, then CT aortogram once highly suspected
2. Monitor vitals and continuous cardiac monitoring in critical care area. Contact CVS the moment AD is suspected.
3. Reduce BP to SBP 100-120mmHg, HR <60bpm:
   A. IV beta-blocker
   - IV labetalol
   - IV esmolol
   - IV propanolol (used with nitroprusside)
   B. IV GTN, nicardipine or nitroprusside
4. Analgesia: IV morphine
5. Insert IDC to monitor I/O especially for anuria/oliguria in renal artery involvement
6. Put patient on circulation and neurological observation chart
7. Send for surgical repair
   - Bentall procedure with Dacron polyester graft - Ascending aorta +/- arch replacement

Question 17

Indications for surgical repair of AD include

Answer 17

• All Stanford type A dissections
• Type B dissections with complications (rupture, severe distal ischaemia, intractable pain, progression and uncontrolled htn). Otherwise, type B dissections can be managed medically
• Uncontrolled hypertension
• Progression of dissection

Question 18

Abdominal aortic aneurysm

Answer 18

Localised dilatation of an artery of >50% of the normal diameter

*dilatation of <50% of the normal arterial diameter is termed ectasia

Question 19

How will patients with AAA present?

Answer 19

• Asymptomatic (75%)
• Sentinel bleed into retroperitoneum -> Ruptures intraperitoneally -> Collapse, shock and death
• Abdominal, flank or back pain (can mimic ureteric colic)
• Pulsatile abdominal mass
• Syncope with postural hypotension
• Embolisation causing ALI

*back pain could be due to expansion of AAA with erosion of the spinal vertebrae or ruptured AAA

Question 20

Any elderly patient presenting with hypotension, shock and back pain must TRO ruptured AAA

Answer 20

-

Question 21

Look for expansile pulsation by placing fingers alongside pulsation; deviation of the fingers laterally is due to aneurysm

Answer 21

-

Question 22

All patients with a pulsatile mass >__cm should have an ultrasound evaluation

Answer 22

3cm

Question 23

Aortic aneurysms are associated with…

Answer 23

atherosclerosis

Question 24

Risk factors of AAA

Answer 24

• Hypertension
• Smoking
• HLD

Question 25

Risk of rupture in aortic aneurysms

Answer 25

Aortic aneurysms have an exponential expansion rate and risk of rupture is proportional to the diameter of the aneurysm:

1. Aneurysms 4-5.5cm diameter have 5% risk of rupture
2. Aneurysms 6-7cm have 33% risk of rupture
3. Aneurysms >7cm have 95% risk of rupture

Question 26

Management of Ruptured AAA

Answer 26

1. ABCs and set 2 large bore IV cannulas. Do not over resuscitate patient, 90-100SBP is acceptable.
   - Bedside: Ultrasound to assess for >3cm diameter abdominal aorta. Or for any free fluid on FAST scan suggesting ruptured AAA
   - Ix: FBC, RP, coagulation, GXM
   - Radiology: CT aortogram in stable patients
2. Ensure patient is monitored in critical care area with resuscitation equipment available.
3. Patient should be placed on continuous cardiac monitoring ECG, vitals, SpO2
4. Inform CTVS and prepare for:
   - emergent repair if ruptured AAA
   - urgent repair for symptomatic non-ruptured AAA
   - conservative management for asymptomatic infrarenal AAA <5.5cm
5. Admission to either GS or CTVS for TEVAR stenting or open aneurysm repair
   - Open surgery preferred in young patients with longer life expectancy