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Cardio Block > 2- aortic disease: aneurysm & dissection > Flashcards

2- aortic disease: aneurysm & dissection Flashcards

1
Q

what is an aneurysm?

A

a permanent, localised dilatation of an artery of more than 50% of the normal arterial diameter (i.e. 50% increase in diameter compared with non dilated adjacent vessel)

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2
Q

what is normal aortic diameter?

A

1.2 - 2 cm

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3
Q

what is a true aneurysm?

A

where all the 3 layers of the artery are involved

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4
Q

what is a false aneurysm?

A

where there is a defect in the wall of the artery and it is the surrounding structures (skin, fat, fascia) that keep the aneurysm restrained

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5
Q

what is the pathogenesis of abdominal aortic aneurysm?

A
  • related to medial degeneration (tunica media degeneration)
  • abnormal regulation of elastin & collagen proteins in the aortic wall by enzymatic agents such as metallo-proteinases not working properly causing a disruption →aneurysmal dilation (abnormal widening & bulging) →increase in aortic wall stress (more pressure & stretching)
  • this continues and makes progressive aneurysmal dilation (process continues to worsen over time)
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6
Q

does atherosclerosis related to aneurysmal formation?

A

no, not directly related - just an incidental finding

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7
Q

what does abdominal aortic aneurysm present like?

A
  • 75% of all are asymptomatic until rupture occurs
  • 35% are symptomatic
  • with sudden onset of abdominal & back pain and/or collapse

*often identified on imaging for other pathology

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8
Q

what are ultrasound limitations?

A

only gives size - not moving up or show if just about to rupture

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9
Q

what happens in CT angiography?

A

inject contrast and wait for contrast to hit arteries, you can then CT all the way down →allows us to see shape, size, what vessels involved, allows you to plan treatment

  • IV contrast
  • scan when contrast is in arterial system
  • aneurysm morphology
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10
Q

what are most ruptured aneurysms still contained in?

A

the retroperitoneum

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11
Q

when is it recommended to repair a asymptomatic abdominal aortic aneurysm?

A

when it reaches 5.5 cm AP (anteroposterior) diameter

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12
Q

what is criteria for aneurysm intervention?

A
  • reaches 5.5 cm
  • undergoes rapid expansion >1cm per year
  • when AAA is symptomatic
    • rupture = if AAA bursts then life threatening emergency
    • thrashing = unstable or rapidly changing characteristics of AAA
    • pain
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13
Q

what is elective aneurysm repair?

A

scheduled intervention for an abdominal aortic aneurysm (AAA) that is performed in a non-emergency setting

= it’s a prophylactic operation to reduce the risk of rupture balanced against risk of procedure

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14
Q

what is emergency aneurysm repair?

A

therapeutic procedure balancing expectation for death against risk of procedure

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15
Q

what is therapeutic procedure?

A

aimed at improving or treating a medical condition

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16
Q

what is prophylactic procedure?

A

aimed at preventing medical condition

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17
Q

what is EVAR?

A

endovascular aneurysm repair
= type of repair within blood vessel using minimally invasive techniques, via percutaneous access in groin with the stent inserted up through the common femoral artery

  • stent-graft reinforces weakened or bulging area of aorta
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18
Q

what are positives & negatives of EVAR?

A

positives = less mortality risk (far safer in complex aneurysms), much faster recovery

negatives = not possible in 25% of patients, needs on going follow up, may need further investigations

19
Q

what is open repair?

A

type of repair of aortic aneurysm through direct surgical intervention where weakened/bulging area assessed and repaired through direct surgical intervention, sewing graft to replace removed section of aorta

20
Q

what are positives and negatives of open repair?

A

positives = possible in just about everyone, rare further investigations, known to be effective for life

negatives = greater mortality risk, much slower recovery

21
Q

what assessments should be carried out to assess fitness for AAA intervention?

A
  • cardiac assessment - echo/ejection fraction
  • respiratory assessment - PFT
  • cardiopulmonary exercise test - CPX testing
  • renal assesment - U&Es
  • vascular assessment - peripheral pulses/ABPI
  • anaesthetic assessment
  • EBT - end of bed or eyeball test
22
Q

what is some criteria of the aorta & vessels to be able to do an EVAR?

A

Aorta above AAA needs to be of correct morphology (size/shape) to land the stent above the AAA and the iliac arteries need to be disease free to be able to insert the device up to the AAA

= this needs imaging & contrast to check

23
Q

how many elective AAA can be treated with EVAR?

A

60-70% of elective AAA can be treated with EVAR

*saying that most scheduled aneurysm repairs can be treated with EVAR

24
Q

what is the outcome of a ruptured AAA?

A
  • 50 - 75% will of patients not make it to hospital
  • Most ruptured AAA are retroperitoneal, contained rupture
  • Free intra-peritoneal rupture is rapidly fatal
  • 50% operative mortality
25
Q

what is operative mortality for
a) elective open AAA?
b) elective EVAR?

