Abdominal aortic aneurysm Flashcards

1
Q

Average lifetime aortic blood flow

A

200 million litres

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2
Q

Layers of arterial wall

A

Tunica intima: covered by endothelium

Tunica media: thick collagen

Tunica adevntita: extrnal coverings containing vasa vasorum

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3
Q

Windkessel function

A

Refers to the secondary pump quality of the aortic

Elastic nature provides pump force during diastole
–> helps to perfuse coronaries

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4
Q

Average aortic expansion

A

Men: 0.9mm per DECADE

Women: 0.7mm per DECADE

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5
Q

Symptoms of aortic disease

A

Acute deep, aching or throbbing chest or abdominal pain that can spread to the back, buttocks, groin or legs, suggestive of AD or other AAS, and best described as ‘feeling of rupture’

Cough, shortness of breath, or difficult or painful swallowing in large TAAs.

Constant or intermittent abdominal pain or discomfort, a pulsating feeling in the abdomen, or feeling of fullnessafter minimal food intake in large AAAs.

Stroke, transient ischaemic attack, or claudication secondary to aortic atherosclerosis.

Hoarseness due to left laryngeal nerve palsy in rapidly progressing lesions.

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6
Q

Ideal place to measure diameter of aorta

A

Measure diameter perpendicular to flow

Measure at set anatomical points

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7
Q

When in cardiac cycle to measure aortic diameter

A

Discussion to be had

Diastolic measurements are the most reproducible

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8
Q

Inter and itnra variability in measurement of diameter on CT

A

Inter assessor variability ~ 5mm

Intra assessor variability ~3mm

Generally changes <5mm unlikely to be significant

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9
Q

Ultrasound measurement of aortic diameter

A

Tend to under report size by 1-3mm

Measured in AP direction

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10
Q

Use of PET CT

A

18F-fluorodeoxyglucose (FDG), which is taken up with high affinity by hypermetabolic cells (e.g. inflammatory
cells), and can be used to detect vascular inflammation in large vessels.

The advantages of PET may be combined with CT imaging with good resolution.

inflammatory vascular disease (e.g. Takayasu arteritis,GCA), to detect endovascular graft infection,
and to track inflammatory activity over a given period of
treatment

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11
Q

Disadvantages of MRA

A

Cannot evaluate calcification which is important for evaluating landing zones of a graft

Availability

Difficulty in patient monitoring during scan

Time taken to perform scan

Gadolinium causes nephrogenic systemic fibrosis

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12
Q

Measuring aortic stiffness

A

Carotid -femoral pulse wave velocity

Fast velocity = stiffer aorta

> 10m/s = stiff aorta

Predictor of CV events and poor otucome

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13
Q

Effect of smoking on aneurysm expansion

A

Quicker aneurysm expansion

Smoking status associated with expansion rate of 0.4mm / YEAR

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14
Q

TEVAR landing zone

A

Diameter <40mm

Length >20mm

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15
Q

CT angiogram pre TEVAR

A

<3mm slices
From supra-aortic vessels down to femoral arteries

Asses landing zones

Asses relationship to side branches

Evaluate femoral access

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16
Q

Stent sizing in dissection vs aneurysm TEVAR

A

Dissection:

  • Land at site of false lumen to occlude lumen and de-pressurise false lumen
  • Do not over-size in diameter

Aneurysm

  • Over-size in diameter by 10-15%
  • Landing zone needs to be clear of aneurysmal disease
17
Q

Definition of proximal aortic neck

A

Segment of aorta below renal arteries up to the most cephalic section of aneurysm

Hostile neck
>60% angulation –> migration and endoleaks
<15mm –> difficult landing
>32mm in diameter means endovascular stent unlikely

18
Q

Features of good proximal aortic neck

A

<60% angulation

> 10-15mm in length

<32mm in diameter

19
Q

Why do you not cover both internal iliacs

A

Causes bilateral hypogastric artery occlusion

Leads to:

