Aortic dysfunction Flashcards

1
Q

What is normal diameter of aorta

A

2cm

increases with age

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2
Q

Define aneurysm

A

Permanent dilation of the artery to TWICE the normal diameter

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3
Q

Difference between a true aneurysm and false aneurysm

A

True - abnormal dilatation that involve all layers of arterial wall
False (pseudoaneurysm) - involves the collection of blood in the OUTER LAYER ONLY (ADVENTITIA) which communicates with the lumen e.g. after trauma from a femoral artery puncture

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4
Q

What arteries are generally involved in a True Aneurysm

A

Abdominal aorta (most common)
Iliac, popliteal and femoral arteries
Thoracic aorta
(abdominal aneurysms are classified as abdominal or thoracic)

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5
Q

Do abdominal aortic aneurysms (AAA) most commonly occur above or below the renal arteries

A

Below

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6
Q

AAA: epidemiology

A

Incidence increases with age
Present in 5% of population >60
More common in men

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7
Q

Abdominal aneurysms are classified as an aortic diameter exceeding what?

A

3cm

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8
Q

Causes/Risk factors of AAAs

A
Often no specific identifiable causes
• Severe atherosclerotic damage
• Family history
• Tobacco smoking
• Male
• Increasing age
• Hypertension
• COPD
• Trauma
• Hyperlipidaemia
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9
Q

AAA: Pathophysiology

A

Degradation of the elastic lamellae resulting in leukocyte infiltrate causing
enhanced proteolysis and smooth muscle cell loss.
The dilatation affects ALL THREE LAYERS of the vascular tunic (if it doesnt then it’s a pseudoaneurysm).

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10
Q

Unruptured AAA clinical presentation

A
  • Often asymptomatic and only picked up via a routing abdominal examination or plain X-ray
  • Pain in abdomen, back, loin or groin
  • Pulsatile abdominal swelling (less pronounced)
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11
Q

Ruptured AAA: clinical presentation

A
  • Intermittent or continuous abdominal pain (radiates to the back, iliac fossa’s or groin)
  • Pulsatile abdominal swelling (more pronounced)
  • Collapse
  • Hypotension
  • Tachycardia
  • Profound anaemia
  • Sudden death
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12
Q

What increases chance of rupturing an AAA

A

Increased BP
Female
Smoker
Strong family history

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13
Q

AAA Differential diagnosis

A
  • GI bleed
  • Ischaemic bowel
  • MSK pain
  • Perforated GI ulcer
  • Pyelonephritis
  • Appendicitis
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14
Q

AAA Diagnosis

A

Abdominal ultrasound - can assess aorta to degree of 3mm

CT and/or MRI angiography scans

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15
Q

AAA Treatment

A

Small aneurysms below 5.5cm are generally just monitored
Treat underlying causes
Modify risk factors e.g. smoking and diet
Vigorous BP control
Lowering of lipid in blood
Surgery

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16
Q

What surgery could be done for a symptomatic AAA patient

A

Open surgical repair

Endovascular repair - stent inserted via femoral or iliac arteries

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17
Q

What is normal size of mid-descending thoracic aorta?

A

26-28mm

18
Q

What patients are more prone to ascending thoracic aorta aneurysm

A

Marfan syndrome

Hypertension

19
Q

What patients are more prone to descending or arch thoracic aorta aneurysms

A

Secondary to atherosclerosis

sometimes Syphilis

20
Q

Causes of Thoracic Aorta Aneurysm

A

STRONG GENETIC LINK - in some families it appears to be an autosomal dominant trait
Connective tissue disorders e.g. Marfan’s syndrome
Weight lifting, cocaine and amphetamine use - perhaps due to the large rise in BP when undertaking these activities
Aortic dissection

21
Q

Risk factors of Thoracic Aorta Aneurysm

A
  • Hypertension
  • Increasing age
  • Smoking
  • Bicuspid or unicuspid aortic valves
  • Atherosclerosis
  • COPD
  • Renal failure
  • Previous aortic aneurysm repair
22
Q

Pathophysiology of Thoracic Aorta Aneurysm

A

Inflammation, proteolysis and reduced survival of the smooth muscle cells in the aortic wall.
Once the aorta reaches a crucial diameter (around 6cm in the ascending and
7cm in the descending) it loses all distensibility so that a rise in BP to around
200mmHg can exceed the arterial wall strength and may trigger dissection
or rupture.

