Aortic Emergencies Flashcards
What is aortic dissection?
Aortic dissection occurs due to an aortic intimal tear, intramural haematoma or separation of the tunica media creating a false lumen
Predisposing factors of Aortic Dissection
Hypertension
Smoking
Atherosclerosis
3rd trimester pregnant patients
Disorders of collagen, or vasculitis (Marfan’s syndrome, Ehlers-Danlos syndrome or giant cell arteritis)
Types of classifications used in Aortic Dissections
Stanford and Debakey
Stanford system is divided into 2 groups
- Type A involves the ascending aorta (+/- descending aorta)
- Type B involves only the descending aorta
DeBakey system is divided into 3 groups
- Type I involves the ascending aorta, aortic arch and descending aorta
- Type II involves the ascending aorta, but does not extend beyond the left subclavian artery
- Type III involves only the descending aorta, starting at, or distal to, the left subclavian artery
3 key questions to ask for AD
- Intensity at onset
- Quality of pain
- Radiation of pain
Classical clinical features of AD
Sudden, severe, maximal pain at onset, tearing migratory chest pain that radiates to the back
What is another possible clinical feature of AD?
Ischemia of the Lower Extremities due to Aortic dissection:
- Migratory pain from the chest to the abdomen to the lower limbs
If AMI (non-migratory) and AD occur together, which would begin first?
Dissection typically begins first and leads to the MI
What type of MI would be seen in AD? Due to involvement of which coronary artery?
Inferior MI, due to involvement of right coronary artery
PE findings for AD
- 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
New onset of what type of murmur can be observed in AD patients
Aortic regurgitation murmur (early diastolic murmur: URSE or Erb’s point)
What can be seen in CXR in AD patients?
- 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)
Overarching principles in medical therapy for AD
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
What investigations should be sent off?
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
Management of AD
- 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 - Monitor vitals and continuous cardiac monitoring in critical care area. Contact CVS the moment AD is suspected.
- 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 - Analgesia: IV morphine
- Insert IDC to monitor I/O especially for anuria/oliguria in renal artery involvement
- Put patient on circulation and neurological observation chart
- Send for surgical repair
- Bentall procedure with Dacron polyester graft - Ascending aorta +/- arch replacement
Indications for surgical repair of AD include
- 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
Abdominal aortic aneurysm
Localised dilatation of an artery of >50% of the normal diameter
*dilatation of <50% of the normal arterial diameter is termed ectasia
How will patients with AAA present?
- 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
Any elderly patient presenting with hypotension, shock and back pain must TRO ruptured AAA
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Look for expansile pulsation by placing fingers alongside pulsation; deviation of the fingers laterally is due to aneurysm
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All patients with a pulsatile mass >__cm should have an ultrasound evaluation
3cm
Aortic aneurysms are associated with…
atherosclerosis
Risk factors of AAA
- Hypertension
- Smoking
- HLD
Risk of rupture in aortic aneurysms
Aortic aneurysms have an exponential expansion rate and risk of rupture is proportional to the diameter of the aneurysm:
- Aneurysms 4-5.5cm diameter have 5% risk of rupture
- Aneurysms 6-7cm have 33% risk of rupture
- Aneurysms >7cm have 95% risk of rupture
Management of Ruptured AAA
- 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 - Ensure patient is monitored in critical care area with resuscitation equipment available.
- Patient should be placed on continuous cardiac monitoring ECG, vitals, SpO2
- 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 - Admission to either GS or CTVS for TEVAR stenting or open aneurysm repair
- Open surgery preferred in young patients with longer life expectancy
