Arterial Disease and Aneurysms

Question 1

List some causes of arterial occlusion

Answer 1

Atherosclerosis
Embolism (cardiac, arterial to arterial)
Pro-coagulant state
Low flow state
Thrombosed aneurysm
Dissection
Fibro-muscular hyperplasia
Arteritis
Entrapment
Adventitial cysts

Question 2

Define claudication

Answer 2

Ischaemic pain in exercising muscles due to imbalance between workload of muscles and ability to maintain aerobic metabolism (angina of the legs)

Question 3

Describe the pathophysiology of claudication

Answer 3

Posterior calf muscles dominate with walking
When flow of oxygenated blood is inadequate, muscles switch to anaerobic metabolism to meet energy demands
Lactic acid builds up and produces aching discomfort
Eases with rest

Question 4

What are the clinical criteria for claudication?

Answer 4

Calf pain on exertion (+/- thigh, +/- buttock)
Onset and severity related to workload
Relieved with rest
Reproducible

Question 5

Where does ischaemic rest pain occur?

Answer 5

Most distal part of the limb

Question 6

Describe the pathophysiology of ischaemic rest pain

Answer 6

Inadequate perfusion resulting in anaerobic metabolism in skin and nerves (cf muscles) of the extremity

Question 7

How is ischaemic rest pain defined clinically?

Answer 7

Burning pain in extremity at rest (often wakes patient in the night)
Usually relieved with gravity

Question 8

What are the features of critical limb ischaemia (CLI)?

Answer 8

Ischaemic rest pain
Ulcers
Gangrene

Question 9

At what ankle and toe pressure does rest pain occur?

Answer 9

Ankle pressure

Question 10

At what ankle and toe pressure do ulcers/gangrene occur?

Answer 10

Ankle pressure

Question 11

What is the trans-cutaneous O2 pressure in CLI?

Question 12

What are some possible patterns of lower limb occlusive disease?

Answer 12

Aorto-iliac (inflow)
Femoro-popliteal (outflow)
Tibial/crural

Question 13

What are the features of aorto-iliac occlusive disease?

Answer 13

Calf, thigh and buttock claudication
Reduced pulses femoral and below
May be bruits over aorta/iliac

Question 14

What are the features of femoro-popliteal occlusive disease?

Answer 14

Calf claudication
Reasonable femoral pulse but weak or absent popliteal and pedal pulses
Bruit along line of femoral or popliteal arteries

Question 15

What are the features of tibial/crural occlusive disease?

Answer 15

May be no claudication
Reasonable popliteal pulses but absent pedal pulses
Bruits over popliteal or upper tibial arteries

Question 16

Describe the epidemiology of peripheral arterial disease

Answer 16

12% of adult population and 20% of population >70 years
Associated with 6-fold increase in CV mortality (patients at high risk need aggressive risk-factor modification and antiplatelet drugs)

Question 17

Management options for claudication

Answer 17

Angioplasty +/- stenting
Endarterectomy
Bypass

Question 18

When are angioplasty, endarterectomy and bypass indicated?

Answer 18

Angioplasty: best for short segments, better in proximal arteries
Endarterectomy: short segments
Bypass: longer blocks

Question 19

What are the risks with endovascular interventions?

Answer 19

Chance of access vessel problems

Chance of thrombosis or embolisation

Question 20

What are the risks with open bypass?

Answer 20

Wound issues
Cardiac risks
Graft thrombosis

Question 21

Describe the recovery from endovascular procedures vs open bypass

Answer 21

Endovascular procedures: quick recovery

Open bypass: 2-3 months or longer before back to normal comfort, mobility, etc

Question 22

What is the typical cause of sudden/severe ischaemia?

Answer 22

Embolus

Question 23

What are the clinical features of sudden/severe ischaemia?

Answer 23

Pain (especially on using muscles; later pain in extremities lessens as nerve function decreases)
Paralysis of muscles (especially weakness of anterior compartment muscles)
Parasthesia
Pallor/mottled extremity
Perishingly cold
Pulseless

Question 24

What is an aneurysm?

Answer 24

Degenerative focal arterial dilatation 1.25-1.5x greater in diameter than adjacent normal artery

Question 25

Describe the pathogenesis and natural history of aneurysms

Answer 25

Weakness in elastin and collagen in adventia and media results in local inflammation with matric proteins and metallo-proteinases, leading to focal arterial dilatation Abnormal wall becomes lined with thrombus Natural history is continued expansion leading to eventual rupture

Question 26

List common sites for aneurysm

Answer 26

``` Abdominal aorta (infra-renal) Common iliac Popliteal Femoral Thoracic aorta ```

Question 27

Describe the risk of aneurysm rupture as related to diameter

Answer 27

Uncommon 6cm annual risk is 9% | >8cm annual risk is 25%

Question 28

What is the 5-year survival of patients with aneurysm >5cm who are not operated on?

Answer 28

20%

Question 29

Describe primary prevention for aneurysm

Answer 29

Smoking cessation | HTN control

Question 30

Describe secondary prevention for aneurysm rupture

Answer 30

Screening and treatment of aneurysms >5-5.5cm

Question 31

What is the average increase in the size of small aneurysms annually?

Answer 31

2.6 mm/year

Question 32

What is the margin of error for U/S measurement of aneurysms?

Answer 32

Minimum +/- 2mm | Commonly +/- 4mm

Question 33

How does ruptured AAA present clinically?

Answer 33

Sudden onset abdominal and/or back pain | Collapse

Question 34

What is the typical demographic affected by ruptured AAA?

Answer 34

Male | >60 years

Question 35

What are the clinical signs of ruptured AAA?

Answer 35

Pulsatile mass in lower abdomen (usually to one side and into iliac fossa) Features of progressive hypovolaemia

Question 36

What are the management options for ruptured AAA?

Answer 36

``` Prompt repair (open or endoluminal) No intervention ```

Question 37

When should "no intervention" be considered for a ruptured AAA?

Answer 37

Already unconscious/intubated on arrival (especially >80 years) Demented/nursing home Already turned down for elective repair in view of co-morbidities

Question 38

Maximum time of surveillance before EVAR indicated?

Answer 38

3. 0-3.9cm: 24 months 4. 0-4.6cm: 12 months 4. 7-5.0cm: 6 months 5. 1-5.5cm: 3 months

Question 39

What is the 5-year prognosis for patients with local vs systemic claudication?

Answer 39

Local: 5% require intervention, 2% amputation Systemic: 30% die, 5-10% suffer non-fatal CV events

Question 40

What is the management philosophy underlying claudication?

Answer 40

Reasonable distance claudication is benign (limb not in jeopardy) Any intervention on an artery is a "controlled injury"; it may or may not work, there may be complications, and it may not be durable

Question 41

When is an intervention for claudication reasonable?

Answer 41

If it is a very significant handicap, the risk is acceptable and the proposed intervention has an acceptable chance of working Patient has to be pushing for an intervention; requires good information and realistic expectations

Question 42

EVAR

Answer 42

EndoVascular Aortic Repair