A

a) 3-4%
b) 1-2%

26
Q

what are complications for open repair?

A
  • MI, CVA
  • pneumonia, wound infection, UTI, graft infection
  • DVT /PE
  • renal failure - dialysis may be required
  • Mesenteric ischaemia – may require bowel resection
  • Lower Limb Ischaemia + ‘Trash’ foot
  • Erectile dysfunction
  • Death
27
Q

what are complications of EVAR?

A
  • Stent misplacement – covering the renal arteries, internal iliac arteries
  • Endoleak (this is defined a blood flow out with the stent in the aneurysm sac)
  • Stent migration and stent dislocation (the stents are modular and inserted into one another and over time they may dislocate from one another)
  • All EVAR require lifelong follow up (~20% of EVAR patients will require further intervention over their lifetime)
28
Q

what is the screening programme for aneurysms?

A

it aims to offer screening to all males >65 years with ultrasound scan (suggests reducing risk of death by 50%)

29
Q

what is aortic dissection?

A

dissection is tear - so it’s an aortic tear

(it’s a distinct separate thing from aortic aneurysm but a dissected aorta may become aneurysmal)

30
Q

what is acute aortic syndrome?

A

group of series & potentially life-threatening conditions affecting aorta

31
Q

what are types of acute aortic syndrome?

A
  • penetrating aortic ulcer = ulcer or lesion that penetrates through inner layers of aortic wall
  • intramural haematoma = collection of blood within the layers of aortic wall without a clear tear or dissection
  • aortic dissection = condition where there is a tear in inner layers of the aorta, allowing blood to flow between the layers, potentially causing layers to separate
32
Q

what do all the types of acute aortic syndrome have in common?

A
  • all have disruption to tunica media layer
  • all have bleeding between the layers
  • all have transmural bleeding which is bleeding that extends through all layers potentially leading to rupture, outwith adventitia
33
Q

why is it tricky to deal with acute aortic syndrome?

A

because since all types have disruption to tunica media it’s tricky to fix - think like toilet paper in a packet (inside cardboard ring is intima, paper itself is media and outer plastic is adventitia), the paper gets all soggy and hard to fix

34
Q

what are some factors associated with acute aortic syndrome?

A
  • Family history
    • specific Gene mutations (fibrillin-1, transforming growth factor β1 etc) can affect structure & function of aorta
  • Connective Tissue Disorders, this can impact integrity of aorta
    • Ehlers Danlos, Marfans, Loeys dietz
  • Trauma including iatrogenic
35
Q

what happens in formation of aortic dissection?

A

cystic medial necrosis & medial degeneration →tear intimal layers →blood propagates within medial layer creating separation of layers →creates a flap; true lumen & false lumen

36
Q

where can the tear (aortic dissection) propagate? (spread)

A

centrally: aortic arch & it’s branches, aortic valve, coronary arteries

distally: mesenteric/renal arteries, iliac arteries down the limb

37
Q

how do you classify aortic dissection?

A

Stanford guide

Type A = involves ascending aorta & arch, cardiothoracic emergency

Type B = involves descending thoracic aorta (distal to left subclavian), vascular surgery

38
Q

how do people present with aortic dissection?

A

excruciating chest or interscapular pain (also back pain, and sometimes abdominal pain)

39
Q

what can propagation of dissection flap lead to?

A
  • if involves valve →disrupted function →Acute aortic valve regurgitation
  • if affects coronary arteries →Myocardial infarction
  • if flap extends into pericardial sac →Cardiac tamponade
  • if involves blood vessels to brain →Stroke
  • if spread to vessels of upper limb →Upper limb ischaemia
  • Lower ischaemia
  • if involves blood vessels supplying intestine →Mesenteric ischaemia
  • if spread to spinal cord →Spinal ischaemia (paraplegia)
40
Q

what does CT angiogram of aortic dissection allow?

A

would be from aortic arch to femorals

  • Delineates (portrays precisely) anatomy
  • Delineates perfusion to end organs
  • Allows surgical planning (if appropriate)
41
Q

what is the aim of treatment of aortic dissection?

A
  • prevent progression of dissection
  • prevent rupture
  • maintain or restore perfusion to end organs

*you want to lower blood pressure & operate if needed

42
Q

what intervention do you want to do for acute phase aortic dissection?

A

acute phase < 2 weeks
= aim to reduce flow in false lumen thereby decreasing diameter expansion of dissection

  • false lumen remodelling
  • complicated type B dissection
    (high risk, tissues like soggy paper)
43
Q

what intervention do you want to do for sub acute phase aortic dissection?

A

sub acute = 2 weeks to 90 days
(tissues more robust)

  • false lumen modelling
  • reduce aortic related complications (aneurysms etc)

*jury’s still out on whether to operate

44
Q

what are complications of intervention?

A
  • 30 day mortality up to 30% - 40%
  • Stroke – up to 10%
  • Spinal cord ischaemia – 2%
  • Retrograde Type A dissection - extension of dissection backward into ascending aorta

Cardio Block (34 decks)

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