  • Impotence
  • Spinal cord ischaemia
  • Visceral ischaemia
  • Buttock caludication
20
Q

When to ligate inferior mesenteric artery (open)

A

Conditions for ligation:

  • brisk back bleeding from IMA
  • bilateral patent hypogastric arteries i.e. not occluding either internal iliac

If sluggish bleeding or occluding one of the iliac –> re-implant IMA

21
Q

Definition of acute thoracic aortic syndrome

A

Defined as emergency conditions with similar clinical characteristics involving the aorta

Essentially a breakdown of the intima and media:

  • intramural thrombus
  • penetrating atherosclerotic ulcer
  • dissection
  • rupture
22
Q

De Bakey classification

A

De Bakey = 1, 2 , 3

Classification of throacic aortic dissection

1: ascending and descending thoracic aorta
2: ascending thoracic aorta prior to innominate artery
3: descending thoracic artery at point of innominate artery

23
Q

Stanford classification

A

A or B

A: involved the ascending thoracic aorta +/- descending thoracic aorta

B: involves only the descending thoracic aorta

24
Q

Classification of aortic dissection

A

1 - 5

1: classic dissection. No communication between to lamina, true and false lumen exist
2: intramural haematoma
3: subtle dissection with bulging of arterial wall
4: penetrating atherosclerotic ulcer
5: traumatic / iatrogenic

25
Q

Recommendations for imaging of aorta (7)

A

1) It is recommended that diameters be measured at pre-specified anatomical landmarks, perpendicular to the longitudinal axis. IC
2) In the case of repetitive imaging of the aorta over time, to assess change in diameter, it is recommended that the imaging modality with the lowest iatrogenic risk be used. IC
3) In the case of repetitive imaging of the aorta over time to assess change in diameter, it is recommended that the same imaging modality be used, with a similar method of measurement. IC
4) It is recommended that all relevant aortic diameters and abnormalities be reported according to the aortic segmentation. IC
5) It is recommended that renal function, pregnancy, and history of allergy to contrast media be assessed, in order to select the optimal imaging modality of the aorta with minimal radiation exposure, except for emergency cases. IC
6) The risk of radiation exposure should be assessed, especially in younger adults and in those undergoing repetitive imaging. IIaB
7) Aortic diameters may be indexed to the body surface area, especially for the outliers in body size. IIbB

26
Q

Recommendations for thoracic endovascular repair (TEVAR) (4)

A

1) It is recommended that the indication for TEVAR or EVAR be decided on an individual basis, according to anatomy, pathology, comorbidity and anticipated durability, of any repair, using a multidisciplinary approach. IC
2) A sufficient proximal and distal landing zone of at least 2 cm is recommended for the safe deployment and durable fixation of TEVAR. IC
3) During stent graft placement, invasive blood pressure monitoring and control (either pharmacologically or by rapid pacing) is recommended. IC
4) Preventive cerebrospinal fluid (CSF) drainage should be considered in high-risk patients. IIaC

27
Q

Recommendations for surgical repair of thoracic aorta

A

Cerebrospinal fluid drainage is recommended in surgery of the thoraco-abdominal aorta, to reduce the risk of paraplegia. IB

Aortic valve repair, using the re-implantation technique or remodelling with aortic annuloplasty, is recommended in young patients with aortic root dilation and tricuspid aortic valves. IC

For repair of acute Type A AD, an open distal anastomotic technique avoiding aortic clamping (hemiarch/complete arch) is recommended. IC

In patients with connective tissue disordersd requiring aortic surgery, the replacement of aortic sinuses is indicated. IC

Selective antegrade cerebral perfusion should be considered in aortic arch surgery, to reduce the risk of stroke. IIaB

The axillary artery should be considered as first choice for cannulation for surgery of the aortic arch and in aortic dissection. IIaC

Left heart bypass should be considered during repair of the descending aorta or the thoraco-abdominal aorta, to ensure distal organ perfusion. IIaC