23
Q

Clinical presentation of Thoracic Aorta Aneurysm

A

-Generally asymptomatic
-May be diagnosed incidentally e.g. on routing CXR or cardiological
investigation or if complicated by dissection, rupture or other complications
- Pain in chest, neck, upper back, mid-back or epigastrium
- Aortic regurgitation
- Fever (if infective cause)
- Symptoms due to compression of local structures
- Acute pain
- Collapse, shock and sudden death
- Cardiac tamponade
- Haemoptysis

24
Q

Differential diagnosis of Thoracic Aorta Aneurysm

A
  • Thoracic back pain
  • Arterial ischaemia
  • Collapse
  • MI
25
Q

Diagnosis of Thoracic Aorta Aneurysm

A
  • CT or MRI used for assessment of TAA
  • Aortography (helpful for assessing the position of the key branches in relation to the aneurysm)
  • Transoesophageal echocardiography (useful for identifying aortic
    dissection)
  • Ultrasound
26
Q

Treatment of Thoracic Aorta Aneurysm

A

Ruptured TAA requires urgent immediate surgery
Symptomatic TAA’s = surgery regardless of size
Regular monitoring by CT or MRI every 6 months
Rigorous BP control using Beta-blockers e.g. Bisoprolol
Smoking cessation
Treat underlying cause

27
Q

Process of aortic dissection

A

Begins with a tear in the intima (inner wall)
Blood then penetrates the diseased medial layer and flows between the layers of aorta
Forces layers apart = results in dissection

Medical emergency that can lead to death

28
Q

What is the most common medical emergency affecting the aorta

A

Aortic dissection

29
Q

What people are more at risk of aortic dissection

A

Men more at risk

Most common between ages of 50-70 (<40 is rare)

30
Q

How can aortic dissection be classified

A

According to the timing of diagnosis from the origin of symptoms:
• Acute - less than 2 weeks
• Subacute - 2-8 weeks
• Chronic - more than 8 weeks

31
Q

Causes of aortic dissection

A
  • Inherited
  • Degenerative
  • Atherosclerotic
  • Inflammatory
  • Trauma e.g. shearing stresses in a road traffic accident (RTA)
32
Q

Pathophysiology of aortic dissection

A

Begins with a tear in the intimal lining of the aorta
Tear allows a column of blood under prssure to enter the aortic wall, forming a haemotoma that separates the intima and adventitia to create a false lumen.
False lumen extends for a variable distance in either direction.

33
Q

Pathophysiology of aortic dissection: In what directions can the false lumen extend

A

Anterograde - towards bifurcations

Retrograde - towards the aortic root

34
Q

Pathophysiology of aortic dissection: What are the most common sites for intimal tears

A

Within 2-3cm of aortic valve

Distal to left subclavian artery in the descending aorta

35
Q

Pathophysiology of aortic dissection: Between which layers of the artery does false lumen form

A

Intima and adventitia

36
Q

Clinical presentation of aortic dissection

A

Sudden onset of central chest pain that radiates to the back and down arms (mimics MI)
Hypertension
Pain is maximal from the onset (but in MI pain gains intensity)
Shock and neurological symptoms secondary to loss of blood supply to spinal cord.
Aortic regurgitation, coronary ischaemia and cardiac tamponade may develop.
Peripheral pulses may be absent.
Acute kidney failure, acute lower limb ischaemia or visceral ischaemia

37
Q

What symptom of MI is mimiced by aortic dissection

A

Sudden onset of sever and central chest pain that radiates to the back and down the arms.
But in MI pain increses from onset, but in aortic dissection the level of pain does not change.

38
Q

Differential diagnosis of aortic dissection

A

Acute coronary syndrome, MI, Aortic regurgitation without dissection, MSK
pain, pericarditis, cholecystitis, atherosclerotic embolism

39
Q

Diagnosis of aortic dissection

A

CXR - widened mediastinum
Urgant CT scan, Transoesophageal echocardiography
or MRI will confirm the diagnosis

40
Q

Treatment of aortic dissection

A
  • At least 50% are hypertensive and may require urgent antihypertensive medication to reduce blood pressure to less than 120mmHg - give IV betablockers e.g. IV metoprolol or vasodilators e.g. IV GTN
  • Adequate analgesia e.g. morphine
  • Surgery to replace aortic arch
  • Endovascular intervention with stents
  • Patients require long term follow-up with CT or